2 * Marvell Orion SPI controller driver
4 * Author: Shadi Ammouri <shadi@marvell.com>
5 * Copyright (C) 2007-2008 Marvell 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 version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/delay.h>
15 #include <linux/platform_device.h>
16 #include <linux/err.h>
18 #include <linux/spi/spi.h>
19 #include <linux/spi/orion_spi.h>
20 #include <linux/module.h>
21 #include <asm/unaligned.h>
23 #define DRIVER_NAME "orion_spi"
25 #define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
26 #define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
28 #define ORION_SPI_IF_CTRL_REG 0x00
29 #define ORION_SPI_IF_CONFIG_REG 0x04
30 #define ORION_SPI_DATA_OUT_REG 0x08
31 #define ORION_SPI_DATA_IN_REG 0x0c
32 #define ORION_SPI_INT_CAUSE_REG 0x10
34 #define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
35 #define ORION_SPI_CLK_PRESCALE_MASK 0x1F
38 struct work_struct work;
40 /* Lock access to transfer list. */
43 struct list_head msg_queue;
44 struct spi_master *master;
46 unsigned int max_speed;
47 unsigned int min_speed;
48 struct orion_spi_info *spi_info;
51 static struct workqueue_struct *orion_spi_wq;
53 static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
55 return orion_spi->base + reg;
59 orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
61 void __iomem *reg_addr = spi_reg(orion_spi, reg);
64 val = readl(reg_addr);
66 writel(val, reg_addr);
70 orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
72 void __iomem *reg_addr = spi_reg(orion_spi, reg);
75 val = readl(reg_addr);
77 writel(val, reg_addr);
80 static int orion_spi_set_transfer_size(struct orion_spi *orion_spi, int size)
83 orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
84 ORION_SPI_IF_8_16_BIT_MODE);
85 } else if (size == 8) {
86 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
87 ORION_SPI_IF_8_16_BIT_MODE);
89 pr_debug("Bad bits per word value %d (only 8 or 16 are "
97 static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
103 struct orion_spi *orion_spi;
105 orion_spi = spi_master_get_devdata(spi->master);
107 tclk_hz = orion_spi->spi_info->tclk;
110 * the supported rates are: 4,6,8...30
111 * round up as we look for equal or less speed
113 rate = DIV_ROUND_UP(tclk_hz, speed);
114 rate = roundup(rate, 2);
116 /* check if requested speed is too small */
123 /* Convert the rate to SPI clock divisor value. */
124 prescale = 0x10 + rate/2;
126 reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
127 reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
128 writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
134 * called only when no transfer is active on the bus
137 orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
139 struct orion_spi *orion_spi;
140 unsigned int speed = spi->max_speed_hz;
141 unsigned int bits_per_word = spi->bits_per_word;
144 orion_spi = spi_master_get_devdata(spi->master);
146 if ((t != NULL) && t->speed_hz)
149 if ((t != NULL) && t->bits_per_word)
150 bits_per_word = t->bits_per_word;
152 rc = orion_spi_baudrate_set(spi, speed);
156 return orion_spi_set_transfer_size(orion_spi, bits_per_word);
159 static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
162 orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
164 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
167 static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
171 for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
172 if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
182 orion_spi_write_read_8bit(struct spi_device *spi,
183 const u8 **tx_buf, u8 **rx_buf)
185 void __iomem *tx_reg, *rx_reg, *int_reg;
186 struct orion_spi *orion_spi;
188 orion_spi = spi_master_get_devdata(spi->master);
189 tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
190 rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
191 int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
193 /* clear the interrupt cause register */
194 writel(0x0, int_reg);
196 if (tx_buf && *tx_buf)
197 writel(*(*tx_buf)++, tx_reg);
201 if (orion_spi_wait_till_ready(orion_spi) < 0) {
202 dev_err(&spi->dev, "TXS timed out\n");
206 if (rx_buf && *rx_buf)
207 *(*rx_buf)++ = readl(rx_reg);
213 orion_spi_write_read_16bit(struct spi_device *spi,
214 const u16 **tx_buf, u16 **rx_buf)
216 void __iomem *tx_reg, *rx_reg, *int_reg;
217 struct orion_spi *orion_spi;
219 orion_spi = spi_master_get_devdata(spi->master);
220 tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
221 rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
222 int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
224 /* clear the interrupt cause register */
225 writel(0x0, int_reg);
227 if (tx_buf && *tx_buf)
228 writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
232 if (orion_spi_wait_till_ready(orion_spi) < 0) {
233 dev_err(&spi->dev, "TXS timed out\n");
237 if (rx_buf && *rx_buf)
238 put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
244 orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
246 struct orion_spi *orion_spi;
250 orion_spi = spi_master_get_devdata(spi->master);
251 word_len = spi->bits_per_word;
255 const u8 *tx = xfer->tx_buf;
256 u8 *rx = xfer->rx_buf;
259 if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
263 } else if (word_len == 16) {
264 const u16 *tx = xfer->tx_buf;
265 u16 *rx = xfer->rx_buf;
268 if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
275 return xfer->len - count;
279 static void orion_spi_work(struct work_struct *work)
281 struct orion_spi *orion_spi =
282 container_of(work, struct orion_spi, work);
284 spin_lock_irq(&orion_spi->lock);
285 while (!list_empty(&orion_spi->msg_queue)) {
286 struct spi_message *m;
287 struct spi_device *spi;
288 struct spi_transfer *t = NULL;
289 int par_override = 0;
293 m = container_of(orion_spi->msg_queue.next, struct spi_message,
296 list_del_init(&m->queue);
297 spin_unlock_irq(&orion_spi->lock);
302 status = orion_spi_setup_transfer(spi, NULL);
307 list_for_each_entry(t, &m->transfers, transfer_list) {
308 if (par_override || t->speed_hz || t->bits_per_word) {
310 status = orion_spi_setup_transfer(spi, t);
313 if (!t->speed_hz && !t->bits_per_word)
318 orion_spi_set_cs(orion_spi, 1);
324 orion_spi_write_read(spi, t);
327 udelay(t->delay_usecs);
330 orion_spi_set_cs(orion_spi, 0);
337 orion_spi_set_cs(orion_spi, 0);
340 m->complete(m->context);
342 spin_lock_irq(&orion_spi->lock);
345 spin_unlock_irq(&orion_spi->lock);
348 static int __init orion_spi_reset(struct orion_spi *orion_spi)
350 /* Verify that the CS is deasserted */
351 orion_spi_set_cs(orion_spi, 0);
356 static int orion_spi_setup(struct spi_device *spi)
358 struct orion_spi *orion_spi;
360 orion_spi = spi_master_get_devdata(spi->master);
362 if ((spi->max_speed_hz == 0)
363 || (spi->max_speed_hz > orion_spi->max_speed))
364 spi->max_speed_hz = orion_spi->max_speed;
366 if (spi->max_speed_hz < orion_spi->min_speed) {
367 dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
373 * baudrate & width will be set orion_spi_setup_transfer
378 static int orion_spi_transfer(struct spi_device *spi, struct spi_message *m)
380 struct orion_spi *orion_spi;
381 struct spi_transfer *t = NULL;
384 m->actual_length = 0;
387 /* reject invalid messages and transfers */
388 if (list_empty(&m->transfers) || !m->complete)
391 orion_spi = spi_master_get_devdata(spi->master);
393 list_for_each_entry(t, &m->transfers, transfer_list) {
394 unsigned int bits_per_word = spi->bits_per_word;
396 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
398 "message rejected : "
399 "invalid transfer data buffers\n");
403 if (t->bits_per_word)
404 bits_per_word = t->bits_per_word;
406 if ((bits_per_word != 8) && (bits_per_word != 16)) {
408 "message rejected : "
409 "invalid transfer bits_per_word (%d bits)\n",
413 /*make sure buffer length is even when working in 16 bit mode*/
414 if ((t->bits_per_word == 16) && (t->len & 1)) {
416 "message rejected : "
417 "odd data length (%d) while in 16 bit mode\n",
422 if (t->speed_hz && t->speed_hz < orion_spi->min_speed) {
424 "message rejected : "
425 "device min speed (%d Hz) exceeds "
426 "required transfer speed (%d Hz)\n",
427 orion_spi->min_speed, t->speed_hz);
433 spin_lock_irqsave(&orion_spi->lock, flags);
434 list_add_tail(&m->queue, &orion_spi->msg_queue);
435 queue_work(orion_spi_wq, &orion_spi->work);
436 spin_unlock_irqrestore(&orion_spi->lock, flags);
440 /* Message rejected and not queued */
443 m->complete(m->context);
447 static int __init orion_spi_probe(struct platform_device *pdev)
449 struct spi_master *master;
450 struct orion_spi *spi;
452 struct orion_spi_info *spi_info;
455 spi_info = pdev->dev.platform_data;
457 master = spi_alloc_master(&pdev->dev, sizeof *spi);
458 if (master == NULL) {
459 dev_dbg(&pdev->dev, "master allocation failed\n");
464 master->bus_num = pdev->id;
466 /* we support only mode 0, and no options */
467 master->mode_bits = 0;
469 master->setup = orion_spi_setup;
470 master->transfer = orion_spi_transfer;
471 master->num_chipselect = ORION_NUM_CHIPSELECTS;
473 dev_set_drvdata(&pdev->dev, master);
475 spi = spi_master_get_devdata(master);
476 spi->master = master;
477 spi->spi_info = spi_info;
479 spi->max_speed = DIV_ROUND_UP(spi_info->tclk, 4);
480 spi->min_speed = DIV_ROUND_UP(spi_info->tclk, 30);
482 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
488 if (!request_mem_region(r->start, resource_size(r),
489 dev_name(&pdev->dev))) {
493 spi->base = ioremap(r->start, SZ_1K);
495 INIT_WORK(&spi->work, orion_spi_work);
497 spin_lock_init(&spi->lock);
498 INIT_LIST_HEAD(&spi->msg_queue);
500 if (orion_spi_reset(spi) < 0)
503 status = spi_register_master(master);
510 release_mem_region(r->start, resource_size(r));
513 spi_master_put(master);
518 static int __exit orion_spi_remove(struct platform_device *pdev)
520 struct spi_master *master;
521 struct orion_spi *spi;
524 master = dev_get_drvdata(&pdev->dev);
525 spi = spi_master_get_devdata(master);
527 cancel_work_sync(&spi->work);
529 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
530 release_mem_region(r->start, resource_size(r));
532 spi_unregister_master(master);
537 MODULE_ALIAS("platform:" DRIVER_NAME);
539 static struct platform_driver orion_spi_driver = {
542 .owner = THIS_MODULE,
544 .remove = __exit_p(orion_spi_remove),
547 static int __init orion_spi_init(void)
549 orion_spi_wq = create_singlethread_workqueue(
550 orion_spi_driver.driver.name);
551 if (orion_spi_wq == NULL)
554 return platform_driver_probe(&orion_spi_driver, orion_spi_probe);
556 module_init(orion_spi_init);
558 static void __exit orion_spi_exit(void)
560 flush_workqueue(orion_spi_wq);
561 platform_driver_unregister(&orion_spi_driver);
563 destroy_workqueue(orion_spi_wq);
565 module_exit(orion_spi_exit);
567 MODULE_DESCRIPTION("Orion SPI driver");
568 MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
569 MODULE_LICENSE("GPL");