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 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/backlight.h>
25 #include <linux/device.h>
26 #include <linux/notifier.h>
27 #include <asm/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);
41 module_param(noinit, int, 0444);
43 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
45 module_param(useaa, int, 0444);
47 struct dcon_platform_data {
49 void (*bus_stabilize_wiggle)(void);
50 void (*set_dconload)(int);
51 u8 (*read_status)(void);
54 static struct dcon_platform_data *pdata;
58 static struct i2c_driver dcon_driver;
59 static struct i2c_client *dcon_client;
61 /* Platform devices */
62 static struct platform_device *dcon_device;
64 /* Backlight device */
65 static struct backlight_device *dcon_bl_dev;
67 static struct fb_info *fbinfo;
69 /* set this to 1 while controlling fb blank state from this driver */
70 static int ignore_fb_events = 0;
72 /* Current source, initialized at probe time */
73 static int dcon_source;
76 static int dcon_pending;
78 /* Current output type */
79 static int dcon_output = DCON_OUTPUT_COLOR;
81 /* Current sleep status (not yet implemented) */
82 static int dcon_sleep_val = DCON_ACTIVE;
84 /* Shadow register for the DCON_REG_MODE register */
85 static unsigned short dcon_disp_mode;
87 /* Variables used during switches */
88 static int dcon_switched;
89 static struct timespec dcon_irq_time;
90 static struct timespec dcon_load_time;
92 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
94 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
96 #define dcon_write(reg,val) i2c_smbus_write_word_data(dcon_client,reg,val)
97 #define dcon_read(reg) i2c_smbus_read_word_data(dcon_client,reg)
99 /* The current backlight value - this saves us some smbus traffic */
100 static int bl_val = -1;
102 /* ===== API functions - these are called by a variety of users ==== */
104 static int dcon_hw_init(struct i2c_client *client, int is_init)
109 ver = i2c_smbus_read_word_data(client, DCON_REG_ID);
110 if ((ver >> 8) != 0xDC) {
111 printk(KERN_ERR "olpc-dcon: DCON ID not 0xDCxx: 0x%04x "
118 printk(KERN_INFO "olpc-dcon: Discovered DCON version %x\n",
120 if ((rc = pdata->init()) != 0) {
121 printk(KERN_ERR "olpc-dcon: Unable to init.\n");
126 if (ver < 0xdc02 && !noinit) {
127 /* Initialize the DCON registers */
129 /* Start with work-arounds for DCON ASIC */
130 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
131 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
132 i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
133 i2c_smbus_write_word_data(client, 0x0b, 0x007a);
134 i2c_smbus_write_word_data(client, 0x36, 0x025c);
135 i2c_smbus_write_word_data(client, 0x37, 0x025e);
137 /* Initialise SDRAM */
139 i2c_smbus_write_word_data(client, 0x3b, 0x002b);
140 i2c_smbus_write_word_data(client, 0x41, 0x0101);
141 i2c_smbus_write_word_data(client, 0x42, 0x0101);
144 /* SDRAM setup/hold time */
145 i2c_smbus_write_word_data(client, 0x3a, 0xc040);
146 i2c_smbus_write_word_data(client, 0x41, 0x0000);
147 i2c_smbus_write_word_data(client, 0x41, 0x0101);
148 i2c_smbus_write_word_data(client, 0x42, 0x0101);
151 /* Colour swizzle, AA, no passthrough, backlight */
153 dcon_disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE | MODE_CSWIZZLE;
155 dcon_disp_mode |= MODE_COL_AA;
157 i2c_smbus_write_word_data(client, DCON_REG_MODE, dcon_disp_mode);
160 /* Set the scanline to interrupt on during resume */
161 i2c_smbus_write_word_data(client, DCON_REG_SCAN_INT, resumeline);
168 * The smbus doesn't always come back due to what is believed to be
169 * hardware (power rail) bugs. For older models where this is known to
170 * occur, our solution is to attempt to wait for the bus to stabilize;
171 * if it doesn't happen, cut power to the dcon, repower it, and wait
172 * for the bus to stabilize. Rinse, repeat until we have a working
173 * smbus. For newer models, we simply BUG(); we want to know if this
174 * still happens despite the power fixes that have been made!
176 static int dcon_bus_stabilize(struct i2c_client *client, int is_powered_down)
178 unsigned long timeout;
182 if (is_powered_down) {
184 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0))) {
185 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
186 "to power up: %d!\n", x);
189 msleep(10); /* we'll be conservative */
192 pdata->bus_stabilize_wiggle();
194 for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
196 x = dcon_read(DCON_REG_ID);
199 printk(KERN_ERR "olpc-dcon: unable to stabilize dcon's "
200 "smbus, reasserting power and praying.\n");
201 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
203 olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
206 goto power_up; /* argh, stupid hardware.. */
210 return dcon_hw_init(client, 0);
214 static int dcon_get_backlight(void)
216 if (dcon_client == NULL)
220 bl_val = dcon_read(DCON_REG_BRIGHT) & 0x0F;
226 static void dcon_set_backlight_hw(int level)
228 bl_val = level & 0x0F;
229 dcon_write(DCON_REG_BRIGHT, bl_val);
231 /* Purposely turn off the backlight when we go to level 0 */
233 dcon_disp_mode &= ~MODE_BL_ENABLE;
234 dcon_write(DCON_REG_MODE, dcon_disp_mode);
235 } else if (!(dcon_disp_mode & MODE_BL_ENABLE)) {
236 dcon_disp_mode |= MODE_BL_ENABLE;
237 dcon_write(DCON_REG_MODE, dcon_disp_mode);
241 static void dcon_set_backlight(int level)
243 if (dcon_client == NULL)
246 if (bl_val == (level & 0x0F))
249 dcon_set_backlight_hw(level);
252 /* Set the output type to either color or mono */
254 static int dcon_set_output(int arg)
256 if (dcon_output == arg)
261 if (arg == DCON_OUTPUT_MONO) {
262 dcon_disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
263 dcon_disp_mode |= MODE_MONO_LUMA;
266 dcon_disp_mode &= ~(MODE_MONO_LUMA);
267 dcon_disp_mode |= MODE_CSWIZZLE;
269 dcon_disp_mode |= MODE_COL_AA;
272 dcon_write(DCON_REG_MODE, dcon_disp_mode);
276 /* For now, this will be really stupid - we need to address how
277 * DCONLOAD works in a sleep and account for it accordingly
280 static void dcon_sleep(int state)
284 /* Turn off the backlight and put the DCON to sleep */
286 if (state == dcon_sleep_val)
289 if (!olpc_board_at_least(olpc_board(0xc2)))
292 if (state == DCON_SLEEP) {
294 if ((x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0)))
295 printk(KERN_WARNING "olpc-dcon: unable to force dcon "
296 "to power down: %d!\n", x);
298 dcon_sleep_val = state;
301 /* Only re-enable the backlight if the backlight value is set */
303 dcon_disp_mode |= MODE_BL_ENABLE;
305 if ((x=dcon_bus_stabilize(dcon_client, 1)))
306 printk(KERN_WARNING "olpc-dcon: unable to reinit dcon"
307 " hardware: %d!\n", x);
309 dcon_sleep_val = state;
311 /* Restore backlight */
312 dcon_set_backlight_hw(bl_val);
315 /* We should turn off some stuff in the framebuffer - but what? */
318 /* the DCON seems to get confused if we change DCONLOAD too
319 * frequently -- i.e., approximately faster than frame time.
320 * normally we don't change it this fast, so in general we won't
323 void dcon_load_holdoff(void)
325 struct timespec delta_t, now;
327 getnstimeofday(&now);
328 delta_t = timespec_sub(now, dcon_load_time);
329 if (delta_t.tv_sec != 0 ||
330 delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
336 /* Set the source of the display (CPU or DCON) */
338 static void dcon_source_switch(struct work_struct *work)
340 DECLARE_WAITQUEUE(wait, current);
341 int source = dcon_pending;
343 if (dcon_source == source)
351 case DCON_SOURCE_CPU:
352 printk("dcon_source_switch to CPU\n");
353 /* Enable the scanline interrupt bit */
354 if (dcon_write(DCON_REG_MODE, dcon_disp_mode | MODE_SCAN_INT))
355 printk(KERN_ERR "olpc-dcon: couldn't enable scanline interrupt!\n");
357 /* Wait up to one second for the scanline interrupt */
358 wait_event_timeout(dcon_wait_queue, dcon_switched == 1, HZ);
362 printk(KERN_ERR "olpc-dcon: Timeout entering CPU mode; expect a screen glitch.\n");
364 /* Turn off the scanline interrupt */
365 if (dcon_write(DCON_REG_MODE, dcon_disp_mode))
366 printk(KERN_ERR "olpc-dcon: couldn't disable scanline interrupt!\n");
369 * Ideally we'd like to disable interrupts here so that the
370 * fb unblanking and DCON turn on happen at a known time value;
371 * however, we can't do that right now with fb_blank
372 * messing with semaphores.
374 * For now, we just hope..
376 acquire_console_sem();
377 ignore_fb_events = 1;
378 if (fb_blank(fbinfo, FB_BLANK_UNBLANK)) {
379 ignore_fb_events = 0;
380 release_console_sem();
381 printk(KERN_ERR "olpc-dcon: Failed to enter CPU mode\n");
382 dcon_pending = DCON_SOURCE_DCON;
385 ignore_fb_events = 0;
386 release_console_sem();
388 /* And turn off the DCON */
389 pdata->set_dconload(1);
390 getnstimeofday(&dcon_load_time);
392 printk(KERN_INFO "olpc-dcon: The CPU has control\n");
394 case DCON_SOURCE_DCON:
397 struct timespec delta_t;
399 printk("dcon_source_switch to DCON\n");
401 add_wait_queue(&dcon_wait_queue, &wait);
402 set_current_state(TASK_UNINTERRUPTIBLE);
404 /* Clear DCONLOAD - this implies that the DCON is in control */
405 pdata->set_dconload(0);
406 getnstimeofday(&dcon_load_time);
408 t = schedule_timeout(HZ/2);
409 remove_wait_queue(&dcon_wait_queue, &wait);
410 set_current_state(TASK_RUNNING);
412 if (!dcon_switched) {
413 printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
415 /* sometimes the DCON doesn't follow its own rules,
416 * and doesn't wait for two vsync pulses before
417 * ack'ing the frame load with an IRQ. the result
418 * is that the display shows the *previously*
419 * loaded frame. we can detect this by looking at
420 * the time between asserting DCONLOAD and the IRQ --
421 * if it's less than 20msec, then the DCON couldn't
422 * have seen two VSYNC pulses. in that case we
423 * deassert and reassert, and hope for the best.
424 * see http://dev.laptop.org/ticket/9664
426 delta_t = timespec_sub(dcon_irq_time, dcon_load_time);
427 if (dcon_switched && delta_t.tv_sec == 0 &&
428 delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
429 printk(KERN_ERR "olpc-dcon: missed loading, retrying\n");
430 pdata->set_dconload(1);
432 pdata->set_dconload(0);
433 getnstimeofday(&dcon_load_time);
438 acquire_console_sem();
439 ignore_fb_events = 1;
440 if (fb_blank(fbinfo, FB_BLANK_POWERDOWN))
441 printk(KERN_ERR "olpc-dcon: couldn't blank fb!\n");
442 ignore_fb_events = 0;
443 release_console_sem();
445 printk(KERN_INFO "olpc-dcon: The DCON has control\n");
452 dcon_source = source;
455 static DECLARE_WORK(dcon_work, dcon_source_switch);
457 static void dcon_set_source(int arg)
459 if (dcon_pending == arg)
464 if ((dcon_source != arg) && !work_pending(&dcon_work))
465 schedule_work(&dcon_work);
468 static void dcon_set_source_sync(int arg)
470 dcon_set_source(arg);
471 flush_scheduled_work();
474 static int dconbl_set(struct backlight_device *dev) {
476 int level = dev->props.brightness;
478 if (dev->props.power != FB_BLANK_UNBLANK)
481 dcon_set_backlight(level);
485 static int dconbl_get(struct backlight_device *dev) {
486 return dcon_get_backlight();
489 static ssize_t dcon_mode_show(struct device *dev,
490 struct device_attribute *attr, char *buf)
492 return sprintf(buf, "%4.4X\n", dcon_disp_mode);
495 static ssize_t dcon_sleep_show(struct device *dev,
496 struct device_attribute *attr, char *buf)
499 return sprintf(buf, "%d\n", dcon_sleep_val);
502 static ssize_t dcon_freeze_show(struct device *dev,
503 struct device_attribute *attr, char *buf)
505 return sprintf(buf, "%d\n", dcon_source == DCON_SOURCE_DCON ? 1 : 0);
508 static ssize_t dcon_output_show(struct device *dev,
509 struct device_attribute *attr, char *buf)
511 return sprintf(buf, "%d\n", dcon_output);
514 static ssize_t dcon_resumeline_show(struct device *dev,
515 struct device_attribute *attr, char *buf)
517 return sprintf(buf, "%d\n", resumeline);
520 static int _strtoul(const char *buf, int len, unsigned int *val)
524 unsigned int output = simple_strtoul(buf, &endp, 0);
525 int size = endp - buf;
527 if (*endp && isspace(*endp))
537 static ssize_t dcon_output_store(struct device *dev,
538 struct device_attribute *attr, const char *buf, size_t count)
543 if (_strtoul(buf, count, &output))
546 if (output == DCON_OUTPUT_COLOR || output == DCON_OUTPUT_MONO) {
547 dcon_set_output(output);
554 static ssize_t dcon_freeze_store(struct device *dev,
555 struct device_attribute *attr, const char *buf, size_t count)
559 if (_strtoul(buf, count, &output))
562 printk("dcon_freeze_store: %d\n", output);
566 dcon_set_source(DCON_SOURCE_CPU);
569 dcon_set_source_sync(DCON_SOURCE_DCON);
571 case 2: // normally unused
572 dcon_set_source(DCON_SOURCE_DCON);
581 static ssize_t dcon_resumeline_store(struct device *dev,
582 struct device_attribute *attr, const char *buf, size_t count)
587 if (_strtoul(buf, count, &rl))
591 dcon_write(DCON_REG_SCAN_INT, resumeline);
597 static ssize_t dcon_sleep_store(struct device *dev,
598 struct device_attribute *attr, const char *buf, size_t count)
602 if (_strtoul(buf, count, &output))
605 dcon_sleep(output ? DCON_SLEEP : DCON_ACTIVE);
609 static struct device_attribute dcon_device_files[] = {
610 __ATTR(mode, 0444, dcon_mode_show, NULL),
611 __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
612 __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
613 __ATTR(output, 0644, dcon_output_show, dcon_output_store),
614 __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
617 static const struct backlight_ops dcon_bl_ops = {
618 .get_brightness = dconbl_get,
619 .update_status = dconbl_set
623 static int dcon_reboot_notify(struct notifier_block *nb, unsigned long foo, void *bar)
625 if (dcon_client == NULL)
628 /* Turn off the DCON. Entirely. */
629 dcon_write(DCON_REG_MODE, 0x39);
630 dcon_write(DCON_REG_MODE, 0x32);
634 static struct notifier_block dcon_nb = {
635 .notifier_call = dcon_reboot_notify,
639 static int unfreeze_on_panic(struct notifier_block *nb, unsigned long e, void *p)
641 pdata->set_dconload(1);
645 static struct notifier_block dcon_panic_nb = {
646 .notifier_call = unfreeze_on_panic,
650 * When the framebuffer sleeps due to external sources (e.g. user idle), power
651 * down the DCON as well. Power it back up when the fb comes back to life.
653 static int fb_notifier_callback(struct notifier_block *self, unsigned long event, void *data)
655 struct fb_event *evdata = data;
656 int *blank = (int *) evdata->data;
657 if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
660 dcon_sleep((*blank) ? DCON_SLEEP : DCON_ACTIVE);
664 static struct notifier_block fb_nb = {
665 .notifier_call = fb_notifier_callback,
668 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
670 strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
675 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
679 if (num_registered_fb >= 1)
680 fbinfo = registered_fb[0];
682 rc = dcon_hw_init(client, 1);
686 /* Add the DCON device */
688 dcon_device = platform_device_alloc("dcon", -1);
690 if (dcon_device == NULL) {
691 printk("dcon: Unable to create the DCON device\n");
696 i2c_set_clientdata(client, dcon_device);
698 if ((rc = platform_device_add(dcon_device))) {
699 printk("dcon: Unable to add the DCON device\n");
703 for(i = 0; i < ARRAY_SIZE(dcon_device_files); i++)
704 device_create_file(&dcon_device->dev, &dcon_device_files[i]);
706 /* Add the backlight device for the DCON */
708 dcon_client = client;
710 dcon_bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
711 NULL, &dcon_bl_ops, NULL);
713 if (IS_ERR(dcon_bl_dev)) {
714 printk("Could not register the backlight device for the DCON (%ld)\n", PTR_ERR(dcon_bl_dev));
718 dcon_bl_dev->props.max_brightness = 15;
719 dcon_bl_dev->props.power = FB_BLANK_UNBLANK;
720 dcon_bl_dev->props.brightness = dcon_get_backlight();
722 backlight_update_status(dcon_bl_dev);
725 register_reboot_notifier(&dcon_nb);
726 atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
727 fb_register_client(&fb_nb);
732 platform_device_unregister(dcon_device);
735 free_irq(DCON_IRQ, &dcon_driver);
740 static int dcon_remove(struct i2c_client *client)
744 fb_unregister_client(&fb_nb);
745 unregister_reboot_notifier(&dcon_nb);
746 atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
748 free_irq(DCON_IRQ, &dcon_driver);
750 if (dcon_bl_dev != NULL)
751 backlight_device_unregister(dcon_bl_dev);
753 if (dcon_device != NULL)
754 platform_device_unregister(dcon_device);
755 cancel_work_sync(&dcon_work);
761 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
763 if (dcon_sleep_val == DCON_ACTIVE) {
764 /* Set up the DCON to have the source */
765 dcon_set_source_sync(DCON_SOURCE_DCON);
771 static int dcon_resume(struct i2c_client *client)
773 if (dcon_sleep_val == DCON_ACTIVE) {
774 dcon_bus_stabilize(client, 0);
775 dcon_set_source(DCON_SOURCE_CPU);
784 static irqreturn_t dcon_interrupt(int irq, void *id)
786 int status = pdata->read_status();
791 switch (status & 3) {
793 printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
796 case 2: /* switch to DCON mode */
797 case 1: /* switch to CPU mode */
799 getnstimeofday(&dcon_irq_time);
800 wake_up(&dcon_wait_queue);
804 /* workaround resume case: the DCON (on 1.5) doesn't
805 * ever assert status 0x01 when switching to CPU mode
806 * during resume. this is because DCONLOAD is de-asserted
807 * _immediately_ upon exiting S3, so the actual release
808 * of the DCON happened long before this point.
809 * see http://dev.laptop.org/ticket/9869
811 if (dcon_source != dcon_pending && !dcon_switched) {
813 getnstimeofday(&dcon_irq_time);
814 wake_up(&dcon_wait_queue);
815 printk(KERN_DEBUG "olpc-dcon: switching w/ status 0/0\n");
817 printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
824 static struct i2c_device_id dcon_idtable[] = {
829 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
831 static struct i2c_driver dcon_driver = {
835 .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
836 .id_table = dcon_idtable,
838 .remove = __devexit_p(dcon_remove),
839 .detect = dcon_detect,
840 .address_list = normal_i2c,
842 .suspend = dcon_suspend,
843 .resume = dcon_resume,
847 #include "olpc_dcon_xo_1.c"
849 static int __init olpc_dcon_init(void)
851 pdata = &dcon_pdata_xo_1;
853 i2c_add_driver(&dcon_driver);
857 static void __exit olpc_dcon_exit(void)
859 i2c_del_driver(&dcon_driver);
862 module_init(olpc_dcon_init);
863 module_exit(olpc_dcon_exit);
865 MODULE_LICENSE("GPL");