4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = to_spi_device(dev); \
88 return spi_statistics_##field##_show(&spi->statistics, buf); \
90 static struct device_attribute dev_attr_spi_device_##field = { \
91 .attr = { .name = file, .mode = S_IRUGO }, \
92 .show = spi_device_##field##_show, \
95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
99 unsigned long flags; \
101 spin_lock_irqsave(&stat->lock, flags); \
102 len = sprintf(buf, format_string, stat->field); \
103 spin_unlock_irqrestore(&stat->lock, flags); \
106 SPI_STATISTICS_ATTRS(name, file)
108 #define SPI_STATISTICS_SHOW(field, format_string) \
109 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
110 field, format_string)
112 SPI_STATISTICS_SHOW(messages, "%lu");
113 SPI_STATISTICS_SHOW(transfers, "%lu");
114 SPI_STATISTICS_SHOW(errors, "%lu");
115 SPI_STATISTICS_SHOW(timedout, "%lu");
117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
119 SPI_STATISTICS_SHOW(spi_async, "%lu");
121 SPI_STATISTICS_SHOW(bytes, "%llu");
122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
126 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
127 "transfer_bytes_histo_" number, \
128 transfer_bytes_histo[index], "%lu")
129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
149 static struct attribute *spi_dev_attrs[] = {
150 &dev_attr_modalias.attr,
154 static const struct attribute_group spi_dev_group = {
155 .attrs = spi_dev_attrs,
158 static struct attribute *spi_device_statistics_attrs[] = {
159 &dev_attr_spi_device_messages.attr,
160 &dev_attr_spi_device_transfers.attr,
161 &dev_attr_spi_device_errors.attr,
162 &dev_attr_spi_device_timedout.attr,
163 &dev_attr_spi_device_spi_sync.attr,
164 &dev_attr_spi_device_spi_sync_immediate.attr,
165 &dev_attr_spi_device_spi_async.attr,
166 &dev_attr_spi_device_bytes.attr,
167 &dev_attr_spi_device_bytes_rx.attr,
168 &dev_attr_spi_device_bytes_tx.attr,
169 &dev_attr_spi_device_transfer_bytes_histo0.attr,
170 &dev_attr_spi_device_transfer_bytes_histo1.attr,
171 &dev_attr_spi_device_transfer_bytes_histo2.attr,
172 &dev_attr_spi_device_transfer_bytes_histo3.attr,
173 &dev_attr_spi_device_transfer_bytes_histo4.attr,
174 &dev_attr_spi_device_transfer_bytes_histo5.attr,
175 &dev_attr_spi_device_transfer_bytes_histo6.attr,
176 &dev_attr_spi_device_transfer_bytes_histo7.attr,
177 &dev_attr_spi_device_transfer_bytes_histo8.attr,
178 &dev_attr_spi_device_transfer_bytes_histo9.attr,
179 &dev_attr_spi_device_transfer_bytes_histo10.attr,
180 &dev_attr_spi_device_transfer_bytes_histo11.attr,
181 &dev_attr_spi_device_transfer_bytes_histo12.attr,
182 &dev_attr_spi_device_transfer_bytes_histo13.attr,
183 &dev_attr_spi_device_transfer_bytes_histo14.attr,
184 &dev_attr_spi_device_transfer_bytes_histo15.attr,
185 &dev_attr_spi_device_transfer_bytes_histo16.attr,
186 &dev_attr_spi_device_transfers_split_maxsize.attr,
190 static const struct attribute_group spi_device_statistics_group = {
191 .name = "statistics",
192 .attrs = spi_device_statistics_attrs,
195 static const struct attribute_group *spi_dev_groups[] = {
197 &spi_device_statistics_group,
201 static struct attribute *spi_master_statistics_attrs[] = {
202 &dev_attr_spi_master_messages.attr,
203 &dev_attr_spi_master_transfers.attr,
204 &dev_attr_spi_master_errors.attr,
205 &dev_attr_spi_master_timedout.attr,
206 &dev_attr_spi_master_spi_sync.attr,
207 &dev_attr_spi_master_spi_sync_immediate.attr,
208 &dev_attr_spi_master_spi_async.attr,
209 &dev_attr_spi_master_bytes.attr,
210 &dev_attr_spi_master_bytes_rx.attr,
211 &dev_attr_spi_master_bytes_tx.attr,
212 &dev_attr_spi_master_transfer_bytes_histo0.attr,
213 &dev_attr_spi_master_transfer_bytes_histo1.attr,
214 &dev_attr_spi_master_transfer_bytes_histo2.attr,
215 &dev_attr_spi_master_transfer_bytes_histo3.attr,
216 &dev_attr_spi_master_transfer_bytes_histo4.attr,
217 &dev_attr_spi_master_transfer_bytes_histo5.attr,
218 &dev_attr_spi_master_transfer_bytes_histo6.attr,
219 &dev_attr_spi_master_transfer_bytes_histo7.attr,
220 &dev_attr_spi_master_transfer_bytes_histo8.attr,
221 &dev_attr_spi_master_transfer_bytes_histo9.attr,
222 &dev_attr_spi_master_transfer_bytes_histo10.attr,
223 &dev_attr_spi_master_transfer_bytes_histo11.attr,
224 &dev_attr_spi_master_transfer_bytes_histo12.attr,
225 &dev_attr_spi_master_transfer_bytes_histo13.attr,
226 &dev_attr_spi_master_transfer_bytes_histo14.attr,
227 &dev_attr_spi_master_transfer_bytes_histo15.attr,
228 &dev_attr_spi_master_transfer_bytes_histo16.attr,
229 &dev_attr_spi_master_transfers_split_maxsize.attr,
233 static const struct attribute_group spi_master_statistics_group = {
234 .name = "statistics",
235 .attrs = spi_master_statistics_attrs,
238 static const struct attribute_group *spi_master_groups[] = {
239 &spi_master_statistics_group,
243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
244 struct spi_transfer *xfer,
245 struct spi_master *master)
248 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
253 spin_lock_irqsave(&stats->lock, flags);
256 stats->transfer_bytes_histo[l2len]++;
258 stats->bytes += xfer->len;
259 if ((xfer->tx_buf) &&
260 (xfer->tx_buf != master->dummy_tx))
261 stats->bytes_tx += xfer->len;
262 if ((xfer->rx_buf) &&
263 (xfer->rx_buf != master->dummy_rx))
264 stats->bytes_rx += xfer->len;
266 spin_unlock_irqrestore(&stats->lock, flags);
268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
271 * and the sysfs version makes coldplug work too.
274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
275 const struct spi_device *sdev)
277 while (id->name[0]) {
278 if (!strcmp(sdev->modalias, id->name))
285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
287 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
289 return spi_match_id(sdrv->id_table, sdev);
291 EXPORT_SYMBOL_GPL(spi_get_device_id);
293 static int spi_match_device(struct device *dev, struct device_driver *drv)
295 const struct spi_device *spi = to_spi_device(dev);
296 const struct spi_driver *sdrv = to_spi_driver(drv);
298 /* Attempt an OF style match */
299 if (of_driver_match_device(dev, drv))
303 if (acpi_driver_match_device(dev, drv))
307 return !!spi_match_id(sdrv->id_table, spi);
309 return strcmp(spi->modalias, drv->name) == 0;
312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
314 const struct spi_device *spi = to_spi_device(dev);
317 rc = acpi_device_uevent_modalias(dev, env);
321 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
325 struct bus_type spi_bus_type = {
327 .dev_groups = spi_dev_groups,
328 .match = spi_match_device,
329 .uevent = spi_uevent,
331 EXPORT_SYMBOL_GPL(spi_bus_type);
334 static int spi_drv_probe(struct device *dev)
336 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
337 struct spi_device *spi = to_spi_device(dev);
340 ret = of_clk_set_defaults(dev->of_node, false);
345 spi->irq = of_irq_get(dev->of_node, 0);
346 if (spi->irq == -EPROBE_DEFER)
347 return -EPROBE_DEFER;
352 ret = dev_pm_domain_attach(dev, true);
353 if (ret != -EPROBE_DEFER) {
354 ret = sdrv->probe(spi);
356 dev_pm_domain_detach(dev, true);
362 static int spi_drv_remove(struct device *dev)
364 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
367 ret = sdrv->remove(to_spi_device(dev));
368 dev_pm_domain_detach(dev, true);
373 static void spi_drv_shutdown(struct device *dev)
375 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
377 sdrv->shutdown(to_spi_device(dev));
381 * __spi_register_driver - register a SPI driver
382 * @owner: owner module of the driver to register
383 * @sdrv: the driver to register
386 * Return: zero on success, else a negative error code.
388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
390 sdrv->driver.owner = owner;
391 sdrv->driver.bus = &spi_bus_type;
393 sdrv->driver.probe = spi_drv_probe;
395 sdrv->driver.remove = spi_drv_remove;
397 sdrv->driver.shutdown = spi_drv_shutdown;
398 return driver_register(&sdrv->driver);
400 EXPORT_SYMBOL_GPL(__spi_register_driver);
402 /*-------------------------------------------------------------------------*/
404 /* SPI devices should normally not be created by SPI device drivers; that
405 * would make them board-specific. Similarly with SPI master drivers.
406 * Device registration normally goes into like arch/.../mach.../board-YYY.c
407 * with other readonly (flashable) information about mainboard devices.
411 struct list_head list;
412 struct spi_board_info board_info;
415 static LIST_HEAD(board_list);
416 static LIST_HEAD(spi_master_list);
419 * Used to protect add/del opertion for board_info list and
420 * spi_master list, and their matching process
422 static DEFINE_MUTEX(board_lock);
425 * spi_alloc_device - Allocate a new SPI device
426 * @master: Controller to which device is connected
429 * Allows a driver to allocate and initialize a spi_device without
430 * registering it immediately. This allows a driver to directly
431 * fill the spi_device with device parameters before calling
432 * spi_add_device() on it.
434 * Caller is responsible to call spi_add_device() on the returned
435 * spi_device structure to add it to the SPI master. If the caller
436 * needs to discard the spi_device without adding it, then it should
437 * call spi_dev_put() on it.
439 * Return: a pointer to the new device, or NULL.
441 struct spi_device *spi_alloc_device(struct spi_master *master)
443 struct spi_device *spi;
445 if (!spi_master_get(master))
448 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
450 spi_master_put(master);
454 spi->master = master;
455 spi->dev.parent = &master->dev;
456 spi->dev.bus = &spi_bus_type;
457 spi->dev.release = spidev_release;
458 spi->cs_gpio = -ENOENT;
460 spin_lock_init(&spi->statistics.lock);
462 device_initialize(&spi->dev);
465 EXPORT_SYMBOL_GPL(spi_alloc_device);
467 static void spi_dev_set_name(struct spi_device *spi)
469 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
472 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
476 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
480 static int spi_dev_check(struct device *dev, void *data)
482 struct spi_device *spi = to_spi_device(dev);
483 struct spi_device *new_spi = data;
485 if (spi->master == new_spi->master &&
486 spi->chip_select == new_spi->chip_select)
492 * spi_add_device - Add spi_device allocated with spi_alloc_device
493 * @spi: spi_device to register
495 * Companion function to spi_alloc_device. Devices allocated with
496 * spi_alloc_device can be added onto the spi bus with this function.
498 * Return: 0 on success; negative errno on failure
500 int spi_add_device(struct spi_device *spi)
502 static DEFINE_MUTEX(spi_add_lock);
503 struct spi_master *master = spi->master;
504 struct device *dev = master->dev.parent;
507 /* Chipselects are numbered 0..max; validate. */
508 if (spi->chip_select >= master->num_chipselect) {
509 dev_err(dev, "cs%d >= max %d\n",
511 master->num_chipselect);
515 /* Set the bus ID string */
516 spi_dev_set_name(spi);
518 /* We need to make sure there's no other device with this
519 * chipselect **BEFORE** we call setup(), else we'll trash
520 * its configuration. Lock against concurrent add() calls.
522 mutex_lock(&spi_add_lock);
524 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
526 dev_err(dev, "chipselect %d already in use\n",
531 if (master->cs_gpios)
532 spi->cs_gpio = master->cs_gpios[spi->chip_select];
534 /* Drivers may modify this initial i/o setup, but will
535 * normally rely on the device being setup. Devices
536 * using SPI_CS_HIGH can't coexist well otherwise...
538 status = spi_setup(spi);
540 dev_err(dev, "can't setup %s, status %d\n",
541 dev_name(&spi->dev), status);
545 /* Device may be bound to an active driver when this returns */
546 status = device_add(&spi->dev);
548 dev_err(dev, "can't add %s, status %d\n",
549 dev_name(&spi->dev), status);
551 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
554 mutex_unlock(&spi_add_lock);
557 EXPORT_SYMBOL_GPL(spi_add_device);
560 * spi_new_device - instantiate one new SPI device
561 * @master: Controller to which device is connected
562 * @chip: Describes the SPI device
565 * On typical mainboards, this is purely internal; and it's not needed
566 * after board init creates the hard-wired devices. Some development
567 * platforms may not be able to use spi_register_board_info though, and
568 * this is exported so that for example a USB or parport based adapter
569 * driver could add devices (which it would learn about out-of-band).
571 * Return: the new device, or NULL.
573 struct spi_device *spi_new_device(struct spi_master *master,
574 struct spi_board_info *chip)
576 struct spi_device *proxy;
579 /* NOTE: caller did any chip->bus_num checks necessary.
581 * Also, unless we change the return value convention to use
582 * error-or-pointer (not NULL-or-pointer), troubleshootability
583 * suggests syslogged diagnostics are best here (ugh).
586 proxy = spi_alloc_device(master);
590 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
592 proxy->chip_select = chip->chip_select;
593 proxy->max_speed_hz = chip->max_speed_hz;
594 proxy->mode = chip->mode;
595 proxy->irq = chip->irq;
596 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
597 proxy->dev.platform_data = (void *) chip->platform_data;
598 proxy->controller_data = chip->controller_data;
599 proxy->controller_state = NULL;
601 status = spi_add_device(proxy);
609 EXPORT_SYMBOL_GPL(spi_new_device);
612 * spi_unregister_device - unregister a single SPI device
613 * @spi: spi_device to unregister
615 * Start making the passed SPI device vanish. Normally this would be handled
616 * by spi_unregister_master().
618 void spi_unregister_device(struct spi_device *spi)
623 if (spi->dev.of_node)
624 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
625 device_unregister(&spi->dev);
627 EXPORT_SYMBOL_GPL(spi_unregister_device);
629 static void spi_match_master_to_boardinfo(struct spi_master *master,
630 struct spi_board_info *bi)
632 struct spi_device *dev;
634 if (master->bus_num != bi->bus_num)
637 dev = spi_new_device(master, bi);
639 dev_err(master->dev.parent, "can't create new device for %s\n",
644 * spi_register_board_info - register SPI devices for a given board
645 * @info: array of chip descriptors
646 * @n: how many descriptors are provided
649 * Board-specific early init code calls this (probably during arch_initcall)
650 * with segments of the SPI device table. Any device nodes are created later,
651 * after the relevant parent SPI controller (bus_num) is defined. We keep
652 * this table of devices forever, so that reloading a controller driver will
653 * not make Linux forget about these hard-wired devices.
655 * Other code can also call this, e.g. a particular add-on board might provide
656 * SPI devices through its expansion connector, so code initializing that board
657 * would naturally declare its SPI devices.
659 * The board info passed can safely be __initdata ... but be careful of
660 * any embedded pointers (platform_data, etc), they're copied as-is.
662 * Return: zero on success, else a negative error code.
664 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
666 struct boardinfo *bi;
672 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
676 for (i = 0; i < n; i++, bi++, info++) {
677 struct spi_master *master;
679 memcpy(&bi->board_info, info, sizeof(*info));
680 mutex_lock(&board_lock);
681 list_add_tail(&bi->list, &board_list);
682 list_for_each_entry(master, &spi_master_list, list)
683 spi_match_master_to_boardinfo(master, &bi->board_info);
684 mutex_unlock(&board_lock);
690 /*-------------------------------------------------------------------------*/
692 static void spi_set_cs(struct spi_device *spi, bool enable)
694 if (spi->mode & SPI_CS_HIGH)
697 if (gpio_is_valid(spi->cs_gpio))
698 gpio_set_value(spi->cs_gpio, !enable);
699 else if (spi->master->set_cs)
700 spi->master->set_cs(spi, !enable);
703 #ifdef CONFIG_HAS_DMA
704 static int spi_map_buf(struct spi_master *master, struct device *dev,
705 struct sg_table *sgt, void *buf, size_t len,
706 enum dma_data_direction dir)
708 const bool vmalloced_buf = is_vmalloc_addr(buf);
709 unsigned int max_seg_size = dma_get_max_seg_size(dev);
712 struct page *vm_page;
718 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
719 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
720 } else if (virt_addr_valid(buf)) {
721 desc_len = min_t(int, max_seg_size, master->max_dma_len);
722 sgs = DIV_ROUND_UP(len, desc_len);
727 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
731 for (i = 0; i < sgs; i++) {
735 len, desc_len - offset_in_page(buf));
736 vm_page = vmalloc_to_page(buf);
741 sg_set_page(&sgt->sgl[i], vm_page,
742 min, offset_in_page(buf));
744 min = min_t(size_t, len, desc_len);
746 sg_set_buf(&sgt->sgl[i], sg_buf, min);
753 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
766 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
767 struct sg_table *sgt, enum dma_data_direction dir)
769 if (sgt->orig_nents) {
770 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
775 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
777 struct device *tx_dev, *rx_dev;
778 struct spi_transfer *xfer;
781 if (!master->can_dma)
785 tx_dev = master->dma_tx->device->dev;
787 tx_dev = &master->dev;
790 rx_dev = master->dma_rx->device->dev;
792 rx_dev = &master->dev;
794 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
795 if (!master->can_dma(master, msg->spi, xfer))
798 if (xfer->tx_buf != NULL) {
799 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
800 (void *)xfer->tx_buf, xfer->len,
806 if (xfer->rx_buf != NULL) {
807 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
808 xfer->rx_buf, xfer->len,
811 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
818 master->cur_msg_mapped = true;
823 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
825 struct spi_transfer *xfer;
826 struct device *tx_dev, *rx_dev;
828 if (!master->cur_msg_mapped || !master->can_dma)
832 tx_dev = master->dma_tx->device->dev;
834 tx_dev = &master->dev;
837 rx_dev = master->dma_rx->device->dev;
839 rx_dev = &master->dev;
841 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
842 if (!master->can_dma(master, msg->spi, xfer))
845 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
846 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
851 #else /* !CONFIG_HAS_DMA */
852 static inline int __spi_map_msg(struct spi_master *master,
853 struct spi_message *msg)
858 static inline int __spi_unmap_msg(struct spi_master *master,
859 struct spi_message *msg)
863 #endif /* !CONFIG_HAS_DMA */
865 static inline int spi_unmap_msg(struct spi_master *master,
866 struct spi_message *msg)
868 struct spi_transfer *xfer;
870 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
872 * Restore the original value of tx_buf or rx_buf if they are
875 if (xfer->tx_buf == master->dummy_tx)
877 if (xfer->rx_buf == master->dummy_rx)
881 return __spi_unmap_msg(master, msg);
884 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
886 struct spi_transfer *xfer;
888 unsigned int max_tx, max_rx;
890 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
894 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
895 if ((master->flags & SPI_MASTER_MUST_TX) &&
897 max_tx = max(xfer->len, max_tx);
898 if ((master->flags & SPI_MASTER_MUST_RX) &&
900 max_rx = max(xfer->len, max_rx);
904 tmp = krealloc(master->dummy_tx, max_tx,
905 GFP_KERNEL | GFP_DMA);
908 master->dummy_tx = tmp;
909 memset(tmp, 0, max_tx);
913 tmp = krealloc(master->dummy_rx, max_rx,
914 GFP_KERNEL | GFP_DMA);
917 master->dummy_rx = tmp;
920 if (max_tx || max_rx) {
921 list_for_each_entry(xfer, &msg->transfers,
924 xfer->tx_buf = master->dummy_tx;
926 xfer->rx_buf = master->dummy_rx;
931 return __spi_map_msg(master, msg);
935 * spi_transfer_one_message - Default implementation of transfer_one_message()
937 * This is a standard implementation of transfer_one_message() for
938 * drivers which implement a transfer_one() operation. It provides
939 * standard handling of delays and chip select management.
941 static int spi_transfer_one_message(struct spi_master *master,
942 struct spi_message *msg)
944 struct spi_transfer *xfer;
945 bool keep_cs = false;
947 unsigned long ms = 1;
948 struct spi_statistics *statm = &master->statistics;
949 struct spi_statistics *stats = &msg->spi->statistics;
951 spi_set_cs(msg->spi, true);
953 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
954 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
956 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
957 trace_spi_transfer_start(msg, xfer);
959 spi_statistics_add_transfer_stats(statm, xfer, master);
960 spi_statistics_add_transfer_stats(stats, xfer, master);
962 if (xfer->tx_buf || xfer->rx_buf) {
963 reinit_completion(&master->xfer_completion);
965 ret = master->transfer_one(master, msg->spi, xfer);
967 SPI_STATISTICS_INCREMENT_FIELD(statm,
969 SPI_STATISTICS_INCREMENT_FIELD(stats,
971 dev_err(&msg->spi->dev,
972 "SPI transfer failed: %d\n", ret);
978 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
979 ms += ms + 100; /* some tolerance */
981 ms = wait_for_completion_timeout(&master->xfer_completion,
982 msecs_to_jiffies(ms));
986 SPI_STATISTICS_INCREMENT_FIELD(statm,
988 SPI_STATISTICS_INCREMENT_FIELD(stats,
990 dev_err(&msg->spi->dev,
991 "SPI transfer timed out\n");
992 msg->status = -ETIMEDOUT;
996 dev_err(&msg->spi->dev,
997 "Bufferless transfer has length %u\n",
1001 trace_spi_transfer_stop(msg, xfer);
1003 if (msg->status != -EINPROGRESS)
1006 if (xfer->delay_usecs)
1007 udelay(xfer->delay_usecs);
1009 if (xfer->cs_change) {
1010 if (list_is_last(&xfer->transfer_list,
1014 spi_set_cs(msg->spi, false);
1016 spi_set_cs(msg->spi, true);
1020 msg->actual_length += xfer->len;
1024 if (ret != 0 || !keep_cs)
1025 spi_set_cs(msg->spi, false);
1027 if (msg->status == -EINPROGRESS)
1030 if (msg->status && master->handle_err)
1031 master->handle_err(master, msg);
1033 spi_res_release(master, msg);
1035 spi_finalize_current_message(master);
1041 * spi_finalize_current_transfer - report completion of a transfer
1042 * @master: the master reporting completion
1044 * Called by SPI drivers using the core transfer_one_message()
1045 * implementation to notify it that the current interrupt driven
1046 * transfer has finished and the next one may be scheduled.
1048 void spi_finalize_current_transfer(struct spi_master *master)
1050 complete(&master->xfer_completion);
1052 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1055 * __spi_pump_messages - function which processes spi message queue
1056 * @master: master to process queue for
1057 * @in_kthread: true if we are in the context of the message pump thread
1058 * @bus_locked: true if the bus mutex is held when calling this function
1060 * This function checks if there is any spi message in the queue that
1061 * needs processing and if so call out to the driver to initialize hardware
1062 * and transfer each message.
1064 * Note that it is called both from the kthread itself and also from
1065 * inside spi_sync(); the queue extraction handling at the top of the
1066 * function should deal with this safely.
1068 static void __spi_pump_messages(struct spi_master *master, bool in_kthread,
1071 unsigned long flags;
1072 bool was_busy = false;
1076 spin_lock_irqsave(&master->queue_lock, flags);
1078 /* Make sure we are not already running a message */
1079 if (master->cur_msg) {
1080 spin_unlock_irqrestore(&master->queue_lock, flags);
1084 /* If another context is idling the device then defer */
1085 if (master->idling) {
1086 queue_kthread_work(&master->kworker, &master->pump_messages);
1087 spin_unlock_irqrestore(&master->queue_lock, flags);
1091 /* Check if the queue is idle */
1092 if (list_empty(&master->queue) || !master->running) {
1093 if (!master->busy) {
1094 spin_unlock_irqrestore(&master->queue_lock, flags);
1098 /* Only do teardown in the thread */
1100 queue_kthread_work(&master->kworker,
1101 &master->pump_messages);
1102 spin_unlock_irqrestore(&master->queue_lock, flags);
1106 master->busy = false;
1107 master->idling = true;
1108 spin_unlock_irqrestore(&master->queue_lock, flags);
1110 kfree(master->dummy_rx);
1111 master->dummy_rx = NULL;
1112 kfree(master->dummy_tx);
1113 master->dummy_tx = NULL;
1114 if (master->unprepare_transfer_hardware &&
1115 master->unprepare_transfer_hardware(master))
1116 dev_err(&master->dev,
1117 "failed to unprepare transfer hardware\n");
1118 if (master->auto_runtime_pm) {
1119 pm_runtime_mark_last_busy(master->dev.parent);
1120 pm_runtime_put_autosuspend(master->dev.parent);
1122 trace_spi_master_idle(master);
1124 spin_lock_irqsave(&master->queue_lock, flags);
1125 master->idling = false;
1126 spin_unlock_irqrestore(&master->queue_lock, flags);
1130 /* Extract head of queue */
1132 list_first_entry(&master->queue, struct spi_message, queue);
1134 list_del_init(&master->cur_msg->queue);
1138 master->busy = true;
1139 spin_unlock_irqrestore(&master->queue_lock, flags);
1141 if (!was_busy && master->auto_runtime_pm) {
1142 ret = pm_runtime_get_sync(master->dev.parent);
1144 dev_err(&master->dev, "Failed to power device: %d\n",
1151 trace_spi_master_busy(master);
1153 if (!was_busy && master->prepare_transfer_hardware) {
1154 ret = master->prepare_transfer_hardware(master);
1156 dev_err(&master->dev,
1157 "failed to prepare transfer hardware\n");
1159 if (master->auto_runtime_pm)
1160 pm_runtime_put(master->dev.parent);
1166 mutex_lock(&master->bus_lock_mutex);
1168 trace_spi_message_start(master->cur_msg);
1170 if (master->prepare_message) {
1171 ret = master->prepare_message(master, master->cur_msg);
1173 dev_err(&master->dev,
1174 "failed to prepare message: %d\n", ret);
1175 master->cur_msg->status = ret;
1176 spi_finalize_current_message(master);
1179 master->cur_msg_prepared = true;
1182 ret = spi_map_msg(master, master->cur_msg);
1184 master->cur_msg->status = ret;
1185 spi_finalize_current_message(master);
1189 ret = master->transfer_one_message(master, master->cur_msg);
1191 dev_err(&master->dev,
1192 "failed to transfer one message from queue\n");
1198 mutex_unlock(&master->bus_lock_mutex);
1200 /* Prod the scheduler in case transfer_one() was busy waiting */
1206 * spi_pump_messages - kthread work function which processes spi message queue
1207 * @work: pointer to kthread work struct contained in the master struct
1209 static void spi_pump_messages(struct kthread_work *work)
1211 struct spi_master *master =
1212 container_of(work, struct spi_master, pump_messages);
1214 __spi_pump_messages(master, true, master->bus_lock_flag);
1217 static int spi_init_queue(struct spi_master *master)
1219 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1221 master->running = false;
1222 master->busy = false;
1224 init_kthread_worker(&master->kworker);
1225 master->kworker_task = kthread_run(kthread_worker_fn,
1226 &master->kworker, "%s",
1227 dev_name(&master->dev));
1228 if (IS_ERR(master->kworker_task)) {
1229 dev_err(&master->dev, "failed to create message pump task\n");
1230 return PTR_ERR(master->kworker_task);
1232 init_kthread_work(&master->pump_messages, spi_pump_messages);
1235 * Master config will indicate if this controller should run the
1236 * message pump with high (realtime) priority to reduce the transfer
1237 * latency on the bus by minimising the delay between a transfer
1238 * request and the scheduling of the message pump thread. Without this
1239 * setting the message pump thread will remain at default priority.
1242 dev_info(&master->dev,
1243 "will run message pump with realtime priority\n");
1244 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1251 * spi_get_next_queued_message() - called by driver to check for queued
1253 * @master: the master to check for queued messages
1255 * If there are more messages in the queue, the next message is returned from
1258 * Return: the next message in the queue, else NULL if the queue is empty.
1260 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1262 struct spi_message *next;
1263 unsigned long flags;
1265 /* get a pointer to the next message, if any */
1266 spin_lock_irqsave(&master->queue_lock, flags);
1267 next = list_first_entry_or_null(&master->queue, struct spi_message,
1269 spin_unlock_irqrestore(&master->queue_lock, flags);
1273 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1276 * spi_finalize_current_message() - the current message is complete
1277 * @master: the master to return the message to
1279 * Called by the driver to notify the core that the message in the front of the
1280 * queue is complete and can be removed from the queue.
1282 void spi_finalize_current_message(struct spi_master *master)
1284 struct spi_message *mesg;
1285 unsigned long flags;
1288 spin_lock_irqsave(&master->queue_lock, flags);
1289 mesg = master->cur_msg;
1290 spin_unlock_irqrestore(&master->queue_lock, flags);
1292 spi_unmap_msg(master, mesg);
1294 if (master->cur_msg_prepared && master->unprepare_message) {
1295 ret = master->unprepare_message(master, mesg);
1297 dev_err(&master->dev,
1298 "failed to unprepare message: %d\n", ret);
1302 spin_lock_irqsave(&master->queue_lock, flags);
1303 master->cur_msg = NULL;
1304 master->cur_msg_prepared = false;
1305 queue_kthread_work(&master->kworker, &master->pump_messages);
1306 spin_unlock_irqrestore(&master->queue_lock, flags);
1308 trace_spi_message_done(mesg);
1312 mesg->complete(mesg->context);
1314 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1316 static int spi_start_queue(struct spi_master *master)
1318 unsigned long flags;
1320 spin_lock_irqsave(&master->queue_lock, flags);
1322 if (master->running || master->busy) {
1323 spin_unlock_irqrestore(&master->queue_lock, flags);
1327 master->running = true;
1328 master->cur_msg = NULL;
1329 spin_unlock_irqrestore(&master->queue_lock, flags);
1331 queue_kthread_work(&master->kworker, &master->pump_messages);
1336 static int spi_stop_queue(struct spi_master *master)
1338 unsigned long flags;
1339 unsigned limit = 500;
1342 spin_lock_irqsave(&master->queue_lock, flags);
1345 * This is a bit lame, but is optimized for the common execution path.
1346 * A wait_queue on the master->busy could be used, but then the common
1347 * execution path (pump_messages) would be required to call wake_up or
1348 * friends on every SPI message. Do this instead.
1350 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1351 spin_unlock_irqrestore(&master->queue_lock, flags);
1352 usleep_range(10000, 11000);
1353 spin_lock_irqsave(&master->queue_lock, flags);
1356 if (!list_empty(&master->queue) || master->busy)
1359 master->running = false;
1361 spin_unlock_irqrestore(&master->queue_lock, flags);
1364 dev_warn(&master->dev,
1365 "could not stop message queue\n");
1371 static int spi_destroy_queue(struct spi_master *master)
1375 ret = spi_stop_queue(master);
1378 * flush_kthread_worker will block until all work is done.
1379 * If the reason that stop_queue timed out is that the work will never
1380 * finish, then it does no good to call flush/stop thread, so
1384 dev_err(&master->dev, "problem destroying queue\n");
1388 flush_kthread_worker(&master->kworker);
1389 kthread_stop(master->kworker_task);
1394 static int __spi_queued_transfer(struct spi_device *spi,
1395 struct spi_message *msg,
1398 struct spi_master *master = spi->master;
1399 unsigned long flags;
1401 spin_lock_irqsave(&master->queue_lock, flags);
1403 if (!master->running) {
1404 spin_unlock_irqrestore(&master->queue_lock, flags);
1407 msg->actual_length = 0;
1408 msg->status = -EINPROGRESS;
1410 list_add_tail(&msg->queue, &master->queue);
1411 if (!master->busy && need_pump)
1412 queue_kthread_work(&master->kworker, &master->pump_messages);
1414 spin_unlock_irqrestore(&master->queue_lock, flags);
1419 * spi_queued_transfer - transfer function for queued transfers
1420 * @spi: spi device which is requesting transfer
1421 * @msg: spi message which is to handled is queued to driver queue
1423 * Return: zero on success, else a negative error code.
1425 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1427 return __spi_queued_transfer(spi, msg, true);
1430 static int spi_master_initialize_queue(struct spi_master *master)
1434 master->transfer = spi_queued_transfer;
1435 if (!master->transfer_one_message)
1436 master->transfer_one_message = spi_transfer_one_message;
1438 /* Initialize and start queue */
1439 ret = spi_init_queue(master);
1441 dev_err(&master->dev, "problem initializing queue\n");
1442 goto err_init_queue;
1444 master->queued = true;
1445 ret = spi_start_queue(master);
1447 dev_err(&master->dev, "problem starting queue\n");
1448 goto err_start_queue;
1454 spi_destroy_queue(master);
1459 /*-------------------------------------------------------------------------*/
1461 #if defined(CONFIG_OF)
1462 static struct spi_device *
1463 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1465 struct spi_device *spi;
1469 /* Alloc an spi_device */
1470 spi = spi_alloc_device(master);
1472 dev_err(&master->dev, "spi_device alloc error for %s\n",
1478 /* Select device driver */
1479 rc = of_modalias_node(nc, spi->modalias,
1480 sizeof(spi->modalias));
1482 dev_err(&master->dev, "cannot find modalias for %s\n",
1487 /* Device address */
1488 rc = of_property_read_u32(nc, "reg", &value);
1490 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1494 spi->chip_select = value;
1496 /* Mode (clock phase/polarity/etc.) */
1497 if (of_find_property(nc, "spi-cpha", NULL))
1498 spi->mode |= SPI_CPHA;
1499 if (of_find_property(nc, "spi-cpol", NULL))
1500 spi->mode |= SPI_CPOL;
1501 if (of_find_property(nc, "spi-cs-high", NULL))
1502 spi->mode |= SPI_CS_HIGH;
1503 if (of_find_property(nc, "spi-3wire", NULL))
1504 spi->mode |= SPI_3WIRE;
1505 if (of_find_property(nc, "spi-lsb-first", NULL))
1506 spi->mode |= SPI_LSB_FIRST;
1508 /* Device DUAL/QUAD mode */
1509 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1514 spi->mode |= SPI_TX_DUAL;
1517 spi->mode |= SPI_TX_QUAD;
1520 dev_warn(&master->dev,
1521 "spi-tx-bus-width %d not supported\n",
1527 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1532 spi->mode |= SPI_RX_DUAL;
1535 spi->mode |= SPI_RX_QUAD;
1538 dev_warn(&master->dev,
1539 "spi-rx-bus-width %d not supported\n",
1546 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1548 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1552 spi->max_speed_hz = value;
1554 /* Store a pointer to the node in the device structure */
1556 spi->dev.of_node = nc;
1558 /* Register the new device */
1559 rc = spi_add_device(spi);
1561 dev_err(&master->dev, "spi_device register error %s\n",
1574 * of_register_spi_devices() - Register child devices onto the SPI bus
1575 * @master: Pointer to spi_master device
1577 * Registers an spi_device for each child node of master node which has a 'reg'
1580 static void of_register_spi_devices(struct spi_master *master)
1582 struct spi_device *spi;
1583 struct device_node *nc;
1585 if (!master->dev.of_node)
1588 for_each_available_child_of_node(master->dev.of_node, nc) {
1589 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1591 spi = of_register_spi_device(master, nc);
1593 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1598 static void of_register_spi_devices(struct spi_master *master) { }
1602 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1604 struct spi_device *spi = data;
1605 struct spi_master *master = spi->master;
1607 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1608 struct acpi_resource_spi_serialbus *sb;
1610 sb = &ares->data.spi_serial_bus;
1611 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1613 * ACPI DeviceSelection numbering is handled by the
1614 * host controller driver in Windows and can vary
1615 * from driver to driver. In Linux we always expect
1616 * 0 .. max - 1 so we need to ask the driver to
1617 * translate between the two schemes.
1619 if (master->fw_translate_cs) {
1620 int cs = master->fw_translate_cs(master,
1621 sb->device_selection);
1624 spi->chip_select = cs;
1626 spi->chip_select = sb->device_selection;
1629 spi->max_speed_hz = sb->connection_speed;
1631 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1632 spi->mode |= SPI_CPHA;
1633 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1634 spi->mode |= SPI_CPOL;
1635 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1636 spi->mode |= SPI_CS_HIGH;
1638 } else if (spi->irq < 0) {
1641 if (acpi_dev_resource_interrupt(ares, 0, &r))
1645 /* Always tell the ACPI core to skip this resource */
1649 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1650 void *data, void **return_value)
1652 struct spi_master *master = data;
1653 struct list_head resource_list;
1654 struct acpi_device *adev;
1655 struct spi_device *spi;
1658 if (acpi_bus_get_device(handle, &adev))
1660 if (acpi_bus_get_status(adev) || !adev->status.present)
1663 spi = spi_alloc_device(master);
1665 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1666 dev_name(&adev->dev));
1667 return AE_NO_MEMORY;
1670 ACPI_COMPANION_SET(&spi->dev, adev);
1673 INIT_LIST_HEAD(&resource_list);
1674 ret = acpi_dev_get_resources(adev, &resource_list,
1675 acpi_spi_add_resource, spi);
1676 acpi_dev_free_resource_list(&resource_list);
1678 if (ret < 0 || !spi->max_speed_hz) {
1684 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1686 adev->power.flags.ignore_parent = true;
1687 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1688 if (spi_add_device(spi)) {
1689 adev->power.flags.ignore_parent = false;
1690 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1691 dev_name(&adev->dev));
1698 static void acpi_register_spi_devices(struct spi_master *master)
1703 handle = ACPI_HANDLE(master->dev.parent);
1707 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1708 acpi_spi_add_device, NULL,
1710 if (ACPI_FAILURE(status))
1711 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1714 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1715 #endif /* CONFIG_ACPI */
1717 static void spi_master_release(struct device *dev)
1719 struct spi_master *master;
1721 master = container_of(dev, struct spi_master, dev);
1725 static struct class spi_master_class = {
1726 .name = "spi_master",
1727 .owner = THIS_MODULE,
1728 .dev_release = spi_master_release,
1729 .dev_groups = spi_master_groups,
1734 * spi_alloc_master - allocate SPI master controller
1735 * @dev: the controller, possibly using the platform_bus
1736 * @size: how much zeroed driver-private data to allocate; the pointer to this
1737 * memory is in the driver_data field of the returned device,
1738 * accessible with spi_master_get_devdata().
1739 * Context: can sleep
1741 * This call is used only by SPI master controller drivers, which are the
1742 * only ones directly touching chip registers. It's how they allocate
1743 * an spi_master structure, prior to calling spi_register_master().
1745 * This must be called from context that can sleep.
1747 * The caller is responsible for assigning the bus number and initializing
1748 * the master's methods before calling spi_register_master(); and (after errors
1749 * adding the device) calling spi_master_put() to prevent a memory leak.
1751 * Return: the SPI master structure on success, else NULL.
1753 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1755 struct spi_master *master;
1760 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1764 device_initialize(&master->dev);
1765 master->bus_num = -1;
1766 master->num_chipselect = 1;
1767 master->dev.class = &spi_master_class;
1768 master->dev.parent = dev;
1769 pm_suspend_ignore_children(&master->dev, true);
1770 spi_master_set_devdata(master, &master[1]);
1774 EXPORT_SYMBOL_GPL(spi_alloc_master);
1777 static int of_spi_register_master(struct spi_master *master)
1780 struct device_node *np = master->dev.of_node;
1785 nb = of_gpio_named_count(np, "cs-gpios");
1786 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1788 /* Return error only for an incorrectly formed cs-gpios property */
1789 if (nb == 0 || nb == -ENOENT)
1794 cs = devm_kzalloc(&master->dev,
1795 sizeof(int) * master->num_chipselect,
1797 master->cs_gpios = cs;
1799 if (!master->cs_gpios)
1802 for (i = 0; i < master->num_chipselect; i++)
1805 for (i = 0; i < nb; i++)
1806 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1811 static int of_spi_register_master(struct spi_master *master)
1818 * spi_register_master - register SPI master controller
1819 * @master: initialized master, originally from spi_alloc_master()
1820 * Context: can sleep
1822 * SPI master controllers connect to their drivers using some non-SPI bus,
1823 * such as the platform bus. The final stage of probe() in that code
1824 * includes calling spi_register_master() to hook up to this SPI bus glue.
1826 * SPI controllers use board specific (often SOC specific) bus numbers,
1827 * and board-specific addressing for SPI devices combines those numbers
1828 * with chip select numbers. Since SPI does not directly support dynamic
1829 * device identification, boards need configuration tables telling which
1830 * chip is at which address.
1832 * This must be called from context that can sleep. It returns zero on
1833 * success, else a negative error code (dropping the master's refcount).
1834 * After a successful return, the caller is responsible for calling
1835 * spi_unregister_master().
1837 * Return: zero on success, else a negative error code.
1839 int spi_register_master(struct spi_master *master)
1841 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1842 struct device *dev = master->dev.parent;
1843 struct boardinfo *bi;
1844 int status = -ENODEV;
1850 status = of_spi_register_master(master);
1854 /* even if it's just one always-selected device, there must
1855 * be at least one chipselect
1857 if (master->num_chipselect == 0)
1860 if ((master->bus_num < 0) && master->dev.of_node)
1861 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1863 /* convention: dynamically assigned bus IDs count down from the max */
1864 if (master->bus_num < 0) {
1865 /* FIXME switch to an IDR based scheme, something like
1866 * I2C now uses, so we can't run out of "dynamic" IDs
1868 master->bus_num = atomic_dec_return(&dyn_bus_id);
1872 INIT_LIST_HEAD(&master->queue);
1873 spin_lock_init(&master->queue_lock);
1874 spin_lock_init(&master->bus_lock_spinlock);
1875 mutex_init(&master->bus_lock_mutex);
1876 master->bus_lock_flag = 0;
1877 init_completion(&master->xfer_completion);
1878 if (!master->max_dma_len)
1879 master->max_dma_len = INT_MAX;
1881 /* register the device, then userspace will see it.
1882 * registration fails if the bus ID is in use.
1884 dev_set_name(&master->dev, "spi%u", master->bus_num);
1885 status = device_add(&master->dev);
1888 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1889 dynamic ? " (dynamic)" : "");
1891 /* If we're using a queued driver, start the queue */
1892 if (master->transfer)
1893 dev_info(dev, "master is unqueued, this is deprecated\n");
1895 status = spi_master_initialize_queue(master);
1897 device_del(&master->dev);
1901 /* add statistics */
1902 spin_lock_init(&master->statistics.lock);
1904 mutex_lock(&board_lock);
1905 list_add_tail(&master->list, &spi_master_list);
1906 list_for_each_entry(bi, &board_list, list)
1907 spi_match_master_to_boardinfo(master, &bi->board_info);
1908 mutex_unlock(&board_lock);
1910 /* Register devices from the device tree and ACPI */
1911 of_register_spi_devices(master);
1912 acpi_register_spi_devices(master);
1916 EXPORT_SYMBOL_GPL(spi_register_master);
1918 static void devm_spi_unregister(struct device *dev, void *res)
1920 spi_unregister_master(*(struct spi_master **)res);
1924 * dev_spi_register_master - register managed SPI master controller
1925 * @dev: device managing SPI master
1926 * @master: initialized master, originally from spi_alloc_master()
1927 * Context: can sleep
1929 * Register a SPI device as with spi_register_master() which will
1930 * automatically be unregister
1932 * Return: zero on success, else a negative error code.
1934 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1936 struct spi_master **ptr;
1939 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1943 ret = spi_register_master(master);
1946 devres_add(dev, ptr);
1953 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1955 static int __unregister(struct device *dev, void *null)
1957 spi_unregister_device(to_spi_device(dev));
1962 * spi_unregister_master - unregister SPI master controller
1963 * @master: the master being unregistered
1964 * Context: can sleep
1966 * This call is used only by SPI master controller drivers, which are the
1967 * only ones directly touching chip registers.
1969 * This must be called from context that can sleep.
1971 void spi_unregister_master(struct spi_master *master)
1975 if (master->queued) {
1976 if (spi_destroy_queue(master))
1977 dev_err(&master->dev, "queue remove failed\n");
1980 mutex_lock(&board_lock);
1981 list_del(&master->list);
1982 mutex_unlock(&board_lock);
1984 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1985 device_unregister(&master->dev);
1987 EXPORT_SYMBOL_GPL(spi_unregister_master);
1989 int spi_master_suspend(struct spi_master *master)
1993 /* Basically no-ops for non-queued masters */
1994 if (!master->queued)
1997 ret = spi_stop_queue(master);
1999 dev_err(&master->dev, "queue stop failed\n");
2003 EXPORT_SYMBOL_GPL(spi_master_suspend);
2005 int spi_master_resume(struct spi_master *master)
2009 if (!master->queued)
2012 ret = spi_start_queue(master);
2014 dev_err(&master->dev, "queue restart failed\n");
2018 EXPORT_SYMBOL_GPL(spi_master_resume);
2020 static int __spi_master_match(struct device *dev, const void *data)
2022 struct spi_master *m;
2023 const u16 *bus_num = data;
2025 m = container_of(dev, struct spi_master, dev);
2026 return m->bus_num == *bus_num;
2030 * spi_busnum_to_master - look up master associated with bus_num
2031 * @bus_num: the master's bus number
2032 * Context: can sleep
2034 * This call may be used with devices that are registered after
2035 * arch init time. It returns a refcounted pointer to the relevant
2036 * spi_master (which the caller must release), or NULL if there is
2037 * no such master registered.
2039 * Return: the SPI master structure on success, else NULL.
2041 struct spi_master *spi_busnum_to_master(u16 bus_num)
2044 struct spi_master *master = NULL;
2046 dev = class_find_device(&spi_master_class, NULL, &bus_num,
2047 __spi_master_match);
2049 master = container_of(dev, struct spi_master, dev);
2050 /* reference got in class_find_device */
2053 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2055 /*-------------------------------------------------------------------------*/
2057 /* Core methods for SPI resource management */
2060 * spi_res_alloc - allocate a spi resource that is life-cycle managed
2061 * during the processing of a spi_message while using
2063 * @spi: the spi device for which we allocate memory
2064 * @release: the release code to execute for this resource
2065 * @size: size to alloc and return
2066 * @gfp: GFP allocation flags
2068 * Return: the pointer to the allocated data
2070 * This may get enhanced in the future to allocate from a memory pool
2071 * of the @spi_device or @spi_master to avoid repeated allocations.
2073 void *spi_res_alloc(struct spi_device *spi,
2074 spi_res_release_t release,
2075 size_t size, gfp_t gfp)
2077 struct spi_res *sres;
2079 sres = kzalloc(sizeof(*sres) + size, gfp);
2083 INIT_LIST_HEAD(&sres->entry);
2084 sres->release = release;
2088 EXPORT_SYMBOL_GPL(spi_res_alloc);
2091 * spi_res_free - free an spi resource
2092 * @res: pointer to the custom data of a resource
2095 void spi_res_free(void *res)
2097 struct spi_res *sres = container_of(res, struct spi_res, data);
2102 WARN_ON(!list_empty(&sres->entry));
2105 EXPORT_SYMBOL_GPL(spi_res_free);
2108 * spi_res_add - add a spi_res to the spi_message
2109 * @message: the spi message
2110 * @res: the spi_resource
2112 void spi_res_add(struct spi_message *message, void *res)
2114 struct spi_res *sres = container_of(res, struct spi_res, data);
2116 WARN_ON(!list_empty(&sres->entry));
2117 list_add_tail(&sres->entry, &message->resources);
2119 EXPORT_SYMBOL_GPL(spi_res_add);
2122 * spi_res_release - release all spi resources for this message
2123 * @master: the @spi_master
2124 * @message: the @spi_message
2126 void spi_res_release(struct spi_master *master,
2127 struct spi_message *message)
2129 struct spi_res *res;
2131 while (!list_empty(&message->resources)) {
2132 res = list_last_entry(&message->resources,
2133 struct spi_res, entry);
2136 res->release(master, message, res->data);
2138 list_del(&res->entry);
2143 EXPORT_SYMBOL_GPL(spi_res_release);
2145 /*-------------------------------------------------------------------------*/
2147 /* Core methods for spi_message alterations */
2149 static void __spi_replace_transfers_release(struct spi_master *master,
2150 struct spi_message *msg,
2153 struct spi_replaced_transfers *rxfer = res;
2156 /* call extra callback if requested */
2158 rxfer->release(master, msg, res);
2160 /* insert replaced transfers back into the message */
2161 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2163 /* remove the formerly inserted entries */
2164 for (i = 0; i < rxfer->inserted; i++)
2165 list_del(&rxfer->inserted_transfers[i].transfer_list);
2169 * spi_replace_transfers - replace transfers with several transfers
2170 * and register change with spi_message.resources
2171 * @msg: the spi_message we work upon
2172 * @xfer_first: the first spi_transfer we want to replace
2173 * @remove: number of transfers to remove
2174 * @insert: the number of transfers we want to insert instead
2175 * @release: extra release code necessary in some circumstances
2176 * @extradatasize: extra data to allocate (with alignment guarantees
2177 * of struct @spi_transfer)
2180 * Returns: pointer to @spi_replaced_transfers,
2181 * PTR_ERR(...) in case of errors.
2183 struct spi_replaced_transfers *spi_replace_transfers(
2184 struct spi_message *msg,
2185 struct spi_transfer *xfer_first,
2188 spi_replaced_release_t release,
2189 size_t extradatasize,
2192 struct spi_replaced_transfers *rxfer;
2193 struct spi_transfer *xfer;
2196 /* allocate the structure using spi_res */
2197 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2198 insert * sizeof(struct spi_transfer)
2199 + sizeof(struct spi_replaced_transfers)
2203 return ERR_PTR(-ENOMEM);
2205 /* the release code to invoke before running the generic release */
2206 rxfer->release = release;
2208 /* assign extradata */
2211 &rxfer->inserted_transfers[insert];
2213 /* init the replaced_transfers list */
2214 INIT_LIST_HEAD(&rxfer->replaced_transfers);
2216 /* assign the list_entry after which we should reinsert
2217 * the @replaced_transfers - it may be spi_message.messages!
2219 rxfer->replaced_after = xfer_first->transfer_list.prev;
2221 /* remove the requested number of transfers */
2222 for (i = 0; i < remove; i++) {
2223 /* if the entry after replaced_after it is msg->transfers
2224 * then we have been requested to remove more transfers
2225 * than are in the list
2227 if (rxfer->replaced_after->next == &msg->transfers) {
2228 dev_err(&msg->spi->dev,
2229 "requested to remove more spi_transfers than are available\n");
2230 /* insert replaced transfers back into the message */
2231 list_splice(&rxfer->replaced_transfers,
2232 rxfer->replaced_after);
2234 /* free the spi_replace_transfer structure */
2235 spi_res_free(rxfer);
2237 /* and return with an error */
2238 return ERR_PTR(-EINVAL);
2241 /* remove the entry after replaced_after from list of
2242 * transfers and add it to list of replaced_transfers
2244 list_move_tail(rxfer->replaced_after->next,
2245 &rxfer->replaced_transfers);
2248 /* create copy of the given xfer with identical settings
2249 * based on the first transfer to get removed
2251 for (i = 0; i < insert; i++) {
2252 /* we need to run in reverse order */
2253 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2255 /* copy all spi_transfer data */
2256 memcpy(xfer, xfer_first, sizeof(*xfer));
2259 list_add(&xfer->transfer_list, rxfer->replaced_after);
2261 /* clear cs_change and delay_usecs for all but the last */
2263 xfer->cs_change = false;
2264 xfer->delay_usecs = 0;
2268 /* set up inserted */
2269 rxfer->inserted = insert;
2271 /* and register it with spi_res/spi_message */
2272 spi_res_add(msg, rxfer);
2276 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2278 static int __spi_split_transfer_maxsize(struct spi_master *master,
2279 struct spi_message *msg,
2280 struct spi_transfer **xferp,
2284 struct spi_transfer *xfer = *xferp, *xfers;
2285 struct spi_replaced_transfers *srt;
2289 /* warn once about this fact that we are splitting a transfer */
2290 dev_warn_once(&msg->spi->dev,
2291 "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2292 xfer->len, maxsize);
2294 /* calculate how many we have to replace */
2295 count = DIV_ROUND_UP(xfer->len, maxsize);
2297 /* create replacement */
2298 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2300 return PTR_ERR(srt);
2301 xfers = srt->inserted_transfers;
2303 /* now handle each of those newly inserted spi_transfers
2304 * note that the replacements spi_transfers all are preset
2305 * to the same values as *xferp, so tx_buf, rx_buf and len
2306 * are all identical (as well as most others)
2307 * so we just have to fix up len and the pointers.
2309 * this also includes support for the depreciated
2310 * spi_message.is_dma_mapped interface
2313 /* the first transfer just needs the length modified, so we
2314 * run it outside the loop
2316 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2318 /* all the others need rx_buf/tx_buf also set */
2319 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2320 /* update rx_buf, tx_buf and dma */
2321 if (xfers[i].rx_buf)
2322 xfers[i].rx_buf += offset;
2323 if (xfers[i].rx_dma)
2324 xfers[i].rx_dma += offset;
2325 if (xfers[i].tx_buf)
2326 xfers[i].tx_buf += offset;
2327 if (xfers[i].tx_dma)
2328 xfers[i].tx_dma += offset;
2331 xfers[i].len = min(maxsize, xfers[i].len - offset);
2334 /* we set up xferp to the last entry we have inserted,
2335 * so that we skip those already split transfers
2337 *xferp = &xfers[count - 1];
2339 /* increment statistics counters */
2340 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2341 transfers_split_maxsize);
2342 SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2343 transfers_split_maxsize);
2349 * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2350 * when an individual transfer exceeds a
2352 * @master: the @spi_master for this transfer
2353 * @msg: the @spi_message to transform
2354 * @maxsize: the maximum when to apply this
2355 * @gfp: GFP allocation flags
2357 * Return: status of transformation
2359 int spi_split_transfers_maxsize(struct spi_master *master,
2360 struct spi_message *msg,
2364 struct spi_transfer *xfer;
2367 /* iterate over the transfer_list,
2368 * but note that xfer is advanced to the last transfer inserted
2369 * to avoid checking sizes again unnecessarily (also xfer does
2370 * potentiall belong to a different list by the time the
2371 * replacement has happened
2373 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2374 if (xfer->len > maxsize) {
2375 ret = __spi_split_transfer_maxsize(
2376 master, msg, &xfer, maxsize, gfp);
2384 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2386 /*-------------------------------------------------------------------------*/
2388 /* Core methods for SPI master protocol drivers. Some of the
2389 * other core methods are currently defined as inline functions.
2392 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2394 if (master->bits_per_word_mask) {
2395 /* Only 32 bits fit in the mask */
2396 if (bits_per_word > 32)
2398 if (!(master->bits_per_word_mask &
2399 SPI_BPW_MASK(bits_per_word)))
2407 * spi_setup - setup SPI mode and clock rate
2408 * @spi: the device whose settings are being modified
2409 * Context: can sleep, and no requests are queued to the device
2411 * SPI protocol drivers may need to update the transfer mode if the
2412 * device doesn't work with its default. They may likewise need
2413 * to update clock rates or word sizes from initial values. This function
2414 * changes those settings, and must be called from a context that can sleep.
2415 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2416 * effect the next time the device is selected and data is transferred to
2417 * or from it. When this function returns, the spi device is deselected.
2419 * Note that this call will fail if the protocol driver specifies an option
2420 * that the underlying controller or its driver does not support. For
2421 * example, not all hardware supports wire transfers using nine bit words,
2422 * LSB-first wire encoding, or active-high chipselects.
2424 * Return: zero on success, else a negative error code.
2426 int spi_setup(struct spi_device *spi)
2428 unsigned bad_bits, ugly_bits;
2431 /* check mode to prevent that DUAL and QUAD set at the same time
2433 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2434 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2436 "setup: can not select dual and quad at the same time\n");
2439 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2441 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2442 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2444 /* help drivers fail *cleanly* when they need options
2445 * that aren't supported with their current master
2447 bad_bits = spi->mode & ~spi->master->mode_bits;
2448 ugly_bits = bad_bits &
2449 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2452 "setup: ignoring unsupported mode bits %x\n",
2454 spi->mode &= ~ugly_bits;
2455 bad_bits &= ~ugly_bits;
2458 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2463 if (!spi->bits_per_word)
2464 spi->bits_per_word = 8;
2466 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2470 if (!spi->max_speed_hz)
2471 spi->max_speed_hz = spi->master->max_speed_hz;
2473 if (spi->master->setup)
2474 status = spi->master->setup(spi);
2476 spi_set_cs(spi, false);
2478 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2479 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2480 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2481 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2482 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2483 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2484 spi->bits_per_word, spi->max_speed_hz,
2489 EXPORT_SYMBOL_GPL(spi_setup);
2491 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2493 struct spi_master *master = spi->master;
2494 struct spi_transfer *xfer;
2497 if (list_empty(&message->transfers))
2500 /* Half-duplex links include original MicroWire, and ones with
2501 * only one data pin like SPI_3WIRE (switches direction) or where
2502 * either MOSI or MISO is missing. They can also be caused by
2503 * software limitations.
2505 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2506 || (spi->mode & SPI_3WIRE)) {
2507 unsigned flags = master->flags;
2509 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2510 if (xfer->rx_buf && xfer->tx_buf)
2512 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2514 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2520 * Set transfer bits_per_word and max speed as spi device default if
2521 * it is not set for this transfer.
2522 * Set transfer tx_nbits and rx_nbits as single transfer default
2523 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2525 message->frame_length = 0;
2526 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2527 message->frame_length += xfer->len;
2528 if (!xfer->bits_per_word)
2529 xfer->bits_per_word = spi->bits_per_word;
2531 if (!xfer->speed_hz)
2532 xfer->speed_hz = spi->max_speed_hz;
2533 if (!xfer->speed_hz)
2534 xfer->speed_hz = master->max_speed_hz;
2536 if (master->max_speed_hz &&
2537 xfer->speed_hz > master->max_speed_hz)
2538 xfer->speed_hz = master->max_speed_hz;
2540 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2544 * SPI transfer length should be multiple of SPI word size
2545 * where SPI word size should be power-of-two multiple
2547 if (xfer->bits_per_word <= 8)
2549 else if (xfer->bits_per_word <= 16)
2554 /* No partial transfers accepted */
2555 if (xfer->len % w_size)
2558 if (xfer->speed_hz && master->min_speed_hz &&
2559 xfer->speed_hz < master->min_speed_hz)
2562 if (xfer->tx_buf && !xfer->tx_nbits)
2563 xfer->tx_nbits = SPI_NBITS_SINGLE;
2564 if (xfer->rx_buf && !xfer->rx_nbits)
2565 xfer->rx_nbits = SPI_NBITS_SINGLE;
2566 /* check transfer tx/rx_nbits:
2567 * 1. check the value matches one of single, dual and quad
2568 * 2. check tx/rx_nbits match the mode in spi_device
2571 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2572 xfer->tx_nbits != SPI_NBITS_DUAL &&
2573 xfer->tx_nbits != SPI_NBITS_QUAD)
2575 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2576 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2578 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2579 !(spi->mode & SPI_TX_QUAD))
2582 /* check transfer rx_nbits */
2584 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2585 xfer->rx_nbits != SPI_NBITS_DUAL &&
2586 xfer->rx_nbits != SPI_NBITS_QUAD)
2588 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2589 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2591 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2592 !(spi->mode & SPI_RX_QUAD))
2597 message->status = -EINPROGRESS;
2602 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2604 struct spi_master *master = spi->master;
2608 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2609 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2611 trace_spi_message_submit(message);
2613 return master->transfer(spi, message);
2617 * spi_async - asynchronous SPI transfer
2618 * @spi: device with which data will be exchanged
2619 * @message: describes the data transfers, including completion callback
2620 * Context: any (irqs may be blocked, etc)
2622 * This call may be used in_irq and other contexts which can't sleep,
2623 * as well as from task contexts which can sleep.
2625 * The completion callback is invoked in a context which can't sleep.
2626 * Before that invocation, the value of message->status is undefined.
2627 * When the callback is issued, message->status holds either zero (to
2628 * indicate complete success) or a negative error code. After that
2629 * callback returns, the driver which issued the transfer request may
2630 * deallocate the associated memory; it's no longer in use by any SPI
2631 * core or controller driver code.
2633 * Note that although all messages to a spi_device are handled in
2634 * FIFO order, messages may go to different devices in other orders.
2635 * Some device might be higher priority, or have various "hard" access
2636 * time requirements, for example.
2638 * On detection of any fault during the transfer, processing of
2639 * the entire message is aborted, and the device is deselected.
2640 * Until returning from the associated message completion callback,
2641 * no other spi_message queued to that device will be processed.
2642 * (This rule applies equally to all the synchronous transfer calls,
2643 * which are wrappers around this core asynchronous primitive.)
2645 * Return: zero on success, else a negative error code.
2647 int spi_async(struct spi_device *spi, struct spi_message *message)
2649 struct spi_master *master = spi->master;
2651 unsigned long flags;
2653 ret = __spi_validate(spi, message);
2657 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2659 if (master->bus_lock_flag)
2662 ret = __spi_async(spi, message);
2664 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2668 EXPORT_SYMBOL_GPL(spi_async);
2671 * spi_async_locked - version of spi_async with exclusive bus usage
2672 * @spi: device with which data will be exchanged
2673 * @message: describes the data transfers, including completion callback
2674 * Context: any (irqs may be blocked, etc)
2676 * This call may be used in_irq and other contexts which can't sleep,
2677 * as well as from task contexts which can sleep.
2679 * The completion callback is invoked in a context which can't sleep.
2680 * Before that invocation, the value of message->status is undefined.
2681 * When the callback is issued, message->status holds either zero (to
2682 * indicate complete success) or a negative error code. After that
2683 * callback returns, the driver which issued the transfer request may
2684 * deallocate the associated memory; it's no longer in use by any SPI
2685 * core or controller driver code.
2687 * Note that although all messages to a spi_device are handled in
2688 * FIFO order, messages may go to different devices in other orders.
2689 * Some device might be higher priority, or have various "hard" access
2690 * time requirements, for example.
2692 * On detection of any fault during the transfer, processing of
2693 * the entire message is aborted, and the device is deselected.
2694 * Until returning from the associated message completion callback,
2695 * no other spi_message queued to that device will be processed.
2696 * (This rule applies equally to all the synchronous transfer calls,
2697 * which are wrappers around this core asynchronous primitive.)
2699 * Return: zero on success, else a negative error code.
2701 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2703 struct spi_master *master = spi->master;
2705 unsigned long flags;
2707 ret = __spi_validate(spi, message);
2711 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2713 ret = __spi_async(spi, message);
2715 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2720 EXPORT_SYMBOL_GPL(spi_async_locked);
2723 int spi_flash_read(struct spi_device *spi,
2724 struct spi_flash_read_message *msg)
2727 struct spi_master *master = spi->master;
2730 if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2731 msg->addr_nbits == SPI_NBITS_DUAL) &&
2732 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2734 if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2735 msg->addr_nbits == SPI_NBITS_QUAD) &&
2736 !(spi->mode & SPI_TX_QUAD))
2738 if (msg->data_nbits == SPI_NBITS_DUAL &&
2739 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2741 if (msg->data_nbits == SPI_NBITS_QUAD &&
2742 !(spi->mode & SPI_RX_QUAD))
2745 if (master->auto_runtime_pm) {
2746 ret = pm_runtime_get_sync(master->dev.parent);
2748 dev_err(&master->dev, "Failed to power device: %d\n",
2753 mutex_lock(&master->bus_lock_mutex);
2754 ret = master->spi_flash_read(spi, msg);
2755 mutex_unlock(&master->bus_lock_mutex);
2756 if (master->auto_runtime_pm)
2757 pm_runtime_put(master->dev.parent);
2761 EXPORT_SYMBOL_GPL(spi_flash_read);
2763 /*-------------------------------------------------------------------------*/
2765 /* Utility methods for SPI master protocol drivers, layered on
2766 * top of the core. Some other utility methods are defined as
2770 static void spi_complete(void *arg)
2775 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2778 DECLARE_COMPLETION_ONSTACK(done);
2780 struct spi_master *master = spi->master;
2781 unsigned long flags;
2783 status = __spi_validate(spi, message);
2787 message->complete = spi_complete;
2788 message->context = &done;
2791 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2792 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2795 mutex_lock(&master->bus_lock_mutex);
2797 /* If we're not using the legacy transfer method then we will
2798 * try to transfer in the calling context so special case.
2799 * This code would be less tricky if we could remove the
2800 * support for driver implemented message queues.
2802 if (master->transfer == spi_queued_transfer) {
2803 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2805 trace_spi_message_submit(message);
2807 status = __spi_queued_transfer(spi, message, false);
2809 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2811 status = spi_async_locked(spi, message);
2815 mutex_unlock(&master->bus_lock_mutex);
2818 /* Push out the messages in the calling context if we
2821 if (master->transfer == spi_queued_transfer) {
2822 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2823 spi_sync_immediate);
2824 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2825 spi_sync_immediate);
2826 __spi_pump_messages(master, false, bus_locked);
2829 wait_for_completion(&done);
2830 status = message->status;
2832 message->context = NULL;
2837 * spi_sync - blocking/synchronous SPI data transfers
2838 * @spi: device with which data will be exchanged
2839 * @message: describes the data transfers
2840 * Context: can sleep
2842 * This call may only be used from a context that may sleep. The sleep
2843 * is non-interruptible, and has no timeout. Low-overhead controller
2844 * drivers may DMA directly into and out of the message buffers.
2846 * Note that the SPI device's chip select is active during the message,
2847 * and then is normally disabled between messages. Drivers for some
2848 * frequently-used devices may want to minimize costs of selecting a chip,
2849 * by leaving it selected in anticipation that the next message will go
2850 * to the same chip. (That may increase power usage.)
2852 * Also, the caller is guaranteeing that the memory associated with the
2853 * message will not be freed before this call returns.
2855 * Return: zero on success, else a negative error code.
2857 int spi_sync(struct spi_device *spi, struct spi_message *message)
2859 return __spi_sync(spi, message, spi->master->bus_lock_flag);
2861 EXPORT_SYMBOL_GPL(spi_sync);
2864 * spi_sync_locked - version of spi_sync with exclusive bus usage
2865 * @spi: device with which data will be exchanged
2866 * @message: describes the data transfers
2867 * Context: can sleep
2869 * This call may only be used from a context that may sleep. The sleep
2870 * is non-interruptible, and has no timeout. Low-overhead controller
2871 * drivers may DMA directly into and out of the message buffers.
2873 * This call should be used by drivers that require exclusive access to the
2874 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2875 * be released by a spi_bus_unlock call when the exclusive access is over.
2877 * Return: zero on success, else a negative error code.
2879 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2881 return __spi_sync(spi, message, 1);
2883 EXPORT_SYMBOL_GPL(spi_sync_locked);
2886 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2887 * @master: SPI bus master that should be locked for exclusive bus access
2888 * Context: can sleep
2890 * This call may only be used from a context that may sleep. The sleep
2891 * is non-interruptible, and has no timeout.
2893 * This call should be used by drivers that require exclusive access to the
2894 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2895 * exclusive access is over. Data transfer must be done by spi_sync_locked
2896 * and spi_async_locked calls when the SPI bus lock is held.
2898 * Return: always zero.
2900 int spi_bus_lock(struct spi_master *master)
2902 unsigned long flags;
2904 mutex_lock(&master->bus_lock_mutex);
2906 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2907 master->bus_lock_flag = 1;
2908 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2910 /* mutex remains locked until spi_bus_unlock is called */
2914 EXPORT_SYMBOL_GPL(spi_bus_lock);
2917 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2918 * @master: SPI bus master that was locked for exclusive bus access
2919 * Context: can sleep
2921 * This call may only be used from a context that may sleep. The sleep
2922 * is non-interruptible, and has no timeout.
2924 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2927 * Return: always zero.
2929 int spi_bus_unlock(struct spi_master *master)
2931 master->bus_lock_flag = 0;
2933 mutex_unlock(&master->bus_lock_mutex);
2937 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2939 /* portable code must never pass more than 32 bytes */
2940 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2945 * spi_write_then_read - SPI synchronous write followed by read
2946 * @spi: device with which data will be exchanged
2947 * @txbuf: data to be written (need not be dma-safe)
2948 * @n_tx: size of txbuf, in bytes
2949 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2950 * @n_rx: size of rxbuf, in bytes
2951 * Context: can sleep
2953 * This performs a half duplex MicroWire style transaction with the
2954 * device, sending txbuf and then reading rxbuf. The return value
2955 * is zero for success, else a negative errno status code.
2956 * This call may only be used from a context that may sleep.
2958 * Parameters to this routine are always copied using a small buffer;
2959 * portable code should never use this for more than 32 bytes.
2960 * Performance-sensitive or bulk transfer code should instead use
2961 * spi_{async,sync}() calls with dma-safe buffers.
2963 * Return: zero on success, else a negative error code.
2965 int spi_write_then_read(struct spi_device *spi,
2966 const void *txbuf, unsigned n_tx,
2967 void *rxbuf, unsigned n_rx)
2969 static DEFINE_MUTEX(lock);
2972 struct spi_message message;
2973 struct spi_transfer x[2];
2976 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2977 * copying here, (as a pure convenience thing), but we can
2978 * keep heap costs out of the hot path unless someone else is
2979 * using the pre-allocated buffer or the transfer is too large.
2981 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2982 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2983 GFP_KERNEL | GFP_DMA);
2990 spi_message_init(&message);
2991 memset(x, 0, sizeof(x));
2994 spi_message_add_tail(&x[0], &message);
2998 spi_message_add_tail(&x[1], &message);
3001 memcpy(local_buf, txbuf, n_tx);
3002 x[0].tx_buf = local_buf;
3003 x[1].rx_buf = local_buf + n_tx;
3006 status = spi_sync(spi, &message);
3008 memcpy(rxbuf, x[1].rx_buf, n_rx);
3010 if (x[0].tx_buf == buf)
3011 mutex_unlock(&lock);
3017 EXPORT_SYMBOL_GPL(spi_write_then_read);
3019 /*-------------------------------------------------------------------------*/
3021 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3022 static int __spi_of_device_match(struct device *dev, void *data)
3024 return dev->of_node == data;
3027 /* must call put_device() when done with returned spi_device device */
3028 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3030 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3031 __spi_of_device_match);
3032 return dev ? to_spi_device(dev) : NULL;
3035 static int __spi_of_master_match(struct device *dev, const void *data)
3037 return dev->of_node == data;
3040 /* the spi masters are not using spi_bus, so we find it with another way */
3041 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3045 dev = class_find_device(&spi_master_class, NULL, node,
3046 __spi_of_master_match);
3050 /* reference got in class_find_device */
3051 return container_of(dev, struct spi_master, dev);
3054 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3057 struct of_reconfig_data *rd = arg;
3058 struct spi_master *master;
3059 struct spi_device *spi;
3061 switch (of_reconfig_get_state_change(action, arg)) {
3062 case OF_RECONFIG_CHANGE_ADD:
3063 master = of_find_spi_master_by_node(rd->dn->parent);
3065 return NOTIFY_OK; /* not for us */
3067 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3068 put_device(&master->dev);
3072 spi = of_register_spi_device(master, rd->dn);
3073 put_device(&master->dev);
3076 pr_err("%s: failed to create for '%s'\n",
3077 __func__, rd->dn->full_name);
3078 return notifier_from_errno(PTR_ERR(spi));
3082 case OF_RECONFIG_CHANGE_REMOVE:
3083 /* already depopulated? */
3084 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3087 /* find our device by node */
3088 spi = of_find_spi_device_by_node(rd->dn);
3090 return NOTIFY_OK; /* no? not meant for us */
3092 /* unregister takes one ref away */
3093 spi_unregister_device(spi);
3095 /* and put the reference of the find */
3096 put_device(&spi->dev);
3103 static struct notifier_block spi_of_notifier = {
3104 .notifier_call = of_spi_notify,
3106 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3107 extern struct notifier_block spi_of_notifier;
3108 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3110 static int __init spi_init(void)
3114 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3120 status = bus_register(&spi_bus_type);
3124 status = class_register(&spi_master_class);
3128 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3129 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3134 bus_unregister(&spi_bus_type);
3142 /* board_info is normally registered in arch_initcall(),
3143 * but even essential drivers wait till later
3145 * REVISIT only boardinfo really needs static linking. the rest (device and
3146 * driver registration) _could_ be dynamically linked (modular) ... costs
3147 * include needing to have boardinfo data structures be much more public.
3149 postcore_initcall(spi_init);