drivers/leds/leds-lm3530.c

   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_led_enable(struct lm3530_data *drvdata)
 191 {
 192         int ret;
 193
 194         if (drvdata->enable)
 195                 return 0;
 196
 197         ret = regulator_enable(drvdata->regulator);
 198         if (ret) {
 199                 dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d\n", ret);
 200                 return ret;
 201         }
 202
 203         drvdata->enable = true;
 204         return 0;
 205 }
 206
 207 static void lm3530_led_disable(struct lm3530_data *drvdata)
 208 {
 209         int ret;
 210
 211         if (!drvdata->enable)
 212                 return;
 213
 214         ret = regulator_disable(drvdata->regulator);
 215         if (ret) {
 216                 dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d\n",
 217                         ret);
 218                 return;
 219         }
 220
 221         drvdata->enable = false;
 222 }
 223
 224 static int lm3530_init_registers(struct lm3530_data *drvdata)
 225 {
 226         int ret = 0;
 227         int i;
 228         u8 gen_config;
 229         u8 brt_ramp;
 230         u8 brightness;
 231         u8 reg_val[LM3530_REG_MAX];
 232         struct lm3530_platform_data *pdata = drvdata->pdata;
 233         struct i2c_client *client = drvdata->client;
 234         struct lm3530_pwm_data *pwm = &pdata->pwm_data;
 235         struct lm3530_als_data als;
 236
 237         memset(&als, 0, sizeof(struct lm3530_als_data));
 238
 239         gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
 240                         ((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
 241
 242         switch (drvdata->mode) {
 243         case LM3530_BL_MODE_MANUAL:
 244                 gen_config |= LM3530_ENABLE_I2C;
 245                 break;
 246         case LM3530_BL_MODE_ALS:
 247                 gen_config |= LM3530_ENABLE_I2C;
 248                 lm3530_als_configure(pdata, &als);
 249                 break;
 250         case LM3530_BL_MODE_PWM:
 251                 gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
 252                               (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
 253                 break;
 254         }
 255
 256         brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
 257                         (pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
 258
 259         if (drvdata->brightness)
 260                 brightness = drvdata->brightness;
 261         else
 262                 brightness = drvdata->brightness = pdata->brt_val;
 263
 264         if (brightness > drvdata->led_dev.max_brightness)
 265                 brightness = drvdata->led_dev.max_brightness;
 266
 267         reg_val[0] = gen_config;        /* LM3530_GEN_CONFIG */
 268         reg_val[1] = als.config;        /* LM3530_ALS_CONFIG */
 269         reg_val[2] = brt_ramp;          /* LM3530_BRT_RAMP_RATE */
 270         reg_val[3] = als.imp_sel;       /* LM3530_ALS_IMP_SELECT */
 271         reg_val[4] = brightness;        /* LM3530_BRT_CTRL_REG */
 272         reg_val[5] = als.zones[0];      /* LM3530_ALS_ZB0_REG */
 273         reg_val[6] = als.zones[1];      /* LM3530_ALS_ZB1_REG */
 274         reg_val[7] = als.zones[2];      /* LM3530_ALS_ZB2_REG */
 275         reg_val[8] = als.zones[3];      /* LM3530_ALS_ZB3_REG */
 276         reg_val[9] = LM3530_DEF_ZT_0;   /* LM3530_ALS_Z0T_REG */
 277         reg_val[10] = LM3530_DEF_ZT_1;  /* LM3530_ALS_Z1T_REG */
 278         reg_val[11] = LM3530_DEF_ZT_2;  /* LM3530_ALS_Z2T_REG */
 279         reg_val[12] = LM3530_DEF_ZT_3;  /* LM3530_ALS_Z3T_REG */
 280         reg_val[13] = LM3530_DEF_ZT_4;  /* LM3530_ALS_Z4T_REG */
 281
 282         ret = lm3530_led_enable(drvdata);
 283         if (ret)
 284                 return ret;
 285
 286         for (i = 0; i < LM3530_REG_MAX; i++) {
 287                 /* do not update brightness register when pwm mode */
 288                 if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
 289                     drvdata->mode == LM3530_BL_MODE_PWM) {
 290                         if (pwm->pwm_set_intensity)
 291                                 pwm->pwm_set_intensity(reg_val[i],
 292                                         drvdata->led_dev.max_brightness);
 293                         continue;
 294                 }
 295
 296                 ret = i2c_smbus_write_byte_data(client,
 297                                 lm3530_reg[i], reg_val[i]);
 298                 if (ret)
 299                         break;
 300         }
 301
 302         return ret;
 303 }
 304
 305 static void lm3530_brightness_set(struct led_classdev *led_cdev,
 306                                      enum led_brightness brt_val)
 307 {
 308         int err;
 309         struct lm3530_data *drvdata =
 310             container_of(led_cdev, struct lm3530_data, led_dev);
 311         struct lm3530_platform_data *pdata = drvdata->pdata;
 312         struct lm3530_pwm_data *pwm = &pdata->pwm_data;
 313         u8 max_brightness = led_cdev->max_brightness;
 314
 315         switch (drvdata->mode) {
 316         case LM3530_BL_MODE_MANUAL:
 317
 318                 if (!drvdata->enable) {
 319                         err = lm3530_init_registers(drvdata);
 320                         if (err) {
 321                                 dev_err(&drvdata->client->dev,
 322                                         "Register Init failed: %d\n", err);
 323                                 break;
 324                         }
 325                 }
 326
 327                 /* set the brightness in brightness control register*/
 328                 err = i2c_smbus_write_byte_data(drvdata->client,
 329                                 LM3530_BRT_CTRL_REG, brt_val);
 330                 if (err)
 331                         dev_err(&drvdata->client->dev,
 332                                 "Unable to set brightness: %d\n", err);
 333                 else
 334                         drvdata->brightness = brt_val;
 335
 336                 if (brt_val == 0)
 337                         lm3530_led_disable(drvdata);
 338                 break;
 339         case LM3530_BL_MODE_ALS:
 340                 break;
 341         case LM3530_BL_MODE_PWM:
 342                 if (pwm->pwm_set_intensity)
 343                         pwm->pwm_set_intensity(brt_val, max_brightness);
 344                 break;
 345         default:
 346                 break;
 347         }
 348 }
 349
 350 static ssize_t lm3530_mode_get(struct device *dev,
 351                 struct device_attribute *attr, char *buf)
 352 {
 353         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 354         struct lm3530_data *drvdata;
 355         int i, len = 0;
 356
 357         drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
 358         for (i = 0; i < ARRAY_SIZE(mode_map); i++)
 359                 if (drvdata->mode == mode_map[i].mode_val)
 360                         len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
 361                 else
 362                         len += sprintf(buf + len, "%s ", mode_map[i].mode);
 363
 364         len += sprintf(buf + len, "\n");
 365
 366         return len;
 367 }
 368
 369 static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
 370                                    *attr, const char *buf, size_t size)
 371 {
 372         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 373         struct lm3530_data *drvdata;
 374         struct lm3530_pwm_data *pwm;
 375         u8 max_brightness;
 376         int mode, err;
 377
 378         drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
 379         pwm = &drvdata->pdata->pwm_data;
 380         max_brightness = led_cdev->max_brightness;
 381         mode = lm3530_get_mode_from_str(buf);
 382         if (mode < 0) {
 383                 dev_err(dev, "Invalid mode\n");
 384                 return mode;
 385         }
 386
 387         drvdata->mode = mode;
 388
 389         /* set pwm to low if unnecessary */
 390         if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
 391                 pwm->pwm_set_intensity(0, max_brightness);
 392
 393         err = lm3530_init_registers(drvdata);
 394         if (err) {
 395                 dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
 396                 return err;
 397         }
 398
 399         return sizeof(drvdata->mode);
 400 }
 401 static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
 402
 403 static struct attribute *lm3530_attrs[] = {
 404         &dev_attr_mode.attr,
 405         NULL
 406 };
 407 ATTRIBUTE_GROUPS(lm3530);
 408
 409 static int lm3530_probe(struct i2c_client *client,
 410                            const struct i2c_device_id *id)
 411 {
 412         struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev);
 413         struct lm3530_data *drvdata;
 414         int err = 0;
 415
 416         if (pdata == NULL) {
 417                 dev_err(&client->dev, "platform data required\n");
 418                 return -ENODEV;
 419         }
 420
 421         /* BL mode */
 422         if (pdata->mode > LM3530_BL_MODE_PWM) {
 423                 dev_err(&client->dev, "Illegal Mode request\n");
 424                 return -EINVAL;
 425         }
 426
 427         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 428                 dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
 429                 return -EIO;
 430         }
 431
 432         drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
 433                                 GFP_KERNEL);
 434         if (drvdata == NULL)
 435                 return -ENOMEM;
 436
 437         drvdata->mode = pdata->mode;
 438         drvdata->client = client;
 439         drvdata->pdata = pdata;
 440         drvdata->brightness = LED_OFF;
 441         drvdata->enable = false;
 442         drvdata->led_dev.name = LM3530_LED_DEV;
 443         drvdata->led_dev.brightness_set = lm3530_brightness_set;
 444         drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
 445         drvdata->led_dev.groups = lm3530_groups;
 446
 447         i2c_set_clientdata(client, drvdata);
 448
 449         drvdata->regulator = devm_regulator_get(&client->dev, "vin");
 450         if (IS_ERR(drvdata->regulator)) {
 451                 dev_err(&client->dev, "regulator get failed\n");
 452                 err = PTR_ERR(drvdata->regulator);
 453                 drvdata->regulator = NULL;
 454                 return err;
 455         }
 456
 457         if (drvdata->pdata->brt_val) {
 458                 err = lm3530_init_registers(drvdata);
 459                 if (err < 0) {
 460                         dev_err(&client->dev,
 461                                 "Register Init failed: %d\n", err);
 462                         return err;
 463                 }
 464         }
 465         err = led_classdev_register(&client->dev, &drvdata->led_dev);
 466         if (err < 0) {
 467                 dev_err(&client->dev, "Register led class failed: %d\n", err);
 468                 return err;
 469         }
 470
 471         return 0;
 472 }
 473
 474 static int lm3530_remove(struct i2c_client *client)
 475 {
 476         struct lm3530_data *drvdata = i2c_get_clientdata(client);
 477
 478         lm3530_led_disable(drvdata);
 479         led_classdev_unregister(&drvdata->led_dev);
 480         return 0;
 481 }
 482
 483 static const struct i2c_device_id lm3530_id[] = {
 484         {LM3530_NAME, 0},
 485         {}
 486 };
 487 MODULE_DEVICE_TABLE(i2c, lm3530_id);
 488
 489 static struct i2c_driver lm3530_i2c_driver = {
 490         .probe = lm3530_probe,
 491         .remove = lm3530_remove,
 492         .id_table = lm3530_id,
 493         .driver = {
 494                 .name = LM3530_NAME,
 495                 .owner = THIS_MODULE,
 496         },
 497 };
 498
 499 module_i2c_driver(lm3530_i2c_driver);
 500
 501 MODULE_DESCRIPTION("Back Light driver for LM3530");
 502 MODULE_LICENSE("GPL v2");
 503 MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");