1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2011 ST-Ericsson SA. 4 * Copyright (C) 2009 Motorola, Inc. 5 * 6 * Simple driver for National Semiconductor LM3530 Backlight driver chip 7 * 8 * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com> 9 * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com> 10 */ 11 12 #include <linux/i2c.h> 13 #include <linux/leds.h> 14 #include <linux/slab.h> 15 #include <linux/platform_device.h> 16 #include <linux/input.h> 17 #include <linux/led-lm3530.h> 18 #include <linux/types.h> 19 #include <linux/regulator/consumer.h> 20 #include <linux/module.h> 21 22 #define LM3530_LED_DEV "lcd-backlight" 23 #define LM3530_NAME "lm3530-led" 24 25 #define LM3530_GEN_CONFIG 0x10 26 #define LM3530_ALS_CONFIG 0x20 27 #define LM3530_BRT_RAMP_RATE 0x30 28 #define LM3530_ALS_IMP_SELECT 0x41 29 #define LM3530_BRT_CTRL_REG 0xA0 30 #define LM3530_ALS_ZB0_REG 0x60 31 #define LM3530_ALS_ZB1_REG 0x61 32 #define LM3530_ALS_ZB2_REG 0x62 33 #define LM3530_ALS_ZB3_REG 0x63 34 #define LM3530_ALS_Z0T_REG 0x70 35 #define LM3530_ALS_Z1T_REG 0x71 36 #define LM3530_ALS_Z2T_REG 0x72 37 #define LM3530_ALS_Z3T_REG 0x73 38 #define LM3530_ALS_Z4T_REG 0x74 39 #define LM3530_REG_MAX 14 40 41 /* General Control Register */ 42 #define LM3530_EN_I2C_SHIFT (0) 43 #define LM3530_RAMP_LAW_SHIFT (1) 44 #define LM3530_MAX_CURR_SHIFT (2) 45 #define LM3530_EN_PWM_SHIFT (5) 46 #define LM3530_PWM_POL_SHIFT (6) 47 #define LM3530_EN_PWM_SIMPLE_SHIFT (7) 48 49 #define LM3530_ENABLE_I2C (1 << LM3530_EN_I2C_SHIFT) 50 #define LM3530_ENABLE_PWM (1 << LM3530_EN_PWM_SHIFT) 51 #define LM3530_POL_LOW (1 << LM3530_PWM_POL_SHIFT) 52 #define LM3530_ENABLE_PWM_SIMPLE (1 << LM3530_EN_PWM_SIMPLE_SHIFT) 53 54 /* ALS Config Register Options */ 55 #define LM3530_ALS_AVG_TIME_SHIFT (0) 56 #define LM3530_EN_ALS_SHIFT (3) 57 #define LM3530_ALS_SEL_SHIFT (5) 58 59 #define LM3530_ENABLE_ALS (3 << LM3530_EN_ALS_SHIFT) 60 61 /* Brightness Ramp Rate Register */ 62 #define LM3530_BRT_RAMP_FALL_SHIFT (0) 63 #define LM3530_BRT_RAMP_RISE_SHIFT (3) 64 65 /* ALS Resistor Select */ 66 #define LM3530_ALS1_IMP_SHIFT (0) 67 #define LM3530_ALS2_IMP_SHIFT (4) 68 69 /* Zone Boundary Register defaults */ 70 #define LM3530_ALS_ZB_MAX (4) 71 #define LM3530_ALS_WINDOW_mV (1000) 72 #define LM3530_ALS_OFFSET_mV (4) 73 74 /* Zone Target Register defaults */ 75 #define LM3530_DEF_ZT_0 (0x7F) 76 #define LM3530_DEF_ZT_1 (0x66) 77 #define LM3530_DEF_ZT_2 (0x4C) 78 #define LM3530_DEF_ZT_3 (0x33) 79 #define LM3530_DEF_ZT_4 (0x19) 80 81 /* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */ 82 #define MAX_BRIGHTNESS (127) 83 84 struct lm3530_mode_map { 85 const char *mode; 86 enum lm3530_mode mode_val; 87 }; 88 89 static struct lm3530_mode_map mode_map[] = { 90 { "man", LM3530_BL_MODE_MANUAL }, 91 { "als", LM3530_BL_MODE_ALS }, 92 { "pwm", LM3530_BL_MODE_PWM }, 93 }; 94 95 /** 96 * struct lm3530_data 97 * @led_dev: led class device 98 * @client: i2c client 99 * @pdata: LM3530 platform data 100 * @mode: mode of operation - manual, ALS, PWM 101 * @regulator: regulator 102 * @brighness: previous brightness value 103 * @enable: regulator is enabled 104 */ 105 struct lm3530_data { 106 struct led_classdev led_dev; 107 struct i2c_client *client; 108 struct lm3530_platform_data *pdata; 109 enum lm3530_mode mode; 110 struct regulator *regulator; 111 enum led_brightness brightness; 112 bool enable; 113 }; 114 115 /* 116 * struct lm3530_als_data 117 * @config : value of ALS configuration register 118 * @imp_sel : value of ALS resistor select register 119 * @zone : values of ALS ZB(Zone Boundary) registers 120 */ 121 struct lm3530_als_data { 122 u8 config; 123 u8 imp_sel; 124 u8 zones[LM3530_ALS_ZB_MAX]; 125 }; 126 127 static const u8 lm3530_reg[LM3530_REG_MAX] = { 128 LM3530_GEN_CONFIG, 129 LM3530_ALS_CONFIG, 130 LM3530_BRT_RAMP_RATE, 131 LM3530_ALS_IMP_SELECT, 132 LM3530_BRT_CTRL_REG, 133 LM3530_ALS_ZB0_REG, 134 LM3530_ALS_ZB1_REG, 135 LM3530_ALS_ZB2_REG, 136 LM3530_ALS_ZB3_REG, 137 LM3530_ALS_Z0T_REG, 138 LM3530_ALS_Z1T_REG, 139 LM3530_ALS_Z2T_REG, 140 LM3530_ALS_Z3T_REG, 141 LM3530_ALS_Z4T_REG, 142 }; 143 144 static int lm3530_get_mode_from_str(const char *str) 145 { 146 int i; 147 148 for (i = 0; i < ARRAY_SIZE(mode_map); i++) 149 if (sysfs_streq(str, mode_map[i].mode)) 150 return mode_map[i].mode_val; 151 152 return -EINVAL; 153 } 154 155 static void lm3530_als_configure(struct lm3530_platform_data *pdata, 156 struct lm3530_als_data *als) 157 { 158 int i; 159 u32 als_vmin, als_vmax, als_vstep; 160 161 if (pdata->als_vmax == 0) { 162 pdata->als_vmin = 0; 163 pdata->als_vmax = LM3530_ALS_WINDOW_mV; 164 } 165 166 als_vmin = pdata->als_vmin; 167 als_vmax = pdata->als_vmax; 168 169 if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV) 170 pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV; 171 172 /* n zone boundary makes n+1 zones */ 173 als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1); 174 175 for (i = 0; i < LM3530_ALS_ZB_MAX; i++) 176 als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) + 177 als_vstep + (i * als_vstep)) * LED_FULL) / 1000; 178 179 als->config = 180 (pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) | 181 (LM3530_ENABLE_ALS) | 182 (pdata->als_input_mode << LM3530_ALS_SEL_SHIFT); 183 184 als->imp_sel = 185 (pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) | 186 (pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT); 187 } 188 189 static int lm3530_led_enable(struct lm3530_data *drvdata) 190 { 191 int ret; 192 193 if (drvdata->enable) 194 return 0; 195 196 ret = regulator_enable(drvdata->regulator); 197 if (ret) { 198 dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d\n", ret); 199 return ret; 200 } 201 202 drvdata->enable = true; 203 return 0; 204 } 205 206 static void lm3530_led_disable(struct lm3530_data *drvdata) 207 { 208 int ret; 209 210 if (!drvdata->enable) 211 return; 212 213 ret = regulator_disable(drvdata->regulator); 214 if (ret) { 215 dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d\n", 216 ret); 217 return; 218 } 219 220 drvdata->enable = false; 221 } 222 223 static int lm3530_init_registers(struct lm3530_data *drvdata) 224 { 225 int ret = 0; 226 int i; 227 u8 gen_config; 228 u8 brt_ramp; 229 u8 brightness; 230 u8 reg_val[LM3530_REG_MAX]; 231 struct lm3530_platform_data *pdata = drvdata->pdata; 232 struct i2c_client *client = drvdata->client; 233 struct lm3530_pwm_data *pwm = &pdata->pwm_data; 234 struct lm3530_als_data als; 235 236 memset(&als, 0, sizeof(struct lm3530_als_data)); 237 238 gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) | 239 ((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT); 240 241 switch (drvdata->mode) { 242 case LM3530_BL_MODE_MANUAL: 243 gen_config |= LM3530_ENABLE_I2C; 244 break; 245 case LM3530_BL_MODE_ALS: 246 gen_config |= LM3530_ENABLE_I2C; 247 lm3530_als_configure(pdata, &als); 248 break; 249 case LM3530_BL_MODE_PWM: 250 gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE | 251 (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT); 252 break; 253 } 254 255 brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) | 256 (pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT); 257 258 if (drvdata->brightness) 259 brightness = drvdata->brightness; 260 else 261 brightness = drvdata->brightness = pdata->brt_val; 262 263 if (brightness > drvdata->led_dev.max_brightness) 264 brightness = drvdata->led_dev.max_brightness; 265 266 reg_val[0] = gen_config; /* LM3530_GEN_CONFIG */ 267 reg_val[1] = als.config; /* LM3530_ALS_CONFIG */ 268 reg_val[2] = brt_ramp; /* LM3530_BRT_RAMP_RATE */ 269 reg_val[3] = als.imp_sel; /* LM3530_ALS_IMP_SELECT */ 270 reg_val[4] = brightness; /* LM3530_BRT_CTRL_REG */ 271 reg_val[5] = als.zones[0]; /* LM3530_ALS_ZB0_REG */ 272 reg_val[6] = als.zones[1]; /* LM3530_ALS_ZB1_REG */ 273 reg_val[7] = als.zones[2]; /* LM3530_ALS_ZB2_REG */ 274 reg_val[8] = als.zones[3]; /* LM3530_ALS_ZB3_REG */ 275 reg_val[9] = LM3530_DEF_ZT_0; /* LM3530_ALS_Z0T_REG */ 276 reg_val[10] = LM3530_DEF_ZT_1; /* LM3530_ALS_Z1T_REG */ 277 reg_val[11] = LM3530_DEF_ZT_2; /* LM3530_ALS_Z2T_REG */ 278 reg_val[12] = LM3530_DEF_ZT_3; /* LM3530_ALS_Z3T_REG */ 279 reg_val[13] = LM3530_DEF_ZT_4; /* LM3530_ALS_Z4T_REG */ 280 281 ret = lm3530_led_enable(drvdata); 282 if (ret) 283 return ret; 284 285 for (i = 0; i < LM3530_REG_MAX; i++) { 286 /* do not update brightness register when pwm mode */ 287 if (lm3530_reg[i] == LM3530_BRT_CTRL_REG && 288 drvdata->mode == LM3530_BL_MODE_PWM) { 289 if (pwm->pwm_set_intensity) 290 pwm->pwm_set_intensity(reg_val[i], 291 drvdata->led_dev.max_brightness); 292 continue; 293 } 294 295 ret = i2c_smbus_write_byte_data(client, 296 lm3530_reg[i], reg_val[i]); 297 if (ret) 298 break; 299 } 300 301 return ret; 302 } 303 304 static void lm3530_brightness_set(struct led_classdev *led_cdev, 305 enum led_brightness brt_val) 306 { 307 int err; 308 struct lm3530_data *drvdata = 309 container_of(led_cdev, struct lm3530_data, led_dev); 310 struct lm3530_platform_data *pdata = drvdata->pdata; 311 struct lm3530_pwm_data *pwm = &pdata->pwm_data; 312 u8 max_brightness = led_cdev->max_brightness; 313 314 switch (drvdata->mode) { 315 case LM3530_BL_MODE_MANUAL: 316 317 if (!drvdata->enable) { 318 err = lm3530_init_registers(drvdata); 319 if (err) { 320 dev_err(&drvdata->client->dev, 321 "Register Init failed: %d\n", err); 322 break; 323 } 324 } 325 326 /* set the brightness in brightness control register*/ 327 err = i2c_smbus_write_byte_data(drvdata->client, 328 LM3530_BRT_CTRL_REG, brt_val); 329 if (err) 330 dev_err(&drvdata->client->dev, 331 "Unable to set brightness: %d\n", err); 332 else 333 drvdata->brightness = brt_val; 334 335 if (brt_val == 0) 336 lm3530_led_disable(drvdata); 337 break; 338 case LM3530_BL_MODE_ALS: 339 break; 340 case LM3530_BL_MODE_PWM: 341 if (pwm->pwm_set_intensity) 342 pwm->pwm_set_intensity(brt_val, max_brightness); 343 break; 344 default: 345 break; 346 } 347 } 348 349 static ssize_t mode_show(struct device *dev, 350 struct device_attribute *attr, char *buf) 351 { 352 struct led_classdev *led_cdev = dev_get_drvdata(dev); 353 struct lm3530_data *drvdata; 354 int i, len = 0; 355 356 drvdata = container_of(led_cdev, struct lm3530_data, led_dev); 357 for (i = 0; i < ARRAY_SIZE(mode_map); i++) 358 if (drvdata->mode == mode_map[i].mode_val) 359 len += sprintf(buf + len, "[%s] ", mode_map[i].mode); 360 else 361 len += sprintf(buf + len, "%s ", mode_map[i].mode); 362 363 len += sprintf(buf + len, "\n"); 364 365 return len; 366 } 367 368 static ssize_t mode_store(struct device *dev, struct device_attribute 369 *attr, const char *buf, size_t size) 370 { 371 struct led_classdev *led_cdev = dev_get_drvdata(dev); 372 struct lm3530_data *drvdata; 373 struct lm3530_pwm_data *pwm; 374 u8 max_brightness; 375 int mode, err; 376 377 drvdata = container_of(led_cdev, struct lm3530_data, led_dev); 378 pwm = &drvdata->pdata->pwm_data; 379 max_brightness = led_cdev->max_brightness; 380 mode = lm3530_get_mode_from_str(buf); 381 if (mode < 0) { 382 dev_err(dev, "Invalid mode\n"); 383 return mode; 384 } 385 386 drvdata->mode = mode; 387 388 /* set pwm to low if unnecessary */ 389 if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity) 390 pwm->pwm_set_intensity(0, max_brightness); 391 392 err = lm3530_init_registers(drvdata); 393 if (err) { 394 dev_err(dev, "Setting %s Mode failed :%d\n", buf, err); 395 return err; 396 } 397 398 return sizeof(drvdata->mode); 399 } 400 static DEVICE_ATTR_RW(mode); 401 402 static struct attribute *lm3530_attrs[] = { 403 &dev_attr_mode.attr, 404 NULL 405 }; 406 ATTRIBUTE_GROUPS(lm3530); 407 408 static int lm3530_probe(struct i2c_client *client, 409 const struct i2c_device_id *id) 410 { 411 struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev); 412 struct lm3530_data *drvdata; 413 int err = 0; 414 415 if (pdata == NULL) { 416 dev_err(&client->dev, "platform data required\n"); 417 return -ENODEV; 418 } 419 420 /* BL mode */ 421 if (pdata->mode > LM3530_BL_MODE_PWM) { 422 dev_err(&client->dev, "Illegal Mode request\n"); 423 return -EINVAL; 424 } 425 426 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 427 dev_err(&client->dev, "I2C_FUNC_I2C not supported\n"); 428 return -EIO; 429 } 430 431 drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data), 432 GFP_KERNEL); 433 if (drvdata == NULL) 434 return -ENOMEM; 435 436 drvdata->mode = pdata->mode; 437 drvdata->client = client; 438 drvdata->pdata = pdata; 439 drvdata->brightness = LED_OFF; 440 drvdata->enable = false; 441 drvdata->led_dev.name = LM3530_LED_DEV; 442 drvdata->led_dev.brightness_set = lm3530_brightness_set; 443 drvdata->led_dev.max_brightness = MAX_BRIGHTNESS; 444 drvdata->led_dev.groups = lm3530_groups; 445 446 i2c_set_clientdata(client, drvdata); 447 448 drvdata->regulator = devm_regulator_get(&client->dev, "vin"); 449 if (IS_ERR(drvdata->regulator)) { 450 dev_err(&client->dev, "regulator get failed\n"); 451 err = PTR_ERR(drvdata->regulator); 452 drvdata->regulator = NULL; 453 return err; 454 } 455 456 if (drvdata->pdata->brt_val) { 457 err = lm3530_init_registers(drvdata); 458 if (err < 0) { 459 dev_err(&client->dev, 460 "Register Init failed: %d\n", err); 461 return err; 462 } 463 } 464 err = led_classdev_register(&client->dev, &drvdata->led_dev); 465 if (err < 0) { 466 dev_err(&client->dev, "Register led class failed: %d\n", err); 467 return err; 468 } 469 470 return 0; 471 } 472 473 static int lm3530_remove(struct i2c_client *client) 474 { 475 struct lm3530_data *drvdata = i2c_get_clientdata(client); 476 477 lm3530_led_disable(drvdata); 478 led_classdev_unregister(&drvdata->led_dev); 479 return 0; 480 } 481 482 static const struct i2c_device_id lm3530_id[] = { 483 {LM3530_NAME, 0}, 484 {} 485 }; 486 MODULE_DEVICE_TABLE(i2c, lm3530_id); 487 488 static struct i2c_driver lm3530_i2c_driver = { 489 .probe = lm3530_probe, 490 .remove = lm3530_remove, 491 .id_table = lm3530_id, 492 .driver = { 493 .name = LM3530_NAME, 494 }, 495 }; 496 497 module_i2c_driver(lm3530_i2c_driver); 498 499 MODULE_DESCRIPTION("Back Light driver for LM3530"); 500 MODULE_LICENSE("GPL v2"); 501 MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>"); 502