linux/drivers/leds/leds-is31fl319x.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2015-16 Golden Delicious Computers
   4 *
   5 * Author: Nikolaus Schaller <hns@goldelico.com>
   6 *
   7 * LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
   8 * effect LEDs.
   9 */
  10
  11#include <linux/err.h>
  12#include <linux/i2c.h>
  13#include <linux/leds.h>
  14#include <linux/module.h>
  15#include <linux/of.h>
  16#include <linux/of_device.h>
  17#include <linux/regmap.h>
  18#include <linux/slab.h>
  19#include <linux/delay.h>
  20#include <linux/gpio/consumer.h>
  21
  22/* register numbers */
  23#define IS31FL319X_SHUTDOWN             0x00
  24#define IS31FL319X_CTRL1                0x01
  25#define IS31FL319X_CTRL2                0x02
  26#define IS31FL319X_CONFIG1              0x03
  27#define IS31FL319X_CONFIG2              0x04
  28#define IS31FL319X_RAMP_MODE            0x05
  29#define IS31FL319X_BREATH_MASK          0x06
  30#define IS31FL319X_PWM(channel)         (0x07 + channel)
  31#define IS31FL319X_DATA_UPDATE          0x10
  32#define IS31FL319X_T0(channel)          (0x11 + channel)
  33#define IS31FL319X_T123_1               0x1a
  34#define IS31FL319X_T123_2               0x1b
  35#define IS31FL319X_T123_3               0x1c
  36#define IS31FL319X_T4(channel)          (0x1d + channel)
  37#define IS31FL319X_TIME_UPDATE          0x26
  38#define IS31FL319X_RESET                0xff
  39
  40#define IS31FL319X_REG_CNT              (IS31FL319X_RESET + 1)
  41
  42#define IS31FL319X_MAX_LEDS             9
  43
  44/* CS (Current Setting) in CONFIG2 register */
  45#define IS31FL319X_CONFIG2_CS_SHIFT     4
  46#define IS31FL319X_CONFIG2_CS_MASK      0x7
  47#define IS31FL319X_CONFIG2_CS_STEP_REF  12
  48
  49#define IS31FL319X_CURRENT_MIN          ((u32)5000)
  50#define IS31FL319X_CURRENT_MAX          ((u32)40000)
  51#define IS31FL319X_CURRENT_STEP         ((u32)5000)
  52#define IS31FL319X_CURRENT_DEFAULT      ((u32)20000)
  53
  54/* Audio gain in CONFIG2 register */
  55#define IS31FL319X_AUDIO_GAIN_DB_MAX    ((u32)21)
  56#define IS31FL319X_AUDIO_GAIN_DB_STEP   ((u32)3)
  57
  58/*
  59 * regmap is used as a cache of chip's register space,
  60 * to avoid reading back brightness values from chip,
  61 * which is known to hang.
  62 */
  63struct is31fl319x_chip {
  64        const struct is31fl319x_chipdef *cdef;
  65        struct i2c_client               *client;
  66        struct gpio_desc                *shutdown_gpio;
  67        struct regmap                   *regmap;
  68        struct mutex                    lock;
  69        u32                             audio_gain_db;
  70
  71        struct is31fl319x_led {
  72                struct is31fl319x_chip  *chip;
  73                struct led_classdev     cdev;
  74                u32                     max_microamp;
  75                bool                    configured;
  76        } leds[IS31FL319X_MAX_LEDS];
  77};
  78
  79struct is31fl319x_chipdef {
  80        int num_leds;
  81};
  82
  83static const struct is31fl319x_chipdef is31fl3190_cdef = {
  84        .num_leds = 1,
  85};
  86
  87static const struct is31fl319x_chipdef is31fl3193_cdef = {
  88        .num_leds = 3,
  89};
  90
  91static const struct is31fl319x_chipdef is31fl3196_cdef = {
  92        .num_leds = 6,
  93};
  94
  95static const struct is31fl319x_chipdef is31fl3199_cdef = {
  96        .num_leds = 9,
  97};
  98
  99static const struct of_device_id of_is31fl319x_match[] = {
 100        { .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
 101        { .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
 102        { .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
 103        { .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
 104        { .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
 105        { .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
 106        { }
 107};
 108MODULE_DEVICE_TABLE(of, of_is31fl319x_match);
 109
 110static int is31fl319x_brightness_set(struct led_classdev *cdev,
 111                                     enum led_brightness brightness)
 112{
 113        struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led,
 114                                                  cdev);
 115        struct is31fl319x_chip *is31 = led->chip;
 116        int chan = led - is31->leds;
 117        int ret;
 118        int i;
 119        u8 ctrl1 = 0, ctrl2 = 0;
 120
 121        dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, chan, brightness);
 122
 123        mutex_lock(&is31->lock);
 124
 125        /* update PWM register */
 126        ret = regmap_write(is31->regmap, IS31FL319X_PWM(chan), brightness);
 127        if (ret < 0)
 128                goto out;
 129
 130        /* read current brightness of all PWM channels */
 131        for (i = 0; i < is31->cdef->num_leds; i++) {
 132                unsigned int pwm_value;
 133                bool on;
 134
 135                /*
 136                 * since neither cdev nor the chip can provide
 137                 * the current setting, we read from the regmap cache
 138                 */
 139
 140                ret = regmap_read(is31->regmap, IS31FL319X_PWM(i), &pwm_value);
 141                dev_dbg(&is31->client->dev, "%s read %d: ret=%d: %d\n",
 142                        __func__, i, ret, pwm_value);
 143                on = ret >= 0 && pwm_value > LED_OFF;
 144
 145                if (i < 3)
 146                        ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
 147                else if (i < 6)
 148                        ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
 149                else
 150                        ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
 151        }
 152
 153        if (ctrl1 > 0 || ctrl2 > 0) {
 154                dev_dbg(&is31->client->dev, "power up %02x %02x\n",
 155                        ctrl1, ctrl2);
 156                regmap_write(is31->regmap, IS31FL319X_CTRL1, ctrl1);
 157                regmap_write(is31->regmap, IS31FL319X_CTRL2, ctrl2);
 158                /* update PWMs */
 159                regmap_write(is31->regmap, IS31FL319X_DATA_UPDATE, 0x00);
 160                /* enable chip from shut down */
 161                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
 162        } else {
 163                dev_dbg(&is31->client->dev, "power down\n");
 164                /* shut down (no need to clear CTRL1/2) */
 165                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
 166        }
 167
 168out:
 169        mutex_unlock(&is31->lock);
 170
 171        return ret;
 172}
 173
 174static int is31fl319x_parse_child_dt(const struct device *dev,
 175                                     const struct device_node *child,
 176                                     struct is31fl319x_led *led)
 177{
 178        struct led_classdev *cdev = &led->cdev;
 179        int ret;
 180
 181        if (of_property_read_string(child, "label", &cdev->name))
 182                cdev->name = child->name;
 183
 184        ret = of_property_read_string(child, "linux,default-trigger",
 185                                      &cdev->default_trigger);
 186        if (ret < 0 && ret != -EINVAL) /* is optional */
 187                return ret;
 188
 189        led->max_microamp = IS31FL319X_CURRENT_DEFAULT;
 190        ret = of_property_read_u32(child, "led-max-microamp",
 191                                   &led->max_microamp);
 192        if (!ret) {
 193                if (led->max_microamp < IS31FL319X_CURRENT_MIN)
 194                        return -EINVAL; /* not supported */
 195                led->max_microamp = min(led->max_microamp,
 196                                          IS31FL319X_CURRENT_MAX);
 197        }
 198
 199        return 0;
 200}
 201
 202static int is31fl319x_parse_dt(struct device *dev,
 203                               struct is31fl319x_chip *is31)
 204{
 205        struct device_node *np = dev_of_node(dev), *child;
 206        int count;
 207        int ret;
 208
 209        if (!np)
 210                return -ENODEV;
 211
 212        is31->shutdown_gpio = devm_gpiod_get_optional(dev,
 213                                                "shutdown",
 214                                                GPIOD_OUT_HIGH);
 215        if (IS_ERR(is31->shutdown_gpio)) {
 216                ret = PTR_ERR(is31->shutdown_gpio);
 217                dev_err(dev, "Failed to get shutdown gpio: %d\n", ret);
 218                return ret;
 219        }
 220
 221        is31->cdef = device_get_match_data(dev);
 222
 223        count = of_get_available_child_count(np);
 224
 225        dev_dbg(dev, "probing with %d leds defined in DT\n", count);
 226
 227        if (!count || count > is31->cdef->num_leds) {
 228                dev_err(dev, "Number of leds defined must be between 1 and %u\n",
 229                        is31->cdef->num_leds);
 230                return -ENODEV;
 231        }
 232
 233        for_each_available_child_of_node(np, child) {
 234                struct is31fl319x_led *led;
 235                u32 reg;
 236
 237                ret = of_property_read_u32(child, "reg", &reg);
 238                if (ret) {
 239                        dev_err(dev, "Failed to read led 'reg' property\n");
 240                        goto put_child_node;
 241                }
 242
 243                if (reg < 1 || reg > is31->cdef->num_leds) {
 244                        dev_err(dev, "invalid led reg %u\n", reg);
 245                        ret = -EINVAL;
 246                        goto put_child_node;
 247                }
 248
 249                led = &is31->leds[reg - 1];
 250
 251                if (led->configured) {
 252                        dev_err(dev, "led %u is already configured\n", reg);
 253                        ret = -EINVAL;
 254                        goto put_child_node;
 255                }
 256
 257                ret = is31fl319x_parse_child_dt(dev, child, led);
 258                if (ret) {
 259                        dev_err(dev, "led %u DT parsing failed\n", reg);
 260                        goto put_child_node;
 261                }
 262
 263                led->configured = true;
 264        }
 265
 266        is31->audio_gain_db = 0;
 267        ret = of_property_read_u32(np, "audio-gain-db", &is31->audio_gain_db);
 268        if (!ret)
 269                is31->audio_gain_db = min(is31->audio_gain_db,
 270                                          IS31FL319X_AUDIO_GAIN_DB_MAX);
 271
 272        return 0;
 273
 274put_child_node:
 275        of_node_put(child);
 276        return ret;
 277}
 278
 279static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
 280{ /* we have no readable registers */
 281        return false;
 282}
 283
 284static bool is31fl319x_volatile_reg(struct device *dev, unsigned int reg)
 285{ /* volatile registers are not cached */
 286        switch (reg) {
 287        case IS31FL319X_DATA_UPDATE:
 288        case IS31FL319X_TIME_UPDATE:
 289        case IS31FL319X_RESET:
 290                return true; /* always write-through */
 291        default:
 292                return false;
 293        }
 294}
 295
 296static const struct reg_default is31fl319x_reg_defaults[] = {
 297        { IS31FL319X_CONFIG1, 0x00},
 298        { IS31FL319X_CONFIG2, 0x00},
 299        { IS31FL319X_PWM(0), 0x00},
 300        { IS31FL319X_PWM(1), 0x00},
 301        { IS31FL319X_PWM(2), 0x00},
 302        { IS31FL319X_PWM(3), 0x00},
 303        { IS31FL319X_PWM(4), 0x00},
 304        { IS31FL319X_PWM(5), 0x00},
 305        { IS31FL319X_PWM(6), 0x00},
 306        { IS31FL319X_PWM(7), 0x00},
 307        { IS31FL319X_PWM(8), 0x00},
 308};
 309
 310static struct regmap_config regmap_config = {
 311        .reg_bits = 8,
 312        .val_bits = 8,
 313        .max_register = IS31FL319X_REG_CNT,
 314        .cache_type = REGCACHE_FLAT,
 315        .readable_reg = is31fl319x_readable_reg,
 316        .volatile_reg = is31fl319x_volatile_reg,
 317        .reg_defaults = is31fl319x_reg_defaults,
 318        .num_reg_defaults = ARRAY_SIZE(is31fl319x_reg_defaults),
 319};
 320
 321static inline int is31fl319x_microamp_to_cs(struct device *dev, u32 microamp)
 322{ /* round down to nearest supported value (range check done by caller) */
 323        u32 step = microamp / IS31FL319X_CURRENT_STEP;
 324
 325        return ((IS31FL319X_CONFIG2_CS_STEP_REF - step) &
 326                IS31FL319X_CONFIG2_CS_MASK) <<
 327                IS31FL319X_CONFIG2_CS_SHIFT; /* CS encoding */
 328}
 329
 330static inline int is31fl319x_db_to_gain(u32 dezibel)
 331{ /* round down to nearest supported value (range check done by caller) */
 332        return dezibel / IS31FL319X_AUDIO_GAIN_DB_STEP;
 333}
 334
 335static int is31fl319x_probe(struct i2c_client *client,
 336                            const struct i2c_device_id *id)
 337{
 338        struct is31fl319x_chip *is31;
 339        struct device *dev = &client->dev;
 340        int err;
 341        int i = 0;
 342        u32 aggregated_led_microamp = IS31FL319X_CURRENT_MAX;
 343
 344        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 345                return -EIO;
 346
 347        is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
 348        if (!is31)
 349                return -ENOMEM;
 350
 351        mutex_init(&is31->lock);
 352
 353        err = is31fl319x_parse_dt(&client->dev, is31);
 354        if (err)
 355                goto free_mutex;
 356
 357        if (is31->shutdown_gpio) {
 358                gpiod_direction_output(is31->shutdown_gpio, 0);
 359                mdelay(5);
 360                gpiod_direction_output(is31->shutdown_gpio, 1);
 361        }
 362
 363        is31->client = client;
 364        is31->regmap = devm_regmap_init_i2c(client, &regmap_config);
 365        if (IS_ERR(is31->regmap)) {
 366                dev_err(&client->dev, "failed to allocate register map\n");
 367                err = PTR_ERR(is31->regmap);
 368                goto free_mutex;
 369        }
 370
 371        i2c_set_clientdata(client, is31);
 372
 373        /* check for write-reply from chip (we can't read any registers) */
 374        err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
 375        if (err < 0) {
 376                dev_err(&client->dev, "no response from chip write: err = %d\n",
 377                        err);
 378                err = -EIO; /* does not answer */
 379                goto free_mutex;
 380        }
 381
 382        /*
 383         * Kernel conventions require per-LED led-max-microamp property.
 384         * But the chip does not allow to limit individual LEDs.
 385         * So we take minimum from all subnodes for safety of hardware.
 386         */
 387        for (i = 0; i < is31->cdef->num_leds; i++)
 388                if (is31->leds[i].configured &&
 389                    is31->leds[i].max_microamp < aggregated_led_microamp)
 390                        aggregated_led_microamp = is31->leds[i].max_microamp;
 391
 392        regmap_write(is31->regmap, IS31FL319X_CONFIG2,
 393                     is31fl319x_microamp_to_cs(dev, aggregated_led_microamp) |
 394                     is31fl319x_db_to_gain(is31->audio_gain_db));
 395
 396        for (i = 0; i < is31->cdef->num_leds; i++) {
 397                struct is31fl319x_led *led = &is31->leds[i];
 398
 399                if (!led->configured)
 400                        continue;
 401
 402                led->chip = is31;
 403                led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
 404
 405                err = devm_led_classdev_register(&client->dev, &led->cdev);
 406                if (err < 0)
 407                        goto free_mutex;
 408        }
 409
 410        return 0;
 411
 412free_mutex:
 413        mutex_destroy(&is31->lock);
 414        return err;
 415}
 416
 417static int is31fl319x_remove(struct i2c_client *client)
 418{
 419        struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
 420
 421        mutex_destroy(&is31->lock);
 422        return 0;
 423}
 424
 425/*
 426 * i2c-core (and modalias) requires that id_table be properly filled,
 427 * even though it is not used for DeviceTree based instantiation.
 428 */
 429static const struct i2c_device_id is31fl319x_id[] = {
 430        { "is31fl3190" },
 431        { "is31fl3191" },
 432        { "is31fl3193" },
 433        { "is31fl3196" },
 434        { "is31fl3199" },
 435        { "sn3199" },
 436        {},
 437};
 438MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
 439
 440static struct i2c_driver is31fl319x_driver = {
 441        .driver   = {
 442                .name           = "leds-is31fl319x",
 443                .of_match_table = of_match_ptr(of_is31fl319x_match),
 444        },
 445        .probe    = is31fl319x_probe,
 446        .remove   = is31fl319x_remove,
 447        .id_table = is31fl319x_id,
 448};
 449
 450module_i2c_driver(is31fl319x_driver);
 451
 452MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
 453MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
 454MODULE_DESCRIPTION("IS31FL319X LED driver");
 455MODULE_LICENSE("GPL v2");
 456