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