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