kernel/drivers/media/usb/gspca/m5602/m5602_ov9650.c

   1 /*
   2  * Driver for the ov9650 sensor
   3  *
   4  * Copyright (C) 2008 Erik Andrén
   5  * Copyright (C) 2007 Ilyes Gouta. Based on the m5603x Linux Driver Project.
   6  * Copyright (C) 2005 m5603x Linux Driver Project <m5602@x3ng.com.br>
   7  *
   8  * Portions of code to USB interface and ALi driver software,
   9  * Copyright (c) 2006 Willem Duinker
  10  * v4l2 interface modeled after the V4L2 driver
  11  * for SN9C10x PC Camera Controllers
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License as
  15  * published by the Free Software Foundation, version 2.
  16  *
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include "m5602_ov9650.h"
  22
  23 static int ov9650_s_ctrl(struct v4l2_ctrl *ctrl);
  24 static void ov9650_dump_registers(struct sd *sd);
  25
  26 /* Vertically and horizontally flips the image if matched, needed for machines
  27    where the sensor is mounted upside down */
  28 static
  29     const
  30         struct dmi_system_id ov9650_flip_dmi_table[] = {
  31         {
  32                 .ident = "ASUS A6Ja",
  33                 .matches = {
  34                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  35                         DMI_MATCH(DMI_PRODUCT_NAME, "A6J")
  36                 }
  37         },
  38         {
  39                 .ident = "ASUS A6JC",
  40                 .matches = {
  41                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  42                         DMI_MATCH(DMI_PRODUCT_NAME, "A6JC")
  43                 }
  44         },
  45         {
  46                 .ident = "ASUS A6K",
  47                 .matches = {
  48                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  49                         DMI_MATCH(DMI_PRODUCT_NAME, "A6K")
  50                 }
  51         },
  52         {
  53                 .ident = "ASUS A6Kt",
  54                 .matches = {
  55                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  56                         DMI_MATCH(DMI_PRODUCT_NAME, "A6Kt")
  57                 }
  58         },
  59         {
  60                 .ident = "ASUS A6VA",
  61                 .matches = {
  62                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  63                         DMI_MATCH(DMI_PRODUCT_NAME, "A6VA")
  64                 }
  65         },
  66         {
  67
  68                 .ident = "ASUS A6VC",
  69                 .matches = {
  70                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  71                         DMI_MATCH(DMI_PRODUCT_NAME, "A6VC")
  72                 }
  73         },
  74         {
  75                 .ident = "ASUS A6VM",
  76                 .matches = {
  77                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  78                         DMI_MATCH(DMI_PRODUCT_NAME, "A6VM")
  79                 }
  80         },
  81         {
  82                 .ident = "ASUS A7V",
  83                 .matches = {
  84                         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  85                         DMI_MATCH(DMI_PRODUCT_NAME, "A7V")
  86                 }
  87         },
  88         {
  89                 .ident = "Alienware Aurora m9700",
  90                 .matches = {
  91                         DMI_MATCH(DMI_SYS_VENDOR, "alienware"),
  92                         DMI_MATCH(DMI_PRODUCT_NAME, "Aurora m9700")
  93                 }
  94         },
  95         {}
  96 };
  97
  98 static struct v4l2_pix_format ov9650_modes[] = {
  99         {
 100                 176,
 101                 144,
 102                 V4L2_PIX_FMT_SBGGR8,
 103                 V4L2_FIELD_NONE,
 104                 .sizeimage =
 105                         176 * 144,
 106                 .bytesperline = 176,
 107                 .colorspace = V4L2_COLORSPACE_SRGB,
 108                 .priv = 9
 109         }, {
 110                 320,
 111                 240,
 112                 V4L2_PIX_FMT_SBGGR8,
 113                 V4L2_FIELD_NONE,
 114                 .sizeimage =
 115                         320 * 240,
 116                 .bytesperline = 320,
 117                 .colorspace = V4L2_COLORSPACE_SRGB,
 118                 .priv = 8
 119         }, {
 120                 352,
 121                 288,
 122                 V4L2_PIX_FMT_SBGGR8,
 123                 V4L2_FIELD_NONE,
 124                 .sizeimage =
 125                         352 * 288,
 126                 .bytesperline = 352,
 127                 .colorspace = V4L2_COLORSPACE_SRGB,
 128                 .priv = 9
 129         }, {
 130                 640,
 131                 480,
 132                 V4L2_PIX_FMT_SBGGR8,
 133                 V4L2_FIELD_NONE,
 134                 .sizeimage =
 135                         640 * 480,
 136                 .bytesperline = 640,
 137                 .colorspace = V4L2_COLORSPACE_SRGB,
 138                 .priv = 9
 139         }
 140 };
 141
 142 static const struct v4l2_ctrl_ops ov9650_ctrl_ops = {
 143         .s_ctrl = ov9650_s_ctrl,
 144 };
 145
 146 int ov9650_probe(struct sd *sd)
 147 {
 148         int err = 0;
 149         u8 prod_id = 0, ver_id = 0, i;
 150         struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
 151
 152         if (force_sensor) {
 153                 if (force_sensor == OV9650_SENSOR) {
 154                         pr_info("Forcing an %s sensor\n", ov9650.name);
 155                         goto sensor_found;
 156                 }
 157                 /* If we want to force another sensor,
 158                    don't try to probe this one */
 159                 return -ENODEV;
 160         }
 161
 162         PDEBUG(D_PROBE, "Probing for an ov9650 sensor");
 163
 164         /* Run the pre-init before probing the sensor */
 165         for (i = 0; i < ARRAY_SIZE(preinit_ov9650) && !err; i++) {
 166                 u8 data = preinit_ov9650[i][2];
 167                 if (preinit_ov9650[i][0] == SENSOR)
 168                         err = m5602_write_sensor(sd,
 169                                 preinit_ov9650[i][1], &data, 1);
 170                 else
 171                         err = m5602_write_bridge(sd,
 172                                 preinit_ov9650[i][1], data);
 173         }
 174
 175         if (err < 0)
 176                 return err;
 177
 178         if (m5602_read_sensor(sd, OV9650_PID, &prod_id, 1))
 179                 return -ENODEV;
 180
 181         if (m5602_read_sensor(sd, OV9650_VER, &ver_id, 1))
 182                 return -ENODEV;
 183
 184         if ((prod_id == 0x96) && (ver_id == 0x52)) {
 185                 pr_info("Detected an ov9650 sensor\n");
 186                 goto sensor_found;
 187         }
 188         return -ENODEV;
 189
 190 sensor_found:
 191         sd->gspca_dev.cam.cam_mode = ov9650_modes;
 192         sd->gspca_dev.cam.nmodes = ARRAY_SIZE(ov9650_modes);
 193
 194         return 0;
 195 }
 196
 197 int ov9650_init(struct sd *sd)
 198 {
 199         int i, err = 0;
 200         u8 data;
 201
 202         if (dump_sensor)
 203                 ov9650_dump_registers(sd);
 204
 205         for (i = 0; i < ARRAY_SIZE(init_ov9650) && !err; i++) {
 206                 data = init_ov9650[i][2];
 207                 if (init_ov9650[i][0] == SENSOR)
 208                         err = m5602_write_sensor(sd, init_ov9650[i][1],
 209                                                   &data, 1);
 210                 else
 211                         err = m5602_write_bridge(sd, init_ov9650[i][1], data);
 212         }
 213
 214         return 0;
 215 }
 216
 217 int ov9650_init_controls(struct sd *sd)
 218 {
 219         struct v4l2_ctrl_handler *hdl = &sd->gspca_dev.ctrl_handler;
 220
 221         sd->gspca_dev.vdev.ctrl_handler = hdl;
 222         v4l2_ctrl_handler_init(hdl, 9);
 223
 224         sd->auto_white_bal = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops,
 225                                                V4L2_CID_AUTO_WHITE_BALANCE,
 226                                                0, 1, 1, 1);
 227         sd->red_bal = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops,
 228                                         V4L2_CID_RED_BALANCE, 0, 255, 1,
 229                                         RED_GAIN_DEFAULT);
 230         sd->blue_bal = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops,
 231                                         V4L2_CID_BLUE_BALANCE, 0, 255, 1,
 232                                         BLUE_GAIN_DEFAULT);
 233
 234         sd->autoexpo = v4l2_ctrl_new_std_menu(hdl, &ov9650_ctrl_ops,
 235                           V4L2_CID_EXPOSURE_AUTO, 1, 0, V4L2_EXPOSURE_AUTO);
 236         sd->expo = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops, V4L2_CID_EXPOSURE,
 237                           0, 0x1ff, 4, EXPOSURE_DEFAULT);
 238
 239         sd->autogain = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops,
 240                                          V4L2_CID_AUTOGAIN, 0, 1, 1, 1);
 241         sd->gain = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops, V4L2_CID_GAIN, 0,
 242                                      0x3ff, 1, GAIN_DEFAULT);
 243
 244         sd->hflip = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops, V4L2_CID_HFLIP,
 245                                       0, 1, 1, 0);
 246         sd->vflip = v4l2_ctrl_new_std(hdl, &ov9650_ctrl_ops, V4L2_CID_VFLIP,
 247                                       0, 1, 1, 0);
 248
 249         if (hdl->error) {
 250                 pr_err("Could not initialize controls\n");
 251                 return hdl->error;
 252         }
 253
 254         v4l2_ctrl_auto_cluster(3, &sd->auto_white_bal, 0, false);
 255         v4l2_ctrl_auto_cluster(2, &sd->autoexpo, 0, false);
 256         v4l2_ctrl_auto_cluster(2, &sd->autogain, 0, false);
 257         v4l2_ctrl_cluster(2, &sd->hflip);
 258
 259         return 0;
 260 }
 261
 262 int ov9650_start(struct sd *sd)
 263 {
 264         u8 data;
 265         int i, err = 0;
 266         struct cam *cam = &sd->gspca_dev.cam;
 267
 268         int width = cam->cam_mode[sd->gspca_dev.curr_mode].width;
 269         int height = cam->cam_mode[sd->gspca_dev.curr_mode].height;
 270         int ver_offs = cam->cam_mode[sd->gspca_dev.curr_mode].priv;
 271         int hor_offs = OV9650_LEFT_OFFSET;
 272         struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
 273
 274         if ((!dmi_check_system(ov9650_flip_dmi_table) &&
 275                 sd->vflip->val) ||
 276                 (dmi_check_system(ov9650_flip_dmi_table) &&
 277                 !sd->vflip->val))
 278                 ver_offs--;
 279
 280         if (width <= 320)
 281                 hor_offs /= 2;
 282
 283         /* Synthesize the vsync/hsync setup */
 284         for (i = 0; i < ARRAY_SIZE(res_init_ov9650) && !err; i++) {
 285                 if (res_init_ov9650[i][0] == BRIDGE)
 286                         err = m5602_write_bridge(sd, res_init_ov9650[i][1],
 287                                 res_init_ov9650[i][2]);
 288                 else if (res_init_ov9650[i][0] == SENSOR) {
 289                         data = res_init_ov9650[i][2];
 290                         err = m5602_write_sensor(sd,
 291                                 res_init_ov9650[i][1], &data, 1);
 292                 }
 293         }
 294         if (err < 0)
 295                 return err;
 296
 297         err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA,
 298                                  ((ver_offs >> 8) & 0xff));
 299         if (err < 0)
 300                 return err;
 301
 302         err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA, (ver_offs & 0xff));
 303         if (err < 0)
 304                 return err;
 305
 306         err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA, 0);
 307         if (err < 0)
 308                 return err;
 309
 310         err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA, (height >> 8) & 0xff);
 311         if (err < 0)
 312                 return err;
 313
 314         err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA, (height & 0xff));
 315         if (err < 0)
 316                 return err;
 317
 318         for (i = 0; i < 2 && !err; i++)
 319                 err = m5602_write_bridge(sd, M5602_XB_VSYNC_PARA, 0);
 320         if (err < 0)
 321                 return err;
 322
 323         err = m5602_write_bridge(sd, M5602_XB_SIG_INI, 0);
 324         if (err < 0)
 325                 return err;
 326
 327         err = m5602_write_bridge(sd, M5602_XB_SIG_INI, 2);
 328         if (err < 0)
 329                 return err;
 330
 331         err = m5602_write_bridge(sd, M5602_XB_HSYNC_PARA,
 332                                  (hor_offs >> 8) & 0xff);
 333         if (err < 0)
 334                 return err;
 335
 336         err = m5602_write_bridge(sd, M5602_XB_HSYNC_PARA, hor_offs & 0xff);
 337         if (err < 0)
 338                 return err;
 339
 340         err = m5602_write_bridge(sd, M5602_XB_HSYNC_PARA,
 341                                  ((width + hor_offs) >> 8) & 0xff);
 342         if (err < 0)
 343                 return err;
 344
 345         err = m5602_write_bridge(sd, M5602_XB_HSYNC_PARA,
 346                                  ((width + hor_offs) & 0xff));
 347         if (err < 0)
 348                 return err;
 349
 350         err = m5602_write_bridge(sd, M5602_XB_SIG_INI, 0);
 351         if (err < 0)
 352                 return err;
 353
 354         switch (width) {
 355         case 640:
 356                 PDEBUG(D_CONF, "Configuring camera for VGA mode");
 357
 358                 data = OV9650_VGA_SELECT | OV9650_RGB_SELECT |
 359                        OV9650_RAW_RGB_SELECT;
 360                 err = m5602_write_sensor(sd, OV9650_COM7, &data, 1);
 361                 break;
 362
 363         case 352:
 364                 PDEBUG(D_CONF, "Configuring camera for CIF mode");
 365
 366                 data = OV9650_CIF_SELECT | OV9650_RGB_SELECT |
 367                                 OV9650_RAW_RGB_SELECT;
 368                 err = m5602_write_sensor(sd, OV9650_COM7, &data, 1);
 369                 break;
 370
 371         case 320:
 372                 PDEBUG(D_CONF, "Configuring camera for QVGA mode");
 373
 374                 data = OV9650_QVGA_SELECT | OV9650_RGB_SELECT |
 375                                 OV9650_RAW_RGB_SELECT;
 376                 err = m5602_write_sensor(sd, OV9650_COM7, &data, 1);
 377                 break;
 378
 379         case 176:
 380                 PDEBUG(D_CONF, "Configuring camera for QCIF mode");
 381
 382                 data = OV9650_QCIF_SELECT | OV9650_RGB_SELECT |
 383                         OV9650_RAW_RGB_SELECT;
 384                 err = m5602_write_sensor(sd, OV9650_COM7, &data, 1);
 385                 break;
 386         }
 387         return err;
 388 }
 389
 390 int ov9650_stop(struct sd *sd)
 391 {
 392         u8 data = OV9650_SOFT_SLEEP | OV9650_OUTPUT_DRIVE_2X;
 393         return m5602_write_sensor(sd, OV9650_COM2, &data, 1);
 394 }
 395
 396 void ov9650_disconnect(struct sd *sd)
 397 {
 398         ov9650_stop(sd);
 399
 400         sd->sensor = NULL;
 401 }
 402
 403 static int ov9650_set_exposure(struct gspca_dev *gspca_dev, __s32 val)
 404 {
 405         struct sd *sd = (struct sd *) gspca_dev;
 406         u8 i2c_data;
 407         int err;
 408
 409         PDEBUG(D_CONF, "Set exposure to %d", val);
 410
 411         /* The 6 MSBs */
 412         i2c_data = (val >> 10) & 0x3f;
 413         err = m5602_write_sensor(sd, OV9650_AECHM,
 414                                   &i2c_data, 1);
 415         if (err < 0)
 416                 return err;
 417
 418         /* The 8 middle bits */
 419         i2c_data = (val >> 2) & 0xff;
 420         err = m5602_write_sensor(sd, OV9650_AECH,
 421                                   &i2c_data, 1);
 422         if (err < 0)
 423                 return err;
 424
 425         /* The 2 LSBs */
 426         i2c_data = val & 0x03;
 427         err = m5602_write_sensor(sd, OV9650_COM1, &i2c_data, 1);
 428         return err;
 429 }
 430
 431 static int ov9650_set_gain(struct gspca_dev *gspca_dev, __s32 val)
 432 {
 433         int err;
 434         u8 i2c_data;
 435         struct sd *sd = (struct sd *) gspca_dev;
 436
 437         PDEBUG(D_CONF, "Setting gain to %d", val);
 438
 439         /* The 2 MSB */
 440         /* Read the OV9650_VREF register first to avoid
 441            corrupting the VREF high and low bits */
 442         err = m5602_read_sensor(sd, OV9650_VREF, &i2c_data, 1);
 443         if (err < 0)
 444                 return err;
 445
 446         /* Mask away all uninteresting bits */
 447         i2c_data = ((val & 0x0300) >> 2) |
 448                         (i2c_data & 0x3f);
 449         err = m5602_write_sensor(sd, OV9650_VREF, &i2c_data, 1);
 450         if (err < 0)
 451                 return err;
 452
 453         /* The 8 LSBs */
 454         i2c_data = val & 0xff;
 455         err = m5602_write_sensor(sd, OV9650_GAIN, &i2c_data, 1);
 456         return err;
 457 }
 458
 459 static int ov9650_set_red_balance(struct gspca_dev *gspca_dev, __s32 val)
 460 {
 461         int err;
 462         u8 i2c_data;
 463         struct sd *sd = (struct sd *) gspca_dev;
 464
 465         PDEBUG(D_CONF, "Set red gain to %d", val);
 466
 467         i2c_data = val & 0xff;
 468         err = m5602_write_sensor(sd, OV9650_RED, &i2c_data, 1);
 469         return err;
 470 }
 471
 472 static int ov9650_set_blue_balance(struct gspca_dev *gspca_dev, __s32 val)
 473 {
 474         int err;
 475         u8 i2c_data;
 476         struct sd *sd = (struct sd *) gspca_dev;
 477
 478         PDEBUG(D_CONF, "Set blue gain to %d", val);
 479
 480         i2c_data = val & 0xff;
 481         err = m5602_write_sensor(sd, OV9650_BLUE, &i2c_data, 1);
 482         return err;
 483 }
 484
 485 static int ov9650_set_hvflip(struct gspca_dev *gspca_dev)
 486 {
 487         int err;
 488         u8 i2c_data;
 489         struct sd *sd = (struct sd *) gspca_dev;
 490         int hflip = sd->hflip->val;
 491         int vflip = sd->vflip->val;
 492
 493         PDEBUG(D_CONF, "Set hvflip to %d %d", hflip, vflip);
 494
 495         if (dmi_check_system(ov9650_flip_dmi_table))
 496                 vflip = !vflip;
 497
 498         i2c_data = (hflip << 5) | (vflip << 4);
 499         err = m5602_write_sensor(sd, OV9650_MVFP, &i2c_data, 1);
 500         if (err < 0)
 501                 return err;
 502
 503         /* When vflip is toggled we need to readjust the bridge hsync/vsync */
 504         if (gspca_dev->streaming)
 505                 err = ov9650_start(sd);
 506
 507         return err;
 508 }
 509
 510 static int ov9650_set_auto_exposure(struct gspca_dev *gspca_dev,
 511                                     __s32 val)
 512 {
 513         int err;
 514         u8 i2c_data;
 515         struct sd *sd = (struct sd *) gspca_dev;
 516
 517         PDEBUG(D_CONF, "Set auto exposure control to %d", val);
 518
 519         err = m5602_read_sensor(sd, OV9650_COM8, &i2c_data, 1);
 520         if (err < 0)
 521                 return err;
 522
 523         val = (val == V4L2_EXPOSURE_AUTO);
 524         i2c_data = ((i2c_data & 0xfe) | ((val & 0x01) << 0));
 525
 526         return m5602_write_sensor(sd, OV9650_COM8, &i2c_data, 1);
 527 }
 528
 529 static int ov9650_set_auto_white_balance(struct gspca_dev *gspca_dev,
 530                                          __s32 val)
 531 {
 532         int err;
 533         u8 i2c_data;
 534         struct sd *sd = (struct sd *) gspca_dev;
 535
 536         PDEBUG(D_CONF, "Set auto white balance to %d", val);
 537
 538         err = m5602_read_sensor(sd, OV9650_COM8, &i2c_data, 1);
 539         if (err < 0)
 540                 return err;
 541
 542         i2c_data = ((i2c_data & 0xfd) | ((val & 0x01) << 1));
 543         err = m5602_write_sensor(sd, OV9650_COM8, &i2c_data, 1);
 544
 545         return err;
 546 }
 547
 548 static int ov9650_set_auto_gain(struct gspca_dev *gspca_dev, __s32 val)
 549 {
 550         int err;
 551         u8 i2c_data;
 552         struct sd *sd = (struct sd *) gspca_dev;
 553
 554         PDEBUG(D_CONF, "Set auto gain control to %d", val);
 555
 556         err = m5602_read_sensor(sd, OV9650_COM8, &i2c_data, 1);
 557         if (err < 0)
 558                 return err;
 559
 560         i2c_data = ((i2c_data & 0xfb) | ((val & 0x01) << 2));
 561
 562         return m5602_write_sensor(sd, OV9650_COM8, &i2c_data, 1);
 563 }
 564
 565 static int ov9650_s_ctrl(struct v4l2_ctrl *ctrl)
 566 {
 567         struct gspca_dev *gspca_dev =
 568                 container_of(ctrl->handler, struct gspca_dev, ctrl_handler);
 569         struct sd *sd = (struct sd *) gspca_dev;
 570         int err;
 571
 572         if (!gspca_dev->streaming)
 573                 return 0;
 574
 575         switch (ctrl->id) {
 576         case V4L2_CID_AUTO_WHITE_BALANCE:
 577                 err = ov9650_set_auto_white_balance(gspca_dev, ctrl->val);
 578                 if (err || ctrl->val)
 579                         return err;
 580                 err = ov9650_set_red_balance(gspca_dev, sd->red_bal->val);
 581                 if (err)
 582                         return err;
 583                 err = ov9650_set_blue_balance(gspca_dev, sd->blue_bal->val);
 584                 break;
 585         case V4L2_CID_EXPOSURE_AUTO:
 586                 err = ov9650_set_auto_exposure(gspca_dev, ctrl->val);
 587                 if (err || ctrl->val == V4L2_EXPOSURE_AUTO)
 588                         return err;
 589                 err = ov9650_set_exposure(gspca_dev, sd->expo->val);
 590                 break;
 591         case V4L2_CID_AUTOGAIN:
 592                 err = ov9650_set_auto_gain(gspca_dev, ctrl->val);
 593                 if (err || ctrl->val)
 594                         return err;
 595                 err = ov9650_set_gain(gspca_dev, sd->gain->val);
 596                 break;
 597         case V4L2_CID_HFLIP:
 598                 err = ov9650_set_hvflip(gspca_dev);
 599                 break;
 600         default:
 601                 return -EINVAL;
 602         }
 603
 604         return err;
 605 }
 606
 607 static void ov9650_dump_registers(struct sd *sd)
 608 {
 609         int address;
 610         pr_info("Dumping the ov9650 register state\n");
 611         for (address = 0; address < 0xa9; address++) {
 612                 u8 value;
 613                 m5602_read_sensor(sd, address, &value, 1);
 614                 pr_info("register 0x%x contains 0x%x\n", address, value);
 615         }
 616
 617         pr_info("ov9650 register state dump complete\n");
 618
 619         pr_info("Probing for which registers that are read/write\n");
 620         for (address = 0; address < 0xff; address++) {
 621                 u8 old_value, ctrl_value;
 622                 u8 test_value[2] = {0xff, 0xff};
 623
 624                 m5602_read_sensor(sd, address, &old_value, 1);
 625                 m5602_write_sensor(sd, address, test_value, 1);
 626                 m5602_read_sensor(sd, address, &ctrl_value, 1);
 627
 628                 if (ctrl_value == test_value[0])
 629                         pr_info("register 0x%x is writeable\n", address);
 630                 else
 631                         pr_info("register 0x%x is read only\n", address);
 632
 633                 /* Restore original value */
 634                 m5602_write_sensor(sd, address, &old_value, 1);
 635         }
 636 }