linux-kernel - [PATCH 4.4 42/91] leds: call led_pwm_set() in leds-pwm to enforce default LED

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Message-Id: <20181211151609.360457680@linuxfoundation.org>
Date:   Tue, 11 Dec 2018 16:41:01 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Markus Hofstaetter <markus.hofstaetter@....ac.at>,
        Jacek Anaszewski <j.anaszewski@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Subject: [PATCH 4.4 42/91] leds: call led_pwm_set() in leds-pwm to enforce default LED_OFF

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Markus Hofstaetter <markus.hofstaetter@....ac.at>

commit f16703360da7731a057df2ffa902306819c22398 upstream.

Some PWMs are disabled by default or the default pin setting
does not match the LED_OFF state (e.g., active-low leds).
Hence, the driver may end up reporting 0 brightness, but
the leds are actually on using full brightness, because
it never enforces its default configuration.
So enforce it by calling led_pwm_set() after successfully
registering the device.

Tested on a Phytec phyFLEX i.MX6Q board based on kernel
v3.19.5.

Signed-off-by: Markus Hofstaetter <markus.hofstaetter@....ac.at>
Tested-by: Markus Hofstaetter <markus.hofstaetter@....ac.at>
Signed-off-by: Jacek Anaszewski <j.anaszewski@...sung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/leds/leds-pwm.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -132,6 +132,7 @@ static int led_pwm_add(struct device *de
 	ret = led_classdev_register(dev, &led_data->cdev);
 	if (ret == 0) {
 		priv->num_leds++;
+		led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
 	} else {
 		dev_err(dev, "failed to register PWM led for %s: %d\n",
 			led->name, ret);