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 /* LP8557 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 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 };
  74
  75 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  76 {
  77         return i2c_smbus_write_byte_data(lp->client, reg, data);
  78 }
  79
  80 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
  81 {
  82         int ret;
  83         u8 tmp;
  84
  85         ret = i2c_smbus_read_byte_data(lp->client, reg);
  86         if (ret < 0) {
  87                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  88                 return ret;
  89         }
  90
  91         tmp = (u8)ret;
  92         tmp &= ~mask;
  93         tmp |= data & mask;
  94
  95         return lp855x_write_byte(lp, reg, tmp);
  96 }
  97
  98 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
  99 {
 100         u8 start, end;
 101
 102         switch (lp->chip_id) {
 103         case LP8550:
 104         case LP8551:
 105         case LP8552:
 106         case LP8553:
 107                 start = LP855X_EEPROM_START;
 108                 end = LP855X_EEPROM_END;
 109                 break;
 110         case LP8556:
 111                 start = LP8556_EPROM_START;
 112                 end = LP8556_EPROM_END;
 113                 break;
 114         case LP8557:
 115                 start = LP8557_EPROM_START;
 116                 end = LP8557_EPROM_END;
 117                 break;
 118         default:
 119                 return false;
 120         }
 121
 122         return (addr >= start && addr <= end);
 123 }
 124
 125 static int lp8557_bl_off(struct lp855x *lp)
 126 {
 127         /* BL_ON = 0 before updating EPROM settings */
 128         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 129                                 LP8557_BL_OFF);
 130 }
 131
 132 static int lp8557_bl_on(struct lp855x *lp)
 133 {
 134         /* BL_ON = 1 after updating EPROM settings */
 135         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 136                                 LP8557_BL_ON);
 137 }
 138
 139 static struct lp855x_device_config lp855x_dev_cfg = {
 140         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
 141         .reg_devicectrl = LP855X_DEVICE_CTRL,
 142 };
 143
 144 static struct lp855x_device_config lp8557_dev_cfg = {
 145         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
 146         .reg_devicectrl = LP8557_CONFIG,
 147         .pre_init_device = lp8557_bl_off,
 148         .post_init_device = lp8557_bl_on,
 149 };
 150
 151 /*
 152  * Device specific configuration flow
 153  *
 154  *    a) pre_init_device(optional)
 155  *    b) update the brightness register
 156  *    c) update device control register
 157  *    d) update ROM area(optional)
 158  *    e) post_init_device(optional)
 159  *
 160  */
 161 static int lp855x_configure(struct lp855x *lp)
 162 {
 163         u8 val, addr;
 164         int i, ret;
 165         struct lp855x_platform_data *pd = lp->pdata;
 166
 167         switch (lp->chip_id) {
 168         case LP8550 ... LP8556:
 169                 lp->cfg = &lp855x_dev_cfg;
 170                 break;
 171         case LP8557:
 172                 lp->cfg = &lp8557_dev_cfg;
 173                 break;
 174         default:
 175                 return -EINVAL;
 176         }
 177
 178         if (lp->cfg->pre_init_device) {
 179                 ret = lp->cfg->pre_init_device(lp);
 180                 if (ret) {
 181                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 182                         goto err;
 183                 }
 184         }
 185
 186         val = pd->initial_brightness;
 187         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 188         if (ret)
 189                 goto err;
 190
 191         val = pd->device_control;
 192         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 193         if (ret)
 194                 goto err;
 195
 196         if (pd->size_program > 0) {
 197                 for (i = 0; i < pd->size_program; i++) {
 198                         addr = pd->rom_data[i].addr;
 199                         val = pd->rom_data[i].val;
 200                         if (!lp855x_is_valid_rom_area(lp, addr))
 201                                 continue;
 202
 203                         ret = lp855x_write_byte(lp, addr, val);
 204                         if (ret)
 205                                 goto err;
 206                 }
 207         }
 208
 209         if (lp->cfg->post_init_device) {
 210                 ret = lp->cfg->post_init_device(lp);
 211                 if (ret) {
 212                         dev_err(lp->dev, "post init device err: %d\n", ret);
 213                         goto err;
 214                 }
 215         }
 216
 217         return 0;
 218
 219 err:
 220         return ret;
 221 }
 222
 223 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 224 {
 225         unsigned int period = lp->pdata->period_ns;
 226         unsigned int duty = br * period / max_br;
 227         struct pwm_device *pwm;
 228
 229         /* request pwm device with the consumer name */
 230         if (!lp->pwm) {
 231                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 232                 if (IS_ERR(pwm))
 233                         return;
 234
 235                 lp->pwm = pwm;
 236         }
 237
 238         pwm_config(lp->pwm, duty, period);
 239         if (duty)
 240                 pwm_enable(lp->pwm);
 241         else
 242                 pwm_disable(lp->pwm);
 243 }
 244
 245 static int lp855x_bl_update_status(struct backlight_device *bl)
 246 {
 247         struct lp855x *lp = bl_get_data(bl);
 248
 249         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 250                 bl->props.brightness = 0;
 251
 252         if (lp->mode == PWM_BASED) {
 253                 int br = bl->props.brightness;
 254                 int max_br = bl->props.max_brightness;
 255
 256                 lp855x_pwm_ctrl(lp, br, max_br);
 257
 258         } else if (lp->mode == REGISTER_BASED) {
 259                 u8 val = bl->props.brightness;
 260                 lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 261         }
 262
 263         return 0;
 264 }
 265
 266 static int lp855x_bl_get_brightness(struct backlight_device *bl)
 267 {
 268         return bl->props.brightness;
 269 }
 270
 271 static const struct backlight_ops lp855x_bl_ops = {
 272         .options = BL_CORE_SUSPENDRESUME,
 273         .update_status = lp855x_bl_update_status,
 274         .get_brightness = lp855x_bl_get_brightness,
 275 };
 276
 277 static int lp855x_backlight_register(struct lp855x *lp)
 278 {
 279         struct backlight_device *bl;
 280         struct backlight_properties props;
 281         struct lp855x_platform_data *pdata = lp->pdata;
 282         const char *name = pdata->name ? : DEFAULT_BL_NAME;
 283
 284         props.type = BACKLIGHT_PLATFORM;
 285         props.max_brightness = MAX_BRIGHTNESS;
 286
 287         if (pdata->initial_brightness > props.max_brightness)
 288                 pdata->initial_brightness = props.max_brightness;
 289
 290         props.brightness = pdata->initial_brightness;
 291
 292         bl = backlight_device_register(name, lp->dev, lp,
 293                                        &lp855x_bl_ops, &props);
 294         if (IS_ERR(bl))
 295                 return PTR_ERR(bl);
 296
 297         lp->bl = bl;
 298
 299         return 0;
 300 }
 301
 302 static void lp855x_backlight_unregister(struct lp855x *lp)
 303 {
 304         if (lp->bl)
 305                 backlight_device_unregister(lp->bl);
 306 }
 307
 308 static ssize_t lp855x_get_chip_id(struct device *dev,
 309                                 struct device_attribute *attr, char *buf)
 310 {
 311         struct lp855x *lp = dev_get_drvdata(dev);
 312         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
 313 }
 314
 315 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 316                                      struct device_attribute *attr, char *buf)
 317 {
 318         struct lp855x *lp = dev_get_drvdata(dev);
 319         char *strmode = NULL;
 320
 321         if (lp->mode == PWM_BASED)
 322                 strmode = "pwm based";
 323         else if (lp->mode == REGISTER_BASED)
 324                 strmode = "register based";
 325
 326         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
 327 }
 328
 329 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 330 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 331
 332 static struct attribute *lp855x_attributes[] = {
 333         &dev_attr_chip_id.attr,
 334         &dev_attr_bl_ctl_mode.attr,
 335         NULL,
 336 };
 337
 338 static const struct attribute_group lp855x_attr_group = {
 339         .attrs = lp855x_attributes,
 340 };
 341
 342 #ifdef CONFIG_OF
 343 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
 344 {
 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         dev->platform_data = pdata;
 384
 385         return 0;
 386 }
 387 #else
 388 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
 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         struct lp855x_platform_data *pdata = cl->dev.platform_data;
 398         struct device_node *node = cl->dev.of_node;
 399         int ret;
 400
 401         if (!pdata) {
 402                 ret = lp855x_parse_dt(&cl->dev, node);
 403                 if (ret < 0)
 404                         return ret;
 405
 406                 pdata = cl->dev.platform_data;
 407         }
 408
 409         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 410                 return -EIO;
 411
 412         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 413         if (!lp)
 414                 return -ENOMEM;
 415
 416         if (pdata->period_ns > 0)
 417                 lp->mode = PWM_BASED;
 418         else
 419                 lp->mode = REGISTER_BASED;
 420
 421         lp->client = cl;
 422         lp->dev = &cl->dev;
 423         lp->pdata = pdata;
 424         lp->chipname = id->name;
 425         lp->chip_id = id->driver_data;
 426         i2c_set_clientdata(cl, lp);
 427
 428         ret = lp855x_configure(lp);
 429         if (ret) {
 430                 dev_err(lp->dev, "device config err: %d", ret);
 431                 goto err_dev;
 432         }
 433
 434         ret = lp855x_backlight_register(lp);
 435         if (ret) {
 436                 dev_err(lp->dev,
 437                         "failed to register backlight. err: %d\n", ret);
 438                 goto err_dev;
 439         }
 440
 441         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 442         if (ret) {
 443                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 444                 goto err_sysfs;
 445         }
 446
 447         backlight_update_status(lp->bl);
 448         return 0;
 449
 450 err_sysfs:
 451         lp855x_backlight_unregister(lp);
 452 err_dev:
 453         return ret;
 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         lp855x_backlight_unregister(lp);
 464
 465         return 0;
 466 }
 467
 468 static const struct of_device_id lp855x_dt_ids[] = {
 469         { .compatible = "ti,lp8550", },
 470         { .compatible = "ti,lp8551", },
 471         { .compatible = "ti,lp8552", },
 472         { .compatible = "ti,lp8553", },
 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         {"lp8556", LP8556},
 485         {"lp8557", LP8557},
 486         { }
 487 };
 488 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 489
 490 static struct i2c_driver lp855x_driver = {
 491         .driver = {
 492                    .name = "lp855x",
 493                    .of_match_table = of_match_ptr(lp855x_dt_ids),
 494                    },
 495         .probe = lp855x_probe,
 496         .remove = lp855x_remove,
 497         .id_table = lp855x_ids,
 498 };
 499
 500 module_i2c_driver(lp855x_driver);
 501
 502 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 503 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 504 MODULE_LICENSE("GPL");