linux/drivers/leds/leds-is31fl319x.c
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   1/*
   2 * Copyright 2015-16 Golden Delicious Computers
   3 *
   4 * Author: Nikolaus Schaller <hns@goldelico.com>
   5 *
   6 * This file is subject to the terms and conditions of version 2 of
   7 * the GNU General Public License.  See the file COPYING in the main
   8 * directory of this archive for more details.
   9 *
  10 * LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
  11 * effect LEDs.
  12 *
  13 */
  14
  15#include <linux/err.h>
  16#include <linux/i2c.h>
  17#include <linux/leds.h>
  18#include <linux/module.h>
  19#include <linux/of.h>
  20#include <linux/of_device.h>
  21#include <linux/regmap.h>
  22#include <linux/slab.h>
  23
  24/* register numbers */
  25#define IS31FL319X_SHUTDOWN             0x00
  26#define IS31FL319X_CTRL1                0x01
  27#define IS31FL319X_CTRL2                0x02
  28#define IS31FL319X_CONFIG1              0x03
  29#define IS31FL319X_CONFIG2              0x04
  30#define IS31FL319X_RAMP_MODE            0x05
  31#define IS31FL319X_BREATH_MASK          0x06
  32#define IS31FL319X_PWM(channel)         (0x07 + channel)
  33#define IS31FL319X_DATA_UPDATE          0x10
  34#define IS31FL319X_T0(channel)          (0x11 + channel)
  35#define IS31FL319X_T123_1               0x1a
  36#define IS31FL319X_T123_2               0x1b
  37#define IS31FL319X_T123_3               0x1c
  38#define IS31FL319X_T4(channel)          (0x1d + channel)
  39#define IS31FL319X_TIME_UPDATE          0x26
  40#define IS31FL319X_RESET                0xff
  41
  42#define IS31FL319X_REG_CNT              (IS31FL319X_RESET + 1)
  43
  44#define IS31FL319X_MAX_LEDS             9
  45
  46/* CS (Current Setting) in CONFIG2 register */
  47#define IS31FL319X_CONFIG2_CS_SHIFT     4
  48#define IS31FL319X_CONFIG2_CS_MASK      0x7
  49#define IS31FL319X_CONFIG2_CS_STEP_REF  12
  50
  51#define IS31FL319X_CURRENT_MIN          ((u32)5000)
  52#define IS31FL319X_CURRENT_MAX          ((u32)40000)
  53#define IS31FL319X_CURRENT_STEP         ((u32)5000)
  54#define IS31FL319X_CURRENT_DEFAULT      ((u32)20000)
  55
  56/* Audio gain in CONFIG2 register */
  57#define IS31FL319X_AUDIO_GAIN_DB_MAX    ((u32)21)
  58#define IS31FL319X_AUDIO_GAIN_DB_STEP   ((u32)3)
  59
  60/*
  61 * regmap is used as a cache of chip's register space,
  62 * to avoid reading back brightness values from chip,
  63 * which is known to hang.
  64 */
  65struct is31fl319x_chip {
  66        const struct is31fl319x_chipdef *cdef;
  67        struct i2c_client               *client;
  68        struct regmap                   *regmap;
  69        struct mutex                    lock;
  70        u32                             audio_gain_db;
  71
  72        struct is31fl319x_led {
  73                struct is31fl319x_chip  *chip;
  74                struct led_classdev     cdev;
  75                u32                     max_microamp;
  76                bool                    configured;
  77        } leds[IS31FL319X_MAX_LEDS];
  78};
  79
  80struct is31fl319x_chipdef {
  81        int num_leds;
  82};
  83
  84static const struct is31fl319x_chipdef is31fl3190_cdef = {
  85        .num_leds = 1,
  86};
  87
  88static const struct is31fl319x_chipdef is31fl3193_cdef = {
  89        .num_leds = 3,
  90};
  91
  92static const struct is31fl319x_chipdef is31fl3196_cdef = {
  93        .num_leds = 6,
  94};
  95
  96static const struct is31fl319x_chipdef is31fl3199_cdef = {
  97        .num_leds = 9,
  98};
  99
 100static const struct of_device_id of_is31fl319x_match[] = {
 101        { .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
 102        { .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
 103        { .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
 104        { .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
 105        { .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
 106        { .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
 107        { }
 108};
 109MODULE_DEVICE_TABLE(of, of_is31fl319x_match);
 110
 111static int is31fl319x_brightness_set(struct led_classdev *cdev,
 112                                     enum led_brightness brightness)
 113{
 114        struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led,
 115                                                  cdev);
 116        struct is31fl319x_chip *is31 = led->chip;
 117        int chan = led - is31->leds;
 118        int ret;
 119        int i;
 120        u8 ctrl1 = 0, ctrl2 = 0;
 121
 122        dev_dbg(&is31->client->dev, "%s %d: %d\n", __func__, chan, brightness);
 123
 124        mutex_lock(&is31->lock);
 125
 126        /* update PWM register */
 127        ret = regmap_write(is31->regmap, IS31FL319X_PWM(chan), brightness);
 128        if (ret < 0)
 129                goto out;
 130
 131        /* read current brightness of all PWM channels */
 132        for (i = 0; i < is31->cdef->num_leds; i++) {
 133                unsigned int pwm_value;
 134                bool on;
 135
 136                /*
 137                 * since neither cdev nor the chip can provide
 138                 * the current setting, we read from the regmap cache
 139                 */
 140
 141                ret = regmap_read(is31->regmap, IS31FL319X_PWM(i), &pwm_value);
 142                dev_dbg(&is31->client->dev, "%s read %d: ret=%d: %d\n",
 143                        __func__, i, ret, pwm_value);
 144                on = ret >= 0 && pwm_value > LED_OFF;
 145
 146                if (i < 3)
 147                        ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
 148                else if (i < 6)
 149                        ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
 150                else
 151                        ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
 152        }
 153
 154        if (ctrl1 > 0 || ctrl2 > 0) {
 155                dev_dbg(&is31->client->dev, "power up %02x %02x\n",
 156                        ctrl1, ctrl2);
 157                regmap_write(is31->regmap, IS31FL319X_CTRL1, ctrl1);
 158                regmap_write(is31->regmap, IS31FL319X_CTRL2, ctrl2);
 159                /* update PWMs */
 160                regmap_write(is31->regmap, IS31FL319X_DATA_UPDATE, 0x00);
 161                /* enable chip from shut down */
 162                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
 163        } else {
 164                dev_dbg(&is31->client->dev, "power down\n");
 165                /* shut down (no need to clear CTRL1/2) */
 166                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
 167        }
 168
 169out:
 170        mutex_unlock(&is31->lock);
 171
 172        return ret;
 173}
 174
 175static int is31fl319x_parse_child_dt(const struct device *dev,
 176                                     const struct device_node *child,
 177                                     struct is31fl319x_led *led)
 178{
 179        struct led_classdev *cdev = &led->cdev;
 180        int ret;
 181
 182        if (of_property_read_string(child, "label", &cdev->name))
 183                cdev->name = child->name;
 184
 185        ret = of_property_read_string(child, "linux,default-trigger",
 186                                      &cdev->default_trigger);
 187        if (ret < 0 && ret != -EINVAL) /* is optional */
 188                return ret;
 189
 190        led->max_microamp = IS31FL319X_CURRENT_DEFAULT;
 191        ret = of_property_read_u32(child, "led-max-microamp",
 192                                   &led->max_microamp);
 193        if (!ret) {
 194                if (led->max_microamp < IS31FL319X_CURRENT_MIN)
 195                        return -EINVAL; /* not supported */
 196                led->max_microamp = min(led->max_microamp,
 197                                          IS31FL319X_CURRENT_MAX);
 198        }
 199
 200        return 0;
 201}
 202
 203static int is31fl319x_parse_dt(struct device *dev,
 204                               struct is31fl319x_chip *is31)
 205{
 206        struct device_node *np = dev->of_node, *child;
 207        const struct of_device_id *of_dev_id;
 208        int count;
 209        int ret;
 210
 211        if (!np)
 212                return -ENODEV;
 213
 214        of_dev_id = of_match_device(of_is31fl319x_match, dev);
 215        if (!of_dev_id) {
 216                dev_err(dev, "Failed to match device with supported chips\n");
 217                return -EINVAL;
 218        }
 219
 220        is31->cdef = of_dev_id->data;
 221
 222        count = of_get_child_count(np);
 223
 224        dev_dbg(dev, "probe %s with %d leds defined in DT\n",
 225                of_dev_id->compatible, 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_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        struct i2c_adapter *adapter = to_i2c_adapter(dev->parent);
 341        int err;
 342        int i = 0;
 343        u32 aggregated_led_microamp = IS31FL319X_CURRENT_MAX;
 344
 345        if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
 346                return -EIO;
 347
 348        is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
 349        if (!is31)
 350                return -ENOMEM;
 351
 352        mutex_init(&is31->lock);
 353
 354        err = is31fl319x_parse_dt(&client->dev, is31);
 355        if (err)
 356                goto free_mutex;
 357
 358        is31->client = client;
 359        is31->regmap = devm_regmap_init_i2c(client, &regmap_config);
 360        if (IS_ERR(is31->regmap)) {
 361                dev_err(&client->dev, "failed to allocate register map\n");
 362                err = PTR_ERR(is31->regmap);
 363                goto free_mutex;
 364        }
 365
 366        i2c_set_clientdata(client, is31);
 367
 368        /* check for write-reply from chip (we can't read any registers) */
 369        err = regmap_write(is31->regmap, IS31FL319X_RESET, 0x00);
 370        if (err < 0) {
 371                dev_err(&client->dev, "no response from chip write: err = %d\n",
 372                        err);
 373                err = -EIO; /* does not answer */
 374                goto free_mutex;
 375        }
 376
 377        /*
 378         * Kernel conventions require per-LED led-max-microamp property.
 379         * But the chip does not allow to limit individual LEDs.
 380         * So we take minimum from all subnodes for safety of hardware.
 381         */
 382        for (i = 0; i < is31->cdef->num_leds; i++)
 383                if (is31->leds[i].configured &&
 384                    is31->leds[i].max_microamp < aggregated_led_microamp)
 385                        aggregated_led_microamp = is31->leds[i].max_microamp;
 386
 387        regmap_write(is31->regmap, IS31FL319X_CONFIG2,
 388                     is31fl319x_microamp_to_cs(dev, aggregated_led_microamp) |
 389                     is31fl319x_db_to_gain(is31->audio_gain_db));
 390
 391        for (i = 0; i < is31->cdef->num_leds; i++) {
 392                struct is31fl319x_led *led = &is31->leds[i];
 393
 394                if (!led->configured)
 395                        continue;
 396
 397                led->chip = is31;
 398                led->cdev.brightness_set_blocking = is31fl319x_brightness_set;
 399
 400                err = devm_led_classdev_register(&client->dev, &led->cdev);
 401                if (err < 0)
 402                        goto free_mutex;
 403        }
 404
 405        return 0;
 406
 407free_mutex:
 408        mutex_destroy(&is31->lock);
 409        return err;
 410}
 411
 412static int is31fl319x_remove(struct i2c_client *client)
 413{
 414        struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
 415
 416        mutex_destroy(&is31->lock);
 417        return 0;
 418}
 419
 420/*
 421 * i2c-core (and modalias) requires that id_table be properly filled,
 422 * even though it is not used for DeviceTree based instantiation.
 423 */
 424static const struct i2c_device_id is31fl319x_id[] = {
 425        { "is31fl3190" },
 426        { "is31fl3191" },
 427        { "is31fl3193" },
 428        { "is31fl3196" },
 429        { "is31fl3199" },
 430        { "sn3199" },
 431        {},
 432};
 433MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
 434
 435static struct i2c_driver is31fl319x_driver = {
 436        .driver   = {
 437                .name           = "leds-is31fl319x",
 438                .of_match_table = of_match_ptr(of_is31fl319x_match),
 439        },
 440        .probe    = is31fl319x_probe,
 441        .remove   = is31fl319x_remove,
 442        .id_table = is31fl319x_id,
 443};
 444
 445module_i2c_driver(is31fl319x_driver);
 446
 447MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
 448MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
 449MODULE_DESCRIPTION("IS31FL319X LED driver");
 450MODULE_LICENSE("GPL v2");
 451