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