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
  21 /* LP8550/1/2/3/6 Registers */
  22 #define LP855X_BRIGHTNESS_CTRL          0x00
  23 #define LP855X_DEVICE_CTRL              0x01
  24 #define LP855X_EEPROM_START             0xA0
  25 #define LP855X_EEPROM_END               0xA7
  26 #define LP8556_EPROM_START              0xA0
  27 #define LP8556_EPROM_END                0xAF
  28
  29 /* LP8555/7 Registers */
  30 #define LP8557_BL_CMD                   0x00
  31 #define LP8557_BL_MASK                  0x01
  32 #define LP8557_BL_ON                    0x01
  33 #define LP8557_BL_OFF                   0x00
  34 #define LP8557_BRIGHTNESS_CTRL          0x04
  35 #define LP8557_CONFIG                   0x10
  36 #define LP8555_EPROM_START              0x10
  37 #define LP8555_EPROM_END                0x7A
  38 #define LP8557_EPROM_START              0x10
  39 #define LP8557_EPROM_END                0x1E
  40
  41 #define DEFAULT_BL_NAME         "lcd-backlight"
  42 #define MAX_BRIGHTNESS          255
  43
  44 enum lp855x_brightness_ctrl_mode {
  45         PWM_BASED = 1,
  46         REGISTER_BASED,
  47 };
  48
  49 struct lp855x;
  50
  51 /*
  52  * struct lp855x_device_config
  53  * @pre_init_device: init device function call before updating the brightness
  54  * @reg_brightness: register address for brigthenss control
  55  * @reg_devicectrl: register address for device control
  56  * @post_init_device: late init device function call
  57  */
  58 struct lp855x_device_config {
  59         int (*pre_init_device)(struct lp855x *);
  60         u8 reg_brightness;
  61         u8 reg_devicectrl;
  62         int (*post_init_device)(struct lp855x *);
  63 };
  64
  65 struct lp855x {
  66         const char *chipname;
  67         enum lp855x_chip_id chip_id;
  68         enum lp855x_brightness_ctrl_mode mode;
  69         struct lp855x_device_config *cfg;
  70         struct i2c_client *client;
  71         struct backlight_device *bl;
  72         struct device *dev;
  73         struct lp855x_platform_data *pdata;
  74         struct pwm_device *pwm;
  75 };
  76
  77 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  78 {
  79         return i2c_smbus_write_byte_data(lp->client, reg, data);
  80 }
  81
  82 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
  83 {
  84         int ret;
  85         u8 tmp;
  86
  87         ret = i2c_smbus_read_byte_data(lp->client, reg);
  88         if (ret < 0) {
  89                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  90                 return ret;
  91         }
  92
  93         tmp = (u8)ret;
  94         tmp &= ~mask;
  95         tmp |= data & mask;
  96
  97         return lp855x_write_byte(lp, reg, tmp);
  98 }
  99
 100 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
 101 {
 102         u8 start, end;
 103
 104         switch (lp->chip_id) {
 105         case LP8550:
 106         case LP8551:
 107         case LP8552:
 108         case LP8553:
 109                 start = LP855X_EEPROM_START;
 110                 end = LP855X_EEPROM_END;
 111                 break;
 112         case LP8556:
 113                 start = LP8556_EPROM_START;
 114                 end = LP8556_EPROM_END;
 115                 break;
 116         case LP8555:
 117                 start = LP8555_EPROM_START;
 118                 end = LP8555_EPROM_END;
 119                 break;
 120         case LP8557:
 121                 start = LP8557_EPROM_START;
 122                 end = LP8557_EPROM_END;
 123                 break;
 124         default:
 125                 return false;
 126         }
 127
 128         return (addr >= start && addr <= end);
 129 }
 130
 131 static int lp8557_bl_off(struct lp855x *lp)
 132 {
 133         /* BL_ON = 0 before updating EPROM settings */
 134         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 135                                 LP8557_BL_OFF);
 136 }
 137
 138 static int lp8557_bl_on(struct lp855x *lp)
 139 {
 140         /* BL_ON = 1 after updating EPROM settings */
 141         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 142                                 LP8557_BL_ON);
 143 }
 144
 145 static struct lp855x_device_config lp855x_dev_cfg = {
 146         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
 147         .reg_devicectrl = LP855X_DEVICE_CTRL,
 148 };
 149
 150 static struct lp855x_device_config lp8557_dev_cfg = {
 151         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
 152         .reg_devicectrl = LP8557_CONFIG,
 153         .pre_init_device = lp8557_bl_off,
 154         .post_init_device = lp8557_bl_on,
 155 };
 156
 157 /*
 158  * Device specific configuration flow
 159  *
 160  *    a) pre_init_device(optional)
 161  *    b) update the brightness register
 162  *    c) update device control register
 163  *    d) update ROM area(optional)
 164  *    e) post_init_device(optional)
 165  *
 166  */
 167 static int lp855x_configure(struct lp855x *lp)
 168 {
 169         u8 val, addr;
 170         int i, ret;
 171         struct lp855x_platform_data *pd = lp->pdata;
 172
 173         switch (lp->chip_id) {
 174         case LP8550:
 175         case LP8551:
 176         case LP8552:
 177         case LP8553:
 178         case LP8556:
 179                 lp->cfg = &lp855x_dev_cfg;
 180                 break;
 181         case LP8555:
 182         case LP8557:
 183                 lp->cfg = &lp8557_dev_cfg;
 184                 break;
 185         default:
 186                 return -EINVAL;
 187         }
 188
 189         if (lp->cfg->pre_init_device) {
 190                 ret = lp->cfg->pre_init_device(lp);
 191                 if (ret) {
 192                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 193                         goto err;
 194                 }
 195         }
 196
 197         val = pd->initial_brightness;
 198         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 199         if (ret)
 200                 goto err;
 201
 202         val = pd->device_control;
 203         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 204         if (ret)
 205                 goto err;
 206
 207         if (pd->size_program > 0) {
 208                 for (i = 0; i < pd->size_program; i++) {
 209                         addr = pd->rom_data[i].addr;
 210                         val = pd->rom_data[i].val;
 211                         if (!lp855x_is_valid_rom_area(lp, addr))
 212                                 continue;
 213
 214                         ret = lp855x_write_byte(lp, addr, val);
 215                         if (ret)
 216                                 goto err;
 217                 }
 218         }
 219
 220         if (lp->cfg->post_init_device) {
 221                 ret = lp->cfg->post_init_device(lp);
 222                 if (ret) {
 223                         dev_err(lp->dev, "post init device err: %d\n", ret);
 224                         goto err;
 225                 }
 226         }
 227
 228         return 0;
 229
 230 err:
 231         return ret;
 232 }
 233
 234 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 235 {
 236         unsigned int period = lp->pdata->period_ns;
 237         unsigned int duty = br * period / max_br;
 238         struct pwm_device *pwm;
 239
 240         /* request pwm device with the consumer name */
 241         if (!lp->pwm) {
 242                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 243                 if (IS_ERR(pwm))
 244                         return;
 245
 246                 lp->pwm = pwm;
 247         }
 248
 249         pwm_config(lp->pwm, duty, period);
 250         if (duty)
 251                 pwm_enable(lp->pwm);
 252         else
 253                 pwm_disable(lp->pwm);
 254 }
 255
 256 static int lp855x_bl_update_status(struct backlight_device *bl)
 257 {
 258         struct lp855x *lp = bl_get_data(bl);
 259
 260         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 261                 bl->props.brightness = 0;
 262
 263         if (lp->mode == PWM_BASED) {
 264                 int br = bl->props.brightness;
 265                 int max_br = bl->props.max_brightness;
 266
 267                 lp855x_pwm_ctrl(lp, br, max_br);
 268
 269         } else if (lp->mode == REGISTER_BASED) {
 270                 u8 val = bl->props.brightness;
 271                 lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 272         }
 273
 274         return 0;
 275 }
 276
 277 static int lp855x_bl_get_brightness(struct backlight_device *bl)
 278 {
 279         return bl->props.brightness;
 280 }
 281
 282 static const struct backlight_ops lp855x_bl_ops = {
 283         .options = BL_CORE_SUSPENDRESUME,
 284         .update_status = lp855x_bl_update_status,
 285         .get_brightness = lp855x_bl_get_brightness,
 286 };
 287
 288 static int lp855x_backlight_register(struct lp855x *lp)
 289 {
 290         struct backlight_device *bl;
 291         struct backlight_properties props;
 292         struct lp855x_platform_data *pdata = lp->pdata;
 293         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 294
 295         props.type = BACKLIGHT_PLATFORM;
 296         props.max_brightness = MAX_BRIGHTNESS;
 297
 298         if (pdata->initial_brightness > props.max_brightness)
 299                 pdata->initial_brightness = props.max_brightness;
 300
 301         props.brightness = pdata->initial_brightness;
 302
 303         bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
 304                                        &lp855x_bl_ops, &props);
 305         if (IS_ERR(bl))
 306                 return PTR_ERR(bl);
 307
 308         lp->bl = bl;
 309
 310         return 0;
 311 }
 312
 313 static ssize_t lp855x_get_chip_id(struct device *dev,
 314                                 struct device_attribute *attr, char *buf)
 315 {
 316         struct lp855x *lp = dev_get_drvdata(dev);
 317         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
 318 }
 319
 320 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 321                                      struct device_attribute *attr, char *buf)
 322 {
 323         struct lp855x *lp = dev_get_drvdata(dev);
 324         char *strmode = NULL;
 325
 326         if (lp->mode == PWM_BASED)
 327                 strmode = "pwm based";
 328         else if (lp->mode == REGISTER_BASED)
 329                 strmode = "register based";
 330
 331         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 332 }
 333
 334 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 335 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 336
 337 static struct attribute *lp855x_attributes[] = {
 338         &dev_attr_chip_id.attr,
 339         &dev_attr_bl_ctl_mode.attr,
 340         NULL,
 341 };
 342
 343 static const struct attribute_group lp855x_attr_group = {
 344         .attrs = lp855x_attributes,
 345 };
 346
 347 #ifdef CONFIG_OF
 348 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
 349 {
 350         struct lp855x_platform_data *pdata;
 351         int rom_length;
 352
 353         if (!node) {
 354                 dev_err(dev, "no platform data\n");
 355                 return -EINVAL;
 356         }
 357
 358         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 359         if (!pdata)
 360                 return -ENOMEM;
 361
 362         of_property_read_string(node, "bl-name", &pdata->name);
 363         of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 364         of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
 365         of_property_read_u32(node, "pwm-period", &pdata->period_ns);
 366
 367         /* Fill ROM platform data if defined */
 368         rom_length = of_get_child_count(node);
 369         if (rom_length > 0) {
 370                 struct lp855x_rom_data *rom;
 371                 struct device_node *child;
 372                 int i = 0;
 373
 374                 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
 375                 if (!rom)
 376                         return -ENOMEM;
 377
 378                 for_each_child_of_node(node, child) {
 379                         of_property_read_u8(child, "rom-addr", &rom[i].addr);
 380                         of_property_read_u8(child, "rom-val", &rom[i].val);
 381                         i++;
 382                 }
 383
 384                 pdata->size_program = rom_length;
 385                 pdata->rom_data = &rom[0];
 386         }
 387
 388         dev->platform_data = pdata;
 389
 390         return 0;
 391 }
 392 #else
 393 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
 394 {
 395         return -EINVAL;
 396 }
 397 #endif
 398
 399 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 400 {
 401         struct lp855x *lp;
 402         struct lp855x_platform_data *pdata = dev_get_platdata(&cl->dev);
 403         struct device_node *node = cl->dev.of_node;
 404         int ret;
 405
 406         if (!pdata) {
 407                 ret = lp855x_parse_dt(&cl->dev, node);
 408                 if (ret < 0)
 409                         return ret;
 410
 411                 pdata = dev_get_platdata(&cl->dev);
 412         }
 413
 414         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 415                 return -EIO;
 416
 417         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 418         if (!lp)
 419                 return -ENOMEM;
 420
 421         if (pdata->period_ns > 0)
 422                 lp->mode = PWM_BASED;
 423         else
 424                 lp->mode = REGISTER_BASED;
 425
 426         lp->client = cl;
 427         lp->dev = &cl->dev;
 428         lp->pdata = pdata;
 429         lp->chipname = id->name;
 430         lp->chip_id = id->driver_data;
 431         i2c_set_clientdata(cl, lp);
 432
 433         ret = lp855x_configure(lp);
 434         if (ret) {
 435                 dev_err(lp->dev, "device config err: %d", ret);
 436                 return ret;
 437         }
 438
 439         ret = lp855x_backlight_register(lp);
 440         if (ret) {
 441                 dev_err(lp->dev,
 442                         "failed to register backlight. err: %d\n", ret);
 443                 return ret;
 444         }
 445
 446         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 447         if (ret) {
 448                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 449                 return ret;
 450         }
 451
 452         backlight_update_status(lp->bl);
 453         return 0;
 454 }
 455
 456 static int lp855x_remove(struct i2c_client *cl)
 457 {
 458         struct lp855x *lp = i2c_get_clientdata(cl);
 459
 460         lp->bl->props.brightness = 0;
 461         backlight_update_status(lp->bl);
 462         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 463
 464         return 0;
 465 }
 466
 467 static const struct of_device_id lp855x_dt_ids[] = {
 468         { .compatible = "ti,lp8550", },
 469         { .compatible = "ti,lp8551", },
 470         { .compatible = "ti,lp8552", },
 471         { .compatible = "ti,lp8553", },
 472         { .compatible = "ti,lp8555", },
 473         { .compatible = "ti,lp8556", },
 474         { .compatible = "ti,lp8557", },
 475         { }
 476 };
 477 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
 478
 479 static const struct i2c_device_id lp855x_ids[] = {
 480         {"lp8550", LP8550},
 481         {"lp8551", LP8551},
 482         {"lp8552", LP8552},
 483         {"lp8553", LP8553},
 484         {"lp8555", LP8555},
 485         {"lp8556", LP8556},
 486         {"lp8557", LP8557},
 487         { }
 488 };
 489 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 490
 491 static struct i2c_driver lp855x_driver = {
 492         .driver = {
 493                    .name = "lp855x",
 494                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 495                    },
 496         .probe = lp855x_probe,
 497         .remove = lp855x_remove,
 498         .id_table = lp855x_ids,
 499 };
 500
 501 module_i2c_driver(lp855x_driver);
 502
 503 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 504 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 505 MODULE_LICENSE("GPL");