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         uint16_t 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
 104         /* Set the scanline to interrupt on during resume */
 105         dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
 106
 107 err:
 108         return rc;
 109 }
 110
 111 /*
 112  * The smbus doesn't always come back due to what is believed to be
 113  * hardware (power rail) bugs.  For older models where this is known to
 114  * occur, our solution is to attempt to wait for the bus to stabilize;
 115  * if it doesn't happen, cut power to the dcon, repower it, and wait
 116  * for the bus to stabilize.  Rinse, repeat until we have a working
 117  * smbus.  For newer models, we simply BUG(); we want to know if this
 118  * still happens despite the power fixes that have been made!
 119  */
 120 static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 121 {
 122         unsigned long timeout;
 123         u8 pm;
 124         int x;
 125
 126 power_up:
 127         if (is_powered_down) {
 128                 pm = 1;
 129                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 130                 if (x) {
 131                         pr_warn("unable to force dcon to power up: %d!\n", x);
 132                         return x;
 133                 }
 134                 usleep_range(10000, 11000);  /* we'll be conservative */
 135         }
 136
 137         pdata->bus_stabilize_wiggle();
 138
 139         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 140                 usleep_range(1000, 1100);
 141                 x = dcon_read(dcon, DCON_REG_ID);
 142         }
 143         if (x < 0) {
 144                 pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
 145                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 146                 pm = 0;
 147                 olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 148                 msleep(100);
 149                 is_powered_down = 1;
 150                 goto power_up;  /* argh, stupid hardware.. */
 151         }
 152
 153         if (is_powered_down)
 154                 return dcon_hw_init(dcon, 0);
 155         return 0;
 156 }
 157
 158 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
 159 {
 160         dcon->bl_val = level;
 161         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
 162
 163         /* Purposely turn off the backlight when we go to level 0 */
 164         if (dcon->bl_val == 0) {
 165                 dcon->disp_mode &= ~MODE_BL_ENABLE;
 166                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 167         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
 168                 dcon->disp_mode |= MODE_BL_ENABLE;
 169                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 170         }
 171 }
 172
 173 /* Set the output type to either color or mono */
 174 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
 175 {
 176         if (dcon->mono == enable_mono)
 177                 return 0;
 178
 179         dcon->mono = enable_mono;
 180
 181         if (enable_mono) {
 182                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
 183                 dcon->disp_mode |= MODE_MONO_LUMA;
 184         } else {
 185                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
 186                 dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
 187         }
 188
 189         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 190         return 0;
 191 }
 192
 193 /* For now, this will be really stupid - we need to address how
 194  * DCONLOAD works in a sleep and account for it accordingly
 195  */
 196
 197 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 198 {
 199         int x;
 200
 201         /* Turn off the backlight and put the DCON to sleep */
 202
 203         if (dcon->asleep == sleep)
 204                 return;
 205
 206         if (!olpc_board_at_least(olpc_board(0xc2)))
 207                 return;
 208
 209         if (sleep) {
 210                 u8 pm = 0;
 211
 212                 x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
 213                 if (x)
 214                         pr_warn("unable to force dcon to power down: %d!\n", x);
 215                 else
 216                         dcon->asleep = sleep;
 217         } else {
 218                 /* Only re-enable the backlight if the backlight value is set */
 219                 if (dcon->bl_val != 0)
 220                         dcon->disp_mode |= MODE_BL_ENABLE;
 221                 x = dcon_bus_stabilize(dcon, 1);
 222                 if (x)
 223                         pr_warn("unable to reinit dcon hardware: %d!\n", x);
 224                 else
 225                         dcon->asleep = sleep;
 226
 227                 /* Restore backlight */
 228                 dcon_set_backlight(dcon, dcon->bl_val);
 229         }
 230
 231         /* We should turn off some stuff in the framebuffer - but what? */
 232 }
 233
 234 /* the DCON seems to get confused if we change DCONLOAD too
 235  * frequently -- i.e., approximately faster than frame time.
 236  * normally we don't change it this fast, so in general we won't
 237  * delay here.
 238  */
 239 static void dcon_load_holdoff(struct dcon_priv *dcon)
 240 {
 241         ktime_t delta_t, now;
 242
 243         while (1) {
 244                 now = ktime_get();
 245                 delta_t = ktime_sub(now, dcon->load_time);
 246                 if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20) {
 247                         break;
 248                 }
 249                 mdelay(4);
 250         }
 251 }
 252
 253 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 254 {
 255         int err;
 256
 257         console_lock();
 258         if (!lock_fb_info(dcon->fbinfo)) {
 259                 console_unlock();
 260                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 261                 return false;
 262         }
 263
 264         dcon->ignore_fb_events = true;
 265         err = fb_blank(dcon->fbinfo,
 266                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 267         dcon->ignore_fb_events = false;
 268         unlock_fb_info(dcon->fbinfo);
 269         console_unlock();
 270
 271         if (err) {
 272                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 273                                 blank ? "" : "un");
 274                 return false;
 275         }
 276         return true;
 277 }
 278
 279 /* Set the source of the display (CPU or DCON) */
 280 static void dcon_source_switch(struct work_struct *work)
 281 {
 282         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 283                         switch_source);
 284         int source = dcon->pending_src;
 285
 286         if (dcon->curr_src == source)
 287                 return;
 288
 289         dcon_load_holdoff(dcon);
 290
 291         dcon->switched = false;
 292
 293         switch (source) {
 294         case DCON_SOURCE_CPU:
 295                 pr_info("dcon_source_switch to CPU\n");
 296                 /* Enable the scanline interrupt bit */
 297                 if (dcon_write(dcon, DCON_REG_MODE,
 298                                 dcon->disp_mode | MODE_SCAN_INT))
 299                         pr_err("couldn't enable scanline interrupt!\n");
 300                 else
 301                         /* Wait up to one second for the scanline interrupt */
 302                         wait_event_timeout(dcon->waitq, dcon->switched, HZ);
 303
 304                 if (!dcon->switched)
 305                         pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
 306
 307                 /* Turn off the scanline interrupt */
 308                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 309                         pr_err("couldn't disable scanline interrupt!\n");
 310
 311                 /*
 312                  * Ideally we'd like to disable interrupts here so that the
 313                  * fb unblanking and DCON turn on happen at a known time value;
 314                  * however, we can't do that right now with fb_blank
 315                  * messing with semaphores.
 316                  *
 317                  * For now, we just hope..
 318                  */
 319                 if (!dcon_blank_fb(dcon, false)) {
 320                         pr_err("Failed to enter CPU mode\n");
 321                         dcon->pending_src = DCON_SOURCE_DCON;
 322                         return;
 323                 }
 324
 325                 /* And turn off the DCON */
 326                 pdata->set_dconload(1);
 327                 dcon->load_time = ktime_get();
 328
 329                 pr_info("The CPU has control\n");
 330                 break;
 331         case DCON_SOURCE_DCON:
 332         {
 333                 ktime_t delta_t;
 334
 335                 pr_info("dcon_source_switch to DCON\n");
 336
 337                 /* Clear DCONLOAD - this implies that the DCON is in control */
 338                 pdata->set_dconload(0);
 339                 dcon->load_time = ktime_get();
 340
 341                 wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
 342
 343                 if (!dcon->switched) {
 344                         pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
 345                 } else {
 346                         /* sometimes the DCON doesn't follow its own rules,
 347                          * and doesn't wait for two vsync pulses before
 348                          * ack'ing the frame load with an IRQ.  the result
 349                          * is that the display shows the *previously*
 350                          * loaded frame.  we can detect this by looking at
 351                          * the time between asserting DCONLOAD and the IRQ --
 352                          * if it's less than 20msec, then the DCON couldn't
 353                          * have seen two VSYNC pulses.  in that case we
 354                          * deassert and reassert, and hope for the best.
 355                          * see http://dev.laptop.org/ticket/9664
 356                          */
 357                         delta_t = ktime_sub(dcon->irq_time, dcon->load_time);
 358                         if (dcon->switched && ktime_to_ns(delta_t)
 359                             < NSEC_PER_MSEC * 20) {
 360                                 pr_err("missed loading, retrying\n");
 361                                 pdata->set_dconload(1);
 362                                 mdelay(41);
 363                                 pdata->set_dconload(0);
 364                                 dcon->load_time = ktime_get();
 365                                 mdelay(41);
 366                         }
 367                 }
 368
 369                 dcon_blank_fb(dcon, true);
 370                 pr_info("The DCON has control\n");
 371                 break;
 372         }
 373         default:
 374                 BUG();
 375         }
 376
 377         dcon->curr_src = source;
 378 }
 379
 380 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 381 {
 382         if (dcon->pending_src == arg)
 383                 return;
 384
 385         dcon->pending_src = arg;
 386
 387         if (dcon->curr_src != arg)
 388                 schedule_work(&dcon->switch_source);
 389 }
 390
 391 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 392 {
 393         dcon_set_source(dcon, arg);
 394         flush_scheduled_work();
 395 }
 396
 397 static ssize_t dcon_mode_show(struct device *dev,
 398         struct device_attribute *attr, char *buf)
 399 {
 400         struct dcon_priv *dcon = dev_get_drvdata(dev);
 401
 402         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 403 }
 404
 405 static ssize_t dcon_sleep_show(struct device *dev,
 406         struct device_attribute *attr, char *buf)
 407 {
 408         struct dcon_priv *dcon = dev_get_drvdata(dev);
 409
 410         return sprintf(buf, "%d\n", dcon->asleep);
 411 }
 412
 413 static ssize_t dcon_freeze_show(struct device *dev,
 414         struct device_attribute *attr, char *buf)
 415 {
 416         struct dcon_priv *dcon = dev_get_drvdata(dev);
 417
 418         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 419 }
 420
 421 static ssize_t dcon_mono_show(struct device *dev,
 422         struct device_attribute *attr, char *buf)
 423 {
 424         struct dcon_priv *dcon = dev_get_drvdata(dev);
 425
 426         return sprintf(buf, "%d\n", dcon->mono);
 427 }
 428
 429 static ssize_t dcon_resumeline_show(struct device *dev,
 430         struct device_attribute *attr, char *buf)
 431 {
 432         return sprintf(buf, "%d\n", resumeline);
 433 }
 434
 435 static ssize_t dcon_mono_store(struct device *dev,
 436         struct device_attribute *attr, const char *buf, size_t count)
 437 {
 438         unsigned long enable_mono;
 439         int rc;
 440
 441         rc = kstrtoul(buf, 10, &enable_mono);
 442         if (rc)
 443                 return rc;
 444
 445         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
 446
 447         return count;
 448 }
 449
 450 static ssize_t dcon_freeze_store(struct device *dev,
 451         struct device_attribute *attr, const char *buf, size_t count)
 452 {
 453         struct dcon_priv *dcon = dev_get_drvdata(dev);
 454         unsigned long output;
 455         int ret;
 456
 457         ret = kstrtoul(buf, 10, &output);
 458         if (ret)
 459                 return ret;
 460
 461         pr_info("dcon_freeze_store: %lu\n", output);
 462
 463         switch (output) {
 464         case 0:
 465                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 466                 break;
 467         case 1:
 468                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 469                 break;
 470         case 2:  /* normally unused */
 471                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 472                 break;
 473         default:
 474                 return -EINVAL;
 475         }
 476
 477         return count;
 478 }
 479
 480 static ssize_t dcon_resumeline_store(struct device *dev,
 481         struct device_attribute *attr, const char *buf, size_t count)
 482 {
 483         unsigned short rl;
 484         int rc;
 485
 486         rc = kstrtou16(buf, 10, &rl);
 487         if (rc)
 488                 return rc;
 489
 490         resumeline = rl;
 491         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
 492
 493         return count;
 494 }
 495
 496 static ssize_t dcon_sleep_store(struct device *dev,
 497         struct device_attribute *attr, const char *buf, size_t count)
 498 {
 499         unsigned long output;
 500         int ret;
 501
 502         ret = kstrtoul(buf, 10, &output);
 503         if (ret)
 504                 return ret;
 505
 506         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 507         return count;
 508 }
 509
 510 static struct device_attribute dcon_device_files[] = {
 511         __ATTR(mode, 0444, dcon_mode_show, NULL),
 512         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 513         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 514         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 515         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 516 };
 517
 518 static int dcon_bl_update(struct backlight_device *dev)
 519 {
 520         struct dcon_priv *dcon = bl_get_data(dev);
 521         u8 level = dev->props.brightness & 0x0F;
 522
 523         if (dev->props.power != FB_BLANK_UNBLANK)
 524                 level = 0;
 525
 526         if (level != dcon->bl_val)
 527                 dcon_set_backlight(dcon, level);
 528
 529         /* power down the DCON when the screen is blanked */
 530         if (!dcon->ignore_fb_events)
 531                 dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
 532
 533         return 0;
 534 }
 535
 536 static int dcon_bl_get(struct backlight_device *dev)
 537 {
 538         struct dcon_priv *dcon = bl_get_data(dev);
 539
 540         return dcon->bl_val;
 541 }
 542
 543 static const struct backlight_ops dcon_bl_ops = {
 544         .update_status = dcon_bl_update,
 545         .get_brightness = dcon_bl_get,
 546 };
 547
 548 static struct backlight_properties dcon_bl_props = {
 549         .max_brightness = 15,
 550         .type = BACKLIGHT_RAW,
 551         .power = FB_BLANK_UNBLANK,
 552 };
 553
 554 static int dcon_reboot_notify(struct notifier_block *nb,
 555                               unsigned long foo, void *bar)
 556 {
 557         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 558
 559         if (!dcon || !dcon->client)
 560                 return NOTIFY_DONE;
 561
 562         /* Turn off the DCON. Entirely. */
 563         dcon_write(dcon, DCON_REG_MODE, 0x39);
 564         dcon_write(dcon, DCON_REG_MODE, 0x32);
 565         return NOTIFY_DONE;
 566 }
 567
 568 static int unfreeze_on_panic(struct notifier_block *nb,
 569                              unsigned long e, void *p)
 570 {
 571         pdata->set_dconload(1);
 572         return NOTIFY_DONE;
 573 }
 574
 575 static struct notifier_block dcon_panic_nb = {
 576         .notifier_call = unfreeze_on_panic,
 577 };
 578
 579 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 580 {
 581         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 582
 583         return 0;
 584 }
 585
 586 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 587 {
 588         struct dcon_priv *dcon;
 589         int rc, i, j;
 590
 591         if (!pdata)
 592                 return -ENXIO;
 593
 594         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 595         if (!dcon)
 596                 return -ENOMEM;
 597
 598         dcon->client = client;
 599         init_waitqueue_head(&dcon->waitq);
 600         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 601         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 602         dcon->reboot_nb.priority = -1;
 603
 604         i2c_set_clientdata(client, dcon);
 605
 606         if (num_registered_fb < 1) {
 607                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 608                 rc = -EIO;
 609                 goto einit;
 610         }
 611         dcon->fbinfo = registered_fb[0];
 612
 613         rc = dcon_hw_init(dcon, 1);
 614         if (rc)
 615                 goto einit;
 616
 617         /* Add the DCON device */
 618
 619         dcon_device = platform_device_alloc("dcon", -1);
 620
 621         if (dcon_device == NULL) {
 622                 pr_err("Unable to create the DCON device\n");
 623                 rc = -ENOMEM;
 624                 goto eirq;
 625         }
 626         rc = platform_device_add(dcon_device);
 627         platform_set_drvdata(dcon_device, dcon);
 628
 629         if (rc) {
 630                 pr_err("Unable to add the DCON device\n");
 631                 goto edev;
 632         }
 633
 634         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 635                 rc = device_create_file(&dcon_device->dev,
 636                                         &dcon_device_files[i]);
 637                 if (rc) {
 638                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 639                         goto ecreate;
 640                 }
 641         }
 642
 643         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 644
 645         /* Add the backlight device for the DCON */
 646         dcon_bl_props.brightness = dcon->bl_val;
 647         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 648                 dcon, &dcon_bl_ops, &dcon_bl_props);
 649         if (IS_ERR(dcon->bl_dev)) {
 650                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 651                                 PTR_ERR(dcon->bl_dev));
 652                 dcon->bl_dev = NULL;
 653         }
 654
 655         register_reboot_notifier(&dcon->reboot_nb);
 656         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 657
 658         return 0;
 659
 660  ecreate:
 661         for (j = 0; j < i; j++)
 662                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 663  edev:
 664         platform_device_unregister(dcon_device);
 665         dcon_device = NULL;
 666  eirq:
 667         free_irq(DCON_IRQ, dcon);
 668  einit:
 669         kfree(dcon);
 670         return rc;
 671 }
 672
 673 static int dcon_remove(struct i2c_client *client)
 674 {
 675         struct dcon_priv *dcon = i2c_get_clientdata(client);
 676
 677         unregister_reboot_notifier(&dcon->reboot_nb);
 678         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 679
 680         free_irq(DCON_IRQ, dcon);
 681
 682         backlight_device_unregister(dcon->bl_dev);
 683
 684         if (dcon_device != NULL)
 685                 platform_device_unregister(dcon_device);
 686         cancel_work_sync(&dcon->switch_source);
 687
 688         kfree(dcon);
 689
 690         return 0;
 691 }
 692
 693 #ifdef CONFIG_PM
 694 static int dcon_suspend(struct device *dev)
 695 {
 696         struct i2c_client *client = to_i2c_client(dev);
 697         struct dcon_priv *dcon = i2c_get_clientdata(client);
 698
 699         if (!dcon->asleep) {
 700                 /* Set up the DCON to have the source */
 701                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 702         }
 703
 704         return 0;
 705 }
 706
 707 static int dcon_resume(struct device *dev)
 708 {
 709         struct i2c_client *client = to_i2c_client(dev);
 710         struct dcon_priv *dcon = i2c_get_clientdata(client);
 711
 712         if (!dcon->asleep) {
 713                 dcon_bus_stabilize(dcon, 0);
 714                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 715         }
 716
 717         return 0;
 718 }
 719
 720 #else
 721
 722 #define dcon_suspend NULL
 723 #define dcon_resume NULL
 724
 725 #endif /* CONFIG_PM */
 726
 727
 728 irqreturn_t dcon_interrupt(int irq, void *id)
 729 {
 730         struct dcon_priv *dcon = id;
 731         u8 status;
 732
 733         if (pdata->read_status(&status))
 734                 return IRQ_NONE;
 735
 736         switch (status & 3) {
 737         case 3:
 738                 pr_debug("DCONLOAD_MISSED interrupt\n");
 739                 break;
 740
 741         case 2: /* switch to DCON mode */
 742         case 1: /* switch to CPU mode */
 743                 dcon->switched = true;
 744                 dcon->irq_time = ktime_get();
 745                 wake_up(&dcon->waitq);
 746                 break;
 747
 748         case 0:
 749                 /* workaround resume case:  the DCON (on 1.5) doesn't
 750                  * ever assert status 0x01 when switching to CPU mode
 751                  * during resume.  this is because DCONLOAD is de-asserted
 752                  * _immediately_ upon exiting S3, so the actual release
 753                  * of the DCON happened long before this point.
 754                  * see http://dev.laptop.org/ticket/9869
 755                  */
 756                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 757                         dcon->switched = true;
 758                         dcon->irq_time = ktime_get();
 759                         wake_up(&dcon->waitq);
 760                         pr_debug("switching w/ status 0/0\n");
 761                 } else {
 762                         pr_debug("scanline interrupt w/CPU\n");
 763                 }
 764         }
 765
 766         return IRQ_HANDLED;
 767 }
 768
 769 static const struct dev_pm_ops dcon_pm_ops = {
 770         .suspend = dcon_suspend,
 771         .resume = dcon_resume,
 772 };
 773
 774 static const struct i2c_device_id dcon_idtable[] = {
 775         { "olpc_dcon",  0 },
 776         { }
 777 };
 778 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 779
 780 static struct i2c_driver dcon_driver = {
 781         .driver = {
 782                 .name   = "olpc_dcon",
 783                 .pm = &dcon_pm_ops,
 784         },
 785         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 786         .id_table = dcon_idtable,
 787         .probe = dcon_probe,
 788         .remove = dcon_remove,
 789         .detect = dcon_detect,
 790         .address_list = normal_i2c,
 791 };
 792
 793 static int __init olpc_dcon_init(void)
 794 {
 795 #ifdef CONFIG_FB_OLPC_DCON_1_5
 796         /* XO-1.5 */
 797         if (olpc_board_at_least(olpc_board(0xd0)))
 798                 pdata = &dcon_pdata_xo_1_5;
 799 #endif
 800 #ifdef CONFIG_FB_OLPC_DCON_1
 801         if (!pdata)
 802                 pdata = &dcon_pdata_xo_1;
 803 #endif
 804
 805         return i2c_add_driver(&dcon_driver);
 806 }
 807
 808 static void __exit olpc_dcon_exit(void)
 809 {
 810         i2c_del_driver(&dcon_driver);
 811 }
 812
 813 module_init(olpc_dcon_init);
 814 module_exit(olpc_dcon_exit);
 815
 816 MODULE_LICENSE("GPL");