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/delay.h>
  17 #include <linux/err.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_data/lp855x.h>
  20 #include <linux/pwm.h>
  21 #include <linux/regulator/consumer.h>
  22
  23 /* LP8550/1/2/3/6 Registers */
  24 #define LP855X_BRIGHTNESS_CTRL          0x00
  25 #define LP855X_DEVICE_CTRL              0x01
  26 #define LP855X_EEPROM_START             0xA0
  27 #define LP855X_EEPROM_END               0xA7
  28 #define LP8556_EPROM_START              0xA0
  29 #define LP8556_EPROM_END                0xAF
  30
  31 /* LP8555/7 Registers */
  32 #define LP8557_BL_CMD                   0x00
  33 #define LP8557_BL_MASK                  0x01
  34 #define LP8557_BL_ON                    0x01
  35 #define LP8557_BL_OFF                   0x00
  36 #define LP8557_BRIGHTNESS_CTRL          0x04
  37 #define LP8557_CONFIG                   0x10
  38 #define LP8555_EPROM_START              0x10
  39 #define LP8555_EPROM_END                0x7A
  40 #define LP8557_EPROM_START              0x10
  41 #define LP8557_EPROM_END                0x1E
  42
  43 #define DEFAULT_BL_NAME         "lcd-backlight"
  44 #define MAX_BRIGHTNESS          255
  45
  46 enum lp855x_brightness_ctrl_mode {
  47         PWM_BASED = 1,
  48         REGISTER_BASED,
  49 };
  50
  51 struct lp855x;
  52
  53 /*
  54  * struct lp855x_device_config
  55  * @pre_init_device: init device function call before updating the brightness
  56  * @reg_brightness: register address for brigthenss control
  57  * @reg_devicectrl: register address for device control
  58  * @post_init_device: late init device function call
  59  */
  60 struct lp855x_device_config {
  61         int (*pre_init_device)(struct lp855x *);
  62         u8 reg_brightness;
  63         u8 reg_devicectrl;
  64         int (*post_init_device)(struct lp855x *);
  65 };
  66
  67 struct lp855x {
  68         const char *chipname;
  69         enum lp855x_chip_id chip_id;
  70         enum lp855x_brightness_ctrl_mode mode;
  71         struct lp855x_device_config *cfg;
  72         struct i2c_client *client;
  73         struct backlight_device *bl;
  74         struct device *dev;
  75         struct lp855x_platform_data *pdata;
  76         struct pwm_device *pwm;
  77         struct regulator *supply;       /* regulator for VDD input */
  78         struct regulator *enable;       /* regulator for EN/VDDIO input */
  79 };
  80
  81 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  82 {
  83         return i2c_smbus_write_byte_data(lp->client, reg, data);
  84 }
  85
  86 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
  87 {
  88         int ret;
  89         u8 tmp;
  90
  91         ret = i2c_smbus_read_byte_data(lp->client, reg);
  92         if (ret < 0) {
  93                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  94                 return ret;
  95         }
  96
  97         tmp = (u8)ret;
  98         tmp &= ~mask;
  99         tmp |= data & mask;
 100
 101         return lp855x_write_byte(lp, reg, tmp);
 102 }
 103
 104 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
 105 {
 106         u8 start, end;
 107
 108         switch (lp->chip_id) {
 109         case LP8550:
 110         case LP8551:
 111         case LP8552:
 112         case LP8553:
 113                 start = LP855X_EEPROM_START;
 114                 end = LP855X_EEPROM_END;
 115                 break;
 116         case LP8556:
 117                 start = LP8556_EPROM_START;
 118                 end = LP8556_EPROM_END;
 119                 break;
 120         case LP8555:
 121                 start = LP8555_EPROM_START;
 122                 end = LP8555_EPROM_END;
 123                 break;
 124         case LP8557:
 125                 start = LP8557_EPROM_START;
 126                 end = LP8557_EPROM_END;
 127                 break;
 128         default:
 129                 return false;
 130         }
 131
 132         return addr >= start && addr <= end;
 133 }
 134
 135 static int lp8557_bl_off(struct lp855x *lp)
 136 {
 137         /* BL_ON = 0 before updating EPROM settings */
 138         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 139                                 LP8557_BL_OFF);
 140 }
 141
 142 static int lp8557_bl_on(struct lp855x *lp)
 143 {
 144         /* BL_ON = 1 after updating EPROM settings */
 145         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 146                                 LP8557_BL_ON);
 147 }
 148
 149 static struct lp855x_device_config lp855x_dev_cfg = {
 150         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
 151         .reg_devicectrl = LP855X_DEVICE_CTRL,
 152 };
 153
 154 static struct lp855x_device_config lp8557_dev_cfg = {
 155         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
 156         .reg_devicectrl = LP8557_CONFIG,
 157         .pre_init_device = lp8557_bl_off,
 158         .post_init_device = lp8557_bl_on,
 159 };
 160
 161 /*
 162  * Device specific configuration flow
 163  *
 164  *    a) pre_init_device(optional)
 165  *    b) update the brightness register
 166  *    c) update device control register
 167  *    d) update ROM area(optional)
 168  *    e) post_init_device(optional)
 169  *
 170  */
 171 static int lp855x_configure(struct lp855x *lp)
 172 {
 173         u8 val, addr;
 174         int i, ret;
 175         struct lp855x_platform_data *pd = lp->pdata;
 176
 177         switch (lp->chip_id) {
 178         case LP8550:
 179         case LP8551:
 180         case LP8552:
 181         case LP8553:
 182         case LP8556:
 183                 lp->cfg = &lp855x_dev_cfg;
 184                 break;
 185         case LP8555:
 186         case LP8557:
 187                 lp->cfg = &lp8557_dev_cfg;
 188                 break;
 189         default:
 190                 return -EINVAL;
 191         }
 192
 193         if (lp->cfg->pre_init_device) {
 194                 ret = lp->cfg->pre_init_device(lp);
 195                 if (ret) {
 196                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 197                         goto err;
 198                 }
 199         }
 200
 201         val = pd->initial_brightness;
 202         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 203         if (ret)
 204                 goto err;
 205
 206         val = pd->device_control;
 207         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 208         if (ret)
 209                 goto err;
 210
 211         if (pd->size_program > 0) {
 212                 for (i = 0; i < pd->size_program; i++) {
 213                         addr = pd->rom_data[i].addr;
 214                         val = pd->rom_data[i].val;
 215                         if (!lp855x_is_valid_rom_area(lp, addr))
 216                                 continue;
 217
 218                         ret = lp855x_write_byte(lp, addr, val);
 219                         if (ret)
 220                                 goto err;
 221                 }
 222         }
 223
 224         if (lp->cfg->post_init_device) {
 225                 ret = lp->cfg->post_init_device(lp);
 226                 if (ret) {
 227                         dev_err(lp->dev, "post init device err: %d\n", ret);
 228                         goto err;
 229                 }
 230         }
 231
 232         return 0;
 233
 234 err:
 235         return ret;
 236 }
 237
 238 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 239 {
 240         unsigned int period = lp->pdata->period_ns;
 241         unsigned int duty = br * period / max_br;
 242         struct pwm_device *pwm;
 243
 244         /* request pwm device with the consumer name */
 245         if (!lp->pwm) {
 246                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 247                 if (IS_ERR(pwm))
 248                         return;
 249
 250                 lp->pwm = pwm;
 251
 252                 /*
 253                  * FIXME: pwm_apply_args() should be removed when switching to
 254                  * the atomic PWM API.
 255                  */
 256                 pwm_apply_args(pwm);
 257         }
 258
 259         pwm_config(lp->pwm, duty, period);
 260         if (duty)
 261                 pwm_enable(lp->pwm);
 262         else
 263                 pwm_disable(lp->pwm);
 264 }
 265
 266 static int lp855x_bl_update_status(struct backlight_device *bl)
 267 {
 268         struct lp855x *lp = bl_get_data(bl);
 269         int brightness = bl->props.brightness;
 270
 271         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 272                 brightness = 0;
 273
 274         if (lp->mode == PWM_BASED)
 275                 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
 276         else if (lp->mode == REGISTER_BASED)
 277                 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
 278
 279         return 0;
 280 }
 281
 282 static const struct backlight_ops lp855x_bl_ops = {
 283         .options = BL_CORE_SUSPENDRESUME,
 284         .update_status = lp855x_bl_update_status,
 285 };
 286
 287 static int lp855x_backlight_register(struct lp855x *lp)
 288 {
 289         struct backlight_device *bl;
 290         struct backlight_properties props;
 291         struct lp855x_platform_data *pdata = lp->pdata;
 292         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 293
 294         memset(&props, 0, sizeof(props));
 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
 318         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
 319 }
 320
 321 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 322                                      struct device_attribute *attr, char *buf)
 323 {
 324         struct lp855x *lp = dev_get_drvdata(dev);
 325         char *strmode = NULL;
 326
 327         if (lp->mode == PWM_BASED)
 328                 strmode = "pwm based";
 329         else if (lp->mode == REGISTER_BASED)
 330                 strmode = "register based";
 331
 332         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 333 }
 334
 335 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 336 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 337
 338 static struct attribute *lp855x_attributes[] = {
 339         &dev_attr_chip_id.attr,
 340         &dev_attr_bl_ctl_mode.attr,
 341         NULL,
 342 };
 343
 344 static const struct attribute_group lp855x_attr_group = {
 345         .attrs = lp855x_attributes,
 346 };
 347
 348 #ifdef CONFIG_OF
 349 static int lp855x_parse_dt(struct lp855x *lp)
 350 {
 351         struct device *dev = lp->dev;
 352         struct device_node *node = dev->of_node;
 353         struct lp855x_platform_data *pdata;
 354         int rom_length;
 355
 356         if (!node) {
 357                 dev_err(dev, "no platform data\n");
 358                 return -EINVAL;
 359         }
 360
 361         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 362         if (!pdata)
 363                 return -ENOMEM;
 364
 365         of_property_read_string(node, "bl-name", &pdata->name);
 366         of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 367         of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
 368         of_property_read_u32(node, "pwm-period", &pdata->period_ns);
 369
 370         /* Fill ROM platform data if defined */
 371         rom_length = of_get_child_count(node);
 372         if (rom_length > 0) {
 373                 struct lp855x_rom_data *rom;
 374                 struct device_node *child;
 375                 int i = 0;
 376
 377                 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
 378                 if (!rom)
 379                         return -ENOMEM;
 380
 381                 for_each_child_of_node(node, child) {
 382                         of_property_read_u8(child, "rom-addr", &rom[i].addr);
 383                         of_property_read_u8(child, "rom-val", &rom[i].val);
 384                         i++;
 385                 }
 386
 387                 pdata->size_program = rom_length;
 388                 pdata->rom_data = &rom[0];
 389         }
 390
 391         lp->pdata = pdata;
 392
 393         return 0;
 394 }
 395 #else
 396 static int lp855x_parse_dt(struct lp855x *lp)
 397 {
 398         return -EINVAL;
 399 }
 400 #endif
 401
 402 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 403 {
 404         struct lp855x *lp;
 405         int ret;
 406
 407         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 408                 return -EIO;
 409
 410         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 411         if (!lp)
 412                 return -ENOMEM;
 413
 414         lp->client = cl;
 415         lp->dev = &cl->dev;
 416         lp->chipname = id->name;
 417         lp->chip_id = id->driver_data;
 418         lp->pdata = dev_get_platdata(&cl->dev);
 419
 420         if (!lp->pdata) {
 421                 ret = lp855x_parse_dt(lp);
 422                 if (ret < 0)
 423                         return ret;
 424         }
 425
 426         if (lp->pdata->period_ns > 0)
 427                 lp->mode = PWM_BASED;
 428         else
 429                 lp->mode = REGISTER_BASED;
 430
 431         lp->supply = devm_regulator_get(lp->dev, "power");
 432         if (IS_ERR(lp->supply)) {
 433                 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
 434                         return -EPROBE_DEFER;
 435                 lp->supply = NULL;
 436         }
 437
 438         lp->enable = devm_regulator_get_optional(lp->dev, "enable");
 439         if (IS_ERR(lp->enable)) {
 440                 ret = PTR_ERR(lp->enable);
 441                 if (ret == -ENODEV) {
 442                         lp->enable = NULL;
 443                 } else {
 444                         if (ret != -EPROBE_DEFER)
 445                                 dev_err(lp->dev, "error getting enable regulator: %d\n",
 446                                         ret);
 447                         return ret;
 448                 }
 449         }
 450
 451         if (lp->supply) {
 452                 ret = regulator_enable(lp->supply);
 453                 if (ret < 0) {
 454                         dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
 455                         return ret;
 456                 }
 457         }
 458
 459         if (lp->enable) {
 460                 ret = regulator_enable(lp->enable);
 461                 if (ret < 0) {
 462                         dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
 463                         return ret;
 464                 }
 465
 466                 /*
 467                  * LP8555 datasheet says t_RESPONSE (time between VDDIO and
 468                  * I2C) is 1ms.
 469                  */
 470                 usleep_range(1000, 2000);
 471         }
 472
 473         i2c_set_clientdata(cl, lp);
 474
 475         ret = lp855x_configure(lp);
 476         if (ret) {
 477                 dev_err(lp->dev, "device config err: %d", ret);
 478                 return ret;
 479         }
 480
 481         ret = lp855x_backlight_register(lp);
 482         if (ret) {
 483                 dev_err(lp->dev,
 484                         "failed to register backlight. err: %d\n", ret);
 485                 return ret;
 486         }
 487
 488         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 489         if (ret) {
 490                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 491                 return ret;
 492         }
 493
 494         backlight_update_status(lp->bl);
 495         return 0;
 496 }
 497
 498 static int lp855x_remove(struct i2c_client *cl)
 499 {
 500         struct lp855x *lp = i2c_get_clientdata(cl);
 501
 502         lp->bl->props.brightness = 0;
 503         backlight_update_status(lp->bl);
 504         if (lp->supply)
 505                 regulator_disable(lp->supply);
 506         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 507
 508         return 0;
 509 }
 510
 511 static const struct of_device_id lp855x_dt_ids[] = {
 512         { .compatible = "ti,lp8550", },
 513         { .compatible = "ti,lp8551", },
 514         { .compatible = "ti,lp8552", },
 515         { .compatible = "ti,lp8553", },
 516         { .compatible = "ti,lp8555", },
 517         { .compatible = "ti,lp8556", },
 518         { .compatible = "ti,lp8557", },
 519         { }
 520 };
 521 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
 522
 523 static const struct i2c_device_id lp855x_ids[] = {
 524         {"lp8550", LP8550},
 525         {"lp8551", LP8551},
 526         {"lp8552", LP8552},
 527         {"lp8553", LP8553},
 528         {"lp8555", LP8555},
 529         {"lp8556", LP8556},
 530         {"lp8557", LP8557},
 531         { }
 532 };
 533 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 534
 535 static struct i2c_driver lp855x_driver = {
 536         .driver = {
 537                    .name = "lp855x",
 538                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 539                    },
 540         .probe = lp855x_probe,
 541         .remove = lp855x_remove,
 542         .id_table = lp855x_ids,
 543 };
 544
 545 module_i2c_driver(lp855x_driver);
 546
 547 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 548 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 549 MODULE_LICENSE("GPL");