drivers/leds/leds-aat1290.c

   1 /*
   2  *      LED Flash class driver for the AAT1290
   3  *      1.5A Step-Up Current Regulator for Flash LEDs
   4  *
   5  *      Copyright (C) 2015, Samsung Electronics Co., Ltd.
   6  *      Author: Jacek Anaszewski <j.anaszewski@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/led-class-flash.h>
  16 #include <linux/leds.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22 #include <linux/workqueue.h>
  23
  24 #define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
  25 #define AAT1290_MAX_MM_CURR_PERCENT_0   16
  26 #define AAT1290_MAX_MM_CURR_PERCENT_100 1
  27
  28 #define AAT1290_FLASH_SAFETY_TIMER_ADDR 18
  29
  30 #define AAT1290_MOVIE_MODE_CONFIG_ADDR  19
  31 #define AAT1290_MOVIE_MODE_OFF          1
  32 #define AAT1290_MOVIE_MODE_ON           3
  33
  34 #define AAT1290_MM_CURRENT_RATIO_ADDR   20
  35 #define AAT1290_MM_TO_FL_1_92           1
  36
  37 #define AAT1290_MM_TO_FL_RATIO          1000 / 1920
  38 #define AAT1290_MAX_MM_CURRENT(fl_max)  (fl_max * AAT1290_MM_TO_FL_RATIO)
  39
  40 #define AAT1290_LATCH_TIME_MIN_US       500
  41 #define AAT1290_LATCH_TIME_MAX_US       1000
  42 #define AAT1290_EN_SET_TICK_TIME_US     1
  43 #define AAT1290_FLEN_OFF_DELAY_TIME_US  10
  44 #define AAT1290_FLASH_TM_NUM_LEVELS     16
  45 #define AAT1290_MM_CURRENT_SCALE_SIZE   15
  46
  47
  48 struct aat1290_led_config_data {
  49         /* maximum LED current in movie mode */
  50         u32 max_mm_current;
  51         /* maximum LED current in flash mode */
  52         u32 max_flash_current;
  53         /* maximum flash timeout */
  54         u32 max_flash_tm;
  55         /* max LED brightness level */
  56         enum led_brightness max_brightness;
  57 };
  58
  59 struct aat1290_led {
  60         /* platform device data */
  61         struct platform_device *pdev;
  62         /* secures access to the device */
  63         struct mutex lock;
  64
  65         /* corresponding LED Flash class device */
  66         struct led_classdev_flash fled_cdev;
  67
  68         /* FLEN pin */
  69         struct gpio_desc *gpio_fl_en;
  70         /* EN|SET pin  */
  71         struct gpio_desc *gpio_en_set;
  72         /* movie mode current scale */
  73         int *mm_current_scale;
  74         /* device mode */
  75         bool movie_mode;
  76
  77         /* brightness cache */
  78         unsigned int torch_brightness;
  79         /* assures led-triggers compatibility */
  80         struct work_struct work_brightness_set;
  81 };
  82
  83 static struct aat1290_led *fled_cdev_to_led(
  84                                 struct led_classdev_flash *fled_cdev)
  85 {
  86         return container_of(fled_cdev, struct aat1290_led, fled_cdev);
  87 }
  88
  89 static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
  90 {
  91         int i;
  92
  93         gpiod_direction_output(led->gpio_fl_en, 0);
  94         gpiod_direction_output(led->gpio_en_set, 0);
  95
  96         udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);
  97
  98         /* write address */
  99         for (i = 0; i < addr; ++i) {
 100                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 101                 gpiod_direction_output(led->gpio_en_set, 0);
 102                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 103                 gpiod_direction_output(led->gpio_en_set, 1);
 104         }
 105
 106         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 107
 108         /* write data */
 109         for (i = 0; i < value; ++i) {
 110                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 111                 gpiod_direction_output(led->gpio_en_set, 0);
 112                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 113                 gpiod_direction_output(led->gpio_en_set, 1);
 114         }
 115
 116         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 117 }
 118
 119 static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
 120                                         unsigned int micro_sec)
 121 {
 122         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 123         struct led_flash_setting *flash_tm = &fled_cdev->timeout;
 124         int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
 125                                 (micro_sec / flash_tm->step) + 1;
 126
 127         aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
 128                                                         flash_tm_reg);
 129 }
 130
 131 static void aat1290_brightness_set(struct aat1290_led *led,
 132                                         enum led_brightness brightness)
 133 {
 134         mutex_lock(&led->lock);
 135
 136         if (brightness == 0) {
 137                 gpiod_direction_output(led->gpio_fl_en, 0);
 138                 gpiod_direction_output(led->gpio_en_set, 0);
 139                 led->movie_mode = false;
 140         } else {
 141                 if (!led->movie_mode) {
 142                         aat1290_as2cwire_write(led,
 143                                 AAT1290_MM_CURRENT_RATIO_ADDR,
 144                                 AAT1290_MM_TO_FL_1_92);
 145                         led->movie_mode = true;
 146                 }
 147
 148                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
 149                                 AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
 150                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
 151                                 AAT1290_MOVIE_MODE_ON);
 152         }
 153
 154         mutex_unlock(&led->lock);
 155 }
 156
 157 /* LED subsystem callbacks */
 158
 159 static void aat1290_brightness_set_work(struct work_struct *work)
 160 {
 161         struct aat1290_led *led =
 162                 container_of(work, struct aat1290_led, work_brightness_set);
 163
 164         aat1290_brightness_set(led, led->torch_brightness);
 165 }
 166
 167 static void aat1290_led_brightness_set(struct led_classdev *led_cdev,
 168                                         enum led_brightness brightness)
 169 {
 170         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 171         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 172
 173         led->torch_brightness = brightness;
 174         schedule_work(&led->work_brightness_set);
 175 }
 176
 177 static int aat1290_led_brightness_set_sync(struct led_classdev *led_cdev,
 178                                         enum led_brightness brightness)
 179 {
 180         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 181         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 182
 183         aat1290_brightness_set(led, brightness);
 184
 185         return 0;
 186 }
 187
 188 static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 189                                          bool state)
 190
 191 {
 192         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 193         struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 194         struct led_flash_setting *timeout = &fled_cdev->timeout;
 195
 196         mutex_lock(&led->lock);
 197
 198         if (state) {
 199                 aat1290_set_flash_safety_timer(led, timeout->val);
 200                 gpiod_direction_output(led->gpio_fl_en, 1);
 201         } else {
 202                 gpiod_direction_output(led->gpio_fl_en, 0);
 203                 gpiod_direction_output(led->gpio_en_set, 0);
 204         }
 205
 206         /*
 207          * To reenter movie mode after a flash event the part must be cycled
 208          * off and back on to reset the movie mode and reprogrammed via the
 209          * AS2Cwire. Therefore the brightness and movie_mode properties needs
 210          * to be updated here to reflect the actual state.
 211          */
 212         led_cdev->brightness = 0;
 213         led->movie_mode = false;
 214
 215         mutex_unlock(&led->lock);
 216
 217         return 0;
 218 }
 219
 220 static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 221                                                 u32 timeout)
 222 {
 223         /*
 224          * Don't do anything - flash timeout is cached in the led-class-flash
 225          * core and will be applied in the strobe_set op, as writing the
 226          * safety timer register spuriously turns the torch mode on.
 227          */
 228
 229         return 0;
 230 }
 231
 232 static int aat1290_led_parse_dt(struct aat1290_led *led,
 233                         struct aat1290_led_config_data *cfg)
 234 {
 235         struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 236         struct device *dev = &led->pdev->dev;
 237         struct device_node *child_node;
 238         int ret = 0;
 239
 240         led->gpio_fl_en = devm_gpiod_get(dev, "flen");
 241         if (IS_ERR(led->gpio_fl_en)) {
 242                 ret = PTR_ERR(led->gpio_fl_en);
 243                 dev_err(dev, "Unable to claim gpio \"flen\".\n");
 244                 return ret;
 245         }
 246
 247         led->gpio_en_set = devm_gpiod_get(dev, "enset");
 248         if (IS_ERR(led->gpio_en_set)) {
 249                 ret = PTR_ERR(led->gpio_en_set);
 250                 dev_err(dev, "Unable to claim gpio \"enset\".\n");
 251                 return ret;
 252         }
 253
 254         child_node = of_get_next_available_child(dev->of_node, NULL);
 255         if (!child_node) {
 256                 dev_err(dev, "No DT child node found for connected LED.\n");
 257                 return -EINVAL;
 258         }
 259
 260         led_cdev->name = of_get_property(child_node, "label", NULL) ? :
 261                                                 child_node->name;
 262
 263         ret = of_property_read_u32(child_node, "led-max-microamp",
 264                                 &cfg->max_mm_current);
 265         /*
 266          * led-max-microamp will default to 1/20 of flash-max-microamp
 267          * in case it is missing.
 268          */
 269         if (ret < 0)
 270                 dev_warn(dev,
 271                         "led-max-microamp DT property missing\n");
 272
 273         ret = of_property_read_u32(child_node, "flash-max-microamp",
 274                                 &cfg->max_flash_current);
 275         if (ret < 0) {
 276                 dev_err(dev,
 277                         "flash-max-microamp DT property missing\n");
 278                 return ret;
 279         }
 280
 281         ret = of_property_read_u32(child_node, "flash-max-timeout-us",
 282                                 &cfg->max_flash_tm);
 283         if (ret < 0) {
 284                 dev_err(dev,
 285                         "flash-max-timeout-us DT property missing\n");
 286                 return ret;
 287         }
 288
 289         of_node_put(child_node);
 290
 291         return ret;
 292 }
 293
 294 static void aat1290_led_validate_mm_current(struct aat1290_led *led,
 295                                         struct aat1290_led_config_data *cfg)
 296 {
 297         int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
 298
 299         while (e - b > 1) {
 300                 i = b + (e - b) / 2;
 301                 if (cfg->max_mm_current < led->mm_current_scale[i])
 302                         e = i;
 303                 else
 304                         b = i;
 305         }
 306
 307         cfg->max_mm_current = led->mm_current_scale[b];
 308         cfg->max_brightness = b + 1;
 309 }
 310
 311 int init_mm_current_scale(struct aat1290_led *led,
 312                         struct aat1290_led_config_data *cfg)
 313 {
 314         int max_mm_current_percent[] = { 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
 315                                                 63, 71, 79, 89, 100 };
 316         int i, max_mm_current =
 317                         AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
 318
 319         led->mm_current_scale = kzalloc(sizeof(max_mm_current_percent),
 320                                         GFP_KERNEL);
 321         if (!led->mm_current_scale)
 322                 return -ENOMEM;
 323
 324         for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
 325                 led->mm_current_scale[i] = max_mm_current *
 326                                           max_mm_current_percent[i] / 100;
 327
 328         return 0;
 329 }
 330
 331 static int aat1290_led_get_configuration(struct aat1290_led *led,
 332                                         struct aat1290_led_config_data *cfg)
 333 {
 334         int ret;
 335
 336         ret = aat1290_led_parse_dt(led, cfg);
 337         if (ret < 0)
 338                 return ret;
 339         /*
 340          * Init non-linear movie mode current scale basing
 341          * on the max flash current from led configuration.
 342          */
 343         ret = init_mm_current_scale(led, cfg);
 344         if (ret < 0)
 345                 return ret;
 346
 347         aat1290_led_validate_mm_current(led, cfg);
 348
 349         kfree(led->mm_current_scale);
 350
 351         return 0;
 352 }
 353
 354 static void aat1290_init_flash_timeout(struct aat1290_led *led,
 355                                 struct aat1290_led_config_data *cfg)
 356 {
 357         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 358         struct led_flash_setting *setting;
 359
 360         /* Init flash timeout setting */
 361         setting = &fled_cdev->timeout;
 362         setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
 363         setting->max = cfg->max_flash_tm;
 364         setting->step = setting->min;
 365         setting->val = setting->max;
 366 }
 367
 368 static const struct led_flash_ops flash_ops = {
 369         .strobe_set = aat1290_led_flash_strobe_set,
 370         .timeout_set = aat1290_led_flash_timeout_set,
 371 };
 372
 373 static int aat1290_led_probe(struct platform_device *pdev)
 374 {
 375         struct device *dev = &pdev->dev;
 376         struct aat1290_led *led;
 377         struct led_classdev *led_cdev;
 378         struct led_classdev_flash *fled_cdev;
 379         struct aat1290_led_config_data led_cfg = {};
 380         int ret;
 381
 382         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 383         if (!led)
 384                 return -ENOMEM;
 385
 386         led->pdev = pdev;
 387         platform_set_drvdata(pdev, led);
 388
 389         fled_cdev = &led->fled_cdev;
 390         fled_cdev->ops = &flash_ops;
 391         led_cdev = &fled_cdev->led_cdev;
 392
 393         ret = aat1290_led_get_configuration(led, &led_cfg);
 394         if (ret < 0)
 395                 return ret;
 396
 397         mutex_init(&led->lock);
 398
 399         /* Initialize LED Flash class device */
 400         led_cdev->brightness_set = aat1290_led_brightness_set;
 401         led_cdev->brightness_set_sync = aat1290_led_brightness_set_sync;
 402         led_cdev->max_brightness = led_cfg.max_brightness;
 403         led_cdev->flags |= LED_DEV_CAP_FLASH;
 404         INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);
 405
 406         aat1290_init_flash_timeout(led, &led_cfg);
 407
 408         /* Register LED Flash class device */
 409         ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
 410         if (ret < 0)
 411                 goto err_flash_register;
 412
 413         return 0;
 414
 415 err_flash_register:
 416         mutex_destroy(&led->lock);
 417
 418         return ret;
 419 }
 420
 421 static int aat1290_led_remove(struct platform_device *pdev)
 422 {
 423         struct aat1290_led *led = platform_get_drvdata(pdev);
 424
 425         led_classdev_flash_unregister(&led->fled_cdev);
 426         cancel_work_sync(&led->work_brightness_set);
 427
 428         mutex_destroy(&led->lock);
 429
 430         return 0;
 431 }
 432
 433 static const struct of_device_id aat1290_led_dt_match[] = {
 434         { .compatible = "skyworks,aat1290" },
 435         {},
 436 };
 437
 438 static struct platform_driver aat1290_led_driver = {
 439         .probe          = aat1290_led_probe,
 440         .remove         = aat1290_led_remove,
 441         .driver         = {
 442                 .name   = "aat1290",
 443                 .of_match_table = aat1290_led_dt_match,
 444         },
 445 };
 446
 447 module_platform_driver(aat1290_led_driver);
 448
 449 MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
 450 MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
 451 MODULE_LICENSE("GPL v2");