Version:  2.0.40 2.2.26 2.4.37 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7

Linux/drivers/staging/olpc_dcon/olpc_dcon.c

  1 /*
  2  * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
  3  *
  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>
  8  *
  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.
 12  */
 13 
 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 15 
 16 #include <linux/kernel.h>
 17 #include <linux/fb.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>
 30 #include <asm/tsc.h>
 31 #include <asm/olpc.h>
 32 
 33 #include "olpc_dcon.h"
 34 
 35 /* Module definitions */
 36 
 37 static ushort resumeline = 898;
 38 module_param(resumeline, ushort, 0444);
 39 
 40 static struct dcon_platform_data *pdata;
 41 
 42 /* I2C structures */
 43 
 44 /* Platform devices */
 45 static struct platform_device *dcon_device;
 46 
 47 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
 48 
 49 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
 50 {
 51         return i2c_smbus_write_word_data(dcon->client, reg, val);
 52 }
 53 
 54 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
 55 {
 56         return i2c_smbus_read_word_data(dcon->client, reg);
 57 }
 58 
 59 /* ===== API functions - these are called by a variety of users ==== */
 60 
 61 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
 62 {
 63         u16 ver;
 64         int rc = 0;
 65 
 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);
 69                 rc = -ENXIO;
 70                 goto err;
 71         }
 72 
 73         if (is_init) {
 74                 pr_info("Discovered DCON version %x\n", ver & 0xFF);
 75                 rc = pdata->init(dcon);
 76                 if (rc != 0) {
 77                         pr_err("Unable to init.\n");
 78                         goto err;
 79                 }
 80         }
 81 
 82         if (ver < 0xdc02) {
 83                 dev_err(&dcon->client->dev,
 84                                 "DCON v1 is unsupported, giving up..\n");
 85                 rc = -ENODEV;
 86                 goto err;
 87         }
 88 
 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);
 95 
 96         /* Colour swizzle, AA, no passthrough, backlight */
 97         if (is_init) {
 98                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
 99                                 MODE_CSWIZZLE | MODE_COL_AA;
100         }
101         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
102 
103         /* Set the scanline to interrupt on during resume */
104         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
105 
106 err:
107         return rc;
108 }
109 
110 /*
111  * The smbus doesn't always come back due to what is believed to be
112  * hardware (power rail) bugs.  For older models where this is known to
113  * occur, our solution is to attempt to wait for the bus to stabilize;
114  * if it doesn't happen, cut power to the dcon, repower it, and wait
115  * for the bus to stabilize.  Rinse, repeat until we have a working
116  * smbus.  For newer models, we simply BUG(); we want to know if this
117  * still happens despite the power fixes that have been made!
118  */
119 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
120 {
121         unsigned long timeout;
122         u8 pm;
123         int x;
124 
125 power_up:
126         if (is_powered_down) {
127                 pm = 1;
128                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
129                 if (x) {
130                         pr_warn("unable to force dcon to power up: %d!\n", x);
131                         return x;
132                 }
133                 usleep_range(10000, 11000);  /* we'll be conservative */
134         }
135 
136         pdata->bus_stabilize_wiggle();
137 
138         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
139                 usleep_range(1000, 1100);
140                 x = dcon_read(dcon, DCON_REG_ID);
141         }
142         if (x < 0) {
143                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
144                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
145                 pm = 0;
146                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
147                 msleep(100);
148                 is_powered_down = 1;
149                 goto power_up;  /* argh, stupid hardware.. */
150         }
151 
152         if (is_powered_down)
153                 return dcon_hw_init(dcon, 0);
154         return 0;
155 }
156 
157 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
158 {
159         dcon->bl_val = level;
160         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
161 
162         /* Purposely turn off the backlight when we go to level 0 */
163         if (dcon->bl_val == 0) {
164                 dcon->disp_mode &= ~MODE_BL_ENABLE;
165                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
166         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
167                 dcon->disp_mode |= MODE_BL_ENABLE;
168                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
169         }
170 }
171 
172 /* Set the output type to either color or mono */
173 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
174 {
175         if (dcon->mono == enable_mono)
176                 return 0;
177 
178         dcon->mono = enable_mono;
179 
180         if (enable_mono) {
181                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
182                 dcon->disp_mode |= MODE_MONO_LUMA;
183         } else {
184                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
185                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
186         }
187 
188         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
189         return 0;
190 }
191 
192 /* For now, this will be really stupid - we need to address how
193  * DCONLOAD works in a sleep and account for it accordingly
194  */
195 
196 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
197 {
198         int x;
199 
200         /* Turn off the backlight and put the DCON to sleep */
201 
202         if (dcon->asleep == sleep)
203                 return;
204 
205         if (!olpc_board_at_least(olpc_board(0xc2)))
206                 return;
207 
208         if (sleep) {
209                 u8 pm = 0;
210 
211                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
212                 if (x)
213                         pr_warn("unable to force dcon to power down: %d!\n", x);
214                 else
215                         dcon->asleep = sleep;
216         } else {
217                 /* Only re-enable the backlight if the backlight value is set */
218                 if (dcon->bl_val != 0)
219                         dcon->disp_mode |= MODE_BL_ENABLE;
220                 x = dcon_bus_stabilize(dcon, 1);
221                 if (x)
222                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
223                 else
224                         dcon->asleep = sleep;
225 
226                 /* Restore backlight */
227                 dcon_set_backlight(dcon, dcon->bl_val);
228         }
229 
230         /* We should turn off some stuff in the framebuffer - but what? */
231 }
232 
233 /* the DCON seems to get confused if we change DCONLOAD too
234  * frequently -- i.e., approximately faster than frame time.
235  * normally we don't change it this fast, so in general we won't
236  * delay here.
237  */
238 static void dcon_load_holdoff(struct dcon_priv *dcon)
239 {
240         ktime_t delta_t, now;
241 
242         while (1) {
243                 now = ktime_get();
244                 delta_t = ktime_sub(now, dcon->load_time);
245                 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
246                         break;
247                 mdelay(4);
248         }
249 }
250 
251 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
252 {
253         int err;
254 
255         console_lock();
256         if (!lock_fb_info(dcon->fbinfo)) {
257                 console_unlock();
258                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
259                 return false;
260         }
261 
262         dcon->ignore_fb_events = true;
263         err = fb_blank(dcon->fbinfo,
264                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
265         dcon->ignore_fb_events = false;
266         unlock_fb_info(dcon->fbinfo);
267         console_unlock();
268 
269         if (err) {
270                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
271                                 blank ? "" : "un");
272                 return false;
273         }
274         return true;
275 }
276 
277 /* Set the source of the display (CPU or DCON) */
278 static void dcon_source_switch(struct work_struct *work)
279 {
280         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
281                         switch_source);
282         int source = dcon->pending_src;
283 
284         if (dcon->curr_src == source)
285                 return;
286 
287         dcon_load_holdoff(dcon);
288 
289         dcon->switched = false;
290 
291         switch (source) {
292         case DCON_SOURCE_CPU:
293                 pr_info("dcon_source_switch to CPU\n");
294                 /* Enable the scanline interrupt bit */
295                 if (dcon_write(dcon, DCON_REG_MODE,
296                                 dcon->disp_mode | MODE_SCAN_INT))
297                         pr_err("couldn't enable scanline interrupt!\n");
298                 else
299                         /* Wait up to one second for the scanline interrupt */
300                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
301 
302                 if (!dcon->switched)
303                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
304 
305                 /* Turn off the scanline interrupt */
306                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
307                         pr_err("couldn't disable scanline interrupt!\n");
308 
309                 /*
310                  * Ideally we'd like to disable interrupts here so that the
311                  * fb unblanking and DCON turn on happen at a known time value;
312                  * however, we can't do that right now with fb_blank
313                  * messing with semaphores.
314                  *
315                  * For now, we just hope..
316                  */
317                 if (!dcon_blank_fb(dcon, false)) {
318                         pr_err("Failed to enter CPU mode\n");
319                         dcon->pending_src = DCON_SOURCE_DCON;
320                         return;
321                 }
322 
323                 /* And turn off the DCON */
324                 pdata->set_dconload(1);
325                 dcon->load_time = ktime_get();
326 
327                 pr_info("The CPU has control\n");
328                 break;
329         case DCON_SOURCE_DCON:
330         {
331                 ktime_t delta_t;
332 
333                 pr_info("dcon_source_switch to DCON\n");
334 
335                 /* Clear DCONLOAD - this implies that the DCON is in control */
336                 pdata->set_dconload(0);
337                 dcon->load_time = ktime_get();
338 
339                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
340 
341                 if (!dcon->switched) {
342                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
343                 } else {
344                         /* sometimes the DCON doesn't follow its own rules,
345                          * and doesn't wait for two vsync pulses before
346                          * ack'ing the frame load with an IRQ.  the result
347                          * is that the display shows the *previously*
348                          * loaded frame.  we can detect this by looking at
349                          * the time between asserting DCONLOAD and the IRQ --
350                          * if it's less than 20msec, then the DCON couldn't
351                          * have seen two VSYNC pulses.  in that case we
352                          * deassert and reassert, and hope for the best.
353                          * see http://dev.laptop.org/ticket/9664
354                          */
355                         delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
356                         if (dcon->switched && ktime_to_ns(delta_t)
357                             < NSEC_PER_MSEC * 20) {
358                                 pr_err("missed loading, retrying\n");
359                                 pdata->set_dconload(1);
360                                 mdelay(41);
361                                 pdata->set_dconload(0);
362                                 dcon->load_time = ktime_get();
363                                 mdelay(41);
364                         }
365                 }
366 
367                 dcon_blank_fb(dcon, true);
368                 pr_info("The DCON has control\n");
369                 break;
370         }
371         default:
372                 BUG();
373         }
374 
375         dcon->curr_src = source;
376 }
377 
378 static void dcon_set_source(struct dcon_priv *dcon, int arg)
379 {
380         if (dcon->pending_src == arg)
381                 return;
382 
383         dcon->pending_src = arg;
384 
385         if (dcon->curr_src != arg)
386                 schedule_work(&dcon->switch_source);
387 }
388 
389 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
390 {
391         dcon_set_source(dcon, arg);
392         flush_scheduled_work();
393 }
394 
395 static ssize_t dcon_mode_show(struct device *dev,
396         struct device_attribute *attr, char *buf)
397 {
398         struct dcon_priv *dcon = dev_get_drvdata(dev);
399 
400         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
401 }
402 
403 static ssize_t dcon_sleep_show(struct device *dev,
404         struct device_attribute *attr, char *buf)
405 {
406         struct dcon_priv *dcon = dev_get_drvdata(dev);
407 
408         return sprintf(buf, "%d\n", dcon->asleep);
409 }
410 
411 static ssize_t dcon_freeze_show(struct device *dev,
412         struct device_attribute *attr, char *buf)
413 {
414         struct dcon_priv *dcon = dev_get_drvdata(dev);
415 
416         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
417 }
418 
419 static ssize_t dcon_mono_show(struct device *dev,
420         struct device_attribute *attr, char *buf)
421 {
422         struct dcon_priv *dcon = dev_get_drvdata(dev);
423 
424         return sprintf(buf, "%d\n", dcon->mono);
425 }
426 
427 static ssize_t dcon_resumeline_show(struct device *dev,
428         struct device_attribute *attr, char *buf)
429 {
430         return sprintf(buf, "%d\n", resumeline);
431 }
432 
433 static ssize_t dcon_mono_store(struct device *dev,
434         struct device_attribute *attr, const char *buf, size_t count)
435 {
436         unsigned long enable_mono;
437         int rc;
438 
439         rc = kstrtoul(buf, 10, &enable_mono);
440         if (rc)
441                 return rc;
442 
443         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
444 
445         return count;
446 }
447 
448 static ssize_t dcon_freeze_store(struct device *dev,
449         struct device_attribute *attr, const char *buf, size_t count)
450 {
451         struct dcon_priv *dcon = dev_get_drvdata(dev);
452         unsigned long output;
453         int ret;
454 
455         ret = kstrtoul(buf, 10, &output);
456         if (ret)
457                 return ret;
458 
459         pr_info("dcon_freeze_store: %lu\n", output);
460 
461         switch (output) {
462         case 0:
463                 dcon_set_source(dcon, DCON_SOURCE_CPU);
464                 break;
465         case 1:
466                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
467                 break;
468         case 2:  /* normally unused */
469                 dcon_set_source(dcon, DCON_SOURCE_DCON);
470                 break;
471         default:
472                 return -EINVAL;
473         }
474 
475         return count;
476 }
477 
478 static ssize_t dcon_resumeline_store(struct device *dev,
479         struct device_attribute *attr, const char *buf, size_t count)
480 {
481         unsigned short rl;
482         int rc;
483 
484         rc = kstrtou16(buf, 10, &rl);
485         if (rc)
486                 return rc;
487 
488         resumeline = rl;
489         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
490 
491         return count;
492 }
493 
494 static ssize_t dcon_sleep_store(struct device *dev,
495         struct device_attribute *attr, const char *buf, size_t count)
496 {
497         unsigned long output;
498         int ret;
499 
500         ret = kstrtoul(buf, 10, &output);
501         if (ret)
502                 return ret;
503 
504         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
505         return count;
506 }
507 
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),
514 };
515 
516 static int dcon_bl_update(struct backlight_device *dev)
517 {
518         struct dcon_priv *dcon = bl_get_data(dev);
519         u8 level = dev->props.brightness & 0x0F;
520 
521         if (dev->props.power != FB_BLANK_UNBLANK)
522                 level = 0;
523 
524         if (level != dcon->bl_val)
525                 dcon_set_backlight(dcon, level);
526 
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));
530 
531         return 0;
532 }
533 
534 static int dcon_bl_get(struct backlight_device *dev)
535 {
536         struct dcon_priv *dcon = bl_get_data(dev);
537 
538         return dcon->bl_val;
539 }
540 
541 static const struct backlight_ops dcon_bl_ops = {
542         .update_status = dcon_bl_update,
543         .get_brightness = dcon_bl_get,
544 };
545 
546 static struct backlight_properties dcon_bl_props = {
547         .max_brightness = 15,
548         .type = BACKLIGHT_RAW,
549         .power = FB_BLANK_UNBLANK,
550 };
551 
552 static int dcon_reboot_notify(struct notifier_block *nb,
553                               unsigned long foo, void *bar)
554 {
555         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
556 
557         if (!dcon || !dcon->client)
558                 return NOTIFY_DONE;
559 
560         /* Turn off the DCON. Entirely. */
561         dcon_write(dcon, DCON_REG_MODE, 0x39);
562         dcon_write(dcon, DCON_REG_MODE, 0x32);
563         return NOTIFY_DONE;
564 }
565 
566 static int unfreeze_on_panic(struct notifier_block *nb,
567                              unsigned long e, void *p)
568 {
569         pdata->set_dconload(1);
570         return NOTIFY_DONE;
571 }
572 
573 static struct notifier_block dcon_panic_nb = {
574         .notifier_call = unfreeze_on_panic,
575 };
576 
577 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
578 {
579         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
580 
581         return 0;
582 }
583 
584 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
585 {
586         struct dcon_priv *dcon;
587         int rc, i, j;
588 
589         if (!pdata)
590                 return -ENXIO;
591 
592         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
593         if (!dcon)
594                 return -ENOMEM;
595 
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;
601 
602         i2c_set_clientdata(client, dcon);
603 
604         if (num_registered_fb < 1) {
605                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
606                 rc = -EIO;
607                 goto einit;
608         }
609         dcon->fbinfo = registered_fb[0];
610 
611         rc = dcon_hw_init(dcon, 1);
612         if (rc)
613                 goto einit;
614 
615         /* Add the DCON device */
616 
617         dcon_device = platform_device_alloc("dcon", -1);
618 
619         if (!dcon_device) {
620                 pr_err("Unable to create the DCON device\n");
621                 rc = -ENOMEM;
622                 goto eirq;
623         }
624         rc = platform_device_add(dcon_device);
625         platform_set_drvdata(dcon_device, dcon);
626 
627         if (rc) {
628                 pr_err("Unable to add the DCON device\n");
629                 goto edev;
630         }
631 
632         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
633                 rc = device_create_file(&dcon_device->dev,
634                                         &dcon_device_files[i]);
635                 if (rc) {
636                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
637                         goto ecreate;
638                 }
639         }
640 
641         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
642 
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,
646                 dcon, &dcon_bl_ops, &dcon_bl_props);
647         if (IS_ERR(dcon->bl_dev)) {
648                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
649                                 PTR_ERR(dcon->bl_dev));
650                 dcon->bl_dev = NULL;
651         }
652 
653         register_reboot_notifier(&dcon->reboot_nb);
654         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
655 
656         return 0;
657 
658  ecreate:
659         for (j = 0; j < i; j++)
660                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
661  edev:
662         platform_device_unregister(dcon_device);
663         dcon_device = NULL;
664  eirq:
665         free_irq(DCON_IRQ, dcon);
666  einit:
667         kfree(dcon);
668         return rc;
669 }
670 
671 static int dcon_remove(struct i2c_client *client)
672 {
673         struct dcon_priv *dcon = i2c_get_clientdata(client);
674 
675         unregister_reboot_notifier(&dcon->reboot_nb);
676         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
677 
678         free_irq(DCON_IRQ, dcon);
679 
680         backlight_device_unregister(dcon->bl_dev);
681 
682         if (dcon_device)
683                 platform_device_unregister(dcon_device);
684         cancel_work_sync(&dcon->switch_source);
685 
686         kfree(dcon);
687 
688         return 0;
689 }
690 
691 #ifdef CONFIG_PM
692 static int dcon_suspend(struct device *dev)
693 {
694         struct i2c_client *client = to_i2c_client(dev);
695         struct dcon_priv *dcon = i2c_get_clientdata(client);
696 
697         if (!dcon->asleep) {
698                 /* Set up the DCON to have the source */
699                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
700         }
701 
702         return 0;
703 }
704 
705 static int dcon_resume(struct device *dev)
706 {
707         struct i2c_client *client = to_i2c_client(dev);
708         struct dcon_priv *dcon = i2c_get_clientdata(client);
709 
710         if (!dcon->asleep) {
711                 dcon_bus_stabilize(dcon, 0);
712                 dcon_set_source(dcon, DCON_SOURCE_CPU);
713         }
714 
715         return 0;
716 }
717 
718 #else
719 
720 #define dcon_suspend NULL
721 #define dcon_resume NULL
722 
723 #endif /* CONFIG_PM */
724 
725 irqreturn_t dcon_interrupt(int irq, void *id)
726 {
727         struct dcon_priv *dcon = id;
728         u8 status;
729 
730         if (pdata->read_status(&status))
731                 return IRQ_NONE;
732 
733         switch (status & 3) {
734         case 3:
735                 pr_debug("DCONLOAD_MISSED interrupt\n");
736                 break;
737 
738         case 2: /* switch to DCON mode */
739         case 1: /* switch to CPU mode */
740                 dcon->switched = true;
741                 dcon->irq_time = ktime_get();
742                 wake_up(&dcon->waitq);
743                 break;
744 
745         case 0:
746                 /* workaround resume case:  the DCON (on 1.5) doesn't
747                  * ever assert status 0x01 when switching to CPU mode
748                  * during resume.  this is because DCONLOAD is de-asserted
749                  * _immediately_ upon exiting S3, so the actual release
750                  * of the DCON happened long before this point.
751                  * see http://dev.laptop.org/ticket/9869
752                  */
753                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
754                         dcon->switched = true;
755                         dcon->irq_time = ktime_get();
756                         wake_up(&dcon->waitq);
757                         pr_debug("switching w/ status 0/0\n");
758                 } else {
759                         pr_debug("scanline interrupt w/CPU\n");
760                 }
761         }
762 
763         return IRQ_HANDLED;
764 }
765 
766 static const struct dev_pm_ops dcon_pm_ops = {
767         .suspend = dcon_suspend,
768         .resume = dcon_resume,
769 };
770 
771 static const struct i2c_device_id dcon_idtable[] = {
772         { "olpc_dcon",  0 },
773         { }
774 };
775 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
776 
777 static struct i2c_driver dcon_driver = {
778         .driver = {
779                 .name   = "olpc_dcon",
780                 .pm = &dcon_pm_ops,
781         },
782         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
783         .id_table = dcon_idtable,
784         .probe = dcon_probe,
785         .remove = dcon_remove,
786         .detect = dcon_detect,
787         .address_list = normal_i2c,
788 };
789 
790 static int __init olpc_dcon_init(void)
791 {
792 #ifdef CONFIG_FB_OLPC_DCON_1_5
793         /* XO-1.5 */
794         if (olpc_board_at_least(olpc_board(0xd0)))
795                 pdata = &dcon_pdata_xo_1_5;
796 #endif
797 #ifdef CONFIG_FB_OLPC_DCON_1
798         if (!pdata)
799                 pdata = &dcon_pdata_xo_1;
800 #endif
801 
802         return i2c_add_driver(&dcon_driver);
803 }
804 
805 static void __exit olpc_dcon_exit(void)
806 {
807         i2c_del_driver(&dcon_driver);
808 }
809 
810 module_init(olpc_dcon_init);
811 module_exit(olpc_dcon_exit);
812 
813 MODULE_LICENSE("GPL");
814 

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