linux-kernel - [PATCH] backlight: led_bl: Add support for an "enable" GPIO

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Date:   Tue,  2 Nov 2021 10:04:55 +0000
From:   Corentin LABBE <clabbe@...libre.com>
To:     lee.jones@...aro.org, daniel.thompson@...aro.org,
        jingoohan1@...il.com
Cc:     dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, khilman@...libre.com,
        Jean-Jacques Hiblot <jjhiblot@...com>,
        Corentin LABBE <clabbe@...libre.com>
Subject: [PATCH] backlight: led_bl: Add support for an "enable" GPIO

From: Jean-Jacques Hiblot <jjhiblot@...com>

This patch adds support for an "enable GPIO".

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@...com>
Signed-off-by: Corentin LABBE <clabbe@...libre.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