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/acpi.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/i2c.h>
  12 #include <linux/backlight.h>
  13 #include <linux/delay.h>
  14 #include <linux/err.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_data/lp855x.h>
  17 #include <linux/pwm.h>
  18 #include <linux/regulator/consumer.h>
  19
  20 /* LP8550/1/2/3/6 Registers */
  21 #define LP855X_BRIGHTNESS_CTRL          0x00
  22 #define LP855X_DEVICE_CTRL              0x01
  23 #define LP855X_EEPROM_START             0xA0
  24 #define LP855X_EEPROM_END               0xA7
  25 #define LP8556_EPROM_START              0xA0
  26 #define LP8556_EPROM_END                0xAF
  27
  28 /* LP8555/7 Registers */
  29 #define LP8557_BL_CMD                   0x00
  30 #define LP8557_BL_MASK                  0x01
  31 #define LP8557_BL_ON                    0x01
  32 #define LP8557_BL_OFF                   0x00
  33 #define LP8557_BRIGHTNESS_CTRL          0x04
  34 #define LP8557_CONFIG                   0x10
  35 #define LP8555_EPROM_START              0x10
  36 #define LP8555_EPROM_END                0x7A
  37 #define LP8557_EPROM_START              0x10
  38 #define LP8557_EPROM_END                0x1E
  39
  40 #define DEFAULT_BL_NAME         "lcd-backlight"
  41 #define MAX_BRIGHTNESS          255
  42
  43 enum lp855x_brightness_ctrl_mode {
  44         PWM_BASED = 1,
  45         REGISTER_BASED,
  46 };
  47
  48 struct lp855x;
  49
  50 /*
  51  * struct lp855x_device_config
  52  * @pre_init_device: init device function call before updating the brightness
  53  * @reg_brightness: register address for brigthenss control
  54  * @reg_devicectrl: register address for device control
  55  * @post_init_device: late init device function call
  56  */
  57 struct lp855x_device_config {
  58         int (*pre_init_device)(struct lp855x *);
  59         u8 reg_brightness;
  60         u8 reg_devicectrl;
  61         int (*post_init_device)(struct lp855x *);
  62 };
  63
  64 struct lp855x {
  65         const char *chipname;
  66         enum lp855x_chip_id chip_id;
  67         enum lp855x_brightness_ctrl_mode mode;
  68         struct lp855x_device_config *cfg;
  69         struct i2c_client *client;
  70         struct backlight_device *bl;
  71         struct device *dev;
  72         struct lp855x_platform_data *pdata;
  73         struct pwm_device *pwm;
  74         struct regulator *supply;       /* regulator for VDD input */
  75         struct regulator *enable;       /* regulator for EN/VDDIO input */
  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         if (lp->cfg->pre_init_device) {
 175                 ret = lp->cfg->pre_init_device(lp);
 176                 if (ret) {
 177                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 178                         goto err;
 179                 }
 180         }
 181
 182         val = pd->initial_brightness;
 183         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 184         if (ret)
 185                 goto err;
 186
 187         val = pd->device_control;
 188         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 189         if (ret)
 190                 goto err;
 191
 192         if (pd->size_program > 0) {
 193                 for (i = 0; i < pd->size_program; i++) {
 194                         addr = pd->rom_data[i].addr;
 195                         val = pd->rom_data[i].val;
 196                         if (!lp855x_is_valid_rom_area(lp, addr))
 197                                 continue;
 198
 199                         ret = lp855x_write_byte(lp, addr, val);
 200                         if (ret)
 201                                 goto err;
 202                 }
 203         }
 204
 205         if (lp->cfg->post_init_device) {
 206                 ret = lp->cfg->post_init_device(lp);
 207                 if (ret) {
 208                         dev_err(lp->dev, "post init device err: %d\n", ret);
 209                         goto err;
 210                 }
 211         }
 212
 213         return 0;
 214
 215 err:
 216         return ret;
 217 }
 218
 219 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 220 {
 221         struct pwm_device *pwm;
 222         struct pwm_state state;
 223
 224         /* request pwm device with the consumer name */
 225         if (!lp->pwm) {
 226                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 227                 if (IS_ERR(pwm))
 228                         return;
 229
 230                 lp->pwm = pwm;
 231
 232                 pwm_init_state(lp->pwm, &state);
 233         } else {
 234                 pwm_get_state(lp->pwm, &state);
 235         }
 236
 237         state.period = lp->pdata->period_ns;
 238         state.duty_cycle = div_u64(br * state.period, max_br);
 239         state.enabled = state.duty_cycle;
 240
 241         pwm_apply_state(lp->pwm, &state);
 242 }
 243
 244 static int lp855x_bl_update_status(struct backlight_device *bl)
 245 {
 246         struct lp855x *lp = bl_get_data(bl);
 247         int brightness = bl->props.brightness;
 248
 249         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 250                 brightness = 0;
 251
 252         if (lp->mode == PWM_BASED)
 253                 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
 254         else if (lp->mode == REGISTER_BASED)
 255                 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
 256
 257         return 0;
 258 }
 259
 260 static const struct backlight_ops lp855x_bl_ops = {
 261         .options = BL_CORE_SUSPENDRESUME,
 262         .update_status = lp855x_bl_update_status,
 263 };
 264
 265 static int lp855x_backlight_register(struct lp855x *lp)
 266 {
 267         struct backlight_device *bl;
 268         struct backlight_properties props;
 269         struct lp855x_platform_data *pdata = lp->pdata;
 270         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 271
 272         memset(&props, 0, sizeof(props));
 273         props.type = BACKLIGHT_PLATFORM;
 274         props.max_brightness = MAX_BRIGHTNESS;
 275
 276         if (pdata->initial_brightness > props.max_brightness)
 277                 pdata->initial_brightness = props.max_brightness;
 278
 279         props.brightness = pdata->initial_brightness;
 280
 281         bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
 282                                        &lp855x_bl_ops, &props);
 283         if (IS_ERR(bl))
 284                 return PTR_ERR(bl);
 285
 286         lp->bl = bl;
 287
 288         return 0;
 289 }
 290
 291 static ssize_t lp855x_get_chip_id(struct device *dev,
 292                                 struct device_attribute *attr, char *buf)
 293 {
 294         struct lp855x *lp = dev_get_drvdata(dev);
 295
 296         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
 297 }
 298
 299 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 300                                      struct device_attribute *attr, char *buf)
 301 {
 302         struct lp855x *lp = dev_get_drvdata(dev);
 303         char *strmode = NULL;
 304
 305         if (lp->mode == PWM_BASED)
 306                 strmode = "pwm based";
 307         else if (lp->mode == REGISTER_BASED)
 308                 strmode = "register based";
 309
 310         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 311 }
 312
 313 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 314 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 315
 316 static struct attribute *lp855x_attributes[] = {
 317         &dev_attr_chip_id.attr,
 318         &dev_attr_bl_ctl_mode.attr,
 319         NULL,
 320 };
 321
 322 static const struct attribute_group lp855x_attr_group = {
 323         .attrs = lp855x_attributes,
 324 };
 325
 326 #ifdef CONFIG_OF
 327 static int lp855x_parse_dt(struct lp855x *lp)
 328 {
 329         struct device *dev = lp->dev;
 330         struct device_node *node = dev->of_node;
 331         struct lp855x_platform_data *pdata = lp->pdata;
 332         int rom_length;
 333
 334         if (!node) {
 335                 dev_err(dev, "no platform data\n");
 336                 return -EINVAL;
 337         }
 338
 339         of_property_read_string(node, "bl-name", &pdata->name);
 340         of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 341         of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
 342         of_property_read_u32(node, "pwm-period", &pdata->period_ns);
 343
 344         /* Fill ROM platform data if defined */
 345         rom_length = of_get_child_count(node);
 346         if (rom_length > 0) {
 347                 struct lp855x_rom_data *rom;
 348                 struct device_node *child;
 349                 int i = 0;
 350
 351                 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
 352                 if (!rom)
 353                         return -ENOMEM;
 354
 355                 for_each_child_of_node(node, child) {
 356                         of_property_read_u8(child, "rom-addr", &rom[i].addr);
 357                         of_property_read_u8(child, "rom-val", &rom[i].val);
 358                         i++;
 359                 }
 360
 361                 pdata->size_program = rom_length;
 362                 pdata->rom_data = &rom[0];
 363         }
 364
 365         return 0;
 366 }
 367 #else
 368 static int lp855x_parse_dt(struct lp855x *lp)
 369 {
 370         return -EINVAL;
 371 }
 372 #endif
 373
 374 static int lp855x_parse_acpi(struct lp855x *lp)
 375 {
 376         int ret;
 377
 378         /*
 379          * On ACPI the device has already been initialized by the firmware
 380          * and is in register mode, so we can read back the settings from
 381          * the registers.
 382          */
 383         ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_brightness);
 384         if (ret < 0)
 385                 return ret;
 386
 387         lp->pdata->initial_brightness = ret;
 388
 389         ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_devicectrl);
 390         if (ret < 0)
 391                 return ret;
 392
 393         lp->pdata->device_control = ret;
 394         return 0;
 395 }
 396
 397 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 398 {
 399         const struct acpi_device_id *acpi_id = NULL;
 400         struct device *dev = &cl->dev;
 401         struct lp855x *lp;
 402         int ret;
 403
 404         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 405                 return -EIO;
 406
 407         lp = devm_kzalloc(dev, sizeof(struct lp855x), GFP_KERNEL);
 408         if (!lp)
 409                 return -ENOMEM;
 410
 411         lp->client = cl;
 412         lp->dev = dev;
 413         lp->pdata = dev_get_platdata(dev);
 414
 415         if (id) {
 416                 lp->chipname = id->name;
 417                 lp->chip_id = id->driver_data;
 418         } else {
 419                 acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev);
 420                 if (!acpi_id)
 421                         return -ENODEV;
 422
 423                 lp->chipname = acpi_id->id;
 424                 lp->chip_id = acpi_id->driver_data;
 425         }
 426
 427         switch (lp->chip_id) {
 428         case LP8550:
 429         case LP8551:
 430         case LP8552:
 431         case LP8553:
 432         case LP8556:
 433                 lp->cfg = &lp855x_dev_cfg;
 434                 break;
 435         case LP8555:
 436         case LP8557:
 437                 lp->cfg = &lp8557_dev_cfg;
 438                 break;
 439         default:
 440                 return -EINVAL;
 441         }
 442
 443         if (!lp->pdata) {
 444                 lp->pdata = devm_kzalloc(dev, sizeof(*lp->pdata), GFP_KERNEL);
 445                 if (!lp->pdata)
 446                         return -ENOMEM;
 447
 448                 if (id) {
 449                         ret = lp855x_parse_dt(lp);
 450                         if (ret < 0)
 451                                 return ret;
 452                 } else {
 453                         ret = lp855x_parse_acpi(lp);
 454                         if (ret < 0)
 455                                 return ret;
 456                 }
 457         }
 458
 459         if (lp->pdata->period_ns > 0)
 460                 lp->mode = PWM_BASED;
 461         else
 462                 lp->mode = REGISTER_BASED;
 463
 464         lp->supply = devm_regulator_get(dev, "power");
 465         if (IS_ERR(lp->supply)) {
 466                 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
 467                         return -EPROBE_DEFER;
 468                 lp->supply = NULL;
 469         }
 470
 471         lp->enable = devm_regulator_get_optional(dev, "enable");
 472         if (IS_ERR(lp->enable)) {
 473                 ret = PTR_ERR(lp->enable);
 474                 if (ret == -ENODEV) {
 475                         lp->enable = NULL;
 476                 } else {
 477                         return dev_err_probe(dev, ret, "getting enable regulator\n");
 478                 }
 479         }
 480
 481         if (lp->supply) {
 482                 ret = regulator_enable(lp->supply);
 483                 if (ret < 0) {
 484                         dev_err(dev, "failed to enable supply: %d\n", ret);
 485                         return ret;
 486                 }
 487         }
 488
 489         if (lp->enable) {
 490                 ret = regulator_enable(lp->enable);
 491                 if (ret < 0) {
 492                         dev_err(dev, "failed to enable vddio: %d\n", ret);
 493                         goto disable_supply;
 494                 }
 495
 496                 /*
 497                  * LP8555 datasheet says t_RESPONSE (time between VDDIO and
 498                  * I2C) is 1ms.
 499                  */
 500                 usleep_range(1000, 2000);
 501         }
 502
 503         i2c_set_clientdata(cl, lp);
 504
 505         ret = lp855x_configure(lp);
 506         if (ret) {
 507                 dev_err(dev, "device config err: %d", ret);
 508                 goto disable_vddio;
 509         }
 510
 511         ret = lp855x_backlight_register(lp);
 512         if (ret) {
 513                 dev_err(dev, "failed to register backlight. err: %d\n", ret);
 514                 goto disable_vddio;
 515         }
 516
 517         ret = sysfs_create_group(&dev->kobj, &lp855x_attr_group);
 518         if (ret) {
 519                 dev_err(dev, "failed to register sysfs. err: %d\n", ret);
 520                 goto disable_vddio;
 521         }
 522
 523         backlight_update_status(lp->bl);
 524
 525         return 0;
 526
 527 disable_vddio:
 528         if (lp->enable)
 529                 regulator_disable(lp->enable);
 530 disable_supply:
 531         if (lp->supply)
 532                 regulator_disable(lp->supply);
 533
 534         return ret;
 535 }
 536
 537 static void lp855x_remove(struct i2c_client *cl)
 538 {
 539         struct lp855x *lp = i2c_get_clientdata(cl);
 540
 541         lp->bl->props.brightness = 0;
 542         backlight_update_status(lp->bl);
 543         if (lp->enable)
 544                 regulator_disable(lp->enable);
 545         if (lp->supply)
 546                 regulator_disable(lp->supply);
 547         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 548 }
 549
 550 static const struct of_device_id lp855x_dt_ids[] = {
 551         { .compatible = "ti,lp8550", },
 552         { .compatible = "ti,lp8551", },
 553         { .compatible = "ti,lp8552", },
 554         { .compatible = "ti,lp8553", },
 555         { .compatible = "ti,lp8555", },
 556         { .compatible = "ti,lp8556", },
 557         { .compatible = "ti,lp8557", },
 558         { }
 559 };
 560 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
 561
 562 static const struct i2c_device_id lp855x_ids[] = {
 563         {"lp8550", LP8550},
 564         {"lp8551", LP8551},
 565         {"lp8552", LP8552},
 566         {"lp8553", LP8553},
 567         {"lp8555", LP8555},
 568         {"lp8556", LP8556},
 569         {"lp8557", LP8557},
 570         { }
 571 };
 572 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 573
 574 #ifdef CONFIG_ACPI
 575 static const struct acpi_device_id lp855x_acpi_match[] = {
 576         /* Xiaomi specific HID used for the LP8556 on the Mi Pad 2 */
 577         { "XMCC0001", LP8556 },
 578         { }
 579 };
 580 MODULE_DEVICE_TABLE(acpi, lp855x_acpi_match);
 581 #endif
 582
 583 static struct i2c_driver lp855x_driver = {
 584         .driver = {
 585                    .name = "lp855x",
 586                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 587                    .acpi_match_table = ACPI_PTR(lp855x_acpi_match),
 588                    },
 589         .probe = lp855x_probe,
 590         .remove = lp855x_remove,
 591         .id_table = lp855x_ids,
 592 };
 593
 594 module_i2c_driver(lp855x_driver);
 595
 596 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 597 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 598 MODULE_LICENSE("GPL");