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/pci.h>
22 #include <linux/pci_ids.h>
23 #include <linux/interrupt.h>
24 #include <linux/delay.h>
25 #include <linux/module.h>
26 #include <linux/backlight.h>
27 #include <linux/device.h>
28 #include <linux/uaccess.h>
29 #include <linux/ctype.h>
30 #include <linux/reboot.h>
31 #include <linux/olpc-ec.h>
35 #include "olpc_dcon.h"
37 /* Module definitions */
39 static ushort resumeline
= 898;
40 module_param(resumeline
, ushort
, 0444);
42 static struct dcon_platform_data
*pdata
;
46 /* Platform devices */
47 static struct platform_device
*dcon_device
;
49 static unsigned short normal_i2c
[] = { 0x0d, I2C_CLIENT_END
};
51 static s32
dcon_write(struct dcon_priv
*dcon
, u8 reg
, u16 val
)
53 return i2c_smbus_write_word_data(dcon
->client
, reg
, val
);
56 static s32
dcon_read(struct dcon_priv
*dcon
, u8 reg
)
58 return i2c_smbus_read_word_data(dcon
->client
, reg
);
61 /* ===== API functions - these are called by a variety of users ==== */
63 static int dcon_hw_init(struct dcon_priv
*dcon
, int is_init
)
68 ver
= dcon_read(dcon
, DCON_REG_ID
);
69 if ((ver
>> 8) != 0xDC) {
70 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver
);
76 pr_info("Discovered DCON version %x\n", ver
& 0xFF);
77 rc
= pdata
->init(dcon
);
79 pr_err("Unable to init.\n");
85 dev_err(&dcon
->client
->dev
,
86 "DCON v1 is unsupported, giving up..\n");
91 /* SDRAM setup/hold time */
92 dcon_write(dcon
, 0x3a, 0xc040);
93 dcon_write(dcon
, DCON_REG_MEM_OPT_A
, 0x0000); /* clear option bits */
94 dcon_write(dcon
, DCON_REG_MEM_OPT_A
,
95 MEM_DLL_CLOCK_DELAY
| MEM_POWER_DOWN
);
96 dcon_write(dcon
, DCON_REG_MEM_OPT_B
, MEM_SOFT_RESET
);
98 /* Colour swizzle, AA, no passthrough, backlight */
100 dcon
->disp_mode
= MODE_PASSTHRU
| MODE_BL_ENABLE
|
101 MODE_CSWIZZLE
| MODE_COL_AA
;
103 dcon_write(dcon
, DCON_REG_MODE
, dcon
->disp_mode
);
106 /* Set the scanline to interrupt on during resume */
107 dcon_write(dcon
, DCON_REG_SCAN_INT
, resumeline
);
114 * The smbus doesn't always come back due to what is believed to be
115 * hardware (power rail) bugs. For older models where this is known to
116 * occur, our solution is to attempt to wait for the bus to stabilize;
117 * if it doesn't happen, cut power to the dcon, repower it, and wait
118 * for the bus to stabilize. Rinse, repeat until we have a working
119 * smbus. For newer models, we simply BUG(); we want to know if this
120 * still happens despite the power fixes that have been made!
122 static int dcon_bus_stabilize(struct dcon_priv
*dcon
, int is_powered_down
)
124 unsigned long timeout
;
129 if (is_powered_down
) {
131 x
= olpc_ec_cmd(EC_DCON_POWER_MODE
, &pm
, 1, NULL
, 0);
133 pr_warn("unable to force dcon to power up: %d!\n", x
);
136 usleep_range(10000, 11000); /* we'll be conservative */
139 pdata
->bus_stabilize_wiggle();
141 for (x
= -1, timeout
= 50; timeout
&& x
< 0; timeout
--) {
142 usleep_range(1000, 1100);
143 x
= dcon_read(dcon
, DCON_REG_ID
);
146 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
147 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
149 olpc_ec_cmd(EC_DCON_POWER_MODE
, &pm
, 1, NULL
, 0);
152 goto power_up
; /* argh, stupid hardware.. */
156 return dcon_hw_init(dcon
, 0);
160 static void dcon_set_backlight(struct dcon_priv
*dcon
, u8 level
)
162 dcon
->bl_val
= level
;
163 dcon_write(dcon
, DCON_REG_BRIGHT
, dcon
->bl_val
);
165 /* Purposely turn off the backlight when we go to level 0 */
166 if (dcon
->bl_val
== 0) {
167 dcon
->disp_mode
&= ~MODE_BL_ENABLE
;
168 dcon_write(dcon
, DCON_REG_MODE
, dcon
->disp_mode
);
169 } else if (!(dcon
->disp_mode
& MODE_BL_ENABLE
)) {
170 dcon
->disp_mode
|= MODE_BL_ENABLE
;
171 dcon_write(dcon
, DCON_REG_MODE
, dcon
->disp_mode
);
175 /* Set the output type to either color or mono */
176 static int dcon_set_mono_mode(struct dcon_priv
*dcon
, bool enable_mono
)
178 if (dcon
->mono
== enable_mono
)
181 dcon
->mono
= enable_mono
;
184 dcon
->disp_mode
&= ~(MODE_CSWIZZLE
| MODE_COL_AA
);
185 dcon
->disp_mode
|= MODE_MONO_LUMA
;
187 dcon
->disp_mode
&= ~(MODE_MONO_LUMA
);
188 dcon
->disp_mode
|= MODE_CSWIZZLE
| MODE_COL_AA
;
191 dcon_write(dcon
, DCON_REG_MODE
, dcon
->disp_mode
);
195 /* For now, this will be really stupid - we need to address how
196 * DCONLOAD works in a sleep and account for it accordingly
199 static void dcon_sleep(struct dcon_priv
*dcon
, bool sleep
)
203 /* Turn off the backlight and put the DCON to sleep */
205 if (dcon
->asleep
== sleep
)
208 if (!olpc_board_at_least(olpc_board(0xc2)))
214 x
= olpc_ec_cmd(EC_DCON_POWER_MODE
, &pm
, 1, NULL
, 0);
216 pr_warn("unable to force dcon to power down: %d!\n", x
);
218 dcon
->asleep
= sleep
;
220 /* Only re-enable the backlight if the backlight value is set */
221 if (dcon
->bl_val
!= 0)
222 dcon
->disp_mode
|= MODE_BL_ENABLE
;
223 x
= dcon_bus_stabilize(dcon
, 1);
225 pr_warn("unable to reinit dcon hardware: %d!\n", x
);
227 dcon
->asleep
= sleep
;
229 /* Restore backlight */
230 dcon_set_backlight(dcon
, dcon
->bl_val
);
233 /* We should turn off some stuff in the framebuffer - but what? */
236 /* the DCON seems to get confused if we change DCONLOAD too
237 * frequently -- i.e., approximately faster than frame time.
238 * normally we don't change it this fast, so in general we won't
241 static void dcon_load_holdoff(struct dcon_priv
*dcon
)
243 struct timespec delta_t
, now
;
246 getnstimeofday(&now
);
247 delta_t
= timespec_sub(now
, dcon
->load_time
);
248 if (delta_t
.tv_sec
!= 0 ||
249 delta_t
.tv_nsec
> NSEC_PER_MSEC
* 20) {
256 static bool dcon_blank_fb(struct dcon_priv
*dcon
, bool blank
)
261 if (!lock_fb_info(dcon
->fbinfo
)) {
263 dev_err(&dcon
->client
->dev
, "unable to lock framebuffer\n");
267 dcon
->ignore_fb_events
= true;
268 err
= fb_blank(dcon
->fbinfo
,
269 blank
? FB_BLANK_POWERDOWN
: FB_BLANK_UNBLANK
);
270 dcon
->ignore_fb_events
= false;
271 unlock_fb_info(dcon
->fbinfo
);
275 dev_err(&dcon
->client
->dev
, "couldn't %sblank framebuffer\n",
282 /* Set the source of the display (CPU or DCON) */
283 static void dcon_source_switch(struct work_struct
*work
)
285 struct dcon_priv
*dcon
= container_of(work
, struct dcon_priv
,
287 int source
= dcon
->pending_src
;
289 if (dcon
->curr_src
== source
)
292 dcon_load_holdoff(dcon
);
294 dcon
->switched
= false;
297 case DCON_SOURCE_CPU
:
298 pr_info("dcon_source_switch to CPU\n");
299 /* Enable the scanline interrupt bit */
300 if (dcon_write(dcon
, DCON_REG_MODE
,
301 dcon
->disp_mode
| MODE_SCAN_INT
))
302 pr_err("couldn't enable scanline interrupt!\n");
304 /* Wait up to one second for the scanline interrupt */
305 wait_event_timeout(dcon
->waitq
, dcon
->switched
, HZ
);
308 pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
310 /* Turn off the scanline interrupt */
311 if (dcon_write(dcon
, DCON_REG_MODE
, dcon
->disp_mode
))
312 pr_err("couldn't disable scanline interrupt!\n");
315 * Ideally we'd like to disable interrupts here so that the
316 * fb unblanking and DCON turn on happen at a known time value;
317 * however, we can't do that right now with fb_blank
318 * messing with semaphores.
320 * For now, we just hope..
322 if (!dcon_blank_fb(dcon
, false)) {
323 pr_err("Failed to enter CPU mode\n");
324 dcon
->pending_src
= DCON_SOURCE_DCON
;
328 /* And turn off the DCON */
329 pdata
->set_dconload(1);
330 getnstimeofday(&dcon
->load_time
);
332 pr_info("The CPU has control\n");
334 case DCON_SOURCE_DCON
:
336 struct timespec delta_t
;
338 pr_info("dcon_source_switch to DCON\n");
340 /* Clear DCONLOAD - this implies that the DCON is in control */
341 pdata
->set_dconload(0);
342 getnstimeofday(&dcon
->load_time
);
344 wait_event_timeout(dcon
->waitq
, dcon
->switched
, HZ
/2);
346 if (!dcon
->switched
) {
347 pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
349 /* sometimes the DCON doesn't follow its own rules,
350 * and doesn't wait for two vsync pulses before
351 * ack'ing the frame load with an IRQ. the result
352 * is that the display shows the *previously*
353 * loaded frame. we can detect this by looking at
354 * the time between asserting DCONLOAD and the IRQ --
355 * if it's less than 20msec, then the DCON couldn't
356 * have seen two VSYNC pulses. in that case we
357 * deassert and reassert, and hope for the best.
358 * see http://dev.laptop.org/ticket/9664
360 delta_t
= timespec_sub(dcon
->irq_time
, dcon
->load_time
);
361 if (dcon
->switched
&& delta_t
.tv_sec
== 0 &&
362 delta_t
.tv_nsec
< NSEC_PER_MSEC
* 20) {
363 pr_err("missed loading, retrying\n");
364 pdata
->set_dconload(1);
366 pdata
->set_dconload(0);
367 getnstimeofday(&dcon
->load_time
);
372 dcon_blank_fb(dcon
, true);
373 pr_info("The DCON has control\n");
380 dcon
->curr_src
= source
;
383 static void dcon_set_source(struct dcon_priv
*dcon
, int arg
)
385 if (dcon
->pending_src
== arg
)
388 dcon
->pending_src
= arg
;
390 if (dcon
->curr_src
!= arg
)
391 schedule_work(&dcon
->switch_source
);
394 static void dcon_set_source_sync(struct dcon_priv
*dcon
, int arg
)
396 dcon_set_source(dcon
, arg
);
397 flush_scheduled_work();
400 static ssize_t
dcon_mode_show(struct device
*dev
,
401 struct device_attribute
*attr
, char *buf
)
403 struct dcon_priv
*dcon
= dev_get_drvdata(dev
);
405 return sprintf(buf
, "%4.4X\n", dcon
->disp_mode
);
408 static ssize_t
dcon_sleep_show(struct device
*dev
,
409 struct device_attribute
*attr
, char *buf
)
411 struct dcon_priv
*dcon
= dev_get_drvdata(dev
);
413 return sprintf(buf
, "%d\n", dcon
->asleep
);
416 static ssize_t
dcon_freeze_show(struct device
*dev
,
417 struct device_attribute
*attr
, char *buf
)
419 struct dcon_priv
*dcon
= dev_get_drvdata(dev
);
421 return sprintf(buf
, "%d\n", dcon
->curr_src
== DCON_SOURCE_DCON
? 1 : 0);
424 static ssize_t
dcon_mono_show(struct device
*dev
,
425 struct device_attribute
*attr
, char *buf
)
427 struct dcon_priv
*dcon
= dev_get_drvdata(dev
);
429 return sprintf(buf
, "%d\n", dcon
->mono
);
432 static ssize_t
dcon_resumeline_show(struct device
*dev
,
433 struct device_attribute
*attr
, char *buf
)
435 return sprintf(buf
, "%d\n", resumeline
);
438 static ssize_t
dcon_mono_store(struct device
*dev
,
439 struct device_attribute
*attr
, const char *buf
, size_t count
)
441 unsigned long enable_mono
;
444 rc
= kstrtoul(buf
, 10, &enable_mono
);
448 dcon_set_mono_mode(dev_get_drvdata(dev
), enable_mono
? true : false);
453 static ssize_t
dcon_freeze_store(struct device
*dev
,
454 struct device_attribute
*attr
, const char *buf
, size_t count
)
456 struct dcon_priv
*dcon
= dev_get_drvdata(dev
);
457 unsigned long output
;
460 ret
= kstrtoul(buf
, 10, &output
);
464 pr_info("dcon_freeze_store: %lu\n", output
);
468 dcon_set_source(dcon
, DCON_SOURCE_CPU
);
471 dcon_set_source_sync(dcon
, DCON_SOURCE_DCON
);
473 case 2: /* normally unused */
474 dcon_set_source(dcon
, DCON_SOURCE_DCON
);
483 static ssize_t
dcon_resumeline_store(struct device
*dev
,
484 struct device_attribute
*attr
, const char *buf
, size_t count
)
489 rc
= kstrtou16(buf
, 10, &rl
);
494 dcon_write(dev_get_drvdata(dev
), DCON_REG_SCAN_INT
, resumeline
);
499 static ssize_t
dcon_sleep_store(struct device
*dev
,
500 struct device_attribute
*attr
, const char *buf
, size_t count
)
502 unsigned long output
;
505 ret
= kstrtoul(buf
, 10, &output
);
509 dcon_sleep(dev_get_drvdata(dev
), output
? true : false);
513 static struct device_attribute dcon_device_files
[] = {
514 __ATTR(mode
, 0444, dcon_mode_show
, NULL
),
515 __ATTR(sleep
, 0644, dcon_sleep_show
, dcon_sleep_store
),
516 __ATTR(freeze
, 0644, dcon_freeze_show
, dcon_freeze_store
),
517 __ATTR(monochrome
, 0644, dcon_mono_show
, dcon_mono_store
),
518 __ATTR(resumeline
, 0644, dcon_resumeline_show
, dcon_resumeline_store
),
521 static int dcon_bl_update(struct backlight_device
*dev
)
523 struct dcon_priv
*dcon
= bl_get_data(dev
);
524 u8 level
= dev
->props
.brightness
& 0x0F;
526 if (dev
->props
.power
!= FB_BLANK_UNBLANK
)
529 if (level
!= dcon
->bl_val
)
530 dcon_set_backlight(dcon
, level
);
532 /* power down the DCON when the screen is blanked */
533 if (!dcon
->ignore_fb_events
)
534 dcon_sleep(dcon
, !!(dev
->props
.state
& BL_CORE_FBBLANK
));
539 static int dcon_bl_get(struct backlight_device
*dev
)
541 struct dcon_priv
*dcon
= bl_get_data(dev
);
546 static const struct backlight_ops dcon_bl_ops
= {
547 .update_status
= dcon_bl_update
,
548 .get_brightness
= dcon_bl_get
,
551 static struct backlight_properties dcon_bl_props
= {
552 .max_brightness
= 15,
553 .type
= BACKLIGHT_RAW
,
554 .power
= FB_BLANK_UNBLANK
,
557 static int dcon_reboot_notify(struct notifier_block
*nb
,
558 unsigned long foo
, void *bar
)
560 struct dcon_priv
*dcon
= container_of(nb
, struct dcon_priv
, reboot_nb
);
562 if (!dcon
|| !dcon
->client
)
565 /* Turn off the DCON. Entirely. */
566 dcon_write(dcon
, DCON_REG_MODE
, 0x39);
567 dcon_write(dcon
, DCON_REG_MODE
, 0x32);
571 static int unfreeze_on_panic(struct notifier_block
*nb
,
572 unsigned long e
, void *p
)
574 pdata
->set_dconload(1);
578 static struct notifier_block dcon_panic_nb
= {
579 .notifier_call
= unfreeze_on_panic
,
582 static int dcon_detect(struct i2c_client
*client
, struct i2c_board_info
*info
)
584 strlcpy(info
->type
, "olpc_dcon", I2C_NAME_SIZE
);
589 static int dcon_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
591 struct dcon_priv
*dcon
;
597 dcon
= kzalloc(sizeof(*dcon
), GFP_KERNEL
);
601 dcon
->client
= client
;
602 init_waitqueue_head(&dcon
->waitq
);
603 INIT_WORK(&dcon
->switch_source
, dcon_source_switch
);
604 dcon
->reboot_nb
.notifier_call
= dcon_reboot_notify
;
605 dcon
->reboot_nb
.priority
= -1;
607 i2c_set_clientdata(client
, dcon
);
609 if (num_registered_fb
< 1) {
610 dev_err(&client
->dev
, "DCON driver requires a registered fb\n");
614 dcon
->fbinfo
= registered_fb
[0];
616 rc
= dcon_hw_init(dcon
, 1);
620 /* Add the DCON device */
622 dcon_device
= platform_device_alloc("dcon", -1);
624 if (dcon_device
== NULL
) {
625 pr_err("Unable to create the DCON device\n");
629 rc
= platform_device_add(dcon_device
);
630 platform_set_drvdata(dcon_device
, dcon
);
633 pr_err("Unable to add the DCON device\n");
637 for (i
= 0; i
< ARRAY_SIZE(dcon_device_files
); i
++) {
638 rc
= device_create_file(&dcon_device
->dev
,
639 &dcon_device_files
[i
]);
641 dev_err(&dcon_device
->dev
, "Cannot create sysfs file\n");
646 dcon
->bl_val
= dcon_read(dcon
, DCON_REG_BRIGHT
) & 0x0F;
648 /* Add the backlight device for the DCON */
649 dcon_bl_props
.brightness
= dcon
->bl_val
;
650 dcon
->bl_dev
= backlight_device_register("dcon-bl", &dcon_device
->dev
,
651 dcon
, &dcon_bl_ops
, &dcon_bl_props
);
652 if (IS_ERR(dcon
->bl_dev
)) {
653 dev_err(&client
->dev
, "cannot register backlight dev (%ld)\n",
654 PTR_ERR(dcon
->bl_dev
));
658 register_reboot_notifier(&dcon
->reboot_nb
);
659 atomic_notifier_chain_register(&panic_notifier_list
, &dcon_panic_nb
);
664 for (j
= 0; j
< i
; j
++)
665 device_remove_file(&dcon_device
->dev
, &dcon_device_files
[j
]);
667 platform_device_unregister(dcon_device
);
670 free_irq(DCON_IRQ
, dcon
);
676 static int dcon_remove(struct i2c_client
*client
)
678 struct dcon_priv
*dcon
= i2c_get_clientdata(client
);
680 unregister_reboot_notifier(&dcon
->reboot_nb
);
681 atomic_notifier_chain_unregister(&panic_notifier_list
, &dcon_panic_nb
);
683 free_irq(DCON_IRQ
, dcon
);
686 backlight_device_unregister(dcon
->bl_dev
);
688 if (dcon_device
!= NULL
)
689 platform_device_unregister(dcon_device
);
690 cancel_work_sync(&dcon
->switch_source
);
698 static int dcon_suspend(struct device
*dev
)
700 struct i2c_client
*client
= to_i2c_client(dev
);
701 struct dcon_priv
*dcon
= i2c_get_clientdata(client
);
704 /* Set up the DCON to have the source */
705 dcon_set_source_sync(dcon
, DCON_SOURCE_DCON
);
711 static int dcon_resume(struct device
*dev
)
713 struct i2c_client
*client
= to_i2c_client(dev
);
714 struct dcon_priv
*dcon
= i2c_get_clientdata(client
);
717 dcon_bus_stabilize(dcon
, 0);
718 dcon_set_source(dcon
, DCON_SOURCE_CPU
);
726 #define dcon_suspend NULL
727 #define dcon_resume NULL
729 #endif /* CONFIG_PM */
732 irqreturn_t
dcon_interrupt(int irq
, void *id
)
734 struct dcon_priv
*dcon
= id
;
737 if (pdata
->read_status(&status
))
740 switch (status
& 3) {
742 pr_debug("DCONLOAD_MISSED interrupt\n");
745 case 2: /* switch to DCON mode */
746 case 1: /* switch to CPU mode */
747 dcon
->switched
= true;
748 getnstimeofday(&dcon
->irq_time
);
749 wake_up(&dcon
->waitq
);
753 /* workaround resume case: the DCON (on 1.5) doesn't
754 * ever assert status 0x01 when switching to CPU mode
755 * during resume. this is because DCONLOAD is de-asserted
756 * _immediately_ upon exiting S3, so the actual release
757 * of the DCON happened long before this point.
758 * see http://dev.laptop.org/ticket/9869
760 if (dcon
->curr_src
!= dcon
->pending_src
&& !dcon
->switched
) {
761 dcon
->switched
= true;
762 getnstimeofday(&dcon
->irq_time
);
763 wake_up(&dcon
->waitq
);
764 pr_debug("switching w/ status 0/0\n");
766 pr_debug("scanline interrupt w/CPU\n");
773 static const struct dev_pm_ops dcon_pm_ops
= {
774 .suspend
= dcon_suspend
,
775 .resume
= dcon_resume
,
778 static const struct i2c_device_id dcon_idtable
[] = {
782 MODULE_DEVICE_TABLE(i2c
, dcon_idtable
);
784 struct i2c_driver dcon_driver
= {
789 .class = I2C_CLASS_DDC
| I2C_CLASS_HWMON
,
790 .id_table
= dcon_idtable
,
792 .remove
= dcon_remove
,
793 .detect
= dcon_detect
,
794 .address_list
= normal_i2c
,
797 static int __init
olpc_dcon_init(void)
799 #ifdef CONFIG_FB_OLPC_DCON_1_5
801 if (olpc_board_at_least(olpc_board(0xd0)))
802 pdata
= &dcon_pdata_xo_1_5
;
804 #ifdef CONFIG_FB_OLPC_DCON_1
806 pdata
= &dcon_pdata_xo_1
;
809 return i2c_add_driver(&dcon_driver
);
812 static void __exit
olpc_dcon_exit(void)
814 i2c_del_driver(&dcon_driver
);
817 module_init(olpc_dcon_init
);
818 module_exit(olpc_dcon_exit
);
820 MODULE_LICENSE("GPL");