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/pinctrl/consumer.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23 #include <media/v4l2-flash-led-class.h>
  24
  25 #define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
  26 #define AAT1290_MAX_MM_CURR_PERCENT_0   16
  27 #define AAT1290_MAX_MM_CURR_PERCENT_100 1
  28
  29 #define AAT1290_FLASH_SAFETY_TIMER_ADDR 18
  30
  31 #define AAT1290_MOVIE_MODE_CONFIG_ADDR  19
  32 #define AAT1290_MOVIE_MODE_OFF          1
  33 #define AAT1290_MOVIE_MODE_ON           3
  34
  35 #define AAT1290_MM_CURRENT_RATIO_ADDR   20
  36 #define AAT1290_MM_TO_FL_1_92           1
  37
  38 #define AAT1290_MM_TO_FL_RATIO          1000 / 1920
  39 #define AAT1290_MAX_MM_CURRENT(fl_max)  (fl_max * AAT1290_MM_TO_FL_RATIO)
  40
  41 #define AAT1290_LATCH_TIME_MIN_US       500
  42 #define AAT1290_LATCH_TIME_MAX_US       1000
  43 #define AAT1290_EN_SET_TICK_TIME_US     1
  44 #define AAT1290_FLEN_OFF_DELAY_TIME_US  10
  45 #define AAT1290_FLASH_TM_NUM_LEVELS     16
  46 #define AAT1290_MM_CURRENT_SCALE_SIZE   15
  47
  48
  49 struct aat1290_led_config_data {
  50         /* maximum LED current in movie mode */
  51         u32 max_mm_current;
  52         /* maximum LED current in flash mode */
  53         u32 max_flash_current;
  54         /* maximum flash timeout */
  55         u32 max_flash_tm;
  56         /* external strobe capability */
  57         bool has_external_strobe;
  58         /* max LED brightness level */
  59         enum led_brightness max_brightness;
  60 };
  61
  62 struct aat1290_led {
  63         /* platform device data */
  64         struct platform_device *pdev;
  65         /* secures access to the device */
  66         struct mutex lock;
  67
  68         /* corresponding LED Flash class device */
  69         struct led_classdev_flash fled_cdev;
  70         /* V4L2 Flash device */
  71         struct v4l2_flash *v4l2_flash;
  72
  73         /* FLEN pin */
  74         struct gpio_desc *gpio_fl_en;
  75         /* EN|SET pin  */
  76         struct gpio_desc *gpio_en_set;
  77         /* movie mode current scale */
  78         int *mm_current_scale;
  79         /* device mode */
  80         bool movie_mode;
  81
  82         /* brightness cache */
  83         unsigned int torch_brightness;
  84 };
  85
  86 static struct aat1290_led *fled_cdev_to_led(
  87                                 struct led_classdev_flash *fled_cdev)
  88 {
  89         return container_of(fled_cdev, struct aat1290_led, fled_cdev);
  90 }
  91
  92 static struct led_classdev_flash *led_cdev_to_fled_cdev(
  93                                 struct led_classdev *led_cdev)
  94 {
  95         return container_of(led_cdev, struct led_classdev_flash, led_cdev);
  96 }
  97
  98 static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
  99 {
 100         int i;
 101
 102         gpiod_direction_output(led->gpio_fl_en, 0);
 103         gpiod_direction_output(led->gpio_en_set, 0);
 104
 105         udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);
 106
 107         /* write address */
 108         for (i = 0; i < addr; ++i) {
 109                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 110                 gpiod_direction_output(led->gpio_en_set, 0);
 111                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 112                 gpiod_direction_output(led->gpio_en_set, 1);
 113         }
 114
 115         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 116
 117         /* write data */
 118         for (i = 0; i < value; ++i) {
 119                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 120                 gpiod_direction_output(led->gpio_en_set, 0);
 121                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 122                 gpiod_direction_output(led->gpio_en_set, 1);
 123         }
 124
 125         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 126 }
 127
 128 static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
 129                                         unsigned int micro_sec)
 130 {
 131         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 132         struct led_flash_setting *flash_tm = &fled_cdev->timeout;
 133         int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
 134                                 (micro_sec / flash_tm->step) + 1;
 135
 136         aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
 137                                                         flash_tm_reg);
 138 }
 139
 140 /* LED subsystem callbacks */
 141
 142 static int aat1290_led_brightness_set(struct led_classdev *led_cdev,
 143                                         enum led_brightness brightness)
 144 {
 145         struct led_classdev_flash *fled_cdev = led_cdev_to_fled_cdev(led_cdev);
 146         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 147
 148         mutex_lock(&led->lock);
 149
 150         if (brightness == 0) {
 151                 gpiod_direction_output(led->gpio_fl_en, 0);
 152                 gpiod_direction_output(led->gpio_en_set, 0);
 153                 led->movie_mode = false;
 154         } else {
 155                 if (!led->movie_mode) {
 156                         aat1290_as2cwire_write(led,
 157                                 AAT1290_MM_CURRENT_RATIO_ADDR,
 158                                 AAT1290_MM_TO_FL_1_92);
 159                         led->movie_mode = true;
 160                 }
 161
 162                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
 163                                 AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
 164                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
 165                                 AAT1290_MOVIE_MODE_ON);
 166         }
 167
 168         mutex_unlock(&led->lock);
 169
 170         return 0;
 171 }
 172
 173 static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 174                                          bool state)
 175
 176 {
 177         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 178         struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 179         struct led_flash_setting *timeout = &fled_cdev->timeout;
 180
 181         mutex_lock(&led->lock);
 182
 183         if (state) {
 184                 aat1290_set_flash_safety_timer(led, timeout->val);
 185                 gpiod_direction_output(led->gpio_fl_en, 1);
 186         } else {
 187                 gpiod_direction_output(led->gpio_fl_en, 0);
 188                 gpiod_direction_output(led->gpio_en_set, 0);
 189         }
 190
 191         /*
 192          * To reenter movie mode after a flash event the part must be cycled
 193          * off and back on to reset the movie mode and reprogrammed via the
 194          * AS2Cwire. Therefore the brightness and movie_mode properties needs
 195          * to be updated here to reflect the actual state.
 196          */
 197         led_cdev->brightness = 0;
 198         led->movie_mode = false;
 199
 200         mutex_unlock(&led->lock);
 201
 202         return 0;
 203 }
 204
 205 static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 206                                                 u32 timeout)
 207 {
 208         /*
 209          * Don't do anything - flash timeout is cached in the led-class-flash
 210          * core and will be applied in the strobe_set op, as writing the
 211          * safety timer register spuriously turns the torch mode on.
 212          */
 213
 214         return 0;
 215 }
 216
 217 static int aat1290_led_parse_dt(struct aat1290_led *led,
 218                         struct aat1290_led_config_data *cfg,
 219                         struct device_node **sub_node)
 220 {
 221         struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 222         struct device *dev = &led->pdev->dev;
 223         struct device_node *child_node;
 224 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 225         struct pinctrl *pinctrl;
 226 #endif
 227         int ret = 0;
 228
 229         led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
 230         if (IS_ERR(led->gpio_fl_en)) {
 231                 ret = PTR_ERR(led->gpio_fl_en);
 232                 dev_err(dev, "Unable to claim gpio \"flen\".\n");
 233                 return ret;
 234         }
 235
 236         led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
 237         if (IS_ERR(led->gpio_en_set)) {
 238                 ret = PTR_ERR(led->gpio_en_set);
 239                 dev_err(dev, "Unable to claim gpio \"enset\".\n");
 240                 return ret;
 241         }
 242
 243 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 244         pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
 245         if (IS_ERR(pinctrl)) {
 246                 cfg->has_external_strobe = false;
 247                 dev_info(dev,
 248                          "No support for external strobe detected.\n");
 249         } else {
 250                 cfg->has_external_strobe = true;
 251         }
 252 #endif
 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                 goto err_parse_dt;
 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                 goto err_parse_dt;
 287         }
 288
 289         *sub_node = child_node;
 290
 291 err_parse_dt:
 292         of_node_put(child_node);
 293
 294         return ret;
 295 }
 296
 297 static void aat1290_led_validate_mm_current(struct aat1290_led *led,
 298                                         struct aat1290_led_config_data *cfg)
 299 {
 300         int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
 301
 302         while (e - b > 1) {
 303                 i = b + (e - b) / 2;
 304                 if (cfg->max_mm_current < led->mm_current_scale[i])
 305                         e = i;
 306                 else
 307                         b = i;
 308         }
 309
 310         cfg->max_mm_current = led->mm_current_scale[b];
 311         cfg->max_brightness = b + 1;
 312 }
 313
 314 static int init_mm_current_scale(struct aat1290_led *led,
 315                         struct aat1290_led_config_data *cfg)
 316 {
 317         static const int max_mm_current_percent[] = {
 318                 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
 319                 63, 71, 79, 89, 100
 320         };
 321         int i, max_mm_current =
 322                         AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
 323
 324         led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
 325                                         sizeof(max_mm_current_percent),
 326                                         GFP_KERNEL);
 327         if (!led->mm_current_scale)
 328                 return -ENOMEM;
 329
 330         for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
 331                 led->mm_current_scale[i] = max_mm_current *
 332                                           max_mm_current_percent[i] / 100;
 333
 334         return 0;
 335 }
 336
 337 static int aat1290_led_get_configuration(struct aat1290_led *led,
 338                                         struct aat1290_led_config_data *cfg,
 339                                         struct device_node **sub_node)
 340 {
 341         int ret;
 342
 343         ret = aat1290_led_parse_dt(led, cfg, sub_node);
 344         if (ret < 0)
 345                 return ret;
 346         /*
 347          * Init non-linear movie mode current scale basing
 348          * on the max flash current from led configuration.
 349          */
 350         ret = init_mm_current_scale(led, cfg);
 351         if (ret < 0)
 352                 return ret;
 353
 354         aat1290_led_validate_mm_current(led, cfg);
 355
 356 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 357 #else
 358         devm_kfree(&led->pdev->dev, led->mm_current_scale);
 359 #endif
 360
 361         return 0;
 362 }
 363
 364 static void aat1290_init_flash_timeout(struct aat1290_led *led,
 365                                 struct aat1290_led_config_data *cfg)
 366 {
 367         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 368         struct led_flash_setting *setting;
 369
 370         /* Init flash timeout setting */
 371         setting = &fled_cdev->timeout;
 372         setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
 373         setting->max = cfg->max_flash_tm;
 374         setting->step = setting->min;
 375         setting->val = setting->max;
 376 }
 377
 378 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 379 static enum led_brightness aat1290_intensity_to_brightness(
 380                                         struct v4l2_flash *v4l2_flash,
 381                                         s32 intensity)
 382 {
 383         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 384         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 385         int i;
 386
 387         for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
 388                 if (intensity >= led->mm_current_scale[i])
 389                         return i + 1;
 390
 391         return 1;
 392 }
 393
 394 static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
 395                                         enum led_brightness brightness)
 396 {
 397         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 398         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 399
 400         return led->mm_current_scale[brightness - 1];
 401 }
 402
 403 static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
 404                                                 bool enable)
 405 {
 406         struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
 407         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 408         struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 409         struct pinctrl *pinctrl;
 410
 411         gpiod_direction_output(led->gpio_fl_en, 0);
 412         gpiod_direction_output(led->gpio_en_set, 0);
 413
 414         led->movie_mode = false;
 415         led_cdev->brightness = 0;
 416
 417         pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
 418                                                 enable ? "isp" : "host");
 419         if (IS_ERR(pinctrl)) {
 420                 dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
 421                 return PTR_ERR(pinctrl);
 422         }
 423
 424         return 0;
 425 }
 426
 427 static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 428                                         struct aat1290_led_config_data *led_cfg,
 429                                         struct v4l2_flash_config *v4l2_sd_cfg)
 430 {
 431         struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 432         struct led_flash_setting *s;
 433
 434         strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
 435                 sizeof(v4l2_sd_cfg->dev_name));
 436
 437         s = &v4l2_sd_cfg->intensity;
 438         s->min = led->mm_current_scale[0];
 439         s->max = led_cfg->max_mm_current;
 440         s->step = 1;
 441         s->val = s->max;
 442
 443         v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
 444 }
 445
 446 static const struct v4l2_flash_ops v4l2_flash_ops = {
 447         .external_strobe_set = aat1290_led_external_strobe_set,
 448         .intensity_to_led_brightness = aat1290_intensity_to_brightness,
 449         .led_brightness_to_intensity = aat1290_brightness_to_intensity,
 450 };
 451 #else
 452 static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 453                                 struct aat1290_led_config_data *led_cfg,
 454                                 struct v4l2_flash_config *v4l2_sd_cfg)
 455 {
 456 }
 457 static const struct v4l2_flash_ops v4l2_flash_ops;
 458 #endif
 459
 460 static const struct led_flash_ops flash_ops = {
 461         .strobe_set = aat1290_led_flash_strobe_set,
 462         .timeout_set = aat1290_led_flash_timeout_set,
 463 };
 464
 465 static int aat1290_led_probe(struct platform_device *pdev)
 466 {
 467         struct device *dev = &pdev->dev;
 468         struct device_node *sub_node = NULL;
 469         struct aat1290_led *led;
 470         struct led_classdev *led_cdev;
 471         struct led_classdev_flash *fled_cdev;
 472         struct aat1290_led_config_data led_cfg = {};
 473         struct v4l2_flash_config v4l2_sd_cfg = {};
 474         int ret;
 475
 476         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 477         if (!led)
 478                 return -ENOMEM;
 479
 480         led->pdev = pdev;
 481         platform_set_drvdata(pdev, led);
 482
 483         fled_cdev = &led->fled_cdev;
 484         fled_cdev->ops = &flash_ops;
 485         led_cdev = &fled_cdev->led_cdev;
 486
 487         ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
 488         if (ret < 0)
 489                 return ret;
 490
 491         mutex_init(&led->lock);
 492
 493         /* Initialize LED Flash class device */
 494         led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
 495         led_cdev->max_brightness = led_cfg.max_brightness;
 496         led_cdev->flags |= LED_DEV_CAP_FLASH;
 497
 498         aat1290_init_flash_timeout(led, &led_cfg);
 499
 500         /* Register LED Flash class device */
 501         ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
 502         if (ret < 0)
 503                 goto err_flash_register;
 504
 505         aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);
 506
 507         /* Create V4L2 Flash subdev. */
 508         led->v4l2_flash = v4l2_flash_init(dev, of_fwnode_handle(sub_node),
 509                                           fled_cdev, &v4l2_flash_ops,
 510                                           &v4l2_sd_cfg);
 511         if (IS_ERR(led->v4l2_flash)) {
 512                 ret = PTR_ERR(led->v4l2_flash);
 513                 goto error_v4l2_flash_init;
 514         }
 515
 516         return 0;
 517
 518 error_v4l2_flash_init:
 519         led_classdev_flash_unregister(fled_cdev);
 520 err_flash_register:
 521         mutex_destroy(&led->lock);
 522
 523         return ret;
 524 }
 525
 526 static int aat1290_led_remove(struct platform_device *pdev)
 527 {
 528         struct aat1290_led *led = platform_get_drvdata(pdev);
 529
 530         v4l2_flash_release(led->v4l2_flash);
 531         led_classdev_flash_unregister(&led->fled_cdev);
 532
 533         mutex_destroy(&led->lock);
 534
 535         return 0;
 536 }
 537
 538 static const struct of_device_id aat1290_led_dt_match[] = {
 539         { .compatible = "skyworks,aat1290" },
 540         {},
 541 };
 542 MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);
 543
 544 static struct platform_driver aat1290_led_driver = {
 545         .probe          = aat1290_led_probe,
 546         .remove         = aat1290_led_remove,
 547         .driver         = {
 548                 .name   = "aat1290",
 549                 .of_match_table = aat1290_led_dt_match,
 550         },
 551 };
 552
 553 module_platform_driver(aat1290_led_driver);
 554
 555 MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
 556 MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
 557 MODULE_LICENSE("GPL v2");