[PATCH 2/3] leds: flash: rt8515: Support single-GPIO flash ICs with unlock gate

Rudraksha Gupta via B4 Relay
2026-03-07T00:58:03Z

From: Rudraksha Gupta <guptarud@gmail.com>

Extend the RT8515 driver to support flash ICs that use only a single
GPIO for both flash and torch modes (no separate ENT pin), with an
optional unlock GPIO that gates the flash circuit.

Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
---
drivers/leds/flash/leds-rt8515.c | 38 ++++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/flash/leds-rt8515.c b/drivers/leds/flash/leds-rt8515.c
index f6b439674c03..3164bf91e4c9 100644
--- a/drivers/leds/flash/leds-rt8515.c
+++ b/drivers/leds/flash/leds-rt8515.c
@@ -52,6 +52,7 @@ struct rt8515 {
struct regulator *reg;
struct gpio_desc *enable_torch;
struct gpio_desc *enable_flash;
+ struct gpio_desc *unlock_gpio;
struct timer_list powerdown_timer;
u32 max_timeout; /* Flash max timeout */
int flash_max_intensity;
@@ -66,7 +67,10 @@ static struct rt8515 *to_rt8515(struct led_classdev_flash *fled)
static void rt8515_gpio_led_off(struct rt8515 *rt)
{
gpiod_set_value(rt->enable_flash, 0);
- gpiod_set_value(rt->enable_torch, 0);
+ if (rt->enable_torch)
+ gpiod_set_value(rt->enable_torch, 0);
+ if (rt->unlock_gpio)
+ gpiod_set_value_cansleep(rt->unlock_gpio, 0);
}

static void rt8515_gpio_brightness_commit(struct gpio_desc *gpiod,
@@ -99,11 +103,19 @@ static int rt8515_led_brightness_set(struct led_classdev *led,
/* 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);
+ /* Unlock the flash circuit if needed */
+ if (rt->unlock_gpio)
+ gpiod_set_value_cansleep(rt->unlock_gpio, 1);
+ /* Step it up to movie mode brightness */
+ rt8515_gpio_brightness_commit(rt->enable_torch ?
+ rt->enable_torch : rt->enable_flash, brightness);
} else {
+ /* Unlock the flash circuit if needed */
+ if (rt->unlock_gpio)
+ gpiod_set_value_cansleep(rt->unlock_gpio, 1);
/* Max torch brightness requested */
- gpiod_set_value(rt->enable_torch, 1);
+ gpiod_set_value(rt->enable_torch ? rt->enable_torch :
+ rt->enable_flash, 1);
}

mutex_unlock(&rt->lock);
@@ -121,6 +133,9 @@ static int rt8515_led_flash_strobe_set(struct led_classdev_flash *fled,
mutex_lock(&rt->lock);

if (state) {
+ /* Unlock the flash circuit if needed */
+ if (rt->unlock_gpio)
+ gpiod_set_value_cansleep(rt->unlock_gpio, 1);
/* Enable LED flash mode and set brightness */
rt8515_gpio_brightness_commit(rt->enable_flash, brightness);
/* Set timeout */
@@ -298,12 +313,23 @@ static int rt8515_probe(struct platform_device *pdev)
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);
+ /* ENT - Enable Torch line (optional for single-GPIO flash ICs) */
+ rt->enable_torch = devm_gpiod_get_optional(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");

+ /* Optional unlock GPIO (e.g. PMIC MPP to gate flash circuit) */
+ rt->unlock_gpio = devm_gpiod_get_optional(dev, "unlock", GPIOD_OUT_LOW);
+ if (IS_ERR(rt->unlock_gpio))
+ return dev_err_probe(dev, PTR_ERR(rt->unlock_gpio),
+ "cannot get unlock GPIO\n");
+
+ /* Exactly one of ENT or unlock must be provided */
+ if (!rt->enable_torch == !rt->unlock_gpio)
+ return dev_err_probe(dev, -EINVAL,
+ "exactly one of ent-gpios or unlock-gpios is required\n");
+
child = device_get_next_child_node(dev, NULL);
if (!child) {
dev_err(dev,

--
2.53.0