linux/drivers/leds/leds-lm3530.c
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   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
  85struct lm3530_mode_map {
  86        const char *mode;
  87        enum lm3530_mode mode_val;
  88};
  89
  90static 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 */
 106struct 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 */
 122struct lm3530_als_data {
 123        u8 config;
 124        u8 imp_sel;
 125        u8 zones[LM3530_ALS_ZB_MAX];
 126};
 127
 128static 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
 145static 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
 156static 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
 190static 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
 207static 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
 224static 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
 305static 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
 350static 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
 369static 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}
 401static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
 402
 403static int lm3530_probe(struct i2c_client *client,
 404                           const struct i2c_device_id *id)
 405{
 406        struct lm3530_platform_data *pdata = client->dev.platform_data;
 407        struct lm3530_data *drvdata;
 408        int err = 0;
 409
 410        if (pdata == NULL) {
 411                dev_err(&client->dev, "platform data required\n");
 412                return -ENODEV;
 413        }
 414
 415        /* BL mode */
 416        if (pdata->mode > LM3530_BL_MODE_PWM) {
 417                dev_err(&client->dev, "Illegal Mode request\n");
 418                return -EINVAL;
 419        }
 420
 421        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 422                dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
 423                return -EIO;
 424        }
 425
 426        drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
 427                                GFP_KERNEL);
 428        if (drvdata == NULL)
 429                return -ENOMEM;
 430
 431        drvdata->mode = pdata->mode;
 432        drvdata->client = client;
 433        drvdata->pdata = pdata;
 434        drvdata->brightness = LED_OFF;
 435        drvdata->enable = false;
 436        drvdata->led_dev.name = LM3530_LED_DEV;
 437        drvdata->led_dev.brightness_set = lm3530_brightness_set;
 438        drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
 439
 440        i2c_set_clientdata(client, drvdata);
 441
 442        drvdata->regulator = devm_regulator_get(&client->dev, "vin");
 443        if (IS_ERR(drvdata->regulator)) {
 444                dev_err(&client->dev, "regulator get failed\n");
 445                err = PTR_ERR(drvdata->regulator);
 446                drvdata->regulator = NULL;
 447                return err;
 448        }
 449
 450        if (drvdata->pdata->brt_val) {
 451                err = lm3530_init_registers(drvdata);
 452                if (err < 0) {
 453                        dev_err(&client->dev,
 454                                "Register Init failed: %d\n", err);
 455                        return err;
 456                }
 457        }
 458        err = led_classdev_register(&client->dev, &drvdata->led_dev);
 459        if (err < 0) {
 460                dev_err(&client->dev, "Register led class failed: %d\n", err);
 461                return err;
 462        }
 463
 464        err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
 465        if (err < 0) {
 466                dev_err(&client->dev, "File device creation failed: %d\n", err);
 467                err = -ENODEV;
 468                goto err_create_file;
 469        }
 470
 471        return 0;
 472
 473err_create_file:
 474        led_classdev_unregister(&drvdata->led_dev);
 475        return err;
 476}
 477
 478static int lm3530_remove(struct i2c_client *client)
 479{
 480        struct lm3530_data *drvdata = i2c_get_clientdata(client);
 481
 482        device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
 483
 484        lm3530_led_disable(drvdata);
 485        led_classdev_unregister(&drvdata->led_dev);
 486        return 0;
 487}
 488
 489static const struct i2c_device_id lm3530_id[] = {
 490        {LM3530_NAME, 0},
 491        {}
 492};
 493MODULE_DEVICE_TABLE(i2c, lm3530_id);
 494
 495static struct i2c_driver lm3530_i2c_driver = {
 496        .probe = lm3530_probe,
 497        .remove = lm3530_remove,
 498        .id_table = lm3530_id,
 499        .driver = {
 500                .name = LM3530_NAME,
 501                .owner = THIS_MODULE,
 502        },
 503};
 504
 505module_i2c_driver(lm3530_i2c_driver);
 506
 507MODULE_DESCRIPTION("Back Light driver for LM3530");
 508MODULE_LICENSE("GPL v2");
 509MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
 510
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