drivers/leds/leds-is31fl319x.c

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