2 * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
4 * Copyright © 2006-2007 Red Hat, Inc.
5 * Copyright © 2006-2007 Advanced Micro Devices, Inc.
6 * Copyright © 2009 VIA Technology, Inc.
7 * Copyright (c) 2010-2011 Andres Salomon <dilinger@queued.net>
9 * This program is free software. You can redistribute it and/or
10 * modify it under the terms of version 2 of the GNU General Public
11 * License as published by the Free Software Foundation.
15 #include <linux/kernel.h>
17 #include <linux/console.h>
18 #include <linux/i2c.h>
19 #include <linux/platform_device.h>
20 #include <linux/pci.h>
21 #include <linux/pci_ids.h>
22 #include <linux/interrupt.h>
23 #include <linux/delay.h>
24 #include <linux/module.h>
25 #include <linux/backlight.h>
26 #include <linux/device.h>
27 #include <linux/uaccess.h>
28 #include <linux/ctype.h>
29 #include <linux/reboot.h>
33 #include "olpc_dcon.h"
35 /* Module definitions */
37 static int resumeline = 898;
38 module_param(resumeline, int, 0444);
40 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
42 module_param(useaa, int, 0444);
44 static struct dcon_platform_data *pdata;
48 /* Platform devices */
49 static struct platform_device *dcon_device;
51 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
53 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
55 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
57 return i2c_smbus_write_word_data(dcon->client, reg, val);
60 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
62 return i2c_smbus_read_word_data(dcon->client, reg);
65 /* ===== API functions - these are called by a variety of users ==== */
67 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
72 ver = dcon_read(dcon, DCON_REG_ID);
73 if ((ver >> 8) != 0xDC) {
74 printk(KERN_ERR "olpc-dcon: DCON ID not 0xDCxx: 0x%04x "
81 printk(KERN_INFO "olpc-dcon: Discovered DCON version %x\n",
83 rc = pdata->init(dcon);
85 printk(KERN_ERR "olpc-dcon: Unable to init.\n");
91 dev_err(&dcon->client->dev,
92 "DCON v1 is unsupported, giving up..\n");
97 /* SDRAM setup/hold time */
98 dcon_write(dcon, 0x3a, 0xc040);
99 dcon_write(dcon, 0x41, 0x0000);
100 dcon_write(dcon, 0x41, 0x0101);
101 dcon_write(dcon, 0x42, 0x0101);
103 /* Colour swizzle, AA, no passthrough, backlight */
105 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
108 dcon->disp_mode |= MODE_COL_AA;
110 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
113 /* Set the scanline to interrupt on during resume */
114 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
121 * The smbus doesn't always come back due to what is believed to be
122 * hardware (power rail) bugs. For older models where this is known to
123 * occur, our solution is to attempt to wait for the bus to stabilize;
124 * if it doesn't happen, cut power to the dcon, repower it, and wait
125 * for the bus to stabilize. Rinse, repeat until we have a working
126 * smbus. For newer models, we simply BUG(); we want to know if this
127 * still happens despite the power fixes that have been made!
129 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
131 unsigned long timeout;
135 if (is_powered_down) {
137 x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
139 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
140 "to power up: %d!\n", x);
143 msleep(10); /* we'll be conservative */
146 pdata->bus_stabilize_wiggle();
148 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
150 x = dcon_read(dcon, DCON_REG_ID);
153 printk(KERN_ERR "olpc-dcon: unable to stabilize dcon's "
154 "smbus, reasserting power and praying.\n");
155 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
157 olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
160 goto power_up; /* argh, stupid hardware.. */
164 return dcon_hw_init(dcon, 0);
168 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
170 dcon->bl_val = level;
171 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
173 /* Purposely turn off the backlight when we go to level 0 */
174 if (dcon->bl_val == 0) {
175 dcon->disp_mode &= ~MODE_BL_ENABLE;
176 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
177 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
178 dcon->disp_mode |= MODE_BL_ENABLE;
179 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
183 /* Set the output type to either color or mono */
184 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
186 if (dcon->mono == enable_mono)
189 dcon->mono = enable_mono;
192 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
193 dcon->disp_mode |= MODE_MONO_LUMA;
195 dcon->disp_mode &= ~(MODE_MONO_LUMA);
196 dcon->disp_mode |= MODE_CSWIZZLE;
198 dcon->disp_mode |= MODE_COL_AA;
201 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
205 /* For now, this will be really stupid - we need to address how
206 * DCONLOAD works in a sleep and account for it accordingly
209 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
213 /* Turn off the backlight and put the DCON to sleep */
215 if (dcon->asleep == sleep)
218 if (!olpc_board_at_least(olpc_board(0xc2)))
223 x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
225 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
226 "to power down: %d!\n", x);
228 dcon->asleep = sleep;
230 /* Only re-enable the backlight if the backlight value is set */
231 if (dcon->bl_val != 0)
232 dcon->disp_mode |= MODE_BL_ENABLE;
233 x = dcon_bus_stabilize(dcon, 1);
235 printk(KERN_WARNING "olpc-dcon: unable to reinit dcon"
236 " hardware: %d!\n", x);
238 dcon->asleep = sleep;
240 /* Restore backlight */
241 dcon_set_backlight(dcon, dcon->bl_val);
244 /* We should turn off some stuff in the framebuffer - but what? */
247 /* the DCON seems to get confused if we change DCONLOAD too
248 * frequently -- i.e., approximately faster than frame time.
249 * normally we don't change it this fast, so in general we won't
252 static void dcon_load_holdoff(struct dcon_priv *dcon)
254 struct timespec delta_t, now;
256 getnstimeofday(&now);
257 delta_t = timespec_sub(now, dcon->load_time);
258 if (delta_t.tv_sec != 0 ||
259 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
266 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
270 if (!lock_fb_info(dcon->fbinfo)) {
271 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
275 dcon->ignore_fb_events = true;
276 err = fb_blank(dcon->fbinfo,
277 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
278 dcon->ignore_fb_events = false;
280 unlock_fb_info(dcon->fbinfo);
283 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
290 /* Set the source of the display (CPU or DCON) */
291 static void dcon_source_switch(struct work_struct *work)
293 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
295 DECLARE_WAITQUEUE(wait, current);
296 int source = dcon->pending_src;
298 if (dcon->curr_src == source)
301 dcon_load_holdoff(dcon);
303 dcon->switched = false;
306 case DCON_SOURCE_CPU:
307 printk("dcon_source_switch to CPU\n");
308 /* Enable the scanline interrupt bit */
309 if (dcon_write(dcon, DCON_REG_MODE,
310 dcon->disp_mode | MODE_SCAN_INT))
312 "olpc-dcon: couldn't enable scanline interrupt!\n");
314 /* Wait up to one second for the scanline interrupt */
315 wait_event_timeout(dcon_wait_queue,
316 dcon->switched == true, HZ);
320 printk(KERN_ERR "olpc-dcon: Timeout entering CPU mode; expect a screen glitch.\n");
322 /* Turn off the scanline interrupt */
323 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
324 printk(KERN_ERR "olpc-dcon: couldn't disable scanline interrupt!\n");
327 * Ideally we'd like to disable interrupts here so that the
328 * fb unblanking and DCON turn on happen at a known time value;
329 * however, we can't do that right now with fb_blank
330 * messing with semaphores.
332 * For now, we just hope..
334 if (!dcon_blank_fb(dcon, false)) {
335 printk(KERN_ERR "olpc-dcon: Failed to enter CPU mode\n");
336 dcon->pending_src = DCON_SOURCE_DCON;
340 /* And turn off the DCON */
341 pdata->set_dconload(1);
342 getnstimeofday(&dcon->load_time);
344 printk(KERN_INFO "olpc-dcon: The CPU has control\n");
346 case DCON_SOURCE_DCON:
349 struct timespec delta_t;
351 printk(KERN_INFO "dcon_source_switch to DCON\n");
353 add_wait_queue(&dcon_wait_queue, &wait);
354 set_current_state(TASK_UNINTERRUPTIBLE);
356 /* Clear DCONLOAD - this implies that the DCON is in control */
357 pdata->set_dconload(0);
358 getnstimeofday(&dcon->load_time);
360 t = schedule_timeout(HZ/2);
361 remove_wait_queue(&dcon_wait_queue, &wait);
362 set_current_state(TASK_RUNNING);
364 if (!dcon->switched) {
365 printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
367 /* sometimes the DCON doesn't follow its own rules,
368 * and doesn't wait for two vsync pulses before
369 * ack'ing the frame load with an IRQ. the result
370 * is that the display shows the *previously*
371 * loaded frame. we can detect this by looking at
372 * the time between asserting DCONLOAD and the IRQ --
373 * if it's less than 20msec, then the DCON couldn't
374 * have seen two VSYNC pulses. in that case we
375 * deassert and reassert, and hope for the best.
376 * see http://dev.laptop.org/ticket/9664
378 delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
379 if (dcon->switched && delta_t.tv_sec == 0 &&
380 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
381 printk(KERN_ERR "olpc-dcon: missed loading, retrying\n");
382 pdata->set_dconload(1);
384 pdata->set_dconload(0);
385 getnstimeofday(&dcon->load_time);
390 dcon_blank_fb(dcon, true);
391 printk(KERN_INFO "olpc-dcon: The DCON has control\n");
398 dcon->curr_src = source;
401 static void dcon_set_source(struct dcon_priv *dcon, int arg)
403 if (dcon->pending_src == arg)
406 dcon->pending_src = arg;
408 if ((dcon->curr_src != arg) && !work_pending(&dcon->switch_source))
409 schedule_work(&dcon->switch_source);
412 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
414 dcon_set_source(dcon, arg);
415 flush_scheduled_work();
418 static ssize_t dcon_mode_show(struct device *dev,
419 struct device_attribute *attr, char *buf)
421 struct dcon_priv *dcon = dev_get_drvdata(dev);
422 return sprintf(buf, "%4.4X\n", dcon->disp_mode);
425 static ssize_t dcon_sleep_show(struct device *dev,
426 struct device_attribute *attr, char *buf)
429 struct dcon_priv *dcon = dev_get_drvdata(dev);
430 return sprintf(buf, "%d\n", dcon->asleep);
433 static ssize_t dcon_freeze_show(struct device *dev,
434 struct device_attribute *attr, char *buf)
436 struct dcon_priv *dcon = dev_get_drvdata(dev);
437 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
440 static ssize_t dcon_mono_show(struct device *dev,
441 struct device_attribute *attr, char *buf)
443 struct dcon_priv *dcon = dev_get_drvdata(dev);
444 return sprintf(buf, "%d\n", dcon->mono);
447 static ssize_t dcon_resumeline_show(struct device *dev,
448 struct device_attribute *attr, char *buf)
450 return sprintf(buf, "%d\n", resumeline);
453 static ssize_t dcon_mono_store(struct device *dev,
454 struct device_attribute *attr, const char *buf, size_t count)
456 unsigned long enable_mono;
459 rc = strict_strtoul(buf, 10, &enable_mono);
463 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
468 static ssize_t dcon_freeze_store(struct device *dev,
469 struct device_attribute *attr, const char *buf, size_t count)
471 struct dcon_priv *dcon = dev_get_drvdata(dev);
472 unsigned long output;
475 ret = strict_strtoul(buf, 10, &output);
479 printk(KERN_INFO "dcon_freeze_store: %lu\n", output);
483 dcon_set_source(dcon, DCON_SOURCE_CPU);
486 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
488 case 2: /* normally unused */
489 dcon_set_source(dcon, DCON_SOURCE_DCON);
498 static ssize_t dcon_resumeline_store(struct device *dev,
499 struct device_attribute *attr, const char *buf, size_t count)
504 rc = strict_strtoul(buf, 10, &rl);
509 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
514 static ssize_t dcon_sleep_store(struct device *dev,
515 struct device_attribute *attr, const char *buf, size_t count)
517 unsigned long output;
520 ret = strict_strtoul(buf, 10, &output);
524 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
528 static struct device_attribute dcon_device_files[] = {
529 __ATTR(mode, 0444, dcon_mode_show, NULL),
530 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
531 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
532 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
533 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
536 static int dcon_bl_update(struct backlight_device *dev)
538 struct dcon_priv *dcon = bl_get_data(dev);
539 u8 level = dev->props.brightness & 0x0F;
541 if (dev->props.power != FB_BLANK_UNBLANK)
544 if (level != dcon->bl_val)
545 dcon_set_backlight(dcon, level);
550 static int dcon_bl_get(struct backlight_device *dev)
552 struct dcon_priv *dcon = bl_get_data(dev);
556 static const struct backlight_ops dcon_bl_ops = {
557 .update_status = dcon_bl_update,
558 .get_brightness = dcon_bl_get,
561 static struct backlight_properties dcon_bl_props = {
562 .max_brightness = 15,
563 .type = BACKLIGHT_RAW,
564 .power = FB_BLANK_UNBLANK,
567 static int dcon_reboot_notify(struct notifier_block *nb,
568 unsigned long foo, void *bar)
570 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
572 if (!dcon || !dcon->client)
575 /* Turn off the DCON. Entirely. */
576 dcon_write(dcon, DCON_REG_MODE, 0x39);
577 dcon_write(dcon, DCON_REG_MODE, 0x32);
581 static int unfreeze_on_panic(struct notifier_block *nb,
582 unsigned long e, void *p)
584 pdata->set_dconload(1);
588 static struct notifier_block dcon_panic_nb = {
589 .notifier_call = unfreeze_on_panic,
593 * When the framebuffer sleeps due to external sources (e.g. user idle), power
594 * down the DCON as well. Power it back up when the fb comes back to life.
596 static int dcon_fb_notifier(struct notifier_block *self,
597 unsigned long event, void *data)
599 struct fb_event *evdata = data;
600 struct dcon_priv *dcon = container_of(self, struct dcon_priv,
602 int *blank = (int *) evdata->data;
603 if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
604 dcon->ignore_fb_events)
606 dcon_sleep(dcon, *blank ? true : false);
610 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
612 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
617 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
619 struct dcon_priv *dcon;
625 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
629 dcon->client = client;
630 INIT_WORK(&dcon->switch_source, dcon_source_switch);
631 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
632 dcon->reboot_nb.priority = -1;
633 dcon->fbevent_nb.notifier_call = dcon_fb_notifier;
635 i2c_set_clientdata(client, dcon);
637 if (num_registered_fb < 1) {
638 dev_err(&client->dev, "DCON driver requires a registered fb\n");
642 dcon->fbinfo = registered_fb[0];
644 rc = dcon_hw_init(dcon, 1);
648 /* Add the DCON device */
650 dcon_device = platform_device_alloc("dcon", -1);
652 if (dcon_device == NULL) {
653 printk(KERN_ERR "dcon: Unable to create the DCON device\n");
657 rc = platform_device_add(dcon_device);
658 platform_set_drvdata(dcon_device, dcon);
661 printk(KERN_ERR "dcon: Unable to add the DCON device\n");
665 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
666 rc = device_create_file(&dcon_device->dev,
667 &dcon_device_files[i]);
669 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
674 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
676 /* Add the backlight device for the DCON */
677 dcon_bl_props.brightness = dcon->bl_val;
678 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
679 dcon, &dcon_bl_ops, &dcon_bl_props);
680 if (IS_ERR(dcon->bl_dev)) {
681 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
682 PTR_ERR(dcon->bl_dev));
686 register_reboot_notifier(&dcon->reboot_nb);
687 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
688 fb_register_client(&dcon->fbevent_nb);
693 for (j = 0; j < i; j++)
694 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
696 platform_device_unregister(dcon_device);
699 free_irq(DCON_IRQ, dcon);
705 static int dcon_remove(struct i2c_client *client)
707 struct dcon_priv *dcon = i2c_get_clientdata(client);
709 fb_unregister_client(&dcon->fbevent_nb);
710 unregister_reboot_notifier(&dcon->reboot_nb);
711 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
713 free_irq(DCON_IRQ, dcon);
716 backlight_device_unregister(dcon->bl_dev);
718 if (dcon_device != NULL)
719 platform_device_unregister(dcon_device);
720 cancel_work_sync(&dcon->switch_source);
728 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
730 struct dcon_priv *dcon = i2c_get_clientdata(client);
733 /* Set up the DCON to have the source */
734 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
740 static int dcon_resume(struct i2c_client *client)
742 struct dcon_priv *dcon = i2c_get_clientdata(client);
745 dcon_bus_stabilize(dcon, 0);
746 dcon_set_source(dcon, DCON_SOURCE_CPU);
755 irqreturn_t dcon_interrupt(int irq, void *id)
757 struct dcon_priv *dcon = id;
758 int status = pdata->read_status();
763 switch (status & 3) {
765 printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
768 case 2: /* switch to DCON mode */
769 case 1: /* switch to CPU mode */
770 dcon->switched = true;
771 getnstimeofday(&dcon->irq_time);
772 wake_up(&dcon_wait_queue);
776 /* workaround resume case: the DCON (on 1.5) doesn't
777 * ever assert status 0x01 when switching to CPU mode
778 * during resume. this is because DCONLOAD is de-asserted
779 * _immediately_ upon exiting S3, so the actual release
780 * of the DCON happened long before this point.
781 * see http://dev.laptop.org/ticket/9869
783 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
784 dcon->switched = true;
785 getnstimeofday(&dcon->irq_time);
786 wake_up(&dcon_wait_queue);
787 printk(KERN_DEBUG "olpc-dcon: switching w/ status 0/0\n");
789 printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
796 static const struct i2c_device_id dcon_idtable[] = {
801 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
803 struct i2c_driver dcon_driver = {
807 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
808 .id_table = dcon_idtable,
810 .remove = __devexit_p(dcon_remove),
811 .detect = dcon_detect,
812 .address_list = normal_i2c,
814 .suspend = dcon_suspend,
815 .resume = dcon_resume,
819 static int __init olpc_dcon_init(void)
821 #ifdef CONFIG_FB_OLPC_DCON_1_5
823 if (olpc_board_at_least(olpc_board(0xd0)))
824 pdata = &dcon_pdata_xo_1_5;
826 #ifdef CONFIG_FB_OLPC_DCON_1
828 pdata = &dcon_pdata_xo_1;
831 return i2c_add_driver(&dcon_driver);
834 static void __exit olpc_dcon_exit(void)
836 i2c_del_driver(&dcon_driver);
839 module_init(olpc_dcon_init);
840 module_exit(olpc_dcon_exit);
842 MODULE_LICENSE("GPL");