drivers/video/backlight/lp855x_bl.c

   1 /*
   2  * TI LP855x Backlight Driver
   3  *
   4  *                      Copyright (C) 2011 Texas Instruments
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/i2c.h>
  15 #include <linux/backlight.h>
  16 #include <linux/err.h>
  17 #include <linux/of.h>
  18 #include <linux/platform_data/lp855x.h>
  19 #include <linux/pwm.h>
  20 #include <linux/regulator/consumer.h>
  21
  22 /* LP8550/1/2/3/6 Registers */
  23 #define LP855X_BRIGHTNESS_CTRL          0x00
  24 #define LP855X_DEVICE_CTRL              0x01
  25 #define LP855X_EEPROM_START             0xA0
  26 #define LP855X_EEPROM_END               0xA7
  27 #define LP8556_EPROM_START              0xA0
  28 #define LP8556_EPROM_END                0xAF
  29
  30 /* LP8555/7 Registers */
  31 #define LP8557_BL_CMD                   0x00
  32 #define LP8557_BL_MASK                  0x01
  33 #define LP8557_BL_ON                    0x01
  34 #define LP8557_BL_OFF                   0x00
  35 #define LP8557_BRIGHTNESS_CTRL          0x04
  36 #define LP8557_CONFIG                   0x10
  37 #define LP8555_EPROM_START              0x10
  38 #define LP8555_EPROM_END                0x7A
  39 #define LP8557_EPROM_START              0x10
  40 #define LP8557_EPROM_END                0x1E
  41
  42 #define DEFAULT_BL_NAME         "lcd-backlight"
  43 #define MAX_BRIGHTNESS          255
  44
  45 enum lp855x_brightness_ctrl_mode {
  46         PWM_BASED = 1,
  47         REGISTER_BASED,
  48 };
  49
  50 struct lp855x;
  51
  52 /*
  53  * struct lp855x_device_config
  54  * @pre_init_device: init device function call before updating the brightness
  55  * @reg_brightness: register address for brigthenss control
  56  * @reg_devicectrl: register address for device control
  57  * @post_init_device: late init device function call
  58  */
  59 struct lp855x_device_config {
  60         int (*pre_init_device)(struct lp855x *);
  61         u8 reg_brightness;
  62         u8 reg_devicectrl;
  63         int (*post_init_device)(struct lp855x *);
  64 };
  65
  66 struct lp855x {
  67         const char *chipname;
  68         enum lp855x_chip_id chip_id;
  69         enum lp855x_brightness_ctrl_mode mode;
  70         struct lp855x_device_config *cfg;
  71         struct i2c_client *client;
  72         struct backlight_device *bl;
  73         struct device *dev;
  74         struct lp855x_platform_data *pdata;
  75         struct pwm_device *pwm;
  76 };
  77
  78 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  79 {
  80         return i2c_smbus_write_byte_data(lp->client, reg, data);
  81 }
  82
  83 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
  84 {
  85         int ret;
  86         u8 tmp;
  87
  88         ret = i2c_smbus_read_byte_data(lp->client, reg);
  89         if (ret < 0) {
  90                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  91                 return ret;
  92         }
  93
  94         tmp = (u8)ret;
  95         tmp &= ~mask;
  96         tmp |= data & mask;
  97
  98         return lp855x_write_byte(lp, reg, tmp);
  99 }
 100
 101 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
 102 {
 103         u8 start, end;
 104
 105         switch (lp->chip_id) {
 106         case LP8550:
 107         case LP8551:
 108         case LP8552:
 109         case LP8553:
 110                 start = LP855X_EEPROM_START;
 111                 end = LP855X_EEPROM_END;
 112                 break;
 113         case LP8556:
 114                 start = LP8556_EPROM_START;
 115                 end = LP8556_EPROM_END;
 116                 break;
 117         case LP8555:
 118                 start = LP8555_EPROM_START;
 119                 end = LP8555_EPROM_END;
 120                 break;
 121         case LP8557:
 122                 start = LP8557_EPROM_START;
 123                 end = LP8557_EPROM_END;
 124                 break;
 125         default:
 126                 return false;
 127         }
 128
 129         return addr >= start && addr <= end;
 130 }
 131
 132 static int lp8557_bl_off(struct lp855x *lp)
 133 {
 134         /* BL_ON = 0 before updating EPROM settings */
 135         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 136                                 LP8557_BL_OFF);
 137 }
 138
 139 static int lp8557_bl_on(struct lp855x *lp)
 140 {
 141         /* BL_ON = 1 after updating EPROM settings */
 142         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 143                                 LP8557_BL_ON);
 144 }
 145
 146 static struct lp855x_device_config lp855x_dev_cfg = {
 147         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
 148         .reg_devicectrl = LP855X_DEVICE_CTRL,
 149 };
 150
 151 static struct lp855x_device_config lp8557_dev_cfg = {
 152         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
 153         .reg_devicectrl = LP8557_CONFIG,
 154         .pre_init_device = lp8557_bl_off,
 155         .post_init_device = lp8557_bl_on,
 156 };
 157
 158 /*
 159  * Device specific configuration flow
 160  *
 161  *    a) pre_init_device(optional)
 162  *    b) update the brightness register
 163  *    c) update device control register
 164  *    d) update ROM area(optional)
 165  *    e) post_init_device(optional)
 166  *
 167  */
 168 static int lp855x_configure(struct lp855x *lp)
 169 {
 170         u8 val, addr;
 171         int i, ret;
 172         struct lp855x_platform_data *pd = lp->pdata;
 173
 174         switch (lp->chip_id) {
 175         case LP8550:
 176         case LP8551:
 177         case LP8552:
 178         case LP8553:
 179         case LP8556:
 180                 lp->cfg = &lp855x_dev_cfg;
 181                 break;
 182         case LP8555:
 183         case LP8557:
 184                 lp->cfg = &lp8557_dev_cfg;
 185                 break;
 186         default:
 187                 return -EINVAL;
 188         }
 189
 190         if (lp->cfg->pre_init_device) {
 191                 ret = lp->cfg->pre_init_device(lp);
 192                 if (ret) {
 193                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 194                         goto err;
 195                 }
 196         }
 197
 198         val = pd->initial_brightness;
 199         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 200         if (ret)
 201                 goto err;
 202
 203         val = pd->device_control;
 204         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 205         if (ret)
 206                 goto err;
 207
 208         if (pd->size_program > 0) {
 209                 for (i = 0; i < pd->size_program; i++) {
 210                         addr = pd->rom_data[i].addr;
 211                         val = pd->rom_data[i].val;
 212                         if (!lp855x_is_valid_rom_area(lp, addr))
 213                                 continue;
 214
 215                         ret = lp855x_write_byte(lp, addr, val);
 216                         if (ret)
 217                                 goto err;
 218                 }
 219         }
 220
 221         if (lp->cfg->post_init_device) {
 222                 ret = lp->cfg->post_init_device(lp);
 223                 if (ret) {
 224                         dev_err(lp->dev, "post init device err: %d\n", ret);
 225                         goto err;
 226                 }
 227         }
 228
 229         return 0;
 230
 231 err:
 232         return ret;
 233 }
 234
 235 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 236 {
 237         unsigned int period = lp->pdata->period_ns;
 238         unsigned int duty = br * period / max_br;
 239         struct pwm_device *pwm;
 240
 241         /* request pwm device with the consumer name */
 242         if (!lp->pwm) {
 243                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 244                 if (IS_ERR(pwm))
 245                         return;
 246
 247                 lp->pwm = pwm;
 248         }
 249
 250         pwm_config(lp->pwm, duty, period);
 251         if (duty)
 252                 pwm_enable(lp->pwm);
 253         else
 254                 pwm_disable(lp->pwm);
 255 }
 256
 257 static int lp855x_bl_update_status(struct backlight_device *bl)
 258 {
 259         struct lp855x *lp = bl_get_data(bl);
 260
 261         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 262                 bl->props.brightness = 0;
 263
 264         if (lp->mode == PWM_BASED) {
 265                 int br = bl->props.brightness;
 266                 int max_br = bl->props.max_brightness;
 267
 268                 lp855x_pwm_ctrl(lp, br, max_br);
 269
 270         } else if (lp->mode == REGISTER_BASED) {
 271                 u8 val = bl->props.brightness;
 272
 273                 lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 274         }
 275
 276         return 0;
 277 }
 278
 279 static const struct backlight_ops lp855x_bl_ops = {
 280         .options = BL_CORE_SUSPENDRESUME,
 281         .update_status = lp855x_bl_update_status,
 282 };
 283
 284 static int lp855x_backlight_register(struct lp855x *lp)
 285 {
 286         struct backlight_device *bl;
 287         struct backlight_properties props;
 288         struct lp855x_platform_data *pdata = lp->pdata;
 289         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 290
 291         props.type = BACKLIGHT_PLATFORM;
 292         props.max_brightness = MAX_BRIGHTNESS;
 293
 294         if (pdata->initial_brightness > props.max_brightness)
 295                 pdata->initial_brightness = props.max_brightness;
 296
 297         props.brightness = pdata->initial_brightness;
 298
 299         bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
 300                                        &lp855x_bl_ops, &props);
 301         if (IS_ERR(bl))
 302                 return PTR_ERR(bl);
 303
 304         lp->bl = bl;
 305
 306         return 0;
 307 }
 308
 309 static ssize_t lp855x_get_chip_id(struct device *dev,
 310                                 struct device_attribute *attr, char *buf)
 311 {
 312         struct lp855x *lp = dev_get_drvdata(dev);
 313
 314         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
 315 }
 316
 317 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 318                                      struct device_attribute *attr, char *buf)
 319 {
 320         struct lp855x *lp = dev_get_drvdata(dev);
 321         char *strmode = NULL;
 322
 323         if (lp->mode == PWM_BASED)
 324                 strmode = "pwm based";
 325         else if (lp->mode == REGISTER_BASED)
 326                 strmode = "register based";
 327
 328         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 329 }
 330
 331 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 332 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 333
 334 static struct attribute *lp855x_attributes[] = {
 335         &dev_attr_chip_id.attr,
 336         &dev_attr_bl_ctl_mode.attr,
 337         NULL,
 338 };
 339
 340 static const struct attribute_group lp855x_attr_group = {
 341         .attrs = lp855x_attributes,
 342 };
 343
 344 #ifdef CONFIG_OF
 345 static int lp855x_parse_dt(struct lp855x *lp)
 346 {
 347         struct device *dev = lp->dev;
 348         struct device_node *node = dev->of_node;
 349         struct lp855x_platform_data *pdata;
 350         int rom_length;
 351
 352         if (!node) {
 353                 dev_err(dev, "no platform data\n");
 354                 return -EINVAL;
 355         }
 356
 357         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 358         if (!pdata)
 359                 return -ENOMEM;
 360
 361         of_property_read_string(node, "bl-name", &pdata->name);
 362         of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 363         of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
 364         of_property_read_u32(node, "pwm-period", &pdata->period_ns);
 365
 366         /* Fill ROM platform data if defined */
 367         rom_length = of_get_child_count(node);
 368         if (rom_length > 0) {
 369                 struct lp855x_rom_data *rom;
 370                 struct device_node *child;
 371                 int i = 0;
 372
 373                 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
 374                 if (!rom)
 375                         return -ENOMEM;
 376
 377                 for_each_child_of_node(node, child) {
 378                         of_property_read_u8(child, "rom-addr", &rom[i].addr);
 379                         of_property_read_u8(child, "rom-val", &rom[i].val);
 380                         i++;
 381                 }
 382
 383                 pdata->size_program = rom_length;
 384                 pdata->rom_data = &rom[0];
 385         }
 386
 387         pdata->supply = devm_regulator_get(dev, "power");
 388         if (IS_ERR(pdata->supply)) {
 389                 if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
 390                         return -EPROBE_DEFER;
 391                 pdata->supply = NULL;
 392         }
 393
 394         lp->pdata = pdata;
 395
 396         return 0;
 397 }
 398 #else
 399 static int lp855x_parse_dt(struct lp855x *lp)
 400 {
 401         return -EINVAL;
 402 }
 403 #endif
 404
 405 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 406 {
 407         struct lp855x *lp;
 408         int ret;
 409
 410         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 411                 return -EIO;
 412
 413         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 414         if (!lp)
 415                 return -ENOMEM;
 416
 417         lp->client = cl;
 418         lp->dev = &cl->dev;
 419         lp->chipname = id->name;
 420         lp->chip_id = id->driver_data;
 421         lp->pdata = dev_get_platdata(&cl->dev);
 422
 423         if (!lp->pdata) {
 424                 ret = lp855x_parse_dt(lp);
 425                 if (ret < 0)
 426                         return ret;
 427         }
 428
 429         if (lp->pdata->period_ns > 0)
 430                 lp->mode = PWM_BASED;
 431         else
 432                 lp->mode = REGISTER_BASED;
 433
 434         if (lp->pdata->supply) {
 435                 ret = regulator_enable(lp->pdata->supply);
 436                 if (ret < 0) {
 437                         dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
 438                         return ret;
 439                 }
 440         }
 441
 442         i2c_set_clientdata(cl, lp);
 443
 444         ret = lp855x_configure(lp);
 445         if (ret) {
 446                 dev_err(lp->dev, "device config err: %d", ret);
 447                 return ret;
 448         }
 449
 450         ret = lp855x_backlight_register(lp);
 451         if (ret) {
 452                 dev_err(lp->dev,
 453                         "failed to register backlight. err: %d\n", ret);
 454                 return ret;
 455         }
 456
 457         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 458         if (ret) {
 459                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 460                 return ret;
 461         }
 462
 463         backlight_update_status(lp->bl);
 464         return 0;
 465 }
 466
 467 static int lp855x_remove(struct i2c_client *cl)
 468 {
 469         struct lp855x *lp = i2c_get_clientdata(cl);
 470
 471         lp->bl->props.brightness = 0;
 472         backlight_update_status(lp->bl);
 473         if (lp->pdata->supply)
 474                 regulator_disable(lp->pdata->supply);
 475         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 476
 477         return 0;
 478 }
 479
 480 static const struct of_device_id lp855x_dt_ids[] = {
 481         { .compatible = "ti,lp8550", },
 482         { .compatible = "ti,lp8551", },
 483         { .compatible = "ti,lp8552", },
 484         { .compatible = "ti,lp8553", },
 485         { .compatible = "ti,lp8555", },
 486         { .compatible = "ti,lp8556", },
 487         { .compatible = "ti,lp8557", },
 488         { }
 489 };
 490 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
 491
 492 static const struct i2c_device_id lp855x_ids[] = {
 493         {"lp8550", LP8550},
 494         {"lp8551", LP8551},
 495         {"lp8552", LP8552},
 496         {"lp8553", LP8553},
 497         {"lp8555", LP8555},
 498         {"lp8556", LP8556},
 499         {"lp8557", LP8557},
 500         { }
 501 };
 502 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 503
 504 static struct i2c_driver lp855x_driver = {
 505         .driver = {
 506                    .name = "lp855x",
 507                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 508                    },
 509         .probe = lp855x_probe,
 510         .remove = lp855x_remove,
 511         .id_table = lp855x_ids,
 512 };
 513
 514 module_i2c_driver(lp855x_driver);
 515
 516 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 517 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 518 MODULE_LICENSE("GPL");