| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * LED driver for Richtek RT8515 flash/torch white LEDs |
| * found on some Samsung mobile phones. |
| * |
| * This is a 1.5A Boost dual channel driver produced around 2011. |
| * |
| * The component lacks a datasheet, but in the schematic picture |
| * from the LG P970 service manual you can see the connections |
| * from the RT8515 to the LED, with two resistors connected |
| * from the pins "RFS" and "RTS" to ground. |
| * |
| * On the LG P970: |
| * RFS (resistance flash setting?) is 20 kOhm |
| * RTS (resistance torch setting?) is 39 kOhm |
| * |
| * Some sleuthing finds us the RT9387A which we have a datasheet for: |
| * https://static5.arrow.com/pdfs/2014/7/27/8/21/12/794/rtt_/manual/94download_ds.jspprt9387a.jspprt9387a.pdf |
| * This apparently works the same way so in theory this driver |
| * should cover RT9387A as well. This has not been tested, please |
| * update the compatibles if you add RT9387A support. |
| * |
| * Linus Walleij <linus.walleij@linaro.org> |
| */ |
| #include <linux/delay.h> |
| #include <linux/err.h> |
| #include <linux/gpio/consumer.h> |
| #include <linux/led-class-flash.h> |
| #include <linux/mod_devicetable.h> |
| #include <linux/module.h> |
| #include <linux/platform_device.h> |
| #include <linux/property.h> |
| #include <linux/regulator/consumer.h> |
| |
| #include <media/v4l2-flash-led-class.h> |
| |
| /* We can provide 15-700 mA out to the LED */ |
| #define RT8515_MIN_IOUT_MA 15 |
| #define RT8515_MAX_IOUT_MA 700 |
| /* The maximum intensity is 1-16 for flash and 1-100 for torch */ |
| #define RT8515_FLASH_MAX 16 |
| #define RT8515_TORCH_MAX 100 |
| |
| #define RT8515_TIMEOUT_US 250000U |
| #define RT8515_MAX_TIMEOUT_US 300000U |
| |
| struct rt8515 { |
| struct led_classdev_flash fled; |
| struct device *dev; |
| struct v4l2_flash *v4l2_flash; |
| struct mutex lock; |
| struct regulator *reg; |
| struct gpio_desc *enable_torch; |
| struct gpio_desc *enable_flash; |
| struct timer_list powerdown_timer; |
| u32 max_timeout; /* Flash max timeout */ |
| int flash_max_intensity; |
| int torch_max_intensity; |
| }; |
| |
| static struct rt8515 *to_rt8515(struct led_classdev_flash *fled) |
| { |
| return container_of(fled, struct rt8515, fled); |
| } |
| |
| static void rt8515_gpio_led_off(struct rt8515 *rt) |
| { |
| gpiod_set_value(rt->enable_flash, 0); |
| gpiod_set_value(rt->enable_torch, 0); |
| } |
| |
| static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod, |
| int brightness) |
| { |
| int i; |
| |
| /* |
| * Toggling a GPIO line with a small delay increases the |
| * brightness one step at a time. |
| */ |
| for (i = 0; i < brightness; i++) { |
| gpiod_set_value(gpiod, 0); |
| udelay(1); |
| gpiod_set_value(gpiod, 1); |
| udelay(1); |
| } |
| } |
| |
| /* This is setting the torch light level */ |
| static int rt8515_led_brightness_set(struct led_classdev *led, |
| enum led_brightness brightness) |
| { |
| struct led_classdev_flash *fled = lcdev_to_flcdev(led); |
| struct rt8515 *rt = to_rt8515(fled); |
| |
| mutex_lock(&rt->lock); |
| |
| if (brightness == LED_OFF) { |
| /* Off */ |
| rt8515_gpio_led_off(rt); |
| } else if (brightness < RT8515_TORCH_MAX) { |
| /* Step it up to movie mode brightness using the flash pin */ |
| rt8515_gpio_brightness_commit(rt->enable_torch, brightness); |
| } else { |
| /* Max torch brightness requested */ |
| gpiod_set_value(rt->enable_torch, 1); |
| } |
| |
| mutex_unlock(&rt->lock); |
| |
| return 0; |
| } |
| |
| static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled, |
| bool state) |
| { |
| struct rt8515 *rt = to_rt8515(fled); |
| struct led_flash_setting *timeout = &fled->timeout; |
| int brightness = rt->flash_max_intensity; |
| |
| mutex_lock(&rt->lock); |
| |
| if (state) { |
| /* Enable LED flash mode and set brightness */ |
| rt8515_gpio_brightness_commit(rt->enable_flash, brightness); |
| /* Set timeout */ |
| mod_timer(&rt->powerdown_timer, |
| jiffies + usecs_to_jiffies(timeout->val)); |
| } else { |
| del_timer_sync(&rt->powerdown_timer); |
| /* Turn the LED off */ |
| rt8515_gpio_led_off(rt); |
| } |
| |
| fled->led_cdev.brightness = LED_OFF; |
| /* After this the torch LED will be disabled */ |
| |
| mutex_unlock(&rt->lock); |
| |
| return 0; |
| } |
| |
| static int rt8515_led_flash_strobe_get(struct led_classdev_flash *fled, |
| bool *state) |
| { |
| struct rt8515 *rt = to_rt8515(fled); |
| |
| *state = timer_pending(&rt->powerdown_timer); |
| |
| return 0; |
| } |
| |
| static int rt8515_led_flash_timeout_set(struct led_classdev_flash *fled, |
| u32 timeout) |
| { |
| /* The timeout is stored in the led-class-flash core */ |
| return 0; |
| } |
| |
| static const struct led_flash_ops rt8515_flash_ops = { |
| .strobe_set = rt8515_led_flash_strobe_set, |
| .strobe_get = rt8515_led_flash_strobe_get, |
| .timeout_set = rt8515_led_flash_timeout_set, |
| }; |
| |
| static void rt8515_powerdown_timer(struct timer_list *t) |
| { |
| struct rt8515 *rt = from_timer(rt, t, powerdown_timer); |
| |
| /* Turn the LED off */ |
| rt8515_gpio_led_off(rt); |
| } |
| |
| static void rt8515_init_flash_timeout(struct rt8515 *rt) |
| { |
| struct led_classdev_flash *fled = &rt->fled; |
| struct led_flash_setting *s; |
| |
| /* Init flash timeout setting */ |
| s = &fled->timeout; |
| s->min = 1; |
| s->max = rt->max_timeout; |
| s->step = 1; |
| /* |
| * Set default timeout to RT8515_TIMEOUT_US except if |
| * max_timeout from DT is lower. |
| */ |
| s->val = min(rt->max_timeout, RT8515_TIMEOUT_US); |
| } |
| |
| #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS) |
| /* Configure the V2L2 flash subdevice */ |
| static void rt8515_init_v4l2_flash_config(struct rt8515 *rt, |
| struct v4l2_flash_config *v4l2_sd_cfg) |
| { |
| struct led_classdev *led = &rt->fled.led_cdev; |
| struct led_flash_setting *s; |
| |
| strscpy(v4l2_sd_cfg->dev_name, led->dev->kobj.name, |
| sizeof(v4l2_sd_cfg->dev_name)); |
| |
| /* |
| * Init flash intensity setting: this is a linear scale |
| * capped from the device tree max intensity setting |
| * 1..flash_max_intensity |
| */ |
| s = &v4l2_sd_cfg->intensity; |
| s->min = 1; |
| s->max = rt->flash_max_intensity; |
| s->step = 1; |
| s->val = s->max; |
| } |
| |
| static void rt8515_v4l2_flash_release(struct rt8515 *rt) |
| { |
| v4l2_flash_release(rt->v4l2_flash); |
| } |
| |
| #else |
| static void rt8515_init_v4l2_flash_config(struct rt8515 *rt, |
| struct v4l2_flash_config *v4l2_sd_cfg) |
| { |
| } |
| |
| static void rt8515_v4l2_flash_release(struct rt8515 *rt) |
| { |
| } |
| #endif |
| |
| static void rt8515_determine_max_intensity(struct rt8515 *rt, |
| struct fwnode_handle *led, |
| const char *resistance, |
| const char *max_ua_prop, int hw_max, |
| int *max_intensity_setting) |
| { |
| u32 res = 0; /* Can't be 0 so 0 is undefined */ |
| u32 ua; |
| u32 max_ma; |
| int max_intensity; |
| int ret; |
| |
| fwnode_property_read_u32(rt->dev->fwnode, resistance, &res); |
| ret = fwnode_property_read_u32(led, max_ua_prop, &ua); |
| |
| /* Missing info in DT, OK go with hardware maxima */ |
| if (ret || res == 0) { |
| dev_err(rt->dev, |
| "either %s or %s missing from DT, using HW max\n", |
| resistance, max_ua_prop); |
| max_ma = RT8515_MAX_IOUT_MA; |
| max_intensity = hw_max; |
| goto out_assign_max; |
| } |
| |
| /* |
| * Formula from the datasheet, this is the maximum current |
| * defined by the hardware. |
| */ |
| max_ma = (5500 * 1000) / res; |
| /* |
| * Calculate max intensity (linear scaling) |
| * Formula is ((ua / 1000) / max_ma) * 100, then simplified |
| */ |
| max_intensity = (ua / 10) / max_ma; |
| |
| dev_info(rt->dev, |
| "current restricted from %u to %u mA, max intensity %d/100\n", |
| max_ma, (ua / 1000), max_intensity); |
| |
| out_assign_max: |
| dev_info(rt->dev, "max intensity %d/%d = %d mA\n", |
| max_intensity, hw_max, max_ma); |
| *max_intensity_setting = max_intensity; |
| } |
| |
| static int rt8515_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct fwnode_handle *child; |
| struct rt8515 *rt; |
| struct led_classdev *led; |
| struct led_classdev_flash *fled; |
| struct led_init_data init_data = {}; |
| struct v4l2_flash_config v4l2_sd_cfg = {}; |
| int ret; |
| |
| rt = devm_kzalloc(dev, sizeof(*rt), GFP_KERNEL); |
| if (!rt) |
| return -ENOMEM; |
| |
| rt->dev = dev; |
| fled = &rt->fled; |
| led = &fled->led_cdev; |
| |
| /* ENF - Enable Flash line */ |
| rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW); |
| if (IS_ERR(rt->enable_flash)) |
| return dev_err_probe(dev, PTR_ERR(rt->enable_flash), |
| "cannot get ENF (enable flash) GPIO\n"); |
| |
| /* ENT - Enable Torch line */ |
| rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW); |
| if (IS_ERR(rt->enable_torch)) |
| return dev_err_probe(dev, PTR_ERR(rt->enable_torch), |
| "cannot get ENT (enable torch) GPIO\n"); |
| |
| child = fwnode_get_next_available_child_node(dev->fwnode, NULL); |
| if (!child) { |
| dev_err(dev, |
| "No fwnode child node found for connected LED.\n"); |
| return -EINVAL; |
| } |
| init_data.fwnode = child; |
| |
| rt8515_determine_max_intensity(rt, child, "richtek,rfs-ohms", |
| "flash-max-microamp", |
| RT8515_FLASH_MAX, |
| &rt->flash_max_intensity); |
| rt8515_determine_max_intensity(rt, child, "richtek,rts-ohms", |
| "led-max-microamp", |
| RT8515_TORCH_MAX, |
| &rt->torch_max_intensity); |
| |
| ret = fwnode_property_read_u32(child, "flash-max-timeout-us", |
| &rt->max_timeout); |
| if (ret) { |
| rt->max_timeout = RT8515_MAX_TIMEOUT_US; |
| dev_warn(dev, |
| "flash-max-timeout-us property missing\n"); |
| } |
| timer_setup(&rt->powerdown_timer, rt8515_powerdown_timer, 0); |
| rt8515_init_flash_timeout(rt); |
| |
| fled->ops = &rt8515_flash_ops; |
| |
| led->max_brightness = rt->torch_max_intensity; |
| led->brightness_set_blocking = rt8515_led_brightness_set; |
| led->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH; |
| |
| mutex_init(&rt->lock); |
| |
| platform_set_drvdata(pdev, rt); |
| |
| ret = devm_led_classdev_flash_register_ext(dev, fled, &init_data); |
| if (ret) { |
| fwnode_handle_put(child); |
| mutex_destroy(&rt->lock); |
| dev_err(dev, "can't register LED %s\n", led->name); |
| return ret; |
| } |
| |
| rt8515_init_v4l2_flash_config(rt, &v4l2_sd_cfg); |
| |
| /* Create a V4L2 Flash device if V4L2 flash is enabled */ |
| rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg); |
| if (IS_ERR(rt->v4l2_flash)) { |
| ret = PTR_ERR(rt->v4l2_flash); |
| dev_err(dev, "failed to register V4L2 flash device (%d)\n", |
| ret); |
| /* |
| * Continue without the V4L2 flash |
| * (we still have the classdev) |
| */ |
| } |
| |
| fwnode_handle_put(child); |
| return 0; |
| } |
| |
| static int rt8515_remove(struct platform_device *pdev) |
| { |
| struct rt8515 *rt = platform_get_drvdata(pdev); |
| |
| rt8515_v4l2_flash_release(rt); |
| del_timer_sync(&rt->powerdown_timer); |
| mutex_destroy(&rt->lock); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id rt8515_match[] = { |
| { .compatible = "richtek,rt8515", }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(of, rt8515_match); |
| |
| static struct platform_driver rt8515_driver = { |
| .driver = { |
| .name = "rt8515", |
| .of_match_table = rt8515_match, |
| }, |
| .probe = rt8515_probe, |
| .remove = rt8515_remove, |
| }; |
| module_platform_driver(rt8515_driver); |
| |
| MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>"); |
| MODULE_DESCRIPTION("Richtek RT8515 LED driver"); |
| MODULE_LICENSE("GPL"); |