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");