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 /* LP8555/7 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 LP8555_EPROM_START 0x10 37 #define LP8555_EPROM_END 0x7A 38 #define LP8557_EPROM_START 0x10 39 #define LP8557_EPROM_END 0x1E 40 41 #define DEFAULT_BL_NAME "lcd-backlight" 42 #define MAX_BRIGHTNESS 255 43 44 enum lp855x_brightness_ctrl_mode { 45 PWM_BASED = 1, 46 REGISTER_BASED, 47 }; 48 49 struct lp855x; 50 51 /* 52 * struct lp855x_device_config 53 * @pre_init_device: init device function call before updating the brightness 54 * @reg_brightness: register address for brigthenss control 55 * @reg_devicectrl: register address for device control 56 * @post_init_device: late init device function call 57 */ 58 struct lp855x_device_config { 59 int (*pre_init_device)(struct lp855x *); 60 u8 reg_brightness; 61 u8 reg_devicectrl; 62 int (*post_init_device)(struct lp855x *); 63 }; 64 65 struct lp855x { 66 const char *chipname; 67 enum lp855x_chip_id chip_id; 68 enum lp855x_brightness_ctrl_mode mode; 69 struct lp855x_device_config *cfg; 70 struct i2c_client *client; 71 struct backlight_device *bl; 72 struct device *dev; 73 struct lp855x_platform_data *pdata; 74 struct pwm_device *pwm; 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 pwm_config(lp->pwm, duty, period); 250 if (duty) 251 pwm_enable(lp->pwm); 252 else 253 pwm_disable(lp->pwm); 254 } 255 256 static int lp855x_bl_update_status(struct backlight_device *bl) 257 { 258 struct lp855x *lp = bl_get_data(bl); 259 260 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 261 bl->props.brightness = 0; 262 263 if (lp->mode == PWM_BASED) { 264 int br = bl->props.brightness; 265 int max_br = bl->props.max_brightness; 266 267 lp855x_pwm_ctrl(lp, br, max_br); 268 269 } else if (lp->mode == REGISTER_BASED) { 270 u8 val = bl->props.brightness; 271 lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 272 } 273 274 return 0; 275 } 276 277 static int lp855x_bl_get_brightness(struct backlight_device *bl) 278 { 279 return bl->props.brightness; 280 } 281 282 static const struct backlight_ops lp855x_bl_ops = { 283 .options = BL_CORE_SUSPENDRESUME, 284 .update_status = lp855x_bl_update_status, 285 .get_brightness = lp855x_bl_get_brightness, 286 }; 287 288 static int lp855x_backlight_register(struct lp855x *lp) 289 { 290 struct backlight_device *bl; 291 struct backlight_properties props; 292 struct lp855x_platform_data *pdata = lp->pdata; 293 const char *name = pdata->name ? : DEFAULT_BL_NAME; 294 295 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 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 318 } 319 320 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 321 struct device_attribute *attr, char *buf) 322 { 323 struct lp855x *lp = dev_get_drvdata(dev); 324 char *strmode = NULL; 325 326 if (lp->mode == PWM_BASED) 327 strmode = "pwm based"; 328 else if (lp->mode == REGISTER_BASED) 329 strmode = "register based"; 330 331 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 332 } 333 334 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 335 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 336 337 static struct attribute *lp855x_attributes[] = { 338 &dev_attr_chip_id.attr, 339 &dev_attr_bl_ctl_mode.attr, 340 NULL, 341 }; 342 343 static const struct attribute_group lp855x_attr_group = { 344 .attrs = lp855x_attributes, 345 }; 346 347 #ifdef CONFIG_OF 348 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 349 { 350 struct lp855x_platform_data *pdata; 351 int rom_length; 352 353 if (!node) { 354 dev_err(dev, "no platform data\n"); 355 return -EINVAL; 356 } 357 358 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 359 if (!pdata) 360 return -ENOMEM; 361 362 of_property_read_string(node, "bl-name", &pdata->name); 363 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 364 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 365 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 366 367 /* Fill ROM platform data if defined */ 368 rom_length = of_get_child_count(node); 369 if (rom_length > 0) { 370 struct lp855x_rom_data *rom; 371 struct device_node *child; 372 int i = 0; 373 374 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); 375 if (!rom) 376 return -ENOMEM; 377 378 for_each_child_of_node(node, child) { 379 of_property_read_u8(child, "rom-addr", &rom[i].addr); 380 of_property_read_u8(child, "rom-val", &rom[i].val); 381 i++; 382 } 383 384 pdata->size_program = rom_length; 385 pdata->rom_data = &rom[0]; 386 } 387 388 dev->platform_data = pdata; 389 390 return 0; 391 } 392 #else 393 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 394 { 395 return -EINVAL; 396 } 397 #endif 398 399 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 400 { 401 struct lp855x *lp; 402 struct lp855x_platform_data *pdata = dev_get_platdata(&cl->dev); 403 struct device_node *node = cl->dev.of_node; 404 int ret; 405 406 if (!pdata) { 407 ret = lp855x_parse_dt(&cl->dev, node); 408 if (ret < 0) 409 return ret; 410 411 pdata = dev_get_platdata(&cl->dev); 412 } 413 414 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 415 return -EIO; 416 417 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 418 if (!lp) 419 return -ENOMEM; 420 421 if (pdata->period_ns > 0) 422 lp->mode = PWM_BASED; 423 else 424 lp->mode = REGISTER_BASED; 425 426 lp->client = cl; 427 lp->dev = &cl->dev; 428 lp->pdata = pdata; 429 lp->chipname = id->name; 430 lp->chip_id = id->driver_data; 431 i2c_set_clientdata(cl, lp); 432 433 ret = lp855x_configure(lp); 434 if (ret) { 435 dev_err(lp->dev, "device config err: %d", ret); 436 return ret; 437 } 438 439 ret = lp855x_backlight_register(lp); 440 if (ret) { 441 dev_err(lp->dev, 442 "failed to register backlight. err: %d\n", ret); 443 return ret; 444 } 445 446 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 447 if (ret) { 448 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 449 return ret; 450 } 451 452 backlight_update_status(lp->bl); 453 return 0; 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); 463 464 return 0; 465 } 466 467 static const struct of_device_id lp855x_dt_ids[] = { 468 { .compatible = "ti,lp8550", }, 469 { .compatible = "ti,lp8551", }, 470 { .compatible = "ti,lp8552", }, 471 { .compatible = "ti,lp8553", }, 472 { .compatible = "ti,lp8555", }, 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 {"lp8555", LP8555}, 485 {"lp8556", LP8556}, 486 {"lp8557", LP8557}, 487 { } 488 }; 489 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 490 491 static struct i2c_driver lp855x_driver = { 492 .driver = { 493 .name = "lp855x", 494 .of_match_table = of_match_ptr(lp855x_dt_ids), 495 }, 496 .probe = lp855x_probe, 497 .remove = lp855x_remove, 498 .id_table = lp855x_ids, 499 }; 500 501 module_i2c_driver(lp855x_driver); 502 503 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 504 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 505 MODULE_LICENSE("GPL"); 506