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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * LED driver for Richtek RT8515 flash/torch white LEDs4 * found on some Samsung mobile phones.5 *6 * This is a 1.5A Boost dual channel driver produced around 2011.7 *8 * The component lacks a datasheet, but in the schematic picture9 * from the LG P970 service manual you can see the connections10 * from the RT8515 to the LED, with two resistors connected11 * from the pins "RFS" and "RTS" to ground.12 *13 * On the LG P970:14 * RFS (resistance flash setting?) is 20 kOhm15 * RTS (resistance torch setting?) is 39 kOhm16 *17 * Some sleuthing finds us the RT9387A which we have a datasheet for:18 * https://static5.arrow.com/pdfs/2014/7/27/8/21/12/794/rtt_/manual/94download_ds.jspprt9387a.jspprt9387a.pdf19 * This apparently works the same way so in theory this driver20 * should cover RT9387A as well. This has not been tested, please21 * update the compatibles if you add RT9387A support.22 *23 * Linus Walleij <linus.walleij@linaro.org>24 */25#include <linux/delay.h>26#include <linux/err.h>27#include <linux/gpio/consumer.h>28#include <linux/led-class-flash.h>29#include <linux/mod_devicetable.h>30#include <linux/module.h>31#include <linux/platform_device.h>32#include <linux/property.h>33#include <linux/regulator/consumer.h>34 35#include <media/v4l2-flash-led-class.h>36 37/* We can provide 15-700 mA out to the LED */38#define RT8515_MIN_IOUT_MA 1539#define RT8515_MAX_IOUT_MA 70040/* The maximum intensity is 1-16 for flash and 1-100 for torch */41#define RT8515_FLASH_MAX 1642#define RT8515_TORCH_MAX 10043 44#define RT8515_TIMEOUT_US 250000U45#define RT8515_MAX_TIMEOUT_US 300000U46 47struct rt8515 {48 struct led_classdev_flash fled;49 struct device *dev;50 struct v4l2_flash *v4l2_flash;51 struct mutex lock;52 struct regulator *reg;53 struct gpio_desc *enable_torch;54 struct gpio_desc *enable_flash;55 struct timer_list powerdown_timer;56 u32 max_timeout; /* Flash max timeout */57 int flash_max_intensity;58 int torch_max_intensity;59};60 61static struct rt8515 *to_rt8515(struct led_classdev_flash *fled)62{63 return container_of(fled, struct rt8515, fled);64}65 66static void rt8515_gpio_led_off(struct rt8515 *rt)67{68 gpiod_set_value(rt->enable_flash, 0);69 gpiod_set_value(rt->enable_torch, 0);70}71 72static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod,73 int brightness)74{75 int i;76 77 /*78 * Toggling a GPIO line with a small delay increases the79 * brightness one step at a time.80 */81 for (i = 0; i < brightness; i++) {82 gpiod_set_value(gpiod, 0);83 udelay(1);84 gpiod_set_value(gpiod, 1);85 udelay(1);86 }87}88 89/* This is setting the torch light level */90static int rt8515_led_brightness_set(struct led_classdev *led,91 enum led_brightness brightness)92{93 struct led_classdev_flash *fled = lcdev_to_flcdev(led);94 struct rt8515 *rt = to_rt8515(fled);95 96 mutex_lock(&rt->lock);97 98 if (brightness == LED_OFF) {99 /* Off */100 rt8515_gpio_led_off(rt);101 } else if (brightness < RT8515_TORCH_MAX) {102 /* Step it up to movie mode brightness using the flash pin */103 rt8515_gpio_brightness_commit(rt->enable_torch, brightness);104 } else {105 /* Max torch brightness requested */106 gpiod_set_value(rt->enable_torch, 1);107 }108 109 mutex_unlock(&rt->lock);110 111 return 0;112}113 114static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled,115 bool state)116{117 struct rt8515 *rt = to_rt8515(fled);118 struct led_flash_setting *timeout = &fled->timeout;119 int brightness = rt->flash_max_intensity;120 121 mutex_lock(&rt->lock);122 123 if (state) {124 /* Enable LED flash mode and set brightness */125 rt8515_gpio_brightness_commit(rt->enable_flash, brightness);126 /* Set timeout */127 mod_timer(&rt->powerdown_timer,128 jiffies + usecs_to_jiffies(timeout->val));129 } else {130 del_timer_sync(&rt->powerdown_timer);131 /* Turn the LED off */132 rt8515_gpio_led_off(rt);133 }134 135 fled->led_cdev.brightness = LED_OFF;136 /* After this the torch LED will be disabled */137 138 mutex_unlock(&rt->lock);139 140 return 0;141}142 143static int rt8515_led_flash_strobe_get(struct led_classdev_flash *fled,144 bool *state)145{146 struct rt8515 *rt = to_rt8515(fled);147 148 *state = timer_pending(&rt->powerdown_timer);149 150 return 0;151}152 153static int rt8515_led_flash_timeout_set(struct led_classdev_flash *fled,154 u32 timeout)155{156 /* The timeout is stored in the led-class-flash core */157 return 0;158}159 160static const struct led_flash_ops rt8515_flash_ops = {161 .strobe_set = rt8515_led_flash_strobe_set,162 .strobe_get = rt8515_led_flash_strobe_get,163 .timeout_set = rt8515_led_flash_timeout_set,164};165 166static void rt8515_powerdown_timer(struct timer_list *t)167{168 struct rt8515 *rt = from_timer(rt, t, powerdown_timer);169 170 /* Turn the LED off */171 rt8515_gpio_led_off(rt);172}173 174static void rt8515_init_flash_timeout(struct rt8515 *rt)175{176 struct led_classdev_flash *fled = &rt->fled;177 struct led_flash_setting *s;178 179 /* Init flash timeout setting */180 s = &fled->timeout;181 s->min = 1;182 s->max = rt->max_timeout;183 s->step = 1;184 /*185 * Set default timeout to RT8515_TIMEOUT_US except if186 * max_timeout from DT is lower.187 */188 s->val = min(rt->max_timeout, RT8515_TIMEOUT_US);189}190 191#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)192/* Configure the V2L2 flash subdevice */193static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,194 struct v4l2_flash_config *v4l2_sd_cfg)195{196 struct led_classdev *led = &rt->fled.led_cdev;197 struct led_flash_setting *s;198 199 strscpy(v4l2_sd_cfg->dev_name, led->dev->kobj.name,200 sizeof(v4l2_sd_cfg->dev_name));201 202 /*203 * Init flash intensity setting: this is a linear scale204 * capped from the device tree max intensity setting205 * 1..flash_max_intensity206 */207 s = &v4l2_sd_cfg->intensity;208 s->min = 1;209 s->max = rt->flash_max_intensity;210 s->step = 1;211 s->val = s->max;212}213 214static void rt8515_v4l2_flash_release(struct rt8515 *rt)215{216 v4l2_flash_release(rt->v4l2_flash);217}218 219#else220static void rt8515_init_v4l2_flash_config(struct rt8515 *rt,221 struct v4l2_flash_config *v4l2_sd_cfg)222{223}224 225static void rt8515_v4l2_flash_release(struct rt8515 *rt)226{227}228#endif229 230static void rt8515_determine_max_intensity(struct rt8515 *rt,231 struct fwnode_handle *led,232 const char *resistance,233 const char *max_ua_prop, int hw_max,234 int *max_intensity_setting)235{236 u32 res = 0; /* Can't be 0 so 0 is undefined */237 u32 ua;238 u32 max_ma;239 int max_intensity;240 int ret;241 242 fwnode_property_read_u32(rt->dev->fwnode, resistance, &res);243 ret = fwnode_property_read_u32(led, max_ua_prop, &ua);244 245 /* Missing info in DT, OK go with hardware maxima */246 if (ret || res == 0) {247 dev_err(rt->dev,248 "either %s or %s missing from DT, using HW max\n",249 resistance, max_ua_prop);250 max_ma = RT8515_MAX_IOUT_MA;251 max_intensity = hw_max;252 goto out_assign_max;253 }254 255 /*256 * Formula from the datasheet, this is the maximum current257 * defined by the hardware.258 */259 max_ma = (5500 * 1000) / res;260 /*261 * Calculate max intensity (linear scaling)262 * Formula is ((ua / 1000) / max_ma) * 100, then simplified263 */264 max_intensity = (ua / 10) / max_ma;265 266 dev_info(rt->dev,267 "current restricted from %u to %u mA, max intensity %d/100\n",268 max_ma, (ua / 1000), max_intensity);269 270out_assign_max:271 dev_info(rt->dev, "max intensity %d/%d = %d mA\n",272 max_intensity, hw_max, max_ma);273 *max_intensity_setting = max_intensity;274}275 276static int rt8515_probe(struct platform_device *pdev)277{278 struct device *dev = &pdev->dev;279 struct fwnode_handle *child;280 struct rt8515 *rt;281 struct led_classdev *led;282 struct led_classdev_flash *fled;283 struct led_init_data init_data = {};284 struct v4l2_flash_config v4l2_sd_cfg = {};285 int ret;286 287 rt = devm_kzalloc(dev, sizeof(*rt), GFP_KERNEL);288 if (!rt)289 return -ENOMEM;290 291 rt->dev = dev;292 fled = &rt->fled;293 led = &fled->led_cdev;294 295 /* ENF - Enable Flash line */296 rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW);297 if (IS_ERR(rt->enable_flash))298 return dev_err_probe(dev, PTR_ERR(rt->enable_flash),299 "cannot get ENF (enable flash) GPIO\n");300 301 /* ENT - Enable Torch line */302 rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW);303 if (IS_ERR(rt->enable_torch))304 return dev_err_probe(dev, PTR_ERR(rt->enable_torch),305 "cannot get ENT (enable torch) GPIO\n");306 307 child = fwnode_get_next_available_child_node(dev->fwnode, NULL);308 if (!child) {309 dev_err(dev,310 "No fwnode child node found for connected LED.\n");311 return -EINVAL;312 }313 init_data.fwnode = child;314 315 rt8515_determine_max_intensity(rt, child, "richtek,rfs-ohms",316 "flash-max-microamp",317 RT8515_FLASH_MAX,318 &rt->flash_max_intensity);319 rt8515_determine_max_intensity(rt, child, "richtek,rts-ohms",320 "led-max-microamp",321 RT8515_TORCH_MAX,322 &rt->torch_max_intensity);323 324 ret = fwnode_property_read_u32(child, "flash-max-timeout-us",325 &rt->max_timeout);326 if (ret) {327 rt->max_timeout = RT8515_MAX_TIMEOUT_US;328 dev_warn(dev,329 "flash-max-timeout-us property missing\n");330 }331 timer_setup(&rt->powerdown_timer, rt8515_powerdown_timer, 0);332 rt8515_init_flash_timeout(rt);333 334 fled->ops = &rt8515_flash_ops;335 336 led->max_brightness = rt->torch_max_intensity;337 led->brightness_set_blocking = rt8515_led_brightness_set;338 led->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;339 340 mutex_init(&rt->lock);341 342 platform_set_drvdata(pdev, rt);343 344 ret = devm_led_classdev_flash_register_ext(dev, fled, &init_data);345 if (ret) {346 fwnode_handle_put(child);347 mutex_destroy(&rt->lock);348 dev_err(dev, "can't register LED %s\n", led->name);349 return ret;350 }351 352 rt8515_init_v4l2_flash_config(rt, &v4l2_sd_cfg);353 354 /* Create a V4L2 Flash device if V4L2 flash is enabled */355 rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg);356 if (IS_ERR(rt->v4l2_flash)) {357 ret = PTR_ERR(rt->v4l2_flash);358 dev_err(dev, "failed to register V4L2 flash device (%d)\n",359 ret);360 /*361 * Continue without the V4L2 flash362 * (we still have the classdev)363 */364 }365 366 fwnode_handle_put(child);367 return 0;368}369 370static void rt8515_remove(struct platform_device *pdev)371{372 struct rt8515 *rt = platform_get_drvdata(pdev);373 374 rt8515_v4l2_flash_release(rt);375 del_timer_sync(&rt->powerdown_timer);376 mutex_destroy(&rt->lock);377}378 379static const struct of_device_id rt8515_match[] = {380 { .compatible = "richtek,rt8515", },381 { /* sentinel */ }382};383MODULE_DEVICE_TABLE(of, rt8515_match);384 385static struct platform_driver rt8515_driver = {386 .driver = {387 .name = "rt8515",388 .of_match_table = rt8515_match,389 },390 .probe = rt8515_probe,391 .remove_new = rt8515_remove,392};393module_platform_driver(rt8515_driver);394 395MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");396MODULE_DESCRIPTION("Richtek RT8515 LED driver");397MODULE_LICENSE("GPL");398