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 const struct backlight_ops lp855x_bl_ops = { 278 .options = BL_CORE_SUSPENDRESUME, 279 .update_status = lp855x_bl_update_status, 280 }; 281 282 static int lp855x_backlight_register(struct lp855x *lp) 283 { 284 struct backlight_device *bl; 285 struct backlight_properties props; 286 struct lp855x_platform_data *pdata = lp->pdata; 287 const char *name = pdata->name ? : DEFAULT_BL_NAME; 288 289 props.type = BACKLIGHT_PLATFORM; 290 props.max_brightness = MAX_BRIGHTNESS; 291 292 if (pdata->initial_brightness > props.max_brightness) 293 pdata->initial_brightness = props.max_brightness; 294 295 props.brightness = pdata->initial_brightness; 296 297 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 298 &lp855x_bl_ops, &props); 299 if (IS_ERR(bl)) 300 return PTR_ERR(bl); 301 302 lp->bl = bl; 303 304 return 0; 305 } 306 307 static ssize_t lp855x_get_chip_id(struct device *dev, 308 struct device_attribute *attr, char *buf) 309 { 310 struct lp855x *lp = dev_get_drvdata(dev); 311 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 312 } 313 314 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 315 struct device_attribute *attr, char *buf) 316 { 317 struct lp855x *lp = dev_get_drvdata(dev); 318 char *strmode = NULL; 319 320 if (lp->mode == PWM_BASED) 321 strmode = "pwm based"; 322 else if (lp->mode == REGISTER_BASED) 323 strmode = "register based"; 324 325 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 326 } 327 328 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 329 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 330 331 static struct attribute *lp855x_attributes[] = { 332 &dev_attr_chip_id.attr, 333 &dev_attr_bl_ctl_mode.attr, 334 NULL, 335 }; 336 337 static const struct attribute_group lp855x_attr_group = { 338 .attrs = lp855x_attributes, 339 }; 340 341 #ifdef CONFIG_OF 342 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 343 { 344 struct lp855x_platform_data *pdata; 345 int rom_length; 346 347 if (!node) { 348 dev_err(dev, "no platform data\n"); 349 return -EINVAL; 350 } 351 352 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 353 if (!pdata) 354 return -ENOMEM; 355 356 of_property_read_string(node, "bl-name", &pdata->name); 357 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 358 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 359 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 360 361 /* Fill ROM platform data if defined */ 362 rom_length = of_get_child_count(node); 363 if (rom_length > 0) { 364 struct lp855x_rom_data *rom; 365 struct device_node *child; 366 int i = 0; 367 368 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); 369 if (!rom) 370 return -ENOMEM; 371 372 for_each_child_of_node(node, child) { 373 of_property_read_u8(child, "rom-addr", &rom[i].addr); 374 of_property_read_u8(child, "rom-val", &rom[i].val); 375 i++; 376 } 377 378 pdata->size_program = rom_length; 379 pdata->rom_data = &rom[0]; 380 } 381 382 dev->platform_data = pdata; 383 384 return 0; 385 } 386 #else 387 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 388 { 389 return -EINVAL; 390 } 391 #endif 392 393 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 394 { 395 struct lp855x *lp; 396 struct lp855x_platform_data *pdata = dev_get_platdata(&cl->dev); 397 struct device_node *node = cl->dev.of_node; 398 int ret; 399 400 if (!pdata) { 401 ret = lp855x_parse_dt(&cl->dev, node); 402 if (ret < 0) 403 return ret; 404 405 pdata = dev_get_platdata(&cl->dev); 406 } 407 408 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 409 return -EIO; 410 411 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 412 if (!lp) 413 return -ENOMEM; 414 415 if (pdata->period_ns > 0) 416 lp->mode = PWM_BASED; 417 else 418 lp->mode = REGISTER_BASED; 419 420 lp->client = cl; 421 lp->dev = &cl->dev; 422 lp->pdata = pdata; 423 lp->chipname = id->name; 424 lp->chip_id = id->driver_data; 425 i2c_set_clientdata(cl, lp); 426 427 ret = lp855x_configure(lp); 428 if (ret) { 429 dev_err(lp->dev, "device config err: %d", ret); 430 return ret; 431 } 432 433 ret = lp855x_backlight_register(lp); 434 if (ret) { 435 dev_err(lp->dev, 436 "failed to register backlight. err: %d\n", ret); 437 return ret; 438 } 439 440 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 441 if (ret) { 442 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 443 return ret; 444 } 445 446 backlight_update_status(lp->bl); 447 return 0; 448 } 449 450 static int lp855x_remove(struct i2c_client *cl) 451 { 452 struct lp855x *lp = i2c_get_clientdata(cl); 453 454 lp->bl->props.brightness = 0; 455 backlight_update_status(lp->bl); 456 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 457 458 return 0; 459 } 460 461 static const struct of_device_id lp855x_dt_ids[] = { 462 { .compatible = "ti,lp8550", }, 463 { .compatible = "ti,lp8551", }, 464 { .compatible = "ti,lp8552", }, 465 { .compatible = "ti,lp8553", }, 466 { .compatible = "ti,lp8555", }, 467 { .compatible = "ti,lp8556", }, 468 { .compatible = "ti,lp8557", }, 469 { } 470 }; 471 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 472 473 static const struct i2c_device_id lp855x_ids[] = { 474 {"lp8550", LP8550}, 475 {"lp8551", LP8551}, 476 {"lp8552", LP8552}, 477 {"lp8553", LP8553}, 478 {"lp8555", LP8555}, 479 {"lp8556", LP8556}, 480 {"lp8557", LP8557}, 481 { } 482 }; 483 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 484 485 static struct i2c_driver lp855x_driver = { 486 .driver = { 487 .name = "lp855x", 488 .of_match_table = of_match_ptr(lp855x_dt_ids), 489 }, 490 .probe = lp855x_probe, 491 .remove = lp855x_remove, 492 .id_table = lp855x_ids, 493 }; 494 495 module_i2c_driver(lp855x_driver); 496 497 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 498 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 499 MODULE_LICENSE("GPL"); 500