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.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/kernel.h>
18 #include <linux/console.h>
19 #include <linux/i2c.h>
20 #include <linux/platform_device.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/module.h>
24 #include <linux/backlight.h>
25 #include <linux/device.h>
26 #include <linux/uaccess.h>
27 #include <linux/ctype.h>
28 #include <linux/reboot.h>
29 #include <linux/olpc-ec.h>
33 #include "olpc_dcon.h"
35 /* Module definitions */
37 static ushort resumeline = 898;
38 module_param(resumeline, ushort, 0444);
40 static struct dcon_platform_data *pdata;
44 /* Platform devices */
45 static struct platform_device *dcon_device;
47 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
49 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
51 return i2c_smbus_write_word_data(dcon->client, reg, val);
54 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
56 return i2c_smbus_read_word_data(dcon->client, reg);
59 /* ===== API functions - these are called by a variety of users ==== */
61 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
66 ver = dcon_read(dcon, DCON_REG_ID);
67 if ((ver >> 8) != 0xDC) {
68 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
74 pr_info("Discovered DCON version %x\n", ver & 0xFF);
75 rc = pdata->init(dcon);
77 pr_err("Unable to init.\n");
83 dev_err(&dcon->client->dev,
84 "DCON v1 is unsupported, giving up..\n");
89 /* SDRAM setup/hold time */
90 dcon_write(dcon, 0x3a, 0xc040);
91 dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000); /* clear option bits */
92 dcon_write(dcon, DCON_REG_MEM_OPT_A,
93 MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
94 dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
96 /* Colour swizzle, AA, no passthrough, backlight */
98 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
99 MODE_CSWIZZLE | MODE_COL_AA;
101 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
104 /* Set the scanline to interrupt on during resume */
105 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
112 * The smbus doesn't always come back due to what is believed to be
113 * hardware (power rail) bugs. For older models where this is known to
114 * occur, our solution is to attempt to wait for the bus to stabilize;
115 * if it doesn't happen, cut power to the dcon, repower it, and wait
116 * for the bus to stabilize. Rinse, repeat until we have a working
117 * smbus. For newer models, we simply BUG(); we want to know if this
118 * still happens despite the power fixes that have been made!
120 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
122 unsigned long timeout;
127 if (is_powered_down) {
129 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
131 pr_warn("unable to force dcon to power up: %d!\n", x);
134 usleep_range(10000, 11000); /* we'll be conservative */
137 pdata->bus_stabilize_wiggle();
139 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
140 usleep_range(1000, 1100);
141 x = dcon_read(dcon, DCON_REG_ID);
144 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
145 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
147 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
150 goto power_up; /* argh, stupid hardware.. */
154 return dcon_hw_init(dcon, 0);
158 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
160 dcon->bl_val = level;
161 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
163 /* Purposely turn off the backlight when we go to level 0 */
164 if (dcon->bl_val == 0) {
165 dcon->disp_mode &= ~MODE_BL_ENABLE;
166 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
167 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
168 dcon->disp_mode |= MODE_BL_ENABLE;
169 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
173 /* Set the output type to either color or mono */
174 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
176 if (dcon->mono == enable_mono)
179 dcon->mono = enable_mono;
182 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
183 dcon->disp_mode |= MODE_MONO_LUMA;
185 dcon->disp_mode &= ~(MODE_MONO_LUMA);
186 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
189 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
193 /* For now, this will be really stupid - we need to address how
194 * DCONLOAD works in a sleep and account for it accordingly
197 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
201 /* Turn off the backlight and put the DCON to sleep */
203 if (dcon->asleep == sleep)
206 if (!olpc_board_at_least(olpc_board(0xc2)))
212 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
214 pr_warn("unable to force dcon to power down: %d!\n", x);
216 dcon->asleep = sleep;
218 /* Only re-enable the backlight if the backlight value is set */
219 if (dcon->bl_val != 0)
220 dcon->disp_mode |= MODE_BL_ENABLE;
221 x = dcon_bus_stabilize(dcon, 1);
223 pr_warn("unable to reinit dcon hardware: %d!\n", x);
225 dcon->asleep = sleep;
227 /* Restore backlight */
228 dcon_set_backlight(dcon, dcon->bl_val);
231 /* We should turn off some stuff in the framebuffer - but what? */
234 /* the DCON seems to get confused if we change DCONLOAD too
235 * frequently -- i.e., approximately faster than frame time.
236 * normally we don't change it this fast, so in general we won't
239 static void dcon_load_holdoff(struct dcon_priv *dcon)
241 struct timespec delta_t, now;
244 getnstimeofday(&now);
245 delta_t = timespec_sub(now, dcon->load_time);
246 if (delta_t.tv_sec != 0 ||
247 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
254 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
259 if (!lock_fb_info(dcon->fbinfo)) {
261 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
265 dcon->ignore_fb_events = true;
266 err = fb_blank(dcon->fbinfo,
267 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
268 dcon->ignore_fb_events = false;
269 unlock_fb_info(dcon->fbinfo);
273 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
280 /* Set the source of the display (CPU or DCON) */
281 static void dcon_source_switch(struct work_struct *work)
283 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
285 int source = dcon->pending_src;
287 if (dcon->curr_src == source)
290 dcon_load_holdoff(dcon);
292 dcon->switched = false;
295 case DCON_SOURCE_CPU:
296 pr_info("dcon_source_switch to CPU\n");
297 /* Enable the scanline interrupt bit */
298 if (dcon_write(dcon, DCON_REG_MODE,
299 dcon->disp_mode | MODE_SCAN_INT))
300 pr_err("couldn't enable scanline interrupt!\n");
302 /* Wait up to one second for the scanline interrupt */
303 wait_event_timeout(dcon->waitq, dcon->switched, HZ);
306 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
308 /* Turn off the scanline interrupt */
309 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
310 pr_err("couldn't disable scanline interrupt!\n");
313 * Ideally we'd like to disable interrupts here so that the
314 * fb unblanking and DCON turn on happen at a known time value;
315 * however, we can't do that right now with fb_blank
316 * messing with semaphores.
318 * For now, we just hope..
320 if (!dcon_blank_fb(dcon, false)) {
321 pr_err("Failed to enter CPU mode\n");
322 dcon->pending_src = DCON_SOURCE_DCON;
326 /* And turn off the DCON */
327 pdata->set_dconload(1);
328 getnstimeofday(&dcon->load_time);
330 pr_info("The CPU has control\n");
332 case DCON_SOURCE_DCON:
334 struct timespec delta_t;
336 pr_info("dcon_source_switch to DCON\n");
338 /* Clear DCONLOAD - this implies that the DCON is in control */
339 pdata->set_dconload(0);
340 getnstimeofday(&dcon->load_time);
342 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
344 if (!dcon->switched) {
345 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
347 /* sometimes the DCON doesn't follow its own rules,
348 * and doesn't wait for two vsync pulses before
349 * ack'ing the frame load with an IRQ. the result
350 * is that the display shows the *previously*
351 * loaded frame. we can detect this by looking at
352 * the time between asserting DCONLOAD and the IRQ --
353 * if it's less than 20msec, then the DCON couldn't
354 * have seen two VSYNC pulses. in that case we
355 * deassert and reassert, and hope for the best.
356 * see http://dev.laptop.org/ticket/9664
358 delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
359 if (dcon->switched && delta_t.tv_sec == 0 &&
360 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
361 pr_err("missed loading, retrying\n");
362 pdata->set_dconload(1);
364 pdata->set_dconload(0);
365 getnstimeofday(&dcon->load_time);
370 dcon_blank_fb(dcon, true);
371 pr_info("The DCON has control\n");
378 dcon->curr_src = source;
381 static void dcon_set_source(struct dcon_priv *dcon, int arg)
383 if (dcon->pending_src == arg)
386 dcon->pending_src = arg;
388 if (dcon->curr_src != arg)
389 schedule_work(&dcon->switch_source);
392 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
394 dcon_set_source(dcon, arg);
395 flush_scheduled_work();
398 static ssize_t dcon_mode_show(struct device *dev,
399 struct device_attribute *attr, char *buf)
401 struct dcon_priv *dcon = dev_get_drvdata(dev);
403 return sprintf(buf, "%4.4X\n", dcon->disp_mode);
406 static ssize_t dcon_sleep_show(struct device *dev,
407 struct device_attribute *attr, char *buf)
409 struct dcon_priv *dcon = dev_get_drvdata(dev);
411 return sprintf(buf, "%d\n", dcon->asleep);
414 static ssize_t dcon_freeze_show(struct device *dev,
415 struct device_attribute *attr, char *buf)
417 struct dcon_priv *dcon = dev_get_drvdata(dev);
419 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
422 static ssize_t dcon_mono_show(struct device *dev,
423 struct device_attribute *attr, char *buf)
425 struct dcon_priv *dcon = dev_get_drvdata(dev);
427 return sprintf(buf, "%d\n", dcon->mono);
430 static ssize_t dcon_resumeline_show(struct device *dev,
431 struct device_attribute *attr, char *buf)
433 return sprintf(buf, "%d\n", resumeline);
436 static ssize_t dcon_mono_store(struct device *dev,
437 struct device_attribute *attr, const char *buf, size_t count)
439 unsigned long enable_mono;
442 rc = kstrtoul(buf, 10, &enable_mono);
446 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
451 static ssize_t dcon_freeze_store(struct device *dev,
452 struct device_attribute *attr, const char *buf, size_t count)
454 struct dcon_priv *dcon = dev_get_drvdata(dev);
455 unsigned long output;
458 ret = kstrtoul(buf, 10, &output);
462 pr_info("dcon_freeze_store: %lu\n", output);
466 dcon_set_source(dcon, DCON_SOURCE_CPU);
469 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
471 case 2: /* normally unused */
472 dcon_set_source(dcon, DCON_SOURCE_DCON);
481 static ssize_t dcon_resumeline_store(struct device *dev,
482 struct device_attribute *attr, const char *buf, size_t count)
487 rc = kstrtou16(buf, 10, &rl);
492 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
497 static ssize_t dcon_sleep_store(struct device *dev,
498 struct device_attribute *attr, const char *buf, size_t count)
500 unsigned long output;
503 ret = kstrtoul(buf, 10, &output);
507 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
511 static struct device_attribute dcon_device_files[] = {
512 __ATTR(mode, 0444, dcon_mode_show, NULL),
513 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
514 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
515 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
516 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
519 static int dcon_bl_update(struct backlight_device *dev)
521 struct dcon_priv *dcon = bl_get_data(dev);
522 u8 level = dev->props.brightness & 0x0F;
524 if (dev->props.power != FB_BLANK_UNBLANK)
527 if (level != dcon->bl_val)
528 dcon_set_backlight(dcon, level);
530 /* power down the DCON when the screen is blanked */
531 if (!dcon->ignore_fb_events)
532 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
537 static int dcon_bl_get(struct backlight_device *dev)
539 struct dcon_priv *dcon = bl_get_data(dev);
544 static const struct backlight_ops dcon_bl_ops = {
545 .update_status = dcon_bl_update,
546 .get_brightness = dcon_bl_get,
549 static struct backlight_properties dcon_bl_props = {
550 .max_brightness = 15,
551 .type = BACKLIGHT_RAW,
552 .power = FB_BLANK_UNBLANK,
555 static int dcon_reboot_notify(struct notifier_block *nb,
556 unsigned long foo, void *bar)
558 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
560 if (!dcon || !dcon->client)
563 /* Turn off the DCON. Entirely. */
564 dcon_write(dcon, DCON_REG_MODE, 0x39);
565 dcon_write(dcon, DCON_REG_MODE, 0x32);
569 static int unfreeze_on_panic(struct notifier_block *nb,
570 unsigned long e, void *p)
572 pdata->set_dconload(1);
576 static struct notifier_block dcon_panic_nb = {
577 .notifier_call = unfreeze_on_panic,
580 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
582 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
587 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
589 struct dcon_priv *dcon;
595 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
599 dcon->client = client;
600 init_waitqueue_head(&dcon->waitq);
601 INIT_WORK(&dcon->switch_source, dcon_source_switch);
602 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
603 dcon->reboot_nb.priority = -1;
605 i2c_set_clientdata(client, dcon);
607 if (num_registered_fb < 1) {
608 dev_err(&client->dev, "DCON driver requires a registered fb\n");
612 dcon->fbinfo = registered_fb[0];
614 rc = dcon_hw_init(dcon, 1);
618 /* Add the DCON device */
620 dcon_device = platform_device_alloc("dcon", -1);
622 if (dcon_device == NULL) {
623 pr_err("Unable to create the DCON device\n");
627 rc = platform_device_add(dcon_device);
628 platform_set_drvdata(dcon_device, dcon);
631 pr_err("Unable to add the DCON device\n");
635 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
636 rc = device_create_file(&dcon_device->dev,
637 &dcon_device_files[i]);
639 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
644 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
646 /* Add the backlight device for the DCON */
647 dcon_bl_props.brightness = dcon->bl_val;
648 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
649 dcon, &dcon_bl_ops, &dcon_bl_props);
650 if (IS_ERR(dcon->bl_dev)) {
651 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
652 PTR_ERR(dcon->bl_dev));
656 register_reboot_notifier(&dcon->reboot_nb);
657 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
662 for (j = 0; j < i; j++)
663 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
665 platform_device_unregister(dcon_device);
668 free_irq(DCON_IRQ, dcon);
674 static int dcon_remove(struct i2c_client *client)
676 struct dcon_priv *dcon = i2c_get_clientdata(client);
678 unregister_reboot_notifier(&dcon->reboot_nb);
679 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
681 free_irq(DCON_IRQ, dcon);
683 backlight_device_unregister(dcon->bl_dev);
685 if (dcon_device != NULL)
686 platform_device_unregister(dcon_device);
687 cancel_work_sync(&dcon->switch_source);
695 static int dcon_suspend(struct device *dev)
697 struct i2c_client *client = to_i2c_client(dev);
698 struct dcon_priv *dcon = i2c_get_clientdata(client);
701 /* Set up the DCON to have the source */
702 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
708 static int dcon_resume(struct device *dev)
710 struct i2c_client *client = to_i2c_client(dev);
711 struct dcon_priv *dcon = i2c_get_clientdata(client);
714 dcon_bus_stabilize(dcon, 0);
715 dcon_set_source(dcon, DCON_SOURCE_CPU);
723 #define dcon_suspend NULL
724 #define dcon_resume NULL
726 #endif /* CONFIG_PM */
729 irqreturn_t dcon_interrupt(int irq, void *id)
731 struct dcon_priv *dcon = id;
734 if (pdata->read_status(&status))
737 switch (status & 3) {
739 pr_debug("DCONLOAD_MISSED interrupt\n");
742 case 2: /* switch to DCON mode */
743 case 1: /* switch to CPU mode */
744 dcon->switched = true;
745 getnstimeofday(&dcon->irq_time);
746 wake_up(&dcon->waitq);
750 /* workaround resume case: the DCON (on 1.5) doesn't
751 * ever assert status 0x01 when switching to CPU mode
752 * during resume. this is because DCONLOAD is de-asserted
753 * _immediately_ upon exiting S3, so the actual release
754 * of the DCON happened long before this point.
755 * see http://dev.laptop.org/ticket/9869
757 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
758 dcon->switched = true;
759 getnstimeofday(&dcon->irq_time);
760 wake_up(&dcon->waitq);
761 pr_debug("switching w/ status 0/0\n");
763 pr_debug("scanline interrupt w/CPU\n");
770 static const struct dev_pm_ops dcon_pm_ops = {
771 .suspend = dcon_suspend,
772 .resume = dcon_resume,
775 static const struct i2c_device_id dcon_idtable[] = {
779 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
781 static struct i2c_driver dcon_driver = {
786 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
787 .id_table = dcon_idtable,
789 .remove = dcon_remove,
790 .detect = dcon_detect,
791 .address_list = normal_i2c,
794 static int __init olpc_dcon_init(void)
796 #ifdef CONFIG_FB_OLPC_DCON_1_5
798 if (olpc_board_at_least(olpc_board(0xd0)))
799 pdata = &dcon_pdata_xo_1_5;
801 #ifdef CONFIG_FB_OLPC_DCON_1
803 pdata = &dcon_pdata_xo_1;
806 return i2c_add_driver(&dcon_driver);
809 static void __exit olpc_dcon_exit(void)
811 i2c_del_driver(&dcon_driver);
814 module_init(olpc_dcon_init);
815 module_exit(olpc_dcon_exit);
817 MODULE_LICENSE("GPL");