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 = devm_backlight_device_register(&pdev->dev,
 244                                        su->type == AS3711_BL_SU1 ?
 245                                        "as3711-su1" : "as3711-su2",
 246                                        &pdev->dev, su,
 247                                        &as3711_bl_ops, &props);
 248         if (IS_ERR(bl)) {
 249                 dev_err(&pdev->dev, "failed to register backlight\n");
 250                 return PTR_ERR(bl);
 251         }
 252
 253         bl->props.brightness = props.max_brightness;
 254
 255         backlight_update_status(bl);
 256
 257         su->bl = bl;
 258
 259         return 0;
 260 }
 261
 262 static int as3711_backlight_parse_dt(struct device *dev)
 263 {
 264         struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
 265         struct device_node *bl =
 266                 of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
 267         int ret;
 268
 269         if (!bl) {
 270                 dev_dbg(dev, "backlight node not found\n");
 271                 return -ENODEV;
 272         }
 273
 274         fb = of_parse_phandle(bl, "su1-dev", 0);
 275         if (fb) {
 276                 pdata->su1_fb = fb->full_name;
 277
 278                 ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
 279                 if (pdata->su1_max_uA <= 0)
 280                         ret = -EINVAL;
 281                 if (ret < 0)
 282                         return ret;
 283         }
 284
 285         fb = of_parse_phandle(bl, "su2-dev", 0);
 286         if (fb) {
 287                 int count = 0;
 288
 289                 pdata->su2_fb = fb->full_name;
 290
 291                 ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
 292                 if (pdata->su2_max_uA <= 0)
 293                         ret = -EINVAL;
 294                 if (ret < 0)
 295                         return ret;
 296
 297                 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
 298                         pdata->su2_feedback = AS3711_SU2_VOLTAGE;
 299                         count++;
 300                 }
 301                 if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
 302                         pdata->su2_feedback = AS3711_SU2_CURR1;
 303                         count++;
 304                 }
 305                 if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
 306                         pdata->su2_feedback = AS3711_SU2_CURR2;
 307                         count++;
 308                 }
 309                 if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
 310                         pdata->su2_feedback = AS3711_SU2_CURR3;
 311                         count++;
 312                 }
 313                 if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
 314                         pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
 315                         count++;
 316                 }
 317                 if (count != 1)
 318                         return -EINVAL;
 319
 320                 count = 0;
 321                 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
 322                         pdata->su2_fbprot = AS3711_SU2_LX_SD4;
 323                         count++;
 324                 }
 325                 if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
 326                         pdata->su2_fbprot = AS3711_SU2_GPIO2;
 327                         count++;
 328                 }
 329                 if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
 330                         pdata->su2_fbprot = AS3711_SU2_GPIO3;
 331                         count++;
 332                 }
 333                 if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
 334                         pdata->su2_fbprot = AS3711_SU2_GPIO4;
 335                         count++;
 336                 }
 337                 if (count != 1)
 338                         return -EINVAL;
 339
 340                 count = 0;
 341                 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
 342                         pdata->su2_auto_curr1 = true;
 343                         count++;
 344                 }
 345                 if (of_find_property(bl, "su2-auto-curr2", NULL)) {
 346                         pdata->su2_auto_curr2 = true;
 347                         count++;
 348                 }
 349                 if (of_find_property(bl, "su2-auto-curr3", NULL)) {
 350                         pdata->su2_auto_curr3 = true;
 351                         count++;
 352                 }
 353
 354                 /*
 355                  * At least one su2-auto-curr* must be specified iff
 356                  * AS3711_SU2_CURR_AUTO is used
 357                  */
 358                 if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
 359                         return -EINVAL;
 360         }
 361
 362         return 0;
 363 }
 364
 365 static int as3711_backlight_probe(struct platform_device *pdev)
 366 {
 367         struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
 368         struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
 369         struct as3711_bl_supply *supply;
 370         struct as3711_bl_data *su;
 371         unsigned int max_brightness;
 372         int ret;
 373
 374         if (!pdata) {
 375                 dev_err(&pdev->dev, "No platform data, exiting...\n");
 376                 return -ENODEV;
 377         }
 378
 379         if (pdev->dev.parent->of_node) {
 380                 ret = as3711_backlight_parse_dt(&pdev->dev);
 381                 if (ret < 0) {
 382                         dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
 383                         return ret;
 384                 }
 385         }
 386
 387         if (!pdata->su1_fb && !pdata->su2_fb) {
 388                 dev_err(&pdev->dev, "No framebuffer specified\n");
 389                 return -EINVAL;
 390         }
 391
 392         /*
 393          * Due to possible hardware damage I chose to block all modes,
 394          * unsupported on my hardware. Anyone, wishing to use any of those modes
 395          * will have to first review the code, then activate and test it.
 396          */
 397         if (pdata->su1_fb ||
 398             pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
 399             pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
 400                 dev_warn(&pdev->dev,
 401                          "Attention! An untested mode has been chosen!\n"
 402                          "Please, review the code, enable, test, and report success:-)\n");
 403                 return -EINVAL;
 404         }
 405
 406         supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
 407         if (!supply)
 408                 return -ENOMEM;
 409
 410         supply->as3711 = as3711;
 411         supply->pdata = pdata;
 412
 413         if (pdata->su1_fb) {
 414                 su = &supply->su1;
 415                 su->fb_name = pdata->su1_fb;
 416                 su->type = AS3711_BL_SU1;
 417
 418                 max_brightness = min(pdata->su1_max_uA, 31);
 419                 ret = as3711_bl_register(pdev, max_brightness, su);
 420                 if (ret < 0)
 421                         return ret;
 422         }
 423
 424         if (pdata->su2_fb) {
 425                 su = &supply->su2;
 426                 su->fb_name = pdata->su2_fb;
 427                 su->type = AS3711_BL_SU2;
 428
 429                 switch (pdata->su2_fbprot) {
 430                 case AS3711_SU2_GPIO2:
 431                 case AS3711_SU2_GPIO3:
 432                 case AS3711_SU2_GPIO4:
 433                 case AS3711_SU2_LX_SD4:
 434                         break;
 435                 default:
 436                         return -EINVAL;
 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                         return -EINVAL;
 451                 }
 452
 453                 ret = as3711_bl_init_su2(supply);
 454                 if (ret < 0)
 455                         return ret;
 456
 457                 ret = as3711_bl_register(pdev, max_brightness, su);
 458                 if (ret < 0)
 459                         return ret;
 460         }
 461
 462         platform_set_drvdata(pdev, supply);
 463
 464         return 0;
 465 }
 466
 467 static struct platform_driver as3711_backlight_driver = {
 468         .driver         = {
 469                 .name   = "as3711-backlight",
 470         },
 471         .probe          = as3711_backlight_probe,
 472 };
 473
 474 module_platform_driver(as3711_backlight_driver);
 475
 476 MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
 477 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
 478 MODULE_LICENSE("GPL");
 479 MODULE_ALIAS("platform:as3711-backlight");