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/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>
  32 #include <asm/tsc.h>
  33 #include <asm/olpc.h>
  34
  35 #include "olpc_dcon.h"
  36
  37 /* Module definitions */
  38
  39 static ushort resumeline = 898;
  40 module_param(resumeline, ushort, 0444);
  41
  42 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
  43 static int useaa = 1;
  44 module_param(useaa, int, 0444);
  45
  46 static struct dcon_platform_data *pdata;
  47
  48 /* I2C structures */
  49
  50 /* Platform devices */
  51 static struct platform_device *dcon_device;
  52
  53 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
  54
  55 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
  56
  57 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
  58 {
  59         return i2c_smbus_write_word_data(dcon->client, reg, val);
  60 }
  61
  62 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
  63 {
  64         return i2c_smbus_read_word_data(dcon->client, reg);
  65 }
  66
  67 /* ===== API functions - these are called by a variety of users ==== */
  68
  69 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
  70 {
  71         uint16_t ver;
  72         int rc = 0;
  73
  74         ver = dcon_read(dcon, DCON_REG_ID);
  75         if ((ver >> 8) != 0xDC) {
  76                 pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
  77                 rc = -ENXIO;
  78                 goto err;
  79         }
  80
  81         if (is_init) {
  82                 pr_info("Discovered DCON version %x\n", ver & 0xFF);
  83                 rc = pdata->init(dcon);
  84                 if (rc != 0) {
  85                         pr_err("Unable to init.\n");
  86                         goto err;
  87                 }
  88         }
  89
  90         if (ver < 0xdc02) {
  91                 dev_err(&dcon->client->dev,
  92                                 "DCON v1 is unsupported, giving up..\n");
  93                 rc = -ENODEV;
  94                 goto err;
  95         }
  96
  97         /* SDRAM setup/hold time */
  98         dcon_write(dcon, 0x3a, 0xc040);
  99         dcon_write(dcon, 0x41, 0x0000);
 100         dcon_write(dcon, 0x41, 0x0101);
 101         dcon_write(dcon, 0x42, 0x0101);
 102
 103         /* Colour swizzle, AA, no passthrough, backlight */
 104         if (is_init) {
 105                 dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
 106                                 MODE_CSWIZZLE;
 107                 if (useaa)
 108                         dcon->disp_mode |= MODE_COL_AA;
 109         }
 110         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 111
 112
 113         /* Set the scanline to interrupt on during resume */
 114         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
 115
 116 err:
 117         return rc;
 118 }
 119
 120 /*
 121  * The smbus doesn't always come back due to what is believed to be
 122  * hardware (power rail) bugs.  For older models where this is known to
 123  * occur, our solution is to attempt to wait for the bus to stabilize;
 124  * if it doesn't happen, cut power to the dcon, repower it, and wait
 125  * for the bus to stabilize.  Rinse, repeat until we have a working
 126  * smbus.  For newer models, we simply BUG(); we want to know if this
 127  * still happens despite the power fixes that have been made!
 128  */
 129 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 130 {
 131         unsigned long timeout;
 132         int x;
 133
 134 power_up:
 135         if (is_powered_down) {
 136                 x = 1;
 137                 x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
 138                 if (x) {
 139                         pr_warn("unable to force dcon to power up: %d!\n", x);
 140                         return x;
 141                 }
 142                 msleep(10); /* we'll be conservative */
 143         }
 144
 145         pdata->bus_stabilize_wiggle();
 146
 147         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 148                 msleep(1);
 149                 x = dcon_read(dcon, DCON_REG_ID);
 150         }
 151         if (x < 0) {
 152                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
 153                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 154                 x = 0;
 155                 olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
 156                 msleep(100);
 157                 is_powered_down = 1;
 158                 goto power_up;  /* argh, stupid hardware.. */
 159         }
 160
 161         if (is_powered_down)
 162                 return dcon_hw_init(dcon, 0);
 163         return 0;
 164 }
 165
 166 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
 167 {
 168         dcon->bl_val = level;
 169         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
 170
 171         /* Purposely turn off the backlight when we go to level 0 */
 172         if (dcon->bl_val == 0) {
 173                 dcon->disp_mode &= ~MODE_BL_ENABLE;
 174                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 175         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
 176                 dcon->disp_mode |= MODE_BL_ENABLE;
 177                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 178         }
 179 }
 180
 181 /* Set the output type to either color or mono */
 182 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
 183 {
 184         if (dcon->mono == enable_mono)
 185                 return 0;
 186
 187         dcon->mono = enable_mono;
 188
 189         if (enable_mono) {
 190                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
 191                 dcon->disp_mode |= MODE_MONO_LUMA;
 192         } else {
 193                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
 194                 dcon->disp_mode |= MODE_CSWIZZLE;
 195                 if (useaa)
 196                         dcon->disp_mode |= MODE_COL_AA;
 197         }
 198
 199         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 200         return 0;
 201 }
 202
 203 /* For now, this will be really stupid - we need to address how
 204  * DCONLOAD works in a sleep and account for it accordingly
 205  */
 206
 207 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 208 {
 209         int x;
 210
 211         /* Turn off the backlight and put the DCON to sleep */
 212
 213         if (dcon->asleep == sleep)
 214                 return;
 215
 216         if (!olpc_board_at_least(olpc_board(0xc2)))
 217                 return;
 218
 219         if (sleep) {
 220                 x = 0;
 221                 x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
 222                 if (x)
 223                         pr_warn("unable to force dcon to power down: %d!\n", x);
 224                 else
 225                         dcon->asleep = sleep;
 226         } else {
 227                 /* Only re-enable the backlight if the backlight value is set */
 228                 if (dcon->bl_val != 0)
 229                         dcon->disp_mode |= MODE_BL_ENABLE;
 230                 x = dcon_bus_stabilize(dcon, 1);
 231                 if (x)
 232                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
 233                 else
 234                         dcon->asleep = sleep;
 235
 236                 /* Restore backlight */
 237                 dcon_set_backlight(dcon, dcon->bl_val);
 238         }
 239
 240         /* We should turn off some stuff in the framebuffer - but what? */
 241 }
 242
 243 /* the DCON seems to get confused if we change DCONLOAD too
 244  * frequently -- i.e., approximately faster than frame time.
 245  * normally we don't change it this fast, so in general we won't
 246  * delay here.
 247  */
 248 static void dcon_load_holdoff(struct dcon_priv *dcon)
 249 {
 250         struct timespec delta_t, now;
 251         while (1) {
 252                 getnstimeofday(&now);
 253                 delta_t = timespec_sub(now, dcon->load_time);
 254                 if (delta_t.tv_sec != 0 ||
 255                         delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
 256                         break;
 257                 }
 258                 mdelay(4);
 259         }
 260 }
 261
 262 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 263 {
 264         int err;
 265
 266         if (!lock_fb_info(dcon->fbinfo)) {
 267                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 268                 return false;
 269         }
 270         console_lock();
 271         dcon->ignore_fb_events = true;
 272         err = fb_blank(dcon->fbinfo,
 273                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 274         dcon->ignore_fb_events = false;
 275         console_unlock();
 276         unlock_fb_info(dcon->fbinfo);
 277
 278         if (err) {
 279                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 280                                 blank ? "" : "un");
 281                 return false;
 282         }
 283         return true;
 284 }
 285
 286 /* Set the source of the display (CPU or DCON) */
 287 static void dcon_source_switch(struct work_struct *work)
 288 {
 289         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 290                         switch_source);
 291         DECLARE_WAITQUEUE(wait, current);
 292         int source = dcon->pending_src;
 293
 294         if (dcon->curr_src == source)
 295                 return;
 296
 297         dcon_load_holdoff(dcon);
 298
 299         dcon->switched = false;
 300
 301         switch (source) {
 302         case DCON_SOURCE_CPU:
 303                 pr_info("dcon_source_switch to CPU\n");
 304                 /* Enable the scanline interrupt bit */
 305                 if (dcon_write(dcon, DCON_REG_MODE,
 306                                 dcon->disp_mode | MODE_SCAN_INT))
 307                         pr_err("couldn't enable scanline interrupt!\n");
 308                 else {
 309                         /* Wait up to one second for the scanline interrupt */
 310                         wait_event_timeout(dcon_wait_queue,
 311                                            dcon->switched == true, HZ);
 312                 }
 313
 314                 if (!dcon->switched)
 315                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 316
 317                 /* Turn off the scanline interrupt */
 318                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 319                         pr_err("couldn't disable scanline interrupt!\n");
 320
 321                 /*
 322                  * Ideally we'd like to disable interrupts here so that the
 323                  * fb unblanking and DCON turn on happen at a known time value;
 324                  * however, we can't do that right now with fb_blank
 325                  * messing with semaphores.
 326                  *
 327                  * For now, we just hope..
 328                  */
 329                 if (!dcon_blank_fb(dcon, false)) {
 330                         pr_err("Failed to enter CPU mode\n");
 331                         dcon->pending_src = DCON_SOURCE_DCON;
 332                         return;
 333                 }
 334
 335                 /* And turn off the DCON */
 336                 pdata->set_dconload(1);
 337                 getnstimeofday(&dcon->load_time);
 338
 339                 pr_info("The CPU has control\n");
 340                 break;
 341         case DCON_SOURCE_DCON:
 342         {
 343                 int t;
 344                 struct timespec delta_t;
 345
 346                 pr_info("dcon_source_switch to DCON\n");
 347
 348                 add_wait_queue(&dcon_wait_queue, &wait);
 349                 set_current_state(TASK_UNINTERRUPTIBLE);
 350
 351                 /* Clear DCONLOAD - this implies that the DCON is in control */
 352                 pdata->set_dconload(0);
 353                 getnstimeofday(&dcon->load_time);
 354
 355                 t = schedule_timeout(HZ/2);
 356                 remove_wait_queue(&dcon_wait_queue, &wait);
 357                 set_current_state(TASK_RUNNING);
 358
 359                 if (!dcon->switched) {
 360                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 361                 } else {
 362                         /* sometimes the DCON doesn't follow its own rules,
 363                          * and doesn't wait for two vsync pulses before
 364                          * ack'ing the frame load with an IRQ.  the result
 365                          * is that the display shows the *previously*
 366                          * loaded frame.  we can detect this by looking at
 367                          * the time between asserting DCONLOAD and the IRQ --
 368                          * if it's less than 20msec, then the DCON couldn't
 369                          * have seen two VSYNC pulses.  in that case we
 370                          * deassert and reassert, and hope for the best.
 371                          * see http://dev.laptop.org/ticket/9664
 372                          */
 373                         delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
 374                         if (dcon->switched && delta_t.tv_sec == 0 &&
 375                                         delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
 376                                 pr_err("missed loading, retrying\n");
 377                                 pdata->set_dconload(1);
 378                                 mdelay(41);
 379                                 pdata->set_dconload(0);
 380                                 getnstimeofday(&dcon->load_time);
 381                                 mdelay(41);
 382                         }
 383                 }
 384
 385                 dcon_blank_fb(dcon, true);
 386                 pr_info("The DCON has control\n");
 387                 break;
 388         }
 389         default:
 390                 BUG();
 391         }
 392
 393         dcon->curr_src = source;
 394 }
 395
 396 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 397 {
 398         if (dcon->pending_src == arg)
 399                 return;
 400
 401         dcon->pending_src = arg;
 402
 403         if ((dcon->curr_src != arg) && !work_pending(&dcon->switch_source))
 404                 schedule_work(&dcon->switch_source);
 405 }
 406
 407 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 408 {
 409         dcon_set_source(dcon, arg);
 410         flush_scheduled_work();
 411 }
 412
 413 static ssize_t dcon_mode_show(struct device *dev,
 414         struct device_attribute *attr, char *buf)
 415 {
 416         struct dcon_priv *dcon = dev_get_drvdata(dev);
 417         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 418 }
 419
 420 static ssize_t dcon_sleep_show(struct device *dev,
 421         struct device_attribute *attr, char *buf)
 422 {
 423
 424         struct dcon_priv *dcon = dev_get_drvdata(dev);
 425         return sprintf(buf, "%d\n", dcon->asleep);
 426 }
 427
 428 static ssize_t dcon_freeze_show(struct device *dev,
 429         struct device_attribute *attr, char *buf)
 430 {
 431         struct dcon_priv *dcon = dev_get_drvdata(dev);
 432         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 433 }
 434
 435 static ssize_t dcon_mono_show(struct device *dev,
 436         struct device_attribute *attr, char *buf)
 437 {
 438         struct dcon_priv *dcon = dev_get_drvdata(dev);
 439         return sprintf(buf, "%d\n", dcon->mono);
 440 }
 441
 442 static ssize_t dcon_resumeline_show(struct device *dev,
 443         struct device_attribute *attr, char *buf)
 444 {
 445         return sprintf(buf, "%d\n", resumeline);
 446 }
 447
 448 static ssize_t dcon_mono_store(struct device *dev,
 449         struct device_attribute *attr, const char *buf, size_t count)
 450 {
 451         unsigned long enable_mono;
 452         int rc;
 453
 454         rc = kstrtoul(buf, 10, &enable_mono);
 455         if (rc)
 456                 return rc;
 457
 458         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
 459
 460         return count;
 461 }
 462
 463 static ssize_t dcon_freeze_store(struct device *dev,
 464         struct device_attribute *attr, const char *buf, size_t count)
 465 {
 466         struct dcon_priv *dcon = dev_get_drvdata(dev);
 467         unsigned long output;
 468         int ret;
 469
 470         ret = kstrtoul(buf, 10, &output);
 471         if (ret)
 472                 return ret;
 473
 474         pr_info("dcon_freeze_store: %lu\n", output);
 475
 476         switch (output) {
 477         case 0:
 478                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 479                 break;
 480         case 1:
 481                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 482                 break;
 483         case 2:  /* normally unused */
 484                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 485                 break;
 486         default:
 487                 return -EINVAL;
 488         }
 489
 490         return count;
 491 }
 492
 493 static ssize_t dcon_resumeline_store(struct device *dev,
 494         struct device_attribute *attr, const char *buf, size_t count)
 495 {
 496         unsigned short rl;
 497         int rc;
 498
 499         rc = kstrtou16(buf, 10, &rl);
 500         if (rc)
 501                 return rc;
 502
 503         resumeline = rl;
 504         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
 505
 506         return count;
 507 }
 508
 509 static ssize_t dcon_sleep_store(struct device *dev,
 510         struct device_attribute *attr, const char *buf, size_t count)
 511 {
 512         unsigned long output;
 513         int ret;
 514
 515         ret = kstrtoul(buf, 10, &output);
 516         if (ret)
 517                 return ret;
 518
 519         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 520         return count;
 521 }
 522
 523 static struct device_attribute dcon_device_files[] = {
 524         __ATTR(mode, 0444, dcon_mode_show, NULL),
 525         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 526         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 527         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 528         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 529 };
 530
 531 static int dcon_bl_update(struct backlight_device *dev)
 532 {
 533         struct dcon_priv *dcon = bl_get_data(dev);
 534         u8 level = dev->props.brightness & 0x0F;
 535
 536         if (dev->props.power != FB_BLANK_UNBLANK)
 537                 level = 0;
 538
 539         if (level != dcon->bl_val)
 540                 dcon_set_backlight(dcon, level);
 541
 542         return 0;
 543 }
 544
 545 static int dcon_bl_get(struct backlight_device *dev)
 546 {
 547         struct dcon_priv *dcon = bl_get_data(dev);
 548         return dcon->bl_val;
 549 }
 550
 551 static const struct backlight_ops dcon_bl_ops = {
 552         .update_status = dcon_bl_update,
 553         .get_brightness = dcon_bl_get,
 554 };
 555
 556 static struct backlight_properties dcon_bl_props = {
 557         .max_brightness = 15,
 558         .type = BACKLIGHT_RAW,
 559         .power = FB_BLANK_UNBLANK,
 560 };
 561
 562 static int dcon_reboot_notify(struct notifier_block *nb,
 563                               unsigned long foo, void *bar)
 564 {
 565         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 566
 567         if (!dcon || !dcon->client)
 568                 return 0;
 569
 570         /* Turn off the DCON. Entirely. */
 571         dcon_write(dcon, DCON_REG_MODE, 0x39);
 572         dcon_write(dcon, DCON_REG_MODE, 0x32);
 573         return 0;
 574 }
 575
 576 static int unfreeze_on_panic(struct notifier_block *nb,
 577                              unsigned long e, void *p)
 578 {
 579         pdata->set_dconload(1);
 580         return NOTIFY_DONE;
 581 }
 582
 583 static struct notifier_block dcon_panic_nb = {
 584         .notifier_call = unfreeze_on_panic,
 585 };
 586
 587 /*
 588  * When the framebuffer sleeps due to external sources (e.g. user idle), power
 589  * down the DCON as well.  Power it back up when the fb comes back to life.
 590  */
 591 static int dcon_fb_notifier(struct notifier_block *self,
 592                                 unsigned long event, void *data)
 593 {
 594         struct fb_event *evdata = data;
 595         struct dcon_priv *dcon = container_of(self, struct dcon_priv,
 596                         fbevent_nb);
 597         int *blank = (int *)evdata->data;
 598         if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
 599                         dcon->ignore_fb_events)
 600                 return 0;
 601         dcon_sleep(dcon, *blank ? true : false);
 602         return 0;
 603 }
 604
 605 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 606 {
 607         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 608
 609         return 0;
 610 }
 611
 612 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 613 {
 614         struct dcon_priv *dcon;
 615         int rc, i, j;
 616
 617         if (!pdata)
 618                 return -ENXIO;
 619
 620         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 621         if (!dcon)
 622                 return -ENOMEM;
 623
 624         dcon->client = client;
 625         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 626         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 627         dcon->reboot_nb.priority = -1;
 628         dcon->fbevent_nb.notifier_call = dcon_fb_notifier;
 629
 630         i2c_set_clientdata(client, dcon);
 631
 632         if (num_registered_fb < 1) {
 633                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 634                 rc = -EIO;
 635                 goto einit;
 636         }
 637         dcon->fbinfo = registered_fb[0];
 638
 639         rc = dcon_hw_init(dcon, 1);
 640         if (rc)
 641                 goto einit;
 642
 643         /* Add the DCON device */
 644
 645         dcon_device = platform_device_alloc("dcon", -1);
 646
 647         if (dcon_device == NULL) {
 648                 pr_err("Unable to create the DCON device\n");
 649                 rc = -ENOMEM;
 650                 goto eirq;
 651         }
 652         rc = platform_device_add(dcon_device);
 653         platform_set_drvdata(dcon_device, dcon);
 654
 655         if (rc) {
 656                 pr_err("Unable to add the DCON device\n");
 657                 goto edev;
 658         }
 659
 660         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 661                 rc = device_create_file(&dcon_device->dev,
 662                                         &dcon_device_files[i]);
 663                 if (rc) {
 664                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 665                         goto ecreate;
 666                 }
 667         }
 668
 669         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 670
 671         /* Add the backlight device for the DCON */
 672         dcon_bl_props.brightness = dcon->bl_val;
 673         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 674                 dcon, &dcon_bl_ops, &dcon_bl_props);
 675         if (IS_ERR(dcon->bl_dev)) {
 676                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 677                                 PTR_ERR(dcon->bl_dev));
 678                 dcon->bl_dev = NULL;
 679         }
 680
 681         register_reboot_notifier(&dcon->reboot_nb);
 682         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 683         fb_register_client(&dcon->fbevent_nb);
 684
 685         return 0;
 686
 687  ecreate:
 688         for (j = 0; j < i; j++)
 689                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 690  edev:
 691         platform_device_unregister(dcon_device);
 692         dcon_device = NULL;
 693  eirq:
 694         free_irq(DCON_IRQ, dcon);
 695  einit:
 696         kfree(dcon);
 697         return rc;
 698 }
 699
 700 static int dcon_remove(struct i2c_client *client)
 701 {
 702         struct dcon_priv *dcon = i2c_get_clientdata(client);
 703
 704         fb_unregister_client(&dcon->fbevent_nb);
 705         unregister_reboot_notifier(&dcon->reboot_nb);
 706         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 707
 708         free_irq(DCON_IRQ, dcon);
 709
 710         if (dcon->bl_dev)
 711                 backlight_device_unregister(dcon->bl_dev);
 712
 713         if (dcon_device != NULL)
 714                 platform_device_unregister(dcon_device);
 715         cancel_work_sync(&dcon->switch_source);
 716
 717         kfree(dcon);
 718
 719         return 0;
 720 }
 721
 722 #ifdef CONFIG_PM
 723 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
 724 {
 725         struct dcon_priv *dcon = i2c_get_clientdata(client);
 726
 727         if (!dcon->asleep) {
 728                 /* Set up the DCON to have the source */
 729                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 730         }
 731
 732         return 0;
 733 }
 734
 735 static int dcon_resume(struct i2c_client *client)
 736 {
 737         struct dcon_priv *dcon = i2c_get_clientdata(client);
 738
 739         if (!dcon->asleep) {
 740                 dcon_bus_stabilize(dcon, 0);
 741                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 742         }
 743
 744         return 0;
 745 }
 746
 747 #endif
 748
 749
 750 irqreturn_t dcon_interrupt(int irq, void *id)
 751 {
 752         struct dcon_priv *dcon = id;
 753         u8 status;
 754
 755         if (pdata->read_status(&status))
 756                 return IRQ_NONE;
 757
 758         switch (status & 3) {
 759         case 3:
 760                 pr_debug("DCONLOAD_MISSED interrupt\n");
 761                 break;
 762
 763         case 2: /* switch to DCON mode */
 764         case 1: /* switch to CPU mode */
 765                 dcon->switched = true;
 766                 getnstimeofday(&dcon->irq_time);
 767                 wake_up(&dcon_wait_queue);
 768                 break;
 769
 770         case 0:
 771                 /* workaround resume case:  the DCON (on 1.5) doesn't
 772                  * ever assert status 0x01 when switching to CPU mode
 773                  * during resume.  this is because DCONLOAD is de-asserted
 774                  * _immediately_ upon exiting S3, so the actual release
 775                  * of the DCON happened long before this point.
 776                  * see http://dev.laptop.org/ticket/9869
 777                  */
 778                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 779                         dcon->switched = true;
 780                         getnstimeofday(&dcon->irq_time);
 781                         wake_up(&dcon_wait_queue);
 782                         pr_debug("switching w/ status 0/0\n");
 783                 } else {
 784                         pr_debug("scanline interrupt w/CPU\n");
 785                 }
 786         }
 787
 788         return IRQ_HANDLED;
 789 }
 790
 791 static const struct i2c_device_id dcon_idtable[] = {
 792         { "olpc_dcon",  0 },
 793         { }
 794 };
 795
 796 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 797
 798 struct i2c_driver dcon_driver = {
 799         .driver = {
 800                 .name   = "olpc_dcon",
 801         },
 802         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 803         .id_table = dcon_idtable,
 804         .probe = dcon_probe,
 805         .remove = __devexit_p(dcon_remove),
 806         .detect = dcon_detect,
 807         .address_list = normal_i2c,
 808 #ifdef CONFIG_PM
 809         .suspend = dcon_suspend,
 810         .resume = dcon_resume,
 811 #endif
 812 };
 813
 814 static int __init olpc_dcon_init(void)
 815 {
 816 #ifdef CONFIG_FB_OLPC_DCON_1_5
 817         /* XO-1.5 */
 818         if (olpc_board_at_least(olpc_board(0xd0)))
 819                 pdata = &dcon_pdata_xo_1_5;
 820 #endif
 821 #ifdef CONFIG_FB_OLPC_DCON_1
 822         if (!pdata)
 823                 pdata = &dcon_pdata_xo_1;
 824 #endif
 825
 826         return i2c_add_driver(&dcon_driver);
 827 }
 828
 829 static void __exit olpc_dcon_exit(void)
 830 {
 831         i2c_del_driver(&dcon_driver);
 832 }
 833
 834 module_init(olpc_dcon_init);
 835 module_exit(olpc_dcon_exit);
 836
 837 MODULE_LICENSE("GPL");