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 <linux/workqueue.h>
  24 #include <media/v4l2-flash-led-class.h>
  25
  26 #define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
  27 #define AAT1290_MAX_MM_CURR_PERCENT_0   16
  28 #define AAT1290_MAX_MM_CURR_PERCENT_100 1
  29
  30 #define AAT1290_FLASH_SAFETY_TIMER_ADDR 18
  31
  32 #define AAT1290_MOVIE_MODE_CONFIG_ADDR  19
  33 #define AAT1290_MOVIE_MODE_OFF          1
  34 #define AAT1290_MOVIE_MODE_ON           3
  35
  36 #define AAT1290_MM_CURRENT_RATIO_ADDR   20
  37 #define AAT1290_MM_TO_FL_1_92           1
  38
  39 #define AAT1290_MM_TO_FL_RATIO          1000 / 1920
  40 #define AAT1290_MAX_MM_CURRENT(fl_max)  (fl_max * AAT1290_MM_TO_FL_RATIO)
  41
  42 #define AAT1290_LATCH_TIME_MIN_US       500
  43 #define AAT1290_LATCH_TIME_MAX_US       1000
  44 #define AAT1290_EN_SET_TICK_TIME_US     1
  45 #define AAT1290_FLEN_OFF_DELAY_TIME_US  10
  46 #define AAT1290_FLASH_TM_NUM_LEVELS     16
  47 #define AAT1290_MM_CURRENT_SCALE_SIZE   15
  48
  49
  50 struct aat1290_led_config_data {
  51         /* maximum LED current in movie mode */
  52         u32 max_mm_current;
  53         /* maximum LED current in flash mode */
  54         u32 max_flash_current;
  55         /* maximum flash timeout */
  56         u32 max_flash_tm;
  57         /* external strobe capability */
  58         bool has_external_strobe;
  59         /* max LED brightness level */
  60         enum led_brightness max_brightness;
  61 };
  62
  63 struct aat1290_led {
  64         /* platform device data */
  65         struct platform_device *pdev;
  66         /* secures access to the device */
  67         struct mutex lock;
  68
  69         /* corresponding LED Flash class device */
  70         struct led_classdev_flash fled_cdev;
  71         /* V4L2 Flash device */
  72         struct v4l2_flash *v4l2_flash;
  73
  74         /* FLEN pin */
  75         struct gpio_desc *gpio_fl_en;
  76         /* EN|SET pin  */
  77         struct gpio_desc *gpio_en_set;
  78         /* movie mode current scale */
  79         int *mm_current_scale;
  80         /* device mode */
  81         bool movie_mode;
  82
  83         /* brightness cache */
  84         unsigned int torch_brightness;
  85         /* assures led-triggers compatibility */
  86         struct work_struct work_brightness_set;
  87 };
  88
  89 static struct aat1290_led *fled_cdev_to_led(
  90                                 struct led_classdev_flash *fled_cdev)
  91 {
  92         return container_of(fled_cdev, struct aat1290_led, fled_cdev);
  93 }
  94
  95 static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
  96 {
  97         int i;
  98
  99         gpiod_direction_output(led->gpio_fl_en, 0);
 100         gpiod_direction_output(led->gpio_en_set, 0);
 101
 102         udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);
 103
 104         /* write address */
 105         for (i = 0; i < addr; ++i) {
 106                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 107                 gpiod_direction_output(led->gpio_en_set, 0);
 108                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 109                 gpiod_direction_output(led->gpio_en_set, 1);
 110         }
 111
 112         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 113
 114         /* write data */
 115         for (i = 0; i < value; ++i) {
 116                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 117                 gpiod_direction_output(led->gpio_en_set, 0);
 118                 udelay(AAT1290_EN_SET_TICK_TIME_US);
 119                 gpiod_direction_output(led->gpio_en_set, 1);
 120         }
 121
 122         usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
 123 }
 124
 125 static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
 126                                         unsigned int micro_sec)
 127 {
 128         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 129         struct led_flash_setting *flash_tm = &fled_cdev->timeout;
 130         int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
 131                                 (micro_sec / flash_tm->step) + 1;
 132
 133         aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
 134                                                         flash_tm_reg);
 135 }
 136
 137 static void aat1290_brightness_set(struct aat1290_led *led,
 138                                         enum led_brightness brightness)
 139 {
 140         mutex_lock(&led->lock);
 141
 142         if (brightness == 0) {
 143                 gpiod_direction_output(led->gpio_fl_en, 0);
 144                 gpiod_direction_output(led->gpio_en_set, 0);
 145                 led->movie_mode = false;
 146         } else {
 147                 if (!led->movie_mode) {
 148                         aat1290_as2cwire_write(led,
 149                                 AAT1290_MM_CURRENT_RATIO_ADDR,
 150                                 AAT1290_MM_TO_FL_1_92);
 151                         led->movie_mode = true;
 152                 }
 153
 154                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
 155                                 AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
 156                 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
 157                                 AAT1290_MOVIE_MODE_ON);
 158         }
 159
 160         mutex_unlock(&led->lock);
 161 }
 162
 163 /* LED subsystem callbacks */
 164
 165 static void aat1290_brightness_set_work(struct work_struct *work)
 166 {
 167         struct aat1290_led *led =
 168                 container_of(work, struct aat1290_led, work_brightness_set);
 169
 170         aat1290_brightness_set(led, led->torch_brightness);
 171 }
 172
 173 static void aat1290_led_brightness_set(struct led_classdev *led_cdev,
 174                                         enum led_brightness brightness)
 175 {
 176         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 177         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 178
 179         led->torch_brightness = brightness;
 180         schedule_work(&led->work_brightness_set);
 181 }
 182
 183 static int aat1290_led_brightness_set_sync(struct led_classdev *led_cdev,
 184                                         enum led_brightness brightness)
 185 {
 186         struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
 187         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 188
 189         aat1290_brightness_set(led, brightness);
 190
 191         return 0;
 192 }
 193
 194 static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
 195                                          bool state)
 196
 197 {
 198         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 199         struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 200         struct led_flash_setting *timeout = &fled_cdev->timeout;
 201
 202         mutex_lock(&led->lock);
 203
 204         if (state) {
 205                 aat1290_set_flash_safety_timer(led, timeout->val);
 206                 gpiod_direction_output(led->gpio_fl_en, 1);
 207         } else {
 208                 gpiod_direction_output(led->gpio_fl_en, 0);
 209                 gpiod_direction_output(led->gpio_en_set, 0);
 210         }
 211
 212         /*
 213          * To reenter movie mode after a flash event the part must be cycled
 214          * off and back on to reset the movie mode and reprogrammed via the
 215          * AS2Cwire. Therefore the brightness and movie_mode properties needs
 216          * to be updated here to reflect the actual state.
 217          */
 218         led_cdev->brightness = 0;
 219         led->movie_mode = false;
 220
 221         mutex_unlock(&led->lock);
 222
 223         return 0;
 224 }
 225
 226 static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
 227                                                 u32 timeout)
 228 {
 229         /*
 230          * Don't do anything - flash timeout is cached in the led-class-flash
 231          * core and will be applied in the strobe_set op, as writing the
 232          * safety timer register spuriously turns the torch mode on.
 233          */
 234
 235         return 0;
 236 }
 237
 238 static int aat1290_led_parse_dt(struct aat1290_led *led,
 239                         struct aat1290_led_config_data *cfg,
 240                         struct device_node **sub_node)
 241 {
 242         struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 243         struct device *dev = &led->pdev->dev;
 244         struct device_node *child_node;
 245 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 246         struct pinctrl *pinctrl;
 247 #endif
 248         int ret = 0;
 249
 250         led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
 251         if (IS_ERR(led->gpio_fl_en)) {
 252                 ret = PTR_ERR(led->gpio_fl_en);
 253                 dev_err(dev, "Unable to claim gpio \"flen\".\n");
 254                 return ret;
 255         }
 256
 257         led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
 258         if (IS_ERR(led->gpio_en_set)) {
 259                 ret = PTR_ERR(led->gpio_en_set);
 260                 dev_err(dev, "Unable to claim gpio \"enset\".\n");
 261                 return ret;
 262         }
 263
 264 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 265         pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
 266         if (IS_ERR(pinctrl)) {
 267                 cfg->has_external_strobe = false;
 268                 dev_info(dev,
 269                          "No support for external strobe detected.\n");
 270         } else {
 271                 cfg->has_external_strobe = true;
 272         }
 273 #endif
 274
 275         child_node = of_get_next_available_child(dev->of_node, NULL);
 276         if (!child_node) {
 277                 dev_err(dev, "No DT child node found for connected LED.\n");
 278                 return -EINVAL;
 279         }
 280
 281         led_cdev->name = of_get_property(child_node, "label", NULL) ? :
 282                                                 child_node->name;
 283
 284         ret = of_property_read_u32(child_node, "led-max-microamp",
 285                                 &cfg->max_mm_current);
 286         /*
 287          * led-max-microamp will default to 1/20 of flash-max-microamp
 288          * in case it is missing.
 289          */
 290         if (ret < 0)
 291                 dev_warn(dev,
 292                         "led-max-microamp DT property missing\n");
 293
 294         ret = of_property_read_u32(child_node, "flash-max-microamp",
 295                                 &cfg->max_flash_current);
 296         if (ret < 0) {
 297                 dev_err(dev,
 298                         "flash-max-microamp DT property missing\n");
 299                 return ret;
 300         }
 301
 302         ret = of_property_read_u32(child_node, "flash-max-timeout-us",
 303                                 &cfg->max_flash_tm);
 304         if (ret < 0) {
 305                 dev_err(dev,
 306                         "flash-max-timeout-us DT property missing\n");
 307                 return ret;
 308         }
 309
 310         of_node_put(child_node);
 311
 312         *sub_node = child_node;
 313
 314         return ret;
 315 }
 316
 317 static void aat1290_led_validate_mm_current(struct aat1290_led *led,
 318                                         struct aat1290_led_config_data *cfg)
 319 {
 320         int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
 321
 322         while (e - b > 1) {
 323                 i = b + (e - b) / 2;
 324                 if (cfg->max_mm_current < led->mm_current_scale[i])
 325                         e = i;
 326                 else
 327                         b = i;
 328         }
 329
 330         cfg->max_mm_current = led->mm_current_scale[b];
 331         cfg->max_brightness = b + 1;
 332 }
 333
 334 static int init_mm_current_scale(struct aat1290_led *led,
 335                         struct aat1290_led_config_data *cfg)
 336 {
 337         int max_mm_current_percent[] = { 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
 338                                                 63, 71, 79, 89, 100 };
 339         int i, max_mm_current =
 340                         AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
 341
 342         led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
 343                                         sizeof(max_mm_current_percent),
 344                                         GFP_KERNEL);
 345         if (!led->mm_current_scale)
 346                 return -ENOMEM;
 347
 348         for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
 349                 led->mm_current_scale[i] = max_mm_current *
 350                                           max_mm_current_percent[i] / 100;
 351
 352         return 0;
 353 }
 354
 355 static int aat1290_led_get_configuration(struct aat1290_led *led,
 356                                         struct aat1290_led_config_data *cfg,
 357                                         struct device_node **sub_node)
 358 {
 359         int ret;
 360
 361         ret = aat1290_led_parse_dt(led, cfg, sub_node);
 362         if (ret < 0)
 363                 return ret;
 364         /*
 365          * Init non-linear movie mode current scale basing
 366          * on the max flash current from led configuration.
 367          */
 368         ret = init_mm_current_scale(led, cfg);
 369         if (ret < 0)
 370                 return ret;
 371
 372         aat1290_led_validate_mm_current(led, cfg);
 373
 374 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 375 #else
 376         devm_kfree(&led->pdev->dev, led->mm_current_scale);
 377 #endif
 378
 379         return 0;
 380 }
 381
 382 static void aat1290_init_flash_timeout(struct aat1290_led *led,
 383                                 struct aat1290_led_config_data *cfg)
 384 {
 385         struct led_classdev_flash *fled_cdev = &led->fled_cdev;
 386         struct led_flash_setting *setting;
 387
 388         /* Init flash timeout setting */
 389         setting = &fled_cdev->timeout;
 390         setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
 391         setting->max = cfg->max_flash_tm;
 392         setting->step = setting->min;
 393         setting->val = setting->max;
 394 }
 395
 396 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
 397 static enum led_brightness aat1290_intensity_to_brightness(
 398                                         struct v4l2_flash *v4l2_flash,
 399                                         s32 intensity)
 400 {
 401         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 402         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 403         int i;
 404
 405         for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
 406                 if (intensity >= led->mm_current_scale[i])
 407                         return i + 1;
 408
 409         return 1;
 410 }
 411
 412 static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
 413                                         enum led_brightness brightness)
 414 {
 415         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 416         struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
 417
 418         return led->mm_current_scale[brightness - 1];
 419 }
 420
 421 static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
 422                                                 bool enable)
 423 {
 424         struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
 425         struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
 426         struct led_classdev *led_cdev = &fled_cdev->led_cdev;
 427         struct pinctrl *pinctrl;
 428
 429         gpiod_direction_output(led->gpio_fl_en, 0);
 430         gpiod_direction_output(led->gpio_en_set, 0);
 431
 432         led->movie_mode = false;
 433         led_cdev->brightness = 0;
 434
 435         pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
 436                                                 enable ? "isp" : "host");
 437         if (IS_ERR(pinctrl)) {
 438                 dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
 439                 return PTR_ERR(pinctrl);
 440         }
 441
 442         return 0;
 443 }
 444
 445 static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 446                                         struct aat1290_led_config_data *led_cfg,
 447                                         struct v4l2_flash_config *v4l2_sd_cfg)
 448 {
 449         struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
 450         struct led_flash_setting *s;
 451
 452         strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
 453                 sizeof(v4l2_sd_cfg->dev_name));
 454
 455         s = &v4l2_sd_cfg->torch_intensity;
 456         s->min = led->mm_current_scale[0];
 457         s->max = led_cfg->max_mm_current;
 458         s->step = 1;
 459         s->val = s->max;
 460
 461         v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
 462 }
 463
 464 static const struct v4l2_flash_ops v4l2_flash_ops = {
 465         .external_strobe_set = aat1290_led_external_strobe_set,
 466         .intensity_to_led_brightness = aat1290_intensity_to_brightness,
 467         .led_brightness_to_intensity = aat1290_brightness_to_intensity,
 468 };
 469 #else
 470 static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
 471                                 struct aat1290_led_config_data *led_cfg,
 472                                 struct v4l2_flash_config *v4l2_sd_cfg)
 473 {
 474 }
 475 static const struct v4l2_flash_ops v4l2_flash_ops;
 476 #endif
 477
 478 static const struct led_flash_ops flash_ops = {
 479         .strobe_set = aat1290_led_flash_strobe_set,
 480         .timeout_set = aat1290_led_flash_timeout_set,
 481 };
 482
 483 static int aat1290_led_probe(struct platform_device *pdev)
 484 {
 485         struct device *dev = &pdev->dev;
 486         struct device_node *sub_node = NULL;
 487         struct aat1290_led *led;
 488         struct led_classdev *led_cdev;
 489         struct led_classdev_flash *fled_cdev;
 490         struct aat1290_led_config_data led_cfg = {};
 491         struct v4l2_flash_config v4l2_sd_cfg = {};
 492         int ret;
 493
 494         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 495         if (!led)
 496                 return -ENOMEM;
 497
 498         led->pdev = pdev;
 499         platform_set_drvdata(pdev, led);
 500
 501         fled_cdev = &led->fled_cdev;
 502         fled_cdev->ops = &flash_ops;
 503         led_cdev = &fled_cdev->led_cdev;
 504
 505         ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
 506         if (ret < 0)
 507                 return ret;
 508
 509         mutex_init(&led->lock);
 510
 511         /* Initialize LED Flash class device */
 512         led_cdev->brightness_set = aat1290_led_brightness_set;
 513         led_cdev->brightness_set_sync = aat1290_led_brightness_set_sync;
 514         led_cdev->max_brightness = led_cfg.max_brightness;
 515         led_cdev->flags |= LED_DEV_CAP_FLASH;
 516         INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);
 517
 518         aat1290_init_flash_timeout(led, &led_cfg);
 519
 520         /* Register LED Flash class device */
 521         ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
 522         if (ret < 0)
 523                 goto err_flash_register;
 524
 525         aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);
 526
 527         /* Create V4L2 Flash subdev. */
 528         led->v4l2_flash = v4l2_flash_init(dev, sub_node, fled_cdev, NULL,
 529                                           &v4l2_flash_ops, &v4l2_sd_cfg);
 530         if (IS_ERR(led->v4l2_flash)) {
 531                 ret = PTR_ERR(led->v4l2_flash);
 532                 goto error_v4l2_flash_init;
 533         }
 534
 535         return 0;
 536
 537 error_v4l2_flash_init:
 538         led_classdev_flash_unregister(fled_cdev);
 539 err_flash_register:
 540         mutex_destroy(&led->lock);
 541
 542         return ret;
 543 }
 544
 545 static int aat1290_led_remove(struct platform_device *pdev)
 546 {
 547         struct aat1290_led *led = platform_get_drvdata(pdev);
 548
 549         v4l2_flash_release(led->v4l2_flash);
 550         led_classdev_flash_unregister(&led->fled_cdev);
 551         cancel_work_sync(&led->work_brightness_set);
 552
 553         mutex_destroy(&led->lock);
 554
 555         return 0;
 556 }
 557
 558 static const struct of_device_id aat1290_led_dt_match[] = {
 559         { .compatible = "skyworks,aat1290" },
 560         {},
 561 };
 562 MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);
 563
 564 static struct platform_driver aat1290_led_driver = {
 565         .probe          = aat1290_led_probe,
 566         .remove         = aat1290_led_remove,
 567         .driver         = {
 568                 .name   = "aat1290",
 569                 .of_match_table = aat1290_led_dt_match,
 570         },
 571 };
 572
 573 module_platform_driver(aat1290_led_driver);
 574
 575 MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
 576 MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
 577 MODULE_LICENSE("GPL v2");