[openwrt/openwrt] mediatek: add support for reset gpio

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/84e4bbf5f049cdb862eb25c446bd6973ed4238aa

commit 84e4bbf5f049cdb862eb25c446bd6973ed4238aa
Author: Sven Wegener <sven.wegener at stealer.net>
AuthorDate: Sat Jun 12 21:56:22 2021 +0200

    mediatek: add support for reset gpio
    
    Some versions of the ledbar MCU have a reset pin. It needs to be
    correctly initialized or we might keep the MCU in reset state.
    
    Signed-off-by: Sven Wegener <sven.wegener at stealer.net>
---
 .../mediatek/files/drivers/leds/leds-ubnt-ledbar.c | 26 ++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/target/linux/mediatek/files/drivers/leds/leds-ubnt-ledbar.c b/target/linux/mediatek/files/drivers/leds/leds-ubnt-ledbar.c
index c62e233e6d..1d687b7686 100644
--- a/target/linux/mediatek/files/drivers/leds/leds-ubnt-ledbar.c
+++ b/target/linux/mediatek/files/drivers/leds/leds-ubnt-ledbar.c
@@ -39,6 +39,7 @@ struct ubnt_ledbar {
 	struct led_classdev led_green;
 	struct led_classdev led_blue;
 	struct gpio_desc *enable_gpio;
+	struct gpio_desc *reset_gpio;
 };
 
 static void ubnt_ledbar_perform_transaction(struct ubnt_ledbar *ledbar,
@@ -96,6 +97,20 @@ out_gpio:
 	return ret;
 }
 
+static void ubnt_ledbar_reset(struct ubnt_ledbar *ledbar)
+{
+	if (!ledbar->reset_gpio)
+		return;
+
+	mutex_lock(&ledbar->lock);
+
+	gpiod_set_value(ledbar->reset_gpio, 1);
+	msleep(10);
+	gpiod_set_value(ledbar->reset_gpio, 0);
+
+	mutex_unlock(&ledbar->lock);
+}
+
 #define UBNT_LEDBAR_CONTROL_RGBS(name)				\
 static int ubnt_ledbar_set_##name##_brightness(struct led_classdev *led_cdev,\
 					enum led_brightness value)	\
@@ -154,12 +169,23 @@ static int ubnt_ledbar_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	ledbar->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
+
+	if (IS_ERR(ledbar->reset_gpio)) {
+		ret = PTR_ERR(ledbar->reset_gpio);
+		dev_err(&client->dev, "Failed to get reset gpio: %d\n", ret);
+		return ret;
+	}
+
 	ledbar->client = client;
 
 	mutex_init(&ledbar->lock);
 
 	i2c_set_clientdata(client, ledbar);
 
+	// Reset and initialize the MCU
+	ubnt_ledbar_reset(ledbar);
+
 	ledbar->led_red.brightness_set_blocking = ubnt_ledbar_set_red_brightness;
 	ubnt_ledbar_init_led(of_get_child_by_name(np, "red"), ledbar, &ledbar->led_red);