This adds a driver for the Richtek RT8515 dual channel torch/flash white LED driver. This LED driver is found in some mobile phones from Samsung such as the GT-S7710 and GT-I8190. A V4L interface is added. We do not have a proper datasheet for the RT8515 but it turns out that RT9387A has a public datasheet and is essentially the same chip. We designed the driver in accordance with this datasheet. The day someone needs to drive a RT9387A this driver can probably easily be augmented to handle that chip too. Cc: Sakari Ailus <sakari.ailus@xxxxxx> Cc: newbytee@xxxxxxxxxxxxxx Cc: Stephan Gerhold <stephan@xxxxxxxxxxx> Cc: linux-media@xxxxxxxxxxxxxxx Cc: phone-devel@xxxxxxxxxxxxxxx Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- ChangeLog v7->v8: - Add comments in the top of the driver and a link to the RT9387A datasheet. ChangeLog v6->v7: - Account for the binding change to use led-max-current rather than torch-specific current. - Collect Sakari's review tag. ChangeLog v5->v6: - Use the configured max flash brightness instead of hardcoded "4". - Implement the new "-ohms" suffixes on the resistors. ChangeLog v4->v5: - Fix a missing static keyword, complaint from the kernel autobuilder robot. ChangeLog v3->v4: - Create a new subdirectory for flash LEDs under drivers/leds/flash as requested by Pavel, move the driver there and set up a kbuild structure for pure flash LEDs. (Others can follow the established pattern.) - Handle the new richtek,rfs and richtek,rts resistor values that make it possible to determine the current range configured in the hardware. - Handle the new flash-max-microamp and torch-max-microamp if present and optionally further restrict the current range using these. Otherwise fall back on the hardware defaults as specified by the RFS and RTS resistors. - Cc phone-devel@xxxxxxxxxxxxxxx - License as GPL-2.0-or-later - Renable ent and enf gpio descriptors to enable_torch and enable_flash Changelog v2->v3: - Expand commit message. - Add Sakari to Cc. - Resend. ChangeLog v1->v2: - Break out routine to bitbang the brightness on a GPIO pin. - Do not hardcode the LED name so that the framework can name it from DT properties. --- drivers/leds/Kconfig | 3 + drivers/leds/Makefile | 3 + drivers/leds/flash/Kconfig | 15 ++ drivers/leds/flash/Makefile | 3 + drivers/leds/flash/leds-rt8515.c | 393 +++++++++++++++++++++++++++++++ 5 files changed, 417 insertions(+) create mode 100644 drivers/leds/flash/Kconfig create mode 100644 drivers/leds/flash/Makefile create mode 100644 drivers/leds/flash/leds-rt8515.c diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index 849d3c5f908e..6c1d8b69a465 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -928,6 +928,9 @@ config LEDS_ACER_A500 This option enables support for the Power Button LED of Acer Iconia Tab A500. +comment "Flash and Torch LED drivers" +source "drivers/leds/flash/Kconfig" + comment "LED Triggers" source "drivers/leds/trigger/Kconfig" diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index 73e603e1727e..156c0b4e60d9 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -103,5 +103,8 @@ obj-$(CONFIG_LEDS_SPI_BYTE) += leds-spi-byte.o # LED Userspace Drivers obj-$(CONFIG_LEDS_USER) += uleds.o +# Flash and Torch LED Drivers +obj-$(CONFIG_LEDS_CLASS_FLASH) += flash/ + # LED Triggers obj-$(CONFIG_LEDS_TRIGGERS) += trigger/ diff --git a/drivers/leds/flash/Kconfig b/drivers/leds/flash/Kconfig new file mode 100644 index 000000000000..d21d273ef3da --- /dev/null +++ b/drivers/leds/flash/Kconfig @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0 + +if LEDS_CLASS_FLASH + +config LEDS_RT8515 + tristate "LED support for Richtek RT8515 flash/torch LED" + depends on GPIOLIB + help + This option enables support for the Richtek RT8515 flash + and torch LEDs found on some mobile phones. + + To compile this driver as a module, choose M here: the module + will be called leds-rt8515. + +endif # LEDS_CLASS_FLASH diff --git a/drivers/leds/flash/Makefile b/drivers/leds/flash/Makefile new file mode 100644 index 000000000000..e990e257f4d7 --- /dev/null +++ b/drivers/leds/flash/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_LEDS_RT8515) += leds-rt8515.o diff --git a/drivers/leds/flash/leds-rt8515.c b/drivers/leds/flash/leds-rt8515.c new file mode 100644 index 000000000000..571aec521619 --- /dev/null +++ b/drivers/leds/flash/leds-rt8515.c @@ -0,0 +1,393 @@ +// 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@xxxxxxxxxx> + */ +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/led-class-flash.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.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_DEFAULT 250000U /* 250ms */ +#define RT8515_MAX_TIMEOUT_DEFAULT 300000U /* 300ms */ + +struct rt8515 { + struct device *dev; + struct led_classdev_flash fled; + 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_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 */ + gpiod_set_value(rt->enable_flash, 0); + gpiod_set_value(rt->enable_torch, 0); + } 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 */ + gpiod_set_value(rt->enable_flash, 0); + gpiod_set_value(rt->enable_torch, 0); + } + + 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 */ + gpiod_set_value(rt->enable_flash, 0); + gpiod_set_value(rt->enable_torch, 0); +} + +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_DEFAULT_TIMEOUT except if + * max_timeout from DT is lower. + */ + s->val = min(rt->max_timeout, RT8515_TIMEOUT_DEFAULT); +} + +#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; +} + +#else +static void rt8515_init_v4l2_flash_config(struct rt8515 *rt, + struct v4l2_flash_config *v4l2_sd_cfg) +{ +} +#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; + u32 ua; + u32 max_ma; + int max_intensity; + int ret1, ret2; + + + ret1 = fwnode_property_read_u32(rt->dev->fwnode, resistance, &res); + ret2 = fwnode_property_read_u32(led, max_ua_prop, &ua); + + /* No info in DT, OK go with hardware maxima */ + if (ret1 && ret2) { + max_ma = RT8515_MAX_IOUT_MA; + max_intensity = hw_max; + goto out_assign_max; + } + + if (ret1 || ret2) { + 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 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)) { + dev_err(dev, "cannot get ENF (enable flash) GPIO\n"); + return PTR_ERR(rt->enable_flash); + } + + /* ENT - Enable Torch line */ + rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW); + if (IS_ERR(rt->enable_torch)) { + dev_err(dev, "cannot get ENT (enable torch) GPIO\n"); + return PTR_ERR(rt->enable_torch); + } + + 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_DEFAULT; + 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) { + dev_err(dev, "can't register LED %s\n", led->name); + mutex_destroy(&rt->lock); + 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) + */ + } + + return 0; +} + +static int rt8515_remove(struct platform_device *pdev) +{ + struct rt8515 *rt = platform_get_drvdata(pdev); + + v4l2_flash_release(rt->v4l2_flash); + 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@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Richtek RT8515 LED driver"); +MODULE_LICENSE("GPL v2"); -- 2.26.2
