drivers/video/backlight/as3711_bl.c

   1 /*
   2  * AS3711 PMIC backlight driver, using DCDC Step Up Converters
   3  *
   4  * Copyright (C) 2012 Renesas Electronics Corporation
   5  * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the version 2 of the GNU General Public License as
   9  * published by the Free Software Foundation
  10  */
  11
  12 #include <linux/backlight.h>
  13 #include <linux/delay.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/fb.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mfd/as3711.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regmap.h>
  22 #include <linux/slab.h>
  23
  24 enum as3711_bl_type {
  25         AS3711_BL_SU1,
  26         AS3711_BL_SU2,
  27 };
  28
  29 struct as3711_bl_data {
  30         bool powered;
  31         const char *fb_name;
  32         struct device *fb_dev;
  33         enum as3711_bl_type type;
  34         int brightness;
  35         struct backlight_device *bl;
  36 };
  37
  38 struct as3711_bl_supply {
  39         struct as3711_bl_data su1;
  40         struct as3711_bl_data su2;
  41         const struct as3711_bl_pdata *pdata;
  42         struct as3711 *as3711;
  43 };
  44
  45 static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
  46 {
  47         switch (su->type) {
  48         case AS3711_BL_SU1:
  49                 return container_of(su, struct as3711_bl_supply, su1);
  50         case AS3711_BL_SU2:
  51                 return container_of(su, struct as3711_bl_supply, su2);
  52         }
  53         return NULL;
  54 }
  55
  56 static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
  57                                         unsigned int brightness)
  58 {
  59         struct as3711_bl_supply *supply = to_supply(data);
  60         struct as3711 *as3711 = supply->as3711;
  61         const struct as3711_bl_pdata *pdata = supply->pdata;
  62         int ret = 0;
  63
  64         /* Only all equal current values are supported */
  65         if (pdata->su2_auto_curr1)
  66                 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
  67                                    brightness);
  68         if (!ret && pdata->su2_auto_curr2)
  69                 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
  70                                    brightness);
  71         if (!ret && pdata->su2_auto_curr3)
  72                 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
  73                                    brightness);
  74
  75         return ret;
  76 }
  77
  78 static int as3711_set_brightness_v(struct as3711 *as3711,
  79                                    unsigned int brightness,
  80                                    unsigned int reg)
  81 {
  82         if (brightness > 31)
  83                 return -EINVAL;
  84
  85         return regmap_update_bits(as3711->regmap, reg, 0xf0,
  86                                   brightness << 4);
  87 }
  88
  89 static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
  90 {
  91         struct as3711 *as3711 = supply->as3711;
  92         int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
  93                                      3, supply->pdata->su2_fbprot);
  94         if (!ret)
  95                 ret = regmap_update_bits(as3711->regmap,
  96                                          AS3711_STEPUP_CONTROL_2, 1, 0);
  97         if (!ret)
  98                 ret = regmap_update_bits(as3711->regmap,
  99                                          AS3711_STEPUP_CONTROL_2, 1, 1);
 100         return ret;
 101 }
 102
 103 /*
 104  * Someone with less fragile or less expensive hardware could try to simplify
 105  * the brightness adjustment procedure.
 106  */
 107 static int as3711_bl_update_status(struct backlight_device *bl)
 108 {
 109         struct as3711_bl_data *data = bl_get_data(bl);
 110         struct as3711_bl_supply *supply = to_supply(data);
 111         struct as3711 *as3711 = supply->as3711;
 112         int brightness = bl->props.brightness;
 113         int ret = 0;
 114
 115         dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
 116                 __func__, bl->props.brightness, bl->props.power,
 117                 bl->props.fb_blank, bl->props.state);
 118
 119         if (bl->props.power != FB_BLANK_UNBLANK ||
 120             bl->props.fb_blank != FB_BLANK_UNBLANK ||
 121             bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 122                 brightness = 0;
 123
 124         if (data->type == AS3711_BL_SU1) {
 125                 ret = as3711_set_brightness_v(as3711, brightness,
 126                                               AS3711_STEPUP_CONTROL_1);
 127         } else {
 128                 const struct as3711_bl_pdata *pdata = supply->pdata;
 129
 130                 switch (pdata->su2_feedback) {
 131                 case AS3711_SU2_VOLTAGE:
 132                         ret = as3711_set_brightness_v(as3711, brightness,
 133                                                       AS3711_STEPUP_CONTROL_2);
 134                         break;
 135                 case AS3711_SU2_CURR_AUTO:
 136                         ret = as3711_set_brightness_auto_i(data, brightness / 4);
 137                         if (ret < 0)
 138                                 return ret;
 139                         if (brightness) {
 140                                 ret = as3711_bl_su2_reset(supply);
 141                                 if (ret < 0)
 142                                         return ret;
 143                                 udelay(500);
 144                                 ret = as3711_set_brightness_auto_i(data, brightness);
 145                         } else {
 146                                 ret = regmap_update_bits(as3711->regmap,
 147                                                 AS3711_STEPUP_CONTROL_2, 1, 0);
 148                         }
 149                         break;
 150                 /* Manual one current feedback pin below */
 151                 case AS3711_SU2_CURR1:
 152                         ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
 153                                            brightness);
 154                         break;
 155                 case AS3711_SU2_CURR2:
 156                         ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
 157                                            brightness);
 158                         break;
 159                 case AS3711_SU2_CURR3:
 160                         ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
 161                                            brightness);
 162                         break;
 163                 default:
 164                         ret = -EINVAL;
 165                 }
 166         }
 167         if (!ret)
 168                 data->brightness = brightness;
 169
 170         return ret;
 171 }
 172
 173 static int as3711_bl_get_brightness(struct backlight_device *bl)
 174 {
 175         struct as3711_bl_data *data = bl_get_data(bl);
 176
 177         return data->brightness;
 178 }
 179
 180 static const struct backlight_ops as3711_bl_ops = {
 181         .update_status  = as3711_bl_update_status,
 182         .get_brightness = as3711_bl_get_brightness,
 183 };
 184
 185 static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
 186 {
 187         struct as3711 *as3711 = supply->as3711;
 188         const struct as3711_bl_pdata *pdata = supply->pdata;
 189         u8 ctl = 0;
 190         int ret;
 191
 192         dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
 193
 194         /* Turn SU2 off */
 195         ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
 196         if (ret < 0)
 197                 return ret;
 198
 199         switch (pdata->su2_feedback) {
 200         case AS3711_SU2_VOLTAGE:
 201                 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
 202                 break;
 203         case AS3711_SU2_CURR1:
 204                 ctl = 1;
 205                 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
 206                 break;
 207         case AS3711_SU2_CURR2:
 208                 ctl = 4;
 209                 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
 210                 break;
 211         case AS3711_SU2_CURR3:
 212                 ctl = 0x10;
 213                 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
 214                 break;
 215         case AS3711_SU2_CURR_AUTO:
 216                 if (pdata->su2_auto_curr1)
 217                         ctl = 2;
 218                 if (pdata->su2_auto_curr2)
 219                         ctl |= 8;
 220                 if (pdata->su2_auto_curr3)
 221                         ctl |= 0x20;
 222                 ret = 0;
 223                 break;
 224         default:
 225                 return -EINVAL;
 226         }
 227
 228         if (!ret)
 229                 ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
 230
 231         return ret;
 232 }
 233
 234 static int as3711_bl_register(struct platform_device *pdev,
 235                               unsigned int max_brightness, struct as3711_bl_data *su)
 236 {
 237         struct backlight_properties props = {.type = BACKLIGHT_RAW,};
 238         struct backlight_device *bl;
 239
 240         /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
 241         props.max_brightness = max_brightness;
 242
 243         bl = backlight_device_register(su->type == AS3711_BL_SU1 ?
 244                                        "as3711-su1" : "as3711-su2",
 245                                        &pdev->dev, su,
 246                                        &as3711_bl_ops, &props);
 247         if (IS_ERR(bl)) {
 248                 dev_err(&pdev->dev, "failed to register backlight\n");
 249                 return PTR_ERR(bl);
 250         }
 251
 252         bl->props.brightness = props.max_brightness;
 253
 254         backlight_update_status(bl);
 255
 256         su->bl = bl;
 257
 258         return 0;
 259 }
 260
 261 static int as3711_backlight_parse_dt(struct device *dev)
 262 {
 263         struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
 264         struct device_node *bl =
 265                 of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
 266         int ret;
 267
 268         if (!bl) {
 269                 dev_dbg(dev, "backlight node not found\n");
 270                 return -ENODEV;
 271         }
 272
 273         fb = of_parse_phandle(bl, "su1-dev", 0);
 274         if (fb) {
 275                 pdata->su1_fb = fb->full_name;
 276
 277                 ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
 278                 if (pdata->su1_max_uA <= 0)
 279                         ret = -EINVAL;
 280                 if (ret < 0)
 281                         return ret;
 282         }
 283
 284         fb = of_parse_phandle(bl, "su2-dev", 0);
 285         if (fb) {
 286                 int count = 0;
 287
 288                 pdata->su2_fb = fb->full_name;
 289
 290                 ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
 291                 if (pdata->su2_max_uA <= 0)
 292                         ret = -EINVAL;
 293                 if (ret < 0)
 294                         return ret;
 295
 296                 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
 297                         pdata->su2_feedback = AS3711_SU2_VOLTAGE;
 298                         count++;
 299                 }
 300                 if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
 301                         pdata->su2_feedback = AS3711_SU2_CURR1;
 302                         count++;
 303                 }
 304                 if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
 305                         pdata->su2_feedback = AS3711_SU2_CURR2;
 306                         count++;
 307                 }
 308                 if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
 309                         pdata->su2_feedback = AS3711_SU2_CURR3;
 310                         count++;
 311                 }
 312                 if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
 313                         pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
 314                         count++;
 315                 }
 316                 if (count != 1)
 317                         return -EINVAL;
 318
 319                 count = 0;
 320                 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
 321                         pdata->su2_fbprot = AS3711_SU2_LX_SD4;
 322                         count++;
 323                 }
 324                 if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
 325                         pdata->su2_fbprot = AS3711_SU2_GPIO2;
 326                         count++;
 327                 }
 328                 if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
 329                         pdata->su2_fbprot = AS3711_SU2_GPIO3;
 330                         count++;
 331                 }
 332                 if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
 333                         pdata->su2_fbprot = AS3711_SU2_GPIO4;
 334                         count++;
 335                 }
 336                 if (count != 1)
 337                         return -EINVAL;
 338
 339                 count = 0;
 340                 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
 341                         pdata->su2_auto_curr1 = true;
 342                         count++;
 343                 }
 344                 if (of_find_property(bl, "su2-auto-curr2", NULL)) {
 345                         pdata->su2_auto_curr2 = true;
 346                         count++;
 347                 }
 348                 if (of_find_property(bl, "su2-auto-curr3", NULL)) {
 349                         pdata->su2_auto_curr3 = true;
 350                         count++;
 351                 }
 352
 353                 /*
 354                  * At least one su2-auto-curr* must be specified iff
 355                  * AS3711_SU2_CURR_AUTO is used
 356                  */
 357                 if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
 358                         return -EINVAL;
 359         }
 360
 361         return 0;
 362 }
 363
 364 static int as3711_backlight_probe(struct platform_device *pdev)
 365 {
 366         struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
 367         struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
 368         struct as3711_bl_supply *supply;
 369         struct as3711_bl_data *su;
 370         unsigned int max_brightness;
 371         int ret;
 372
 373         if (!pdata) {
 374                 dev_err(&pdev->dev, "No platform data, exiting...\n");
 375                 return -ENODEV;
 376         }
 377
 378         if (pdev->dev.parent->of_node) {
 379                 ret = as3711_backlight_parse_dt(&pdev->dev);
 380                 if (ret < 0) {
 381                         dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
 382                         return ret;
 383                 }
 384         }
 385
 386         if (!pdata->su1_fb && !pdata->su2_fb) {
 387                 dev_err(&pdev->dev, "No framebuffer specified\n");
 388                 return -EINVAL;
 389         }
 390
 391         /*
 392          * Due to possible hardware damage I chose to block all modes,
 393          * unsupported on my hardware. Anyone, wishing to use any of those modes
 394          * will have to first review the code, then activate and test it.
 395          */
 396         if (pdata->su1_fb ||
 397             pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
 398             pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
 399                 dev_warn(&pdev->dev,
 400                          "Attention! An untested mode has been chosen!\n"
 401                          "Please, review the code, enable, test, and report success:-)\n");
 402                 return -EINVAL;
 403         }
 404
 405         supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
 406         if (!supply)
 407                 return -ENOMEM;
 408
 409         supply->as3711 = as3711;
 410         supply->pdata = pdata;
 411
 412         if (pdata->su1_fb) {
 413                 su = &supply->su1;
 414                 su->fb_name = pdata->su1_fb;
 415                 su->type = AS3711_BL_SU1;
 416
 417                 max_brightness = min(pdata->su1_max_uA, 31);
 418                 ret = as3711_bl_register(pdev, max_brightness, su);
 419                 if (ret < 0)
 420                         return ret;
 421         }
 422
 423         if (pdata->su2_fb) {
 424                 su = &supply->su2;
 425                 su->fb_name = pdata->su2_fb;
 426                 su->type = AS3711_BL_SU2;
 427
 428                 switch (pdata->su2_fbprot) {
 429                 case AS3711_SU2_GPIO2:
 430                 case AS3711_SU2_GPIO3:
 431                 case AS3711_SU2_GPIO4:
 432                 case AS3711_SU2_LX_SD4:
 433                         break;
 434                 default:
 435                         ret = -EINVAL;
 436                         goto esu2;
 437                 }
 438
 439                 switch (pdata->su2_feedback) {
 440                 case AS3711_SU2_VOLTAGE:
 441                         max_brightness = min(pdata->su2_max_uA, 31);
 442                         break;
 443                 case AS3711_SU2_CURR1:
 444                 case AS3711_SU2_CURR2:
 445                 case AS3711_SU2_CURR3:
 446                 case AS3711_SU2_CURR_AUTO:
 447                         max_brightness = min(pdata->su2_max_uA / 150, 255);
 448                         break;
 449                 default:
 450                         ret = -EINVAL;
 451                         goto esu2;
 452                 }
 453
 454                 ret = as3711_bl_init_su2(supply);
 455                 if (ret < 0)
 456                         return ret;
 457
 458                 ret = as3711_bl_register(pdev, max_brightness, su);
 459                 if (ret < 0)
 460                         goto esu2;
 461         }
 462
 463         platform_set_drvdata(pdev, supply);
 464
 465         return 0;
 466
 467 esu2:
 468         backlight_device_unregister(supply->su1.bl);
 469         return ret;
 470 }
 471
 472 static int as3711_backlight_remove(struct platform_device *pdev)
 473 {
 474         struct as3711_bl_supply *supply = platform_get_drvdata(pdev);
 475
 476         backlight_device_unregister(supply->su1.bl);
 477         backlight_device_unregister(supply->su2.bl);
 478
 479         return 0;
 480 }
 481
 482 static struct platform_driver as3711_backlight_driver = {
 483         .driver         = {
 484                 .name   = "as3711-backlight",
 485                 .owner  = THIS_MODULE,
 486         },
 487         .probe          = as3711_backlight_probe,
 488         .remove         = as3711_backlight_remove,
 489 };
 490
 491 module_platform_driver(as3711_backlight_driver);
 492
 493 MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
 494 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
 495 MODULE_LICENSE("GPL");
 496 MODULE_ALIAS("platform:as3711-backlight");