drivers/video/backlight/lp855x_bl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI LP855x Backlight Driver
   4  *
   5  *                      Copyright (C) 2011 Texas Instruments
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/i2c.h>
  11 #include <linux/backlight.h>
  12 #include <linux/delay.h>
  13 #include <linux/err.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_data/lp855x.h>
  16 #include <linux/pwm.h>
  17 #include <linux/regulator/consumer.h>
  18
  19 /* LP8550/1/2/3/6 Registers */
  20 #define LP855X_BRIGHTNESS_CTRL          0x00
  21 #define LP855X_DEVICE_CTRL              0x01
  22 #define LP855X_EEPROM_START             0xA0
  23 #define LP855X_EEPROM_END               0xA7
  24 #define LP8556_EPROM_START              0xA0
  25 #define LP8556_EPROM_END                0xAF
  26
  27 /* LP8555/7 Registers */
  28 #define LP8557_BL_CMD                   0x00
  29 #define LP8557_BL_MASK                  0x01
  30 #define LP8557_BL_ON                    0x01
  31 #define LP8557_BL_OFF                   0x00
  32 #define LP8557_BRIGHTNESS_CTRL          0x04
  33 #define LP8557_CONFIG                   0x10
  34 #define LP8555_EPROM_START              0x10
  35 #define LP8555_EPROM_END                0x7A
  36 #define LP8557_EPROM_START              0x10
  37 #define LP8557_EPROM_END                0x1E
  38
  39 #define DEFAULT_BL_NAME         "lcd-backlight"
  40 #define MAX_BRIGHTNESS          255
  41
  42 enum lp855x_brightness_ctrl_mode {
  43         PWM_BASED = 1,
  44         REGISTER_BASED,
  45 };
  46
  47 struct lp855x;
  48
  49 /*
  50  * struct lp855x_device_config
  51  * @pre_init_device: init device function call before updating the brightness
  52  * @reg_brightness: register address for brigthenss control
  53  * @reg_devicectrl: register address for device control
  54  * @post_init_device: late init device function call
  55  */
  56 struct lp855x_device_config {
  57         int (*pre_init_device)(struct lp855x *);
  58         u8 reg_brightness;
  59         u8 reg_devicectrl;
  60         int (*post_init_device)(struct lp855x *);
  61 };
  62
  63 struct lp855x {
  64         const char *chipname;
  65         enum lp855x_chip_id chip_id;
  66         enum lp855x_brightness_ctrl_mode mode;
  67         struct lp855x_device_config *cfg;
  68         struct i2c_client *client;
  69         struct backlight_device *bl;
  70         struct device *dev;
  71         struct lp855x_platform_data *pdata;
  72         struct pwm_device *pwm;
  73         struct regulator *supply;       /* regulator for VDD input */
  74         struct regulator *enable;       /* regulator for EN/VDDIO input */
  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                  * FIXME: pwm_apply_args() should be removed when switching to
 250                  * the atomic PWM API.
 251                  */
 252                 pwm_apply_args(pwm);
 253         }
 254
 255         pwm_config(lp->pwm, duty, period);
 256         if (duty)
 257                 pwm_enable(lp->pwm);
 258         else
 259                 pwm_disable(lp->pwm);
 260 }
 261
 262 static int lp855x_bl_update_status(struct backlight_device *bl)
 263 {
 264         struct lp855x *lp = bl_get_data(bl);
 265         int brightness = bl->props.brightness;
 266
 267         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 268                 brightness = 0;
 269
 270         if (lp->mode == PWM_BASED)
 271                 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
 272         else if (lp->mode == REGISTER_BASED)
 273                 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
 274
 275         return 0;
 276 }
 277
 278 static const struct backlight_ops lp855x_bl_ops = {
 279         .options = BL_CORE_SUSPENDRESUME,
 280         .update_status = lp855x_bl_update_status,
 281 };
 282
 283 static int lp855x_backlight_register(struct lp855x *lp)
 284 {
 285         struct backlight_device *bl;
 286         struct backlight_properties props;
 287         struct lp855x_platform_data *pdata = lp->pdata;
 288         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 289
 290         memset(&props, 0, sizeof(props));
 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_kcalloc(dev, rom_length, sizeof(*rom), 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         lp->pdata = pdata;
 388
 389         return 0;
 390 }
 391 #else
 392 static int lp855x_parse_dt(struct lp855x *lp)
 393 {
 394         return -EINVAL;
 395 }
 396 #endif
 397
 398 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 399 {
 400         struct lp855x *lp;
 401         int ret;
 402
 403         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 404                 return -EIO;
 405
 406         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 407         if (!lp)
 408                 return -ENOMEM;
 409
 410         lp->client = cl;
 411         lp->dev = &cl->dev;
 412         lp->chipname = id->name;
 413         lp->chip_id = id->driver_data;
 414         lp->pdata = dev_get_platdata(&cl->dev);
 415
 416         if (!lp->pdata) {
 417                 ret = lp855x_parse_dt(lp);
 418                 if (ret < 0)
 419                         return ret;
 420         }
 421
 422         if (lp->pdata->period_ns > 0)
 423                 lp->mode = PWM_BASED;
 424         else
 425                 lp->mode = REGISTER_BASED;
 426
 427         lp->supply = devm_regulator_get(lp->dev, "power");
 428         if (IS_ERR(lp->supply)) {
 429                 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
 430                         return -EPROBE_DEFER;
 431                 lp->supply = NULL;
 432         }
 433
 434         lp->enable = devm_regulator_get_optional(lp->dev, "enable");
 435         if (IS_ERR(lp->enable)) {
 436                 ret = PTR_ERR(lp->enable);
 437                 if (ret == -ENODEV) {
 438                         lp->enable = NULL;
 439                 } else {
 440                         if (ret != -EPROBE_DEFER)
 441                                 dev_err(lp->dev, "error getting enable regulator: %d\n",
 442                                         ret);
 443                         return ret;
 444                 }
 445         }
 446
 447         if (lp->supply) {
 448                 ret = regulator_enable(lp->supply);
 449                 if (ret < 0) {
 450                         dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
 451                         return ret;
 452                 }
 453         }
 454
 455         if (lp->enable) {
 456                 ret = regulator_enable(lp->enable);
 457                 if (ret < 0) {
 458                         dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
 459                         return ret;
 460                 }
 461
 462                 /*
 463                  * LP8555 datasheet says t_RESPONSE (time between VDDIO and
 464                  * I2C) is 1ms.
 465                  */
 466                 usleep_range(1000, 2000);
 467         }
 468
 469         i2c_set_clientdata(cl, lp);
 470
 471         ret = lp855x_configure(lp);
 472         if (ret) {
 473                 dev_err(lp->dev, "device config err: %d", ret);
 474                 return ret;
 475         }
 476
 477         ret = lp855x_backlight_register(lp);
 478         if (ret) {
 479                 dev_err(lp->dev,
 480                         "failed to register backlight. err: %d\n", ret);
 481                 return ret;
 482         }
 483
 484         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 485         if (ret) {
 486                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 487                 return ret;
 488         }
 489
 490         backlight_update_status(lp->bl);
 491         return 0;
 492 }
 493
 494 static int lp855x_remove(struct i2c_client *cl)
 495 {
 496         struct lp855x *lp = i2c_get_clientdata(cl);
 497
 498         lp->bl->props.brightness = 0;
 499         backlight_update_status(lp->bl);
 500         if (lp->supply)
 501                 regulator_disable(lp->supply);
 502         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 503
 504         return 0;
 505 }
 506
 507 static const struct of_device_id lp855x_dt_ids[] = {
 508         { .compatible = "ti,lp8550", },
 509         { .compatible = "ti,lp8551", },
 510         { .compatible = "ti,lp8552", },
 511         { .compatible = "ti,lp8553", },
 512         { .compatible = "ti,lp8555", },
 513         { .compatible = "ti,lp8556", },
 514         { .compatible = "ti,lp8557", },
 515         { }
 516 };
 517 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
 518
 519 static const struct i2c_device_id lp855x_ids[] = {
 520         {"lp8550", LP8550},
 521         {"lp8551", LP8551},
 522         {"lp8552", LP8552},
 523         {"lp8553", LP8553},
 524         {"lp8555", LP8555},
 525         {"lp8556", LP8556},
 526         {"lp8557", LP8557},
 527         { }
 528 };
 529 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 530
 531 static struct i2c_driver lp855x_driver = {
 532         .driver = {
 533                    .name = "lp855x",
 534                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 535                    },
 536         .probe = lp855x_probe,
 537         .remove = lp855x_remove,
 538         .id_table = lp855x_ids,
 539 };
 540
 541 module_i2c_driver(lp855x_driver);
 542
 543 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 544 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 545 MODULE_LICENSE("GPL");