1 // SPDX-License-Identifier: GPL-2.0
3 * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
5 * Copyright © 2006-2007 Red Hat, Inc.
6 * Copyright © 2006-2007 Advanced Micro Devices, Inc.
7 * Copyright © 2009 VIA Technology, Inc.
8 * Copyright (c) 2010-2011 Andres Salomon <dilinger@queued.net>
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/kernel.h>
15 #include <linux/console.h>
16 #include <linux/i2c.h>
17 #include <linux/platform_device.h>
18 #include <linux/interrupt.h>
19 #include <linux/delay.h>
20 #include <linux/module.h>
21 #include <linux/backlight.h>
22 #include <linux/device.h>
23 #include <linux/uaccess.h>
24 #include <linux/ctype.h>
25 #include <linux/reboot.h>
26 #include <linux/olpc-ec.h>
30 #include "olpc_dcon.h"
32 /* Module definitions */
34 static ushort resumeline = 898;
35 module_param(resumeline, ushort, 0444);
37 static struct dcon_platform_data *pdata;
41 /* Platform devices */
42 static struct platform_device *dcon_device;
44 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
46 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
48 return i2c_smbus_write_word_data(dcon->client, reg, val);
51 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
53 return i2c_smbus_read_word_data(dcon->client, reg);
56 /* ===== API functions - these are called by a variety of users ==== */
58 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
63 ver = dcon_read(dcon, DCON_REG_ID);
64 if ((ver >> 8) != 0xDC) {
65 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
71 pr_info("Discovered DCON version %x\n", ver & 0xFF);
72 rc = pdata->init(dcon);
74 pr_err("Unable to init.\n");
80 dev_err(&dcon->client->dev,
81 "DCON v1 is unsupported, giving up..\n");
86 /* SDRAM setup/hold time */
87 dcon_write(dcon, 0x3a, 0xc040);
88 dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000); /* clear option bits */
89 dcon_write(dcon, DCON_REG_MEM_OPT_A,
90 MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
91 dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
93 /* Colour swizzle, AA, no passthrough, backlight */
95 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
96 MODE_CSWIZZLE | MODE_COL_AA;
98 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
100 /* Set the scanline to interrupt on during resume */
101 dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
108 * The smbus doesn't always come back due to what is believed to be
109 * hardware (power rail) bugs. For older models where this is known to
110 * occur, our solution is to attempt to wait for the bus to stabilize;
111 * if it doesn't happen, cut power to the dcon, repower it, and wait
112 * for the bus to stabilize. Rinse, repeat until we have a working
113 * smbus. For newer models, we simply BUG(); we want to know if this
114 * still happens despite the power fixes that have been made!
116 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
118 unsigned long timeout;
123 if (is_powered_down) {
125 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
127 pr_warn("unable to force dcon to power up: %d!\n", x);
130 usleep_range(10000, 11000); /* we'll be conservative */
133 pdata->bus_stabilize_wiggle();
135 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
136 usleep_range(1000, 1100);
137 x = dcon_read(dcon, DCON_REG_ID);
140 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
141 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
143 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
146 goto power_up; /* argh, stupid hardware.. */
150 return dcon_hw_init(dcon, 0);
154 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
156 dcon->bl_val = level;
157 dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
159 /* Purposely turn off the backlight when we go to level 0 */
160 if (dcon->bl_val == 0) {
161 dcon->disp_mode &= ~MODE_BL_ENABLE;
162 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
163 } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
164 dcon->disp_mode |= MODE_BL_ENABLE;
165 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
169 /* Set the output type to either color or mono */
170 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
172 if (dcon->mono == enable_mono)
175 dcon->mono = enable_mono;
178 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
179 dcon->disp_mode |= MODE_MONO_LUMA;
181 dcon->disp_mode &= ~(MODE_MONO_LUMA);
182 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
185 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
189 /* For now, this will be really stupid - we need to address how
190 * DCONLOAD works in a sleep and account for it accordingly
193 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
197 /* Turn off the backlight and put the DCON to sleep */
199 if (dcon->asleep == sleep)
202 if (!olpc_board_at_least(olpc_board(0xc2)))
208 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
210 pr_warn("unable to force dcon to power down: %d!\n", x);
212 dcon->asleep = sleep;
214 /* Only re-enable the backlight if the backlight value is set */
215 if (dcon->bl_val != 0)
216 dcon->disp_mode |= MODE_BL_ENABLE;
217 x = dcon_bus_stabilize(dcon, 1);
219 pr_warn("unable to reinit dcon hardware: %d!\n", x);
221 dcon->asleep = sleep;
223 /* Restore backlight */
224 dcon_set_backlight(dcon, dcon->bl_val);
227 /* We should turn off some stuff in the framebuffer - but what? */
230 /* the DCON seems to get confused if we change DCONLOAD too
231 * frequently -- i.e., approximately faster than frame time.
232 * normally we don't change it this fast, so in general we won't
235 static void dcon_load_holdoff(struct dcon_priv *dcon)
237 ktime_t delta_t, now;
241 delta_t = ktime_sub(now, dcon->load_time);
242 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
248 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
253 lock_fb_info(dcon->fbinfo);
255 dcon->ignore_fb_events = true;
256 err = fb_blank(dcon->fbinfo,
257 blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
258 dcon->ignore_fb_events = false;
259 unlock_fb_info(dcon->fbinfo);
263 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
270 /* Set the source of the display (CPU or DCON) */
271 static void dcon_source_switch(struct work_struct *work)
273 struct dcon_priv *dcon = container_of(work, struct dcon_priv,
275 int source = dcon->pending_src;
277 if (dcon->curr_src == source)
280 dcon_load_holdoff(dcon);
282 dcon->switched = false;
285 case DCON_SOURCE_CPU:
286 pr_info("%s to CPU\n", __func__);
287 /* Enable the scanline interrupt bit */
288 if (dcon_write(dcon, DCON_REG_MODE,
289 dcon->disp_mode | MODE_SCAN_INT))
290 pr_err("couldn't enable scanline interrupt!\n");
292 /* Wait up to one second for the scanline interrupt */
293 wait_event_timeout(dcon->waitq, dcon->switched, HZ);
296 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
298 /* Turn off the scanline interrupt */
299 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
300 pr_err("couldn't disable scanline interrupt!\n");
303 * Ideally we'd like to disable interrupts here so that the
304 * fb unblanking and DCON turn on happen at a known time value;
305 * however, we can't do that right now with fb_blank
306 * messing with semaphores.
308 * For now, we just hope..
310 if (!dcon_blank_fb(dcon, false)) {
311 pr_err("Failed to enter CPU mode\n");
312 dcon->pending_src = DCON_SOURCE_DCON;
316 /* And turn off the DCON */
317 pdata->set_dconload(1);
318 dcon->load_time = ktime_get();
320 pr_info("The CPU has control\n");
322 case DCON_SOURCE_DCON:
326 pr_info("%s to DCON\n", __func__);
328 /* Clear DCONLOAD - this implies that the DCON is in control */
329 pdata->set_dconload(0);
330 dcon->load_time = ktime_get();
332 wait_event_timeout(dcon->waitq, dcon->switched, HZ / 2);
334 if (!dcon->switched) {
335 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
337 /* sometimes the DCON doesn't follow its own rules,
338 * and doesn't wait for two vsync pulses before
339 * ack'ing the frame load with an IRQ. the result
340 * is that the display shows the *previously*
341 * loaded frame. we can detect this by looking at
342 * the time between asserting DCONLOAD and the IRQ --
343 * if it's less than 20msec, then the DCON couldn't
344 * have seen two VSYNC pulses. in that case we
345 * deassert and reassert, and hope for the best.
346 * see http://dev.laptop.org/ticket/9664
348 delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
349 if (dcon->switched && ktime_to_ns(delta_t)
350 < NSEC_PER_MSEC * 20) {
351 pr_err("missed loading, retrying\n");
352 pdata->set_dconload(1);
354 pdata->set_dconload(0);
355 dcon->load_time = ktime_get();
360 dcon_blank_fb(dcon, true);
361 pr_info("The DCON has control\n");
368 dcon->curr_src = source;
371 static void dcon_set_source(struct dcon_priv *dcon, int arg)
373 if (dcon->pending_src == arg)
376 dcon->pending_src = arg;
378 if (dcon->curr_src != arg)
379 schedule_work(&dcon->switch_source);
382 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
384 dcon_set_source(dcon, arg);
385 flush_scheduled_work();
388 static ssize_t dcon_mode_show(struct device *dev,
389 struct device_attribute *attr,
392 struct dcon_priv *dcon = dev_get_drvdata(dev);
394 return sprintf(buf, "%4.4X\n", dcon->disp_mode);
397 static ssize_t dcon_sleep_show(struct device *dev,
398 struct device_attribute *attr,
401 struct dcon_priv *dcon = dev_get_drvdata(dev);
403 return sprintf(buf, "%d\n", dcon->asleep);
406 static ssize_t dcon_freeze_show(struct device *dev,
407 struct device_attribute *attr,
410 struct dcon_priv *dcon = dev_get_drvdata(dev);
412 return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
415 static ssize_t dcon_mono_show(struct device *dev,
416 struct device_attribute *attr,
419 struct dcon_priv *dcon = dev_get_drvdata(dev);
421 return sprintf(buf, "%d\n", dcon->mono);
424 static ssize_t dcon_resumeline_show(struct device *dev,
425 struct device_attribute *attr,
428 return sprintf(buf, "%d\n", resumeline);
431 static ssize_t dcon_mono_store(struct device *dev,
432 struct device_attribute *attr,
433 const char *buf, size_t count)
435 unsigned long enable_mono;
438 rc = kstrtoul(buf, 10, &enable_mono);
442 dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
447 static ssize_t dcon_freeze_store(struct device *dev,
448 struct device_attribute *attr,
449 const char *buf, size_t count)
451 struct dcon_priv *dcon = dev_get_drvdata(dev);
452 unsigned long output;
455 ret = kstrtoul(buf, 10, &output);
461 dcon_set_source(dcon, DCON_SOURCE_CPU);
464 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
466 case 2: /* normally unused */
467 dcon_set_source(dcon, DCON_SOURCE_DCON);
476 static ssize_t dcon_resumeline_store(struct device *dev,
477 struct device_attribute *attr,
478 const char *buf, size_t count)
483 rc = kstrtou16(buf, 10, &rl);
488 dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
493 static ssize_t dcon_sleep_store(struct device *dev,
494 struct device_attribute *attr,
495 const char *buf, size_t count)
497 unsigned long output;
500 ret = kstrtoul(buf, 10, &output);
504 dcon_sleep(dev_get_drvdata(dev), output ? true : false);
508 static struct device_attribute dcon_device_files[] = {
509 __ATTR(mode, 0444, dcon_mode_show, NULL),
510 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
511 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
512 __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
513 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
516 static int dcon_bl_update(struct backlight_device *dev)
518 struct dcon_priv *dcon = bl_get_data(dev);
519 u8 level = dev->props.brightness & 0x0F;
521 if (dev->props.power != FB_BLANK_UNBLANK)
524 if (level != dcon->bl_val)
525 dcon_set_backlight(dcon, level);
527 /* power down the DCON when the screen is blanked */
528 if (!dcon->ignore_fb_events)
529 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
534 static int dcon_bl_get(struct backlight_device *dev)
536 struct dcon_priv *dcon = bl_get_data(dev);
541 static const struct backlight_ops dcon_bl_ops = {
542 .update_status = dcon_bl_update,
543 .get_brightness = dcon_bl_get,
546 static struct backlight_properties dcon_bl_props = {
547 .max_brightness = 15,
548 .type = BACKLIGHT_RAW,
549 .power = FB_BLANK_UNBLANK,
552 static int dcon_reboot_notify(struct notifier_block *nb,
553 unsigned long foo, void *bar)
555 struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
557 if (!dcon || !dcon->client)
560 /* Turn off the DCON. Entirely. */
561 dcon_write(dcon, DCON_REG_MODE, 0x39);
562 dcon_write(dcon, DCON_REG_MODE, 0x32);
566 static int unfreeze_on_panic(struct notifier_block *nb,
567 unsigned long e, void *p)
569 pdata->set_dconload(1);
573 static struct notifier_block dcon_panic_nb = {
574 .notifier_call = unfreeze_on_panic,
577 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
579 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
584 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
586 struct dcon_priv *dcon;
592 dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
596 dcon->client = client;
597 init_waitqueue_head(&dcon->waitq);
598 INIT_WORK(&dcon->switch_source, dcon_source_switch);
599 dcon->reboot_nb.notifier_call = dcon_reboot_notify;
600 dcon->reboot_nb.priority = -1;
602 i2c_set_clientdata(client, dcon);
604 if (num_registered_fb < 1) {
605 dev_err(&client->dev, "DCON driver requires a registered fb\n");
609 dcon->fbinfo = registered_fb[0];
611 rc = dcon_hw_init(dcon, 1);
615 /* Add the DCON device */
617 dcon_device = platform_device_alloc("dcon", -1);
620 pr_err("Unable to create the DCON device\n");
624 rc = platform_device_add(dcon_device);
625 platform_set_drvdata(dcon_device, dcon);
628 pr_err("Unable to add the DCON device\n");
632 for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
633 rc = device_create_file(&dcon_device->dev,
634 &dcon_device_files[i]);
636 dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
641 dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
643 /* Add the backlight device for the DCON */
644 dcon_bl_props.brightness = dcon->bl_val;
645 dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
648 if (IS_ERR(dcon->bl_dev)) {
649 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
650 PTR_ERR(dcon->bl_dev));
654 register_reboot_notifier(&dcon->reboot_nb);
655 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
660 for (j = 0; j < i; j++)
661 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
663 platform_device_unregister(dcon_device);
666 free_irq(DCON_IRQ, dcon);
672 static int dcon_remove(struct i2c_client *client)
674 struct dcon_priv *dcon = i2c_get_clientdata(client);
676 unregister_reboot_notifier(&dcon->reboot_nb);
677 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
679 free_irq(DCON_IRQ, dcon);
681 backlight_device_unregister(dcon->bl_dev);
684 platform_device_unregister(dcon_device);
685 cancel_work_sync(&dcon->switch_source);
693 static int dcon_suspend(struct device *dev)
695 struct i2c_client *client = to_i2c_client(dev);
696 struct dcon_priv *dcon = i2c_get_clientdata(client);
699 /* Set up the DCON to have the source */
700 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
706 static int dcon_resume(struct device *dev)
708 struct i2c_client *client = to_i2c_client(dev);
709 struct dcon_priv *dcon = i2c_get_clientdata(client);
712 dcon_bus_stabilize(dcon, 0);
713 dcon_set_source(dcon, DCON_SOURCE_CPU);
721 #define dcon_suspend NULL
722 #define dcon_resume NULL
724 #endif /* CONFIG_PM */
726 irqreturn_t dcon_interrupt(int irq, void *id)
728 struct dcon_priv *dcon = id;
731 if (pdata->read_status(&status))
734 switch (status & 3) {
736 pr_debug("DCONLOAD_MISSED interrupt\n");
739 case 2: /* switch to DCON mode */
740 case 1: /* switch to CPU mode */
741 dcon->switched = true;
742 dcon->irq_time = ktime_get();
743 wake_up(&dcon->waitq);
747 /* workaround resume case: the DCON (on 1.5) doesn't
748 * ever assert status 0x01 when switching to CPU mode
749 * during resume. this is because DCONLOAD is de-asserted
750 * _immediately_ upon exiting S3, so the actual release
751 * of the DCON happened long before this point.
752 * see http://dev.laptop.org/ticket/9869
754 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
755 dcon->switched = true;
756 dcon->irq_time = ktime_get();
757 wake_up(&dcon->waitq);
758 pr_debug("switching w/ status 0/0\n");
760 pr_debug("scanline interrupt w/CPU\n");
767 static const struct dev_pm_ops dcon_pm_ops = {
768 .suspend = dcon_suspend,
769 .resume = dcon_resume,
772 static const struct i2c_device_id dcon_idtable[] = {
776 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
778 static struct i2c_driver dcon_driver = {
783 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
784 .id_table = dcon_idtable,
786 .remove = dcon_remove,
787 .detect = dcon_detect,
788 .address_list = normal_i2c,
791 static int __init olpc_dcon_init(void)
794 if (olpc_board_at_least(olpc_board(0xd0)))
795 pdata = &dcon_pdata_xo_1_5;
797 pdata = &dcon_pdata_xo_1;
799 return i2c_add_driver(&dcon_driver);
802 static void __exit olpc_dcon_exit(void)
804 i2c_del_driver(&dcon_driver);
807 module_init(olpc_dcon_init);
808 module_exit(olpc_dcon_exit);
810 MODULE_LICENSE("GPL");