On Tue, Nov 02, 2021 at 11:19:42AM +0000, Daniel Thompson wrote:

On Tue, Nov 02, 2021 at 10:04:55AM +0000, Corentin LABBE wrote:

...

From: Jean-Jacques Hiblot jjhiblot@ti.com

This patch adds support for an "enable GPIO".

Before taking this kind of change is there a good reason why backlight should manage the GPIO? I thought that the LED subsystem was a sub system for LEDs (not LED controllers). In other words if you direct that the LED be lit up then isn't it the LED driver's job to manage the GPIO and ensure that it lights up?

Sorry... I should have paid more attention to my sense of déjà vu with this patch.

This approach was discussed and rejected when we first introduced the led_bl driver: https://lore.kernel.org/linux-leds/20190705100851.zn2jkipj4fxq5we6@devuan/

Daniel.

...

Signed-off-by: Jean-Jacques Hiblot jjhiblot@ti.com Signed-off-by: Corentin LABBE clabbe@baylibre.com

---

drivers/video/backlight/led_bl.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)

diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c index f54d256e2d54..ebd7acc32980 100644 --- a/drivers/video/backlight/led_bl.c +++ b/drivers/video/backlight/led_bl.c @@ -8,6 +8,7 @@

#include <linux/backlight.h> #include <linux/leds.h> +#include <linux/gpio.h> #include <linux/module.h> #include <linux/platform_device.h>

@@ -15,6 +16,7 @@ struct led_bl_data { struct device *dev; struct backlight_device *bl_dev; struct led_classdev **leds;

• struct gpio_desc *enable_gpio; bool enabled; int nb_leds; unsigned int *levels;

@@ -35,6 +37,9 @@ static void led_bl_set_brightness(struct led_bl_data *priv, int level) for (i = 0; i < priv->nb_leds; i++) led_set_brightness(priv->leds[i], bkl_brightness);

• if (!priv->enabled)

• gpiod_set_value_cansleep(priv->enable_gpio, 1);
  

• priv->enabled = true;

}

@@ -48,6 +53,9 @@ static void led_bl_power_off(struct led_bl_data *priv) for (i = 0; i < priv->nb_leds; i++) led_set_brightness(priv->leds[i], LED_OFF);

• if (priv->enabled)

• gpiod_set_value_cansleep(priv->enable_gpio, 0);
  

• priv->enabled = false;

}

@@ -209,6 +217,11 @@ static int led_bl_probe(struct platform_device *pdev) return PTR_ERR(priv->bl_dev); }

• priv->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",

• 				    GPIOD_OUT_LOW);
  

• if (IS_ERR(priv->enable_gpio))

• return PTR_ERR(priv->enable_gpio);
  

• for (i = 0; i < priv->nb_leds; i++) led_sysfs_disable(priv->leds[i]);

-- 2.25.1