1 /* 2 * Copyright (C) 2011 ST-Ericsson SA. 3 * Copyright (C) 2009 Motorola, Inc. 4 * 5 * License Terms: GNU General Public License v2 6 * 7 * Simple driver for National Semiconductor LM3530 Backlight driver chip 8 * 9 * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com> 10 * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com> 11 */ 12 13 #include <linux/i2c.h> 14 #include <linux/leds.h> 15 #include <linux/slab.h> 16 #include <linux/platform_device.h> 17 #include <linux/input.h> 18 #include <linux/led-lm3530.h> 19 #include <linux/types.h> 20 #include <linux/regulator/consumer.h> 21 #include <linux/module.h> 22 23 #define LM3530_LED_DEV "lcd-backlight" 24 #define LM3530_NAME "lm3530-led" 25 26 #define LM3530_GEN_CONFIG 0x10 27 #define LM3530_ALS_CONFIG 0x20 28 #define LM3530_BRT_RAMP_RATE 0x30 29 #define LM3530_ALS_IMP_SELECT 0x41 30 #define LM3530_BRT_CTRL_REG 0xA0 31 #define LM3530_ALS_ZB0_REG 0x60 32 #define LM3530_ALS_ZB1_REG 0x61 33 #define LM3530_ALS_ZB2_REG 0x62 34 #define LM3530_ALS_ZB3_REG 0x63 35 #define LM3530_ALS_Z0T_REG 0x70 36 #define LM3530_ALS_Z1T_REG 0x71 37 #define LM3530_ALS_Z2T_REG 0x72 38 #define LM3530_ALS_Z3T_REG 0x73 39 #define LM3530_ALS_Z4T_REG 0x74 40 #define LM3530_REG_MAX 14 41 42 /* General Control Register */ 43 #define LM3530_EN_I2C_SHIFT (0) 44 #define LM3530_RAMP_LAW_SHIFT (1) 45 #define LM3530_MAX_CURR_SHIFT (2) 46 #define LM3530_EN_PWM_SHIFT (5) 47 #define LM3530_PWM_POL_SHIFT (6) 48 #define LM3530_EN_PWM_SIMPLE_SHIFT (7) 49 50 #define LM3530_ENABLE_I2C (1 << LM3530_EN_I2C_SHIFT) 51 #define LM3530_ENABLE_PWM (1 << LM3530_EN_PWM_SHIFT) 52 #define LM3530_POL_LOW (1 << LM3530_PWM_POL_SHIFT) 53 #define LM3530_ENABLE_PWM_SIMPLE (1 << LM3530_EN_PWM_SIMPLE_SHIFT) 54 55 /* ALS Config Register Options */ 56 #define LM3530_ALS_AVG_TIME_SHIFT (0) 57 #define LM3530_EN_ALS_SHIFT (3) 58 #define LM3530_ALS_SEL_SHIFT (5) 59 60 #define LM3530_ENABLE_ALS (3 << LM3530_EN_ALS_SHIFT) 61 62 /* Brightness Ramp Rate Register */ 63 #define LM3530_BRT_RAMP_FALL_SHIFT (0) 64 #define LM3530_BRT_RAMP_RISE_SHIFT (3) 65 66 /* ALS Resistor Select */ 67 #define LM3530_ALS1_IMP_SHIFT (0) 68 #define LM3530_ALS2_IMP_SHIFT (4) 69 70 /* Zone Boundary Register defaults */ 71 #define LM3530_ALS_ZB_MAX (4) 72 #define LM3530_ALS_WINDOW_mV (1000) 73 #define LM3530_ALS_OFFSET_mV (4) 74 75 /* Zone Target Register defaults */ 76 #define LM3530_DEF_ZT_0 (0x7F) 77 #define LM3530_DEF_ZT_1 (0x66) 78 #define LM3530_DEF_ZT_2 (0x4C) 79 #define LM3530_DEF_ZT_3 (0x33) 80 #define LM3530_DEF_ZT_4 (0x19) 81 82 /* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */ 83 #define MAX_BRIGHTNESS (127) 84 85 struct lm3530_mode_map { 86 const char *mode; 87 enum lm3530_mode mode_val; 88 }; 89 90 static struct lm3530_mode_map mode_map[] = { 91 { "man", LM3530_BL_MODE_MANUAL }, 92 { "als", LM3530_BL_MODE_ALS }, 93 { "pwm", LM3530_BL_MODE_PWM }, 94 }; 95 96 /** 97 * struct lm3530_data 98 * @led_dev: led class device 99 * @client: i2c client 100 * @pdata: LM3530 platform data 101 * @mode: mode of operation - manual, ALS, PWM 102 * @regulator: regulator 103 * @brighness: previous brightness value 104 * @enable: regulator is enabled 105 */ 106 struct lm3530_data { 107 struct led_classdev led_dev; 108 struct i2c_client *client; 109 struct lm3530_platform_data *pdata; 110 enum lm3530_mode mode; 111 struct regulator *regulator; 112 enum led_brightness brightness; 113 bool enable; 114 }; 115 116 /* 117 * struct lm3530_als_data 118 * @config : value of ALS configuration register 119 * @imp_sel : value of ALS resistor select register 120 * @zone : values of ALS ZB(Zone Boundary) registers 121 */ 122 struct lm3530_als_data { 123 u8 config; 124 u8 imp_sel; 125 u8 zones[LM3530_ALS_ZB_MAX]; 126 }; 127 128 static const u8 lm3530_reg[LM3530_REG_MAX] = { 129 LM3530_GEN_CONFIG, 130 LM3530_ALS_CONFIG, 131 LM3530_BRT_RAMP_RATE, 132 LM3530_ALS_IMP_SELECT, 133 LM3530_BRT_CTRL_REG, 134 LM3530_ALS_ZB0_REG, 135 LM3530_ALS_ZB1_REG, 136 LM3530_ALS_ZB2_REG, 137 LM3530_ALS_ZB3_REG, 138 LM3530_ALS_Z0T_REG, 139 LM3530_ALS_Z1T_REG, 140 LM3530_ALS_Z2T_REG, 141 LM3530_ALS_Z3T_REG, 142 LM3530_ALS_Z4T_REG, 143 }; 144 145 static int lm3530_get_mode_from_str(const char *str) 146 { 147 int i; 148 149 for (i = 0; i < ARRAY_SIZE(mode_map); i++) 150 if (sysfs_streq(str, mode_map[i].mode)) 151 return mode_map[i].mode_val; 152 153 return -EINVAL; 154 } 155 156 static void lm3530_als_configure(struct lm3530_platform_data *pdata, 157 struct lm3530_als_data *als) 158 { 159 int i; 160 u32 als_vmin, als_vmax, als_vstep; 161 162 if (pdata->als_vmax == 0) { 163 pdata->als_vmin = 0; 164 pdata->als_vmax = LM3530_ALS_WINDOW_mV; 165 } 166 167 als_vmin = pdata->als_vmin; 168 als_vmax = pdata->als_vmax; 169 170 if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV) 171 pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV; 172 173 /* n zone boundary makes n+1 zones */ 174 als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1); 175 176 for (i = 0; i < LM3530_ALS_ZB_MAX; i++) 177 als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) + 178 als_vstep + (i * als_vstep)) * LED_FULL) / 1000; 179 180 als->config = 181 (pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) | 182 (LM3530_ENABLE_ALS) | 183 (pdata->als_input_mode << LM3530_ALS_SEL_SHIFT); 184 185 als->imp_sel = 186 (pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) | 187 (pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT); 188 } 189 190 static int lm3530_init_registers(struct lm3530_data *drvdata) 191 { 192 int ret = 0; 193 int i; 194 u8 gen_config; 195 u8 brt_ramp; 196 u8 brightness; 197 u8 reg_val[LM3530_REG_MAX]; 198 struct lm3530_platform_data *pdata = drvdata->pdata; 199 struct i2c_client *client = drvdata->client; 200 struct lm3530_pwm_data *pwm = &pdata->pwm_data; 201 struct lm3530_als_data als; 202 203 memset(&als, 0, sizeof(struct lm3530_als_data)); 204 205 gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) | 206 ((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT); 207 208 switch (drvdata->mode) { 209 case LM3530_BL_MODE_MANUAL: 210 gen_config |= LM3530_ENABLE_I2C; 211 break; 212 case LM3530_BL_MODE_ALS: 213 gen_config |= LM3530_ENABLE_I2C; 214 lm3530_als_configure(pdata, &als); 215 break; 216 case LM3530_BL_MODE_PWM: 217 gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE | 218 (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT); 219 break; 220 } 221 222 brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) | 223 (pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT); 224 225 if (drvdata->brightness) 226 brightness = drvdata->brightness; 227 else 228 brightness = drvdata->brightness = pdata->brt_val; 229 230 if (brightness > drvdata->led_dev.max_brightness) 231 brightness = drvdata->led_dev.max_brightness; 232 233 reg_val[0] = gen_config; /* LM3530_GEN_CONFIG */ 234 reg_val[1] = als.config; /* LM3530_ALS_CONFIG */ 235 reg_val[2] = brt_ramp; /* LM3530_BRT_RAMP_RATE */ 236 reg_val[3] = als.imp_sel; /* LM3530_ALS_IMP_SELECT */ 237 reg_val[4] = brightness; /* LM3530_BRT_CTRL_REG */ 238 reg_val[5] = als.zones[0]; /* LM3530_ALS_ZB0_REG */ 239 reg_val[6] = als.zones[1]; /* LM3530_ALS_ZB1_REG */ 240 reg_val[7] = als.zones[2]; /* LM3530_ALS_ZB2_REG */ 241 reg_val[8] = als.zones[3]; /* LM3530_ALS_ZB3_REG */ 242 reg_val[9] = LM3530_DEF_ZT_0; /* LM3530_ALS_Z0T_REG */ 243 reg_val[10] = LM3530_DEF_ZT_1; /* LM3530_ALS_Z1T_REG */ 244 reg_val[11] = LM3530_DEF_ZT_2; /* LM3530_ALS_Z2T_REG */ 245 reg_val[12] = LM3530_DEF_ZT_3; /* LM3530_ALS_Z3T_REG */ 246 reg_val[13] = LM3530_DEF_ZT_4; /* LM3530_ALS_Z4T_REG */ 247 248 if (!drvdata->enable) { 249 ret = regulator_enable(drvdata->regulator); 250 if (ret) { 251 dev_err(&drvdata->client->dev, 252 "Enable regulator failed\n"); 253 return ret; 254 } 255 drvdata->enable = true; 256 } 257 258 for (i = 0; i < LM3530_REG_MAX; i++) { 259 /* do not update brightness register when pwm mode */ 260 if (lm3530_reg[i] == LM3530_BRT_CTRL_REG && 261 drvdata->mode == LM3530_BL_MODE_PWM) { 262 if (pwm->pwm_set_intensity) 263 pwm->pwm_set_intensity(reg_val[i], 264 drvdata->led_dev.max_brightness); 265 continue; 266 } 267 268 ret = i2c_smbus_write_byte_data(client, 269 lm3530_reg[i], reg_val[i]); 270 if (ret) 271 break; 272 } 273 274 return ret; 275 } 276 277 static void lm3530_brightness_set(struct led_classdev *led_cdev, 278 enum led_brightness brt_val) 279 { 280 int err; 281 struct lm3530_data *drvdata = 282 container_of(led_cdev, struct lm3530_data, led_dev); 283 struct lm3530_platform_data *pdata = drvdata->pdata; 284 struct lm3530_pwm_data *pwm = &pdata->pwm_data; 285 u8 max_brightness = led_cdev->max_brightness; 286 287 switch (drvdata->mode) { 288 case LM3530_BL_MODE_MANUAL: 289 290 if (!drvdata->enable) { 291 err = lm3530_init_registers(drvdata); 292 if (err) { 293 dev_err(&drvdata->client->dev, 294 "Register Init failed: %d\n", err); 295 break; 296 } 297 } 298 299 /* set the brightness in brightness control register*/ 300 err = i2c_smbus_write_byte_data(drvdata->client, 301 LM3530_BRT_CTRL_REG, brt_val); 302 if (err) 303 dev_err(&drvdata->client->dev, 304 "Unable to set brightness: %d\n", err); 305 else 306 drvdata->brightness = brt_val; 307 308 if (brt_val == 0) { 309 err = regulator_disable(drvdata->regulator); 310 if (err) 311 dev_err(&drvdata->client->dev, 312 "Disable regulator failed\n"); 313 drvdata->enable = false; 314 } 315 break; 316 case LM3530_BL_MODE_ALS: 317 break; 318 case LM3530_BL_MODE_PWM: 319 if (pwm->pwm_set_intensity) 320 pwm->pwm_set_intensity(brt_val, max_brightness); 321 break; 322 default: 323 break; 324 } 325 } 326 327 static ssize_t lm3530_mode_get(struct device *dev, 328 struct device_attribute *attr, char *buf) 329 { 330 struct led_classdev *led_cdev = dev_get_drvdata(dev); 331 struct lm3530_data *drvdata; 332 int i, len = 0; 333 334 drvdata = container_of(led_cdev, struct lm3530_data, led_dev); 335 for (i = 0; i < ARRAY_SIZE(mode_map); i++) 336 if (drvdata->mode == mode_map[i].mode_val) 337 len += sprintf(buf + len, "[%s] ", mode_map[i].mode); 338 else 339 len += sprintf(buf + len, "%s ", mode_map[i].mode); 340 341 len += sprintf(buf + len, "\n"); 342 343 return len; 344 } 345 346 static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute 347 *attr, const char *buf, size_t size) 348 { 349 struct led_classdev *led_cdev = dev_get_drvdata(dev); 350 struct lm3530_data *drvdata; 351 struct lm3530_pwm_data *pwm; 352 u8 max_brightness; 353 int mode, err; 354 355 drvdata = container_of(led_cdev, struct lm3530_data, led_dev); 356 pwm = &drvdata->pdata->pwm_data; 357 max_brightness = led_cdev->max_brightness; 358 mode = lm3530_get_mode_from_str(buf); 359 if (mode < 0) { 360 dev_err(dev, "Invalid mode\n"); 361 return mode; 362 } 363 364 drvdata->mode = mode; 365 366 /* set pwm to low if unnecessary */ 367 if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity) 368 pwm->pwm_set_intensity(0, max_brightness); 369 370 err = lm3530_init_registers(drvdata); 371 if (err) { 372 dev_err(dev, "Setting %s Mode failed :%d\n", buf, err); 373 return err; 374 } 375 376 return sizeof(drvdata->mode); 377 } 378 static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set); 379 380 static int lm3530_probe(struct i2c_client *client, 381 const struct i2c_device_id *id) 382 { 383 struct lm3530_platform_data *pdata = client->dev.platform_data; 384 struct lm3530_data *drvdata; 385 int err = 0; 386 387 if (pdata == NULL) { 388 dev_err(&client->dev, "platform data required\n"); 389 return -ENODEV; 390 } 391 392 /* BL mode */ 393 if (pdata->mode > LM3530_BL_MODE_PWM) { 394 dev_err(&client->dev, "Illegal Mode request\n"); 395 return -EINVAL; 396 } 397 398 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 399 dev_err(&client->dev, "I2C_FUNC_I2C not supported\n"); 400 return -EIO; 401 } 402 403 drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data), 404 GFP_KERNEL); 405 if (drvdata == NULL) 406 return -ENOMEM; 407 408 drvdata->mode = pdata->mode; 409 drvdata->client = client; 410 drvdata->pdata = pdata; 411 drvdata->brightness = LED_OFF; 412 drvdata->enable = false; 413 drvdata->led_dev.name = LM3530_LED_DEV; 414 drvdata->led_dev.brightness_set = lm3530_brightness_set; 415 drvdata->led_dev.max_brightness = MAX_BRIGHTNESS; 416 417 i2c_set_clientdata(client, drvdata); 418 419 drvdata->regulator = devm_regulator_get(&client->dev, "vin"); 420 if (IS_ERR(drvdata->regulator)) { 421 dev_err(&client->dev, "regulator get failed\n"); 422 err = PTR_ERR(drvdata->regulator); 423 drvdata->regulator = NULL; 424 return err; 425 } 426 427 if (drvdata->pdata->brt_val) { 428 err = lm3530_init_registers(drvdata); 429 if (err < 0) { 430 dev_err(&client->dev, 431 "Register Init failed: %d\n", err); 432 return err; 433 } 434 } 435 err = led_classdev_register(&client->dev, &drvdata->led_dev); 436 if (err < 0) { 437 dev_err(&client->dev, "Register led class failed: %d\n", err); 438 return err; 439 } 440 441 err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode); 442 if (err < 0) { 443 dev_err(&client->dev, "File device creation failed: %d\n", err); 444 err = -ENODEV; 445 goto err_create_file; 446 } 447 448 return 0; 449 450 err_create_file: 451 led_classdev_unregister(&drvdata->led_dev); 452 return err; 453 } 454 455 static int lm3530_remove(struct i2c_client *client) 456 { 457 struct lm3530_data *drvdata = i2c_get_clientdata(client); 458 459 device_remove_file(drvdata->led_dev.dev, &dev_attr_mode); 460 461 if (drvdata->enable) 462 regulator_disable(drvdata->regulator); 463 led_classdev_unregister(&drvdata->led_dev); 464 return 0; 465 } 466 467 static const struct i2c_device_id lm3530_id[] = { 468 {LM3530_NAME, 0}, 469 {} 470 }; 471 MODULE_DEVICE_TABLE(i2c, lm3530_id); 472 473 static struct i2c_driver lm3530_i2c_driver = { 474 .probe = lm3530_probe, 475 .remove = lm3530_remove, 476 .id_table = lm3530_id, 477 .driver = { 478 .name = LM3530_NAME, 479 .owner = THIS_MODULE, 480 }, 481 }; 482 483 module_i2c_driver(lm3530_i2c_driver); 484 485 MODULE_DESCRIPTION("Back Light driver for LM3530"); 486 MODULE_LICENSE("GPL v2"); 487 MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>"); 488