drivers/leds/leds-ktd2692.c

   1 /*
   2  * LED driver : leds-ktd2692.c
   3  *
   4  * Copyright (C) 2015 Samsung Electronics
   5  * Ingi Kim <ingi2.kim@samsung.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/delay.h>
  13 #include <linux/err.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/led-class-flash.h>
  16 #include <linux/module.h>
  17 #include <linux/mutex.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <linux/workqueue.h>
  22
  23 /* Value related the movie mode */
  24 #define KTD2692_MOVIE_MODE_CURRENT_LEVELS       16
  25 #define KTD2692_MM_TO_FL_RATIO(x)               ((x) / 3)
  26 #define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE     8
  27
  28 /* Value related the flash mode */
  29 #define KTD2692_FLASH_MODE_TIMEOUT_LEVELS       8
  30 #define KTD2692_FLASH_MODE_TIMEOUT_DISABLE      0
  31 #define KTD2692_FLASH_MODE_CURR_PERCENT(x)      (((x) * 16) / 100)
  32
  33 /* Macro for getting offset of flash timeout */
  34 #define GET_TIMEOUT_OFFSET(timeout, step)       ((timeout) / (step))
  35
  36 /* Base register address */
  37 #define KTD2692_REG_LVP_BASE                    0x00
  38 #define KTD2692_REG_FLASH_TIMEOUT_BASE          0x20
  39 #define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE  0x40
  40 #define KTD2692_REG_MOVIE_CURRENT_BASE          0x60
  41 #define KTD2692_REG_FLASH_CURRENT_BASE          0x80
  42 #define KTD2692_REG_MODE_BASE                   0xA0
  43
  44 /* Set bit coding time for expresswire interface */
  45 #define KTD2692_TIME_RESET_US                   700
  46 #define KTD2692_TIME_DATA_START_TIME_US         10
  47 #define KTD2692_TIME_HIGH_END_OF_DATA_US        350
  48 #define KTD2692_TIME_LOW_END_OF_DATA_US         10
  49 #define KTD2692_TIME_SHORT_BITSET_US            4
  50 #define KTD2692_TIME_LONG_BITSET_US             12
  51
  52 /* KTD2692 default length of name */
  53 #define KTD2692_NAME_LENGTH                     20
  54
  55 enum ktd2692_bitset {
  56         KTD2692_LOW = 0,
  57         KTD2692_HIGH,
  58 };
  59
  60 /* Movie / Flash Mode Control */
  61 enum ktd2692_led_mode {
  62         KTD2692_MODE_DISABLE = 0,       /* default */
  63         KTD2692_MODE_MOVIE,
  64         KTD2692_MODE_FLASH,
  65 };
  66
  67 struct ktd2692_led_config_data {
  68         /* maximum LED current in movie mode */
  69         u32 movie_max_microamp;
  70         /* maximum LED current in flash mode */
  71         u32 flash_max_microamp;
  72         /* maximum flash timeout */
  73         u32 flash_max_timeout;
  74         /* max LED brightness level */
  75         enum led_brightness max_brightness;
  76 };
  77
  78 struct ktd2692_context {
  79         /* Related LED Flash class device */
  80         struct led_classdev_flash fled_cdev;
  81
  82         /* secures access to the device */
  83         struct mutex lock;
  84         struct regulator *regulator;
  85         struct work_struct work_brightness_set;
  86
  87         struct gpio_desc *aux_gpio;
  88         struct gpio_desc *ctrl_gpio;
  89
  90         enum ktd2692_led_mode mode;
  91         enum led_brightness torch_brightness;
  92 };
  93
  94 static struct ktd2692_context *fled_cdev_to_led(
  95                                 struct led_classdev_flash *fled_cdev)
  96 {
  97         return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
  98 }
  99
 100 static void ktd2692_expresswire_start(struct ktd2692_context *led)
 101 {
 102         gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 103         udelay(KTD2692_TIME_DATA_START_TIME_US);
 104 }
 105
 106 static void ktd2692_expresswire_reset(struct ktd2692_context *led)
 107 {
 108         gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 109         udelay(KTD2692_TIME_RESET_US);
 110 }
 111
 112 static void ktd2692_expresswire_end(struct ktd2692_context *led)
 113 {
 114         gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 115         udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
 116         gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 117         udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
 118 }
 119
 120 static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
 121 {
 122         /*
 123          * The Low Bit(0) and High Bit(1) is based on a time detection
 124          * algorithm between time low and time high
 125          * Time_(L_LB) : Low time of the Low Bit(0)
 126          * Time_(H_LB) : High time of the LOW Bit(0)
 127          * Time_(L_HB) : Low time of the High Bit(1)
 128          * Time_(H_HB) : High time of the High Bit(1)
 129          *
 130          * It can be simplified to:
 131          * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
 132          * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
 133          * HIGH  ___           ____    _..     _________    ___
 134          *          |_________|    |_..  |____|         |__|
 135          * LOW        <L_LB>  <H_LB>     <L_HB>  <H_HB>
 136          *          [  Low Bit (0) ]     [  High Bit(1) ]
 137          */
 138         if (bit) {
 139                 gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 140                 udelay(KTD2692_TIME_SHORT_BITSET_US);
 141                 gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 142                 udelay(KTD2692_TIME_LONG_BITSET_US);
 143         } else {
 144                 gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
 145                 udelay(KTD2692_TIME_LONG_BITSET_US);
 146                 gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
 147                 udelay(KTD2692_TIME_SHORT_BITSET_US);
 148         }
 149 }
 150
 151 static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
 152 {
 153         int i;
 154
 155         ktd2692_expresswire_start(led);
 156         for (i = 7; i >= 0; i--)
 157                 ktd2692_expresswire_set_bit(led, value & BIT(i));
 158         ktd2692_expresswire_end(led);
 159 }
 160
 161 static void ktd2692_brightness_set(struct ktd2692_context *led,
 162                                    enum led_brightness brightness)
 163 {
 164         mutex_lock(&led->lock);
 165
 166         if (brightness == LED_OFF) {
 167                 led->mode = KTD2692_MODE_DISABLE;
 168                 gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
 169         } else {
 170                 ktd2692_expresswire_write(led, brightness |
 171                                         KTD2692_REG_MOVIE_CURRENT_BASE);
 172                 led->mode = KTD2692_MODE_MOVIE;
 173         }
 174
 175         ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
 176         mutex_unlock(&led->lock);
 177 }
 178
 179 static void ktd2692_brightness_set_work(struct work_struct *work)
 180 {
 181         struct ktd2692_context *led =
 182                 container_of(work, struct ktd2692_context, work_brightness_set);
 183
 184         ktd2692_brightness_set(led, led->torch_brightness);
 185 }
 186
 187 static void ktd2692_led_brightness_set(struct led_classdev *led_cdev,
 188                                        enum led_brightness brightness)
 189 {
 190         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 191         struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
 192
 193         led->torch_brightness = brightness;
 194         schedule_work(&led->work_brightness_set);
 195 }
 196
 197 static int ktd2692_led_brightness_set_sync(struct led_classdev *led_cdev,
 198                                            enum led_brightness brightness)
 199 {
 200         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 201         struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
 202
 203         ktd2692_brightness_set(led, brightness);
 204
 205         return 0;
 206 }
 207
 208 static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 209                                         bool state)
 210 {
 211         struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
 212         struct led_flash_setting *timeout = &fled_cdev->timeout;
 213         u32 flash_tm_reg;
 214
 215         mutex_lock(&led->lock);
 216
 217         if (state) {
 218                 flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
 219                 ktd2692_expresswire_write(led, flash_tm_reg
 220                                 | KTD2692_REG_FLASH_TIMEOUT_BASE);
 221
 222                 led->mode = KTD2692_MODE_FLASH;
 223                 gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
 224         } else {
 225                 led->mode = KTD2692_MODE_DISABLE;
 226                 gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
 227         }
 228
 229         ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
 230
 231         fled_cdev->led_cdev.brightness = LED_OFF;
 232         led->mode = KTD2692_MODE_DISABLE;
 233
 234         mutex_unlock(&led->lock);
 235
 236         return 0;
 237 }
 238
 239 static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 240                                          u32 timeout)
 241 {
 242         return 0;
 243 }
 244
 245 static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
 246 {
 247         u32 offset, step;
 248         u32 movie_current_microamp;
 249
 250         offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
 251         step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
 252                 / KTD2692_MOVIE_MODE_CURRENT_LEVELS;
 253
 254         do {
 255                 movie_current_microamp = step * offset;
 256                 offset--;
 257         } while ((movie_current_microamp > cfg->movie_max_microamp) &&
 258                 (offset > 0));
 259
 260         cfg->max_brightness = offset;
 261 }
 262
 263 static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
 264                                        struct ktd2692_led_config_data *cfg)
 265 {
 266         struct led_flash_setting *setting;
 267
 268         setting = &fled_cdev->timeout;
 269         setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
 270         setting->max = cfg->flash_max_timeout;
 271         setting->step = cfg->flash_max_timeout
 272                         / (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
 273         setting->val = cfg->flash_max_timeout;
 274 }
 275
 276 static void ktd2692_setup(struct ktd2692_context *led)
 277 {
 278         led->mode = KTD2692_MODE_DISABLE;
 279         ktd2692_expresswire_reset(led);
 280         gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
 281
 282         ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
 283                                  | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
 284         ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
 285                                  | KTD2692_REG_FLASH_CURRENT_BASE);
 286 }
 287
 288 static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
 289                             struct ktd2692_led_config_data *cfg)
 290 {
 291         struct device_node *np = dev->of_node;
 292         struct device_node *child_node;
 293         int ret;
 294
 295         if (!dev->of_node)
 296                 return -ENXIO;
 297
 298         led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
 299         if (IS_ERR(led->ctrl_gpio)) {
 300                 ret = PTR_ERR(led->ctrl_gpio);
 301                 dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
 302                 return ret;
 303         }
 304
 305         led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
 306         if (IS_ERR(led->aux_gpio)) {
 307                 ret = PTR_ERR(led->aux_gpio);
 308                 dev_err(dev, "cannot get aux-gpios %d\n", ret);
 309                 return ret;
 310         }
 311
 312         led->regulator = devm_regulator_get(dev, "vin");
 313         if (IS_ERR(led->regulator))
 314                 led->regulator = NULL;
 315
 316         if (led->regulator) {
 317                 ret = regulator_enable(led->regulator);
 318                 if (ret)
 319                         dev_err(dev, "Failed to enable supply: %d\n", ret);
 320         }
 321
 322         child_node = of_get_next_available_child(np, NULL);
 323         if (!child_node) {
 324                 dev_err(dev, "No DT child node found for connected LED.\n");
 325                 return -EINVAL;
 326         }
 327
 328         led->fled_cdev.led_cdev.name =
 329                 of_get_property(child_node, "label", NULL) ? : child_node->name;
 330
 331         ret = of_property_read_u32(child_node, "led-max-microamp",
 332                                    &cfg->movie_max_microamp);
 333         if (ret) {
 334                 dev_err(dev, "failed to parse led-max-microamp\n");
 335                 return ret;
 336         }
 337
 338         ret = of_property_read_u32(child_node, "flash-max-microamp",
 339                                    &cfg->flash_max_microamp);
 340         if (ret) {
 341                 dev_err(dev, "failed to parse flash-max-microamp\n");
 342                 return ret;
 343         }
 344
 345         ret = of_property_read_u32(child_node, "flash-max-timeout-us",
 346                                    &cfg->flash_max_timeout);
 347         if (ret)
 348                 dev_err(dev, "failed to parse flash-max-timeout-us\n");
 349
 350         of_node_put(child_node);
 351         return ret;
 352 }
 353
 354 static const struct led_flash_ops flash_ops = {
 355         .strobe_set = ktd2692_led_flash_strobe_set,
 356         .timeout_set = ktd2692_led_flash_timeout_set,
 357 };
 358
 359 static int ktd2692_probe(struct platform_device *pdev)
 360 {
 361         struct ktd2692_context *led;
 362         struct led_classdev *led_cdev;
 363         struct led_classdev_flash *fled_cdev;
 364         struct ktd2692_led_config_data led_cfg;
 365         int ret;
 366
 367         led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
 368         if (!led)
 369                 return -ENOMEM;
 370
 371         fled_cdev = &led->fled_cdev;
 372         led_cdev = &fled_cdev->led_cdev;
 373
 374         ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
 375         if (ret)
 376                 return ret;
 377
 378         ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
 379         ktd2692_init_movie_current_max(&led_cfg);
 380
 381         fled_cdev->ops = &flash_ops;
 382
 383         led_cdev->max_brightness = led_cfg.max_brightness;
 384         led_cdev->brightness_set = ktd2692_led_brightness_set;
 385         led_cdev->brightness_set_sync = ktd2692_led_brightness_set_sync;
 386         led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
 387
 388         mutex_init(&led->lock);
 389         INIT_WORK(&led->work_brightness_set, ktd2692_brightness_set_work);
 390
 391         platform_set_drvdata(pdev, led);
 392
 393         ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
 394         if (ret) {
 395                 dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
 396                 mutex_destroy(&led->lock);
 397                 return ret;
 398         }
 399
 400         ktd2692_setup(led);
 401
 402         return 0;
 403 }
 404
 405 static int ktd2692_remove(struct platform_device *pdev)
 406 {
 407         struct ktd2692_context *led = platform_get_drvdata(pdev);
 408         int ret;
 409
 410         led_classdev_flash_unregister(&led->fled_cdev);
 411         cancel_work_sync(&led->work_brightness_set);
 412
 413         if (led->regulator) {
 414                 ret = regulator_disable(led->regulator);
 415                 if (ret)
 416                         dev_err(&pdev->dev,
 417                                 "Failed to disable supply: %d\n", ret);
 418         }
 419
 420         mutex_destroy(&led->lock);
 421
 422         return 0;
 423 }
 424
 425 static const struct of_device_id ktd2692_match[] = {
 426         { .compatible = "kinetic,ktd2692", },
 427         { /* sentinel */ },
 428 };
 429 MODULE_DEVICE_TABLE(of, ktd2692_match);
 430
 431 static struct platform_driver ktd2692_driver = {
 432         .driver = {
 433                 .name  = "ktd2692",
 434                 .of_match_table = ktd2692_match,
 435         },
 436         .probe  = ktd2692_probe,
 437         .remove = ktd2692_remove,
 438 };
 439
 440 module_platform_driver(ktd2692_driver);
 441
 442 MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
 443 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
 444 MODULE_LICENSE("GPL v2");