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

Hi Rudraksha,

thanks for your patch!

Overall this looks fine but:

On Sat, Mar 7, 2026 at 1:58 AM Rudraksha Gupta via B4 Relay
<devnull+guptarud.gmail.com@kernel.org> wrote:

>         struct regulator *reg;

struct rt8515 actually has an unused regulator struct
that was never implemented, but should represent the
vin signal.

>         struct gpio_desc *enable_torch;
>         struct gpio_desc *enable_flash;
> +       struct gpio_desc *unlock_gpio;

Skip this unless you can explain how it works, use the
*reg from vin instead. I think this is just a GPIO-controlled
regulator.

> +       if (rt->unlock_gpio)
> +               gpiod_set_value_cansleep(rt->unlock_gpio, 0);

Add code to disable the vin regulator instead.

> +               /* Unlock the flash circuit if needed */
> +               if (rt->unlock_gpio)
> +                       gpiod_set_value_cansleep(rt->unlock_gpio, 1);

Add code to enable and stablize the vin regulator instead.

>         if (state) {
> +               /* Unlock the flash circuit if needed */
> +               if (rt->unlock_gpio)
> +                       gpiod_set_value_cansleep(rt->unlock_gpio, 1);

Add code to enable and stablize the vin regulator instead.

Yours,
Linus Walleij