Pileus Git - ~andy/linux/blob - 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
  15 #include <linux/kernel.h>
  16 #include <linux/fb.h>
  17 #include <linux/console.h>
  18 #include <linux/i2c.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/pci.h>
  21 #include <linux/pci_ids.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/delay.h>
  24 #include <linux/module.h>
  25 #include <linux/backlight.h>
  26 #include <linux/device.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/ctype.h>
  29 #include <linux/reboot.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 /* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
  41 static int useaa = 1;
  42 module_param(useaa, int, 0444);
  43
  44 static struct dcon_platform_data *pdata;
  45
  46 /* I2C structures */
  47
  48 /* Platform devices */
  49 static struct platform_device *dcon_device;
  50
  51 static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
  52
  53 static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
  54
  55 static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
  56 {
  57         return i2c_smbus_write_word_data(dcon->client, reg, val);
  58 }
  59
  60 static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
  61 {
  62         return i2c_smbus_read_word_data(dcon->client, reg);
  63 }
  64
  65 /* ===== API functions - these are called by a variety of users ==== */
  66
  67 static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
  68 {
  69         uint16_t ver;
  70         int rc = 0;
  71
  72         ver = dcon_read(dcon, DCON_REG_ID);
  73         if ((ver >> 8) != 0xDC) {
  74                 printk(KERN_ERR "olpc-dcon:  DCON ID not 0xDCxx: 0x%04x "
  75                                 "instead.\n", ver);
  76                 rc = -ENXIO;
  77                 goto err;
  78         }
  79
  80         if (is_init) {
  81                 printk(KERN_INFO "olpc-dcon:  Discovered DCON version %x\n",
  82                                 ver & 0xFF);
  83                 rc = pdata->init(dcon);
  84                 if (rc != 0) {
  85                         printk(KERN_ERR "olpc-dcon:  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                         printk(KERN_WARNING "olpc-dcon:  unable to force dcon "
 140                                         "to power up: %d!\n", x);
 141                         return x;
 142                 }
 143                 msleep(10); /* we'll be conservative */
 144         }
 145
 146         pdata->bus_stabilize_wiggle();
 147
 148         for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
 149                 msleep(1);
 150                 x = dcon_read(dcon, DCON_REG_ID);
 151         }
 152         if (x < 0) {
 153                 printk(KERN_ERR "olpc-dcon:  unable to stabilize dcon's "
 154                                 "smbus, reasserting power and praying.\n");
 155                 BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 156                 x = 0;
 157                 olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
 158                 msleep(100);
 159                 is_powered_down = 1;
 160                 goto power_up;  /* argh, stupid hardware.. */
 161         }
 162
 163         if (is_powered_down)
 164                 return dcon_hw_init(dcon, 0);
 165         return 0;
 166 }
 167
 168 static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
 169 {
 170         dcon->bl_val = level;
 171         dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
 172
 173         /* Purposely turn off the backlight when we go to level 0 */
 174         if (dcon->bl_val == 0) {
 175                 dcon->disp_mode &= ~MODE_BL_ENABLE;
 176                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 177         } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
 178                 dcon->disp_mode |= MODE_BL_ENABLE;
 179                 dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 180         }
 181 }
 182
 183 /* Set the output type to either color or mono */
 184 static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
 185 {
 186         if (dcon->mono == enable_mono)
 187                 return 0;
 188
 189         dcon->mono = enable_mono;
 190
 191         if (enable_mono) {
 192                 dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
 193                 dcon->disp_mode |= MODE_MONO_LUMA;
 194         } else {
 195                 dcon->disp_mode &= ~(MODE_MONO_LUMA);
 196                 dcon->disp_mode |= MODE_CSWIZZLE;
 197                 if (useaa)
 198                         dcon->disp_mode |= MODE_COL_AA;
 199         }
 200
 201         dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
 202         return 0;
 203 }
 204
 205 /* For now, this will be really stupid - we need to address how
 206  * DCONLOAD works in a sleep and account for it accordingly
 207  */
 208
 209 static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 210 {
 211         int x;
 212
 213         /* Turn off the backlight and put the DCON to sleep */
 214
 215         if (dcon->asleep == sleep)
 216                 return;
 217
 218         if (!olpc_board_at_least(olpc_board(0xc2)))
 219                 return;
 220
 221         if (sleep) {
 222                 x = 0;
 223                 x = olpc_ec_cmd(0x26, (unsigned char *) &x, 1, NULL, 0);
 224                 if (x)
 225                         printk(KERN_WARNING "olpc-dcon:  unable to force dcon "
 226                                         "to power down: %d!\n", x);
 227                 else
 228                         dcon->asleep = sleep;
 229         } else {
 230                 /* Only re-enable the backlight if the backlight value is set */
 231                 if (dcon->bl_val != 0)
 232                         dcon->disp_mode |= MODE_BL_ENABLE;
 233                 x = dcon_bus_stabilize(dcon, 1);
 234                 if (x)
 235                         printk(KERN_WARNING "olpc-dcon:  unable to reinit dcon"
 236                                         " hardware: %d!\n", x);
 237                 else
 238                         dcon->asleep = sleep;
 239
 240                 /* Restore backlight */
 241                 dcon_set_backlight(dcon, dcon->bl_val);
 242         }
 243
 244         /* We should turn off some stuff in the framebuffer - but what? */
 245 }
 246
 247 /* the DCON seems to get confused if we change DCONLOAD too
 248  * frequently -- i.e., approximately faster than frame time.
 249  * normally we don't change it this fast, so in general we won't
 250  * delay here.
 251  */
 252 static void dcon_load_holdoff(struct dcon_priv *dcon)
 253 {
 254         struct timespec delta_t, now;
 255         while (1) {
 256                 getnstimeofday(&now);
 257                 delta_t = timespec_sub(now, dcon->load_time);
 258                 if (delta_t.tv_sec != 0 ||
 259                         delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
 260                         break;
 261                 }
 262                 mdelay(4);
 263         }
 264 }
 265
 266 static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
 267 {
 268         int err;
 269
 270         if (!lock_fb_info(dcon->fbinfo)) {
 271                 dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
 272                 return false;
 273         }
 274         console_lock();
 275         dcon->ignore_fb_events = true;
 276         err = fb_blank(dcon->fbinfo,
 277                         blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
 278         dcon->ignore_fb_events = false;
 279         console_unlock();
 280         unlock_fb_info(dcon->fbinfo);
 281
 282         if (err) {
 283                 dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
 284                                 blank ? "" : "un");
 285                 return false;
 286         }
 287         return true;
 288 }
 289
 290 /* Set the source of the display (CPU or DCON) */
 291 static void dcon_source_switch(struct work_struct *work)
 292 {
 293         struct dcon_priv *dcon = container_of(work, struct dcon_priv,
 294                         switch_source);
 295         DECLARE_WAITQUEUE(wait, current);
 296         int source = dcon->pending_src;
 297
 298         if (dcon->curr_src == source)
 299                 return;
 300
 301         dcon_load_holdoff(dcon);
 302
 303         dcon->switched = false;
 304
 305         switch (source) {
 306         case DCON_SOURCE_CPU:
 307                 printk("dcon_source_switch to CPU\n");
 308                 /* Enable the scanline interrupt bit */
 309                 if (dcon_write(dcon, DCON_REG_MODE,
 310                                 dcon->disp_mode | MODE_SCAN_INT))
 311                         printk(KERN_ERR
 312                                "olpc-dcon:  couldn't enable scanline interrupt!\n");
 313                 else {
 314                         /* Wait up to one second for the scanline interrupt */
 315                         wait_event_timeout(dcon_wait_queue,
 316                                            dcon->switched == true, HZ);
 317                 }
 318
 319                 if (!dcon->switched)
 320                         printk(KERN_ERR "olpc-dcon:  Timeout entering CPU mode; expect a screen glitch.\n");
 321
 322                 /* Turn off the scanline interrupt */
 323                 if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
 324                         printk(KERN_ERR "olpc-dcon:  couldn't disable scanline interrupt!\n");
 325
 326                 /*
 327                  * Ideally we'd like to disable interrupts here so that the
 328                  * fb unblanking and DCON turn on happen at a known time value;
 329                  * however, we can't do that right now with fb_blank
 330                  * messing with semaphores.
 331                  *
 332                  * For now, we just hope..
 333                  */
 334                 if (!dcon_blank_fb(dcon, false)) {
 335                         printk(KERN_ERR "olpc-dcon:  Failed to enter CPU mode\n");
 336                         dcon->pending_src = DCON_SOURCE_DCON;
 337                         return;
 338                 }
 339
 340                 /* And turn off the DCON */
 341                 pdata->set_dconload(1);
 342                 getnstimeofday(&dcon->load_time);
 343
 344                 printk(KERN_INFO "olpc-dcon: The CPU has control\n");
 345                 break;
 346         case DCON_SOURCE_DCON:
 347         {
 348                 int t;
 349                 struct timespec delta_t;
 350
 351                 printk(KERN_INFO "dcon_source_switch to DCON\n");
 352
 353                 add_wait_queue(&dcon_wait_queue, &wait);
 354                 set_current_state(TASK_UNINTERRUPTIBLE);
 355
 356                 /* Clear DCONLOAD - this implies that the DCON is in control */
 357                 pdata->set_dconload(0);
 358                 getnstimeofday(&dcon->load_time);
 359
 360                 t = schedule_timeout(HZ/2);
 361                 remove_wait_queue(&dcon_wait_queue, &wait);
 362                 set_current_state(TASK_RUNNING);
 363
 364                 if (!dcon->switched) {
 365                         printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
 366                 } else {
 367                         /* sometimes the DCON doesn't follow its own rules,
 368                          * and doesn't wait for two vsync pulses before
 369                          * ack'ing the frame load with an IRQ.  the result
 370                          * is that the display shows the *previously*
 371                          * loaded frame.  we can detect this by looking at
 372                          * the time between asserting DCONLOAD and the IRQ --
 373                          * if it's less than 20msec, then the DCON couldn't
 374                          * have seen two VSYNC pulses.  in that case we
 375                          * deassert and reassert, and hope for the best.
 376                          * see http://dev.laptop.org/ticket/9664
 377                          */
 378                         delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
 379                         if (dcon->switched && delta_t.tv_sec == 0 &&
 380                                         delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
 381                                 printk(KERN_ERR "olpc-dcon: missed loading, retrying\n");
 382                                 pdata->set_dconload(1);
 383                                 mdelay(41);
 384                                 pdata->set_dconload(0);
 385                                 getnstimeofday(&dcon->load_time);
 386                                 mdelay(41);
 387                         }
 388                 }
 389
 390                 dcon_blank_fb(dcon, true);
 391                 printk(KERN_INFO "olpc-dcon: The DCON has control\n");
 392                 break;
 393         }
 394         default:
 395                 BUG();
 396         }
 397
 398         dcon->curr_src = source;
 399 }
 400
 401 static void dcon_set_source(struct dcon_priv *dcon, int arg)
 402 {
 403         if (dcon->pending_src == arg)
 404                 return;
 405
 406         dcon->pending_src = arg;
 407
 408         if ((dcon->curr_src != arg) && !work_pending(&dcon->switch_source))
 409                 schedule_work(&dcon->switch_source);
 410 }
 411
 412 static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
 413 {
 414         dcon_set_source(dcon, arg);
 415         flush_scheduled_work();
 416 }
 417
 418 static ssize_t dcon_mode_show(struct device *dev,
 419         struct device_attribute *attr, char *buf)
 420 {
 421         struct dcon_priv *dcon = dev_get_drvdata(dev);
 422         return sprintf(buf, "%4.4X\n", dcon->disp_mode);
 423 }
 424
 425 static ssize_t dcon_sleep_show(struct device *dev,
 426         struct device_attribute *attr, char *buf)
 427 {
 428
 429         struct dcon_priv *dcon = dev_get_drvdata(dev);
 430         return sprintf(buf, "%d\n", dcon->asleep);
 431 }
 432
 433 static ssize_t dcon_freeze_show(struct device *dev,
 434         struct device_attribute *attr, char *buf)
 435 {
 436         struct dcon_priv *dcon = dev_get_drvdata(dev);
 437         return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
 438 }
 439
 440 static ssize_t dcon_mono_show(struct device *dev,
 441         struct device_attribute *attr, char *buf)
 442 {
 443         struct dcon_priv *dcon = dev_get_drvdata(dev);
 444         return sprintf(buf, "%d\n", dcon->mono);
 445 }
 446
 447 static ssize_t dcon_resumeline_show(struct device *dev,
 448         struct device_attribute *attr, char *buf)
 449 {
 450         return sprintf(buf, "%d\n", resumeline);
 451 }
 452
 453 static ssize_t dcon_mono_store(struct device *dev,
 454         struct device_attribute *attr, const char *buf, size_t count)
 455 {
 456         unsigned long enable_mono;
 457         int rc;
 458
 459         rc = kstrtoul(buf, 10, &enable_mono);
 460         if (rc)
 461                 return rc;
 462
 463         dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
 464
 465         return count;
 466 }
 467
 468 static ssize_t dcon_freeze_store(struct device *dev,
 469         struct device_attribute *attr, const char *buf, size_t count)
 470 {
 471         struct dcon_priv *dcon = dev_get_drvdata(dev);
 472         unsigned long output;
 473         int ret;
 474
 475         ret = kstrtoul(buf, 10, &output);
 476         if (ret)
 477                 return ret;
 478
 479         printk(KERN_INFO "dcon_freeze_store: %lu\n", output);
 480
 481         switch (output) {
 482         case 0:
 483                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 484                 break;
 485         case 1:
 486                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 487                 break;
 488         case 2:  /* normally unused */
 489                 dcon_set_source(dcon, DCON_SOURCE_DCON);
 490                 break;
 491         default:
 492                 return -EINVAL;
 493         }
 494
 495         return count;
 496 }
 497
 498 static ssize_t dcon_resumeline_store(struct device *dev,
 499         struct device_attribute *attr, const char *buf, size_t count)
 500 {
 501         unsigned short rl;
 502         int rc;
 503
 504         rc = kstrtou16(buf, 10, &rl);
 505         if (rc)
 506                 return rc;
 507
 508         resumeline = rl;
 509         dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
 510
 511         return count;
 512 }
 513
 514 static ssize_t dcon_sleep_store(struct device *dev,
 515         struct device_attribute *attr, const char *buf, size_t count)
 516 {
 517         unsigned long output;
 518         int ret;
 519
 520         ret = kstrtoul(buf, 10, &output);
 521         if (ret)
 522                 return ret;
 523
 524         dcon_sleep(dev_get_drvdata(dev), output ? true : false);
 525         return count;
 526 }
 527
 528 static struct device_attribute dcon_device_files[] = {
 529         __ATTR(mode, 0444, dcon_mode_show, NULL),
 530         __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
 531         __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
 532         __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
 533         __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
 534 };
 535
 536 static int dcon_bl_update(struct backlight_device *dev)
 537 {
 538         struct dcon_priv *dcon = bl_get_data(dev);
 539         u8 level = dev->props.brightness & 0x0F;
 540
 541         if (dev->props.power != FB_BLANK_UNBLANK)
 542                 level = 0;
 543
 544         if (level != dcon->bl_val)
 545                 dcon_set_backlight(dcon, level);
 546
 547         return 0;
 548 }
 549
 550 static int dcon_bl_get(struct backlight_device *dev)
 551 {
 552         struct dcon_priv *dcon = bl_get_data(dev);
 553         return dcon->bl_val;
 554 }
 555
 556 static const struct backlight_ops dcon_bl_ops = {
 557         .update_status = dcon_bl_update,
 558         .get_brightness = dcon_bl_get,
 559 };
 560
 561 static struct backlight_properties dcon_bl_props = {
 562         .max_brightness = 15,
 563         .type = BACKLIGHT_RAW,
 564         .power = FB_BLANK_UNBLANK,
 565 };
 566
 567 static int dcon_reboot_notify(struct notifier_block *nb,
 568                               unsigned long foo, void *bar)
 569 {
 570         struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
 571
 572         if (!dcon || !dcon->client)
 573                 return 0;
 574
 575         /* Turn off the DCON. Entirely. */
 576         dcon_write(dcon, DCON_REG_MODE, 0x39);
 577         dcon_write(dcon, DCON_REG_MODE, 0x32);
 578         return 0;
 579 }
 580
 581 static int unfreeze_on_panic(struct notifier_block *nb,
 582                              unsigned long e, void *p)
 583 {
 584         pdata->set_dconload(1);
 585         return NOTIFY_DONE;
 586 }
 587
 588 static struct notifier_block dcon_panic_nb = {
 589         .notifier_call = unfreeze_on_panic,
 590 };
 591
 592 /*
 593  * When the framebuffer sleeps due to external sources (e.g. user idle), power
 594  * down the DCON as well.  Power it back up when the fb comes back to life.
 595  */
 596 static int dcon_fb_notifier(struct notifier_block *self,
 597                                 unsigned long event, void *data)
 598 {
 599         struct fb_event *evdata = data;
 600         struct dcon_priv *dcon = container_of(self, struct dcon_priv,
 601                         fbevent_nb);
 602         int *blank = (int *) evdata->data;
 603         if (((event != FB_EVENT_BLANK) && (event != FB_EVENT_CONBLANK)) ||
 604                         dcon->ignore_fb_events)
 605                 return 0;
 606         dcon_sleep(dcon, *blank ? true : false);
 607         return 0;
 608 }
 609
 610 static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
 611 {
 612         strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
 613
 614         return 0;
 615 }
 616
 617 static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
 618 {
 619         struct dcon_priv *dcon;
 620         int rc, i, j;
 621
 622         if (!pdata)
 623                 return -ENXIO;
 624
 625         dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
 626         if (!dcon)
 627                 return -ENOMEM;
 628
 629         dcon->client = client;
 630         INIT_WORK(&dcon->switch_source, dcon_source_switch);
 631         dcon->reboot_nb.notifier_call = dcon_reboot_notify;
 632         dcon->reboot_nb.priority = -1;
 633         dcon->fbevent_nb.notifier_call = dcon_fb_notifier;
 634
 635         i2c_set_clientdata(client, dcon);
 636
 637         if (num_registered_fb < 1) {
 638                 dev_err(&client->dev, "DCON driver requires a registered fb\n");
 639                 rc = -EIO;
 640                 goto einit;
 641         }
 642         dcon->fbinfo = registered_fb[0];
 643
 644         rc = dcon_hw_init(dcon, 1);
 645         if (rc)
 646                 goto einit;
 647
 648         /* Add the DCON device */
 649
 650         dcon_device = platform_device_alloc("dcon", -1);
 651
 652         if (dcon_device == NULL) {
 653                 printk(KERN_ERR "dcon:  Unable to create the DCON device\n");
 654                 rc = -ENOMEM;
 655                 goto eirq;
 656         }
 657         rc = platform_device_add(dcon_device);
 658         platform_set_drvdata(dcon_device, dcon);
 659
 660         if (rc) {
 661                 printk(KERN_ERR "dcon:  Unable to add the DCON device\n");
 662                 goto edev;
 663         }
 664
 665         for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
 666                 rc = device_create_file(&dcon_device->dev,
 667                                         &dcon_device_files[i]);
 668                 if (rc) {
 669                         dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
 670                         goto ecreate;
 671                 }
 672         }
 673
 674         dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
 675
 676         /* Add the backlight device for the DCON */
 677         dcon_bl_props.brightness = dcon->bl_val;
 678         dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
 679                 dcon, &dcon_bl_ops, &dcon_bl_props);
 680         if (IS_ERR(dcon->bl_dev)) {
 681                 dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
 682                                 PTR_ERR(dcon->bl_dev));
 683                 dcon->bl_dev = NULL;
 684         }
 685
 686         register_reboot_notifier(&dcon->reboot_nb);
 687         atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
 688         fb_register_client(&dcon->fbevent_nb);
 689
 690         return 0;
 691
 692  ecreate:
 693         for (j = 0; j < i; j++)
 694                 device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
 695  edev:
 696         platform_device_unregister(dcon_device);
 697         dcon_device = NULL;
 698  eirq:
 699         free_irq(DCON_IRQ, dcon);
 700  einit:
 701         kfree(dcon);
 702         return rc;
 703 }
 704
 705 static int dcon_remove(struct i2c_client *client)
 706 {
 707         struct dcon_priv *dcon = i2c_get_clientdata(client);
 708
 709         fb_unregister_client(&dcon->fbevent_nb);
 710         unregister_reboot_notifier(&dcon->reboot_nb);
 711         atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
 712
 713         free_irq(DCON_IRQ, dcon);
 714
 715         if (dcon->bl_dev)
 716                 backlight_device_unregister(dcon->bl_dev);
 717
 718         if (dcon_device != NULL)
 719                 platform_device_unregister(dcon_device);
 720         cancel_work_sync(&dcon->switch_source);
 721
 722         kfree(dcon);
 723
 724         return 0;
 725 }
 726
 727 #ifdef CONFIG_PM
 728 static int dcon_suspend(struct i2c_client *client, pm_message_t state)
 729 {
 730         struct dcon_priv *dcon = i2c_get_clientdata(client);
 731
 732         if (!dcon->asleep) {
 733                 /* Set up the DCON to have the source */
 734                 dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
 735         }
 736
 737         return 0;
 738 }
 739
 740 static int dcon_resume(struct i2c_client *client)
 741 {
 742         struct dcon_priv *dcon = i2c_get_clientdata(client);
 743
 744         if (!dcon->asleep) {
 745                 dcon_bus_stabilize(dcon, 0);
 746                 dcon_set_source(dcon, DCON_SOURCE_CPU);
 747         }
 748
 749         return 0;
 750 }
 751
 752 #endif
 753
 754
 755 irqreturn_t dcon_interrupt(int irq, void *id)
 756 {
 757         struct dcon_priv *dcon = id;
 758         u8 status;
 759
 760         if (pdata->read_status(&status))
 761                 return IRQ_NONE;
 762
 763         switch (status & 3) {
 764         case 3:
 765                 printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
 766                 break;
 767
 768         case 2: /* switch to DCON mode */
 769         case 1: /* switch to CPU mode */
 770                 dcon->switched = true;
 771                 getnstimeofday(&dcon->irq_time);
 772                 wake_up(&dcon_wait_queue);
 773                 break;
 774
 775         case 0:
 776                 /* workaround resume case:  the DCON (on 1.5) doesn't
 777                  * ever assert status 0x01 when switching to CPU mode
 778                  * during resume.  this is because DCONLOAD is de-asserted
 779                  * _immediately_ upon exiting S3, so the actual release
 780                  * of the DCON happened long before this point.
 781                  * see http://dev.laptop.org/ticket/9869
 782                  */
 783                 if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
 784                         dcon->switched = true;
 785                         getnstimeofday(&dcon->irq_time);
 786                         wake_up(&dcon_wait_queue);
 787                         printk(KERN_DEBUG "olpc-dcon: switching w/ status 0/0\n");
 788                 } else {
 789                         printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
 790                 }
 791         }
 792
 793         return IRQ_HANDLED;
 794 }
 795
 796 static const struct i2c_device_id dcon_idtable[] = {
 797         { "olpc_dcon",  0 },
 798         { }
 799 };
 800
 801 MODULE_DEVICE_TABLE(i2c, dcon_idtable);
 802
 803 struct i2c_driver dcon_driver = {
 804         .driver = {
 805                 .name   = "olpc_dcon",
 806         },
 807         .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
 808         .id_table = dcon_idtable,
 809         .probe = dcon_probe,
 810         .remove = __devexit_p(dcon_remove),
 811         .detect = dcon_detect,
 812         .address_list = normal_i2c,
 813 #ifdef CONFIG_PM
 814         .suspend = dcon_suspend,
 815         .resume = dcon_resume,
 816 #endif
 817 };
 818
 819 static int __init olpc_dcon_init(void)
 820 {
 821 #ifdef CONFIG_FB_OLPC_DCON_1_5
 822         /* XO-1.5 */
 823         if (olpc_board_at_least(olpc_board(0xd0)))
 824                 pdata = &dcon_pdata_xo_1_5;
 825 #endif
 826 #ifdef CONFIG_FB_OLPC_DCON_1
 827         if (!pdata)
 828                 pdata = &dcon_pdata_xo_1;
 829 #endif
 830
 831         return i2c_add_driver(&dcon_driver);
 832 }
 833
 834 static void __exit olpc_dcon_exit(void)
 835 {
 836         i2c_del_driver(&dcon_driver);
 837 }
 838
 839 module_init(olpc_dcon_init);
 840 module_exit(olpc_dcon_exit);
 841
 842 MODULE_LICENSE("GPL");