linux-kernel - [PATCH 2/2] ledtrig-gpio: 0 is a valid GPIO number

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Message-Id: <20190516214209.139726-3-kunyi@google.com>
Date:   Thu, 16 May 2019 14:42:09 -0700
From:   Kun Yi <kunyi@...gle.com>
To:     linux-leds@...r.kernel.org
Cc:     Kun Yi <kunyi@...gle.com>, jacek.anaszewski@...il.com,
        pavel@....cz, dmurphy@...com, u.kleine-koenig@...gutronix.de,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] ledtrig-gpio: 0 is a valid GPIO number

GPIO number 0 is a valid case to handle. Use -1 as initial value
and use gpio_is_valid() to determine validity of the GPIO
number.

Signed-off-by: Kun Yi <kunyi@...gle.com>
Change-Id: I4a29f98b237fd0d8ba4dd2a28219d4429f2ccfff
---
 drivers/leds/trigger/ledtrig-gpio.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c
index f6d50e031492..48d8ef8538bd 100644
--- a/drivers/leds/trigger/ledtrig-gpio.c
+++ b/drivers/leds/trigger/ledtrig-gpio.c
@@ -22,7 +22,7 @@ struct gpio_trig_data {
 
 	unsigned desired_brightness;	/* desired brightness when led is on */
 	unsigned inverted;		/* true when gpio is inverted */
-	unsigned gpio;			/* gpio that triggers the leds */
+	int gpio;			/* gpio that triggers the leds */
 };
 
 static irqreturn_t gpio_trig_irq(int irq, void *_led)
@@ -114,13 +114,12 @@ static ssize_t gpio_trig_gpio_show(struct device *dev,
 {
 	struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
 
-	return sprintf(buf, "%u\n", gpio_data->gpio);
+	return sprintf(buf, "%d\n", gpio_data->gpio);
 }
 
-static inline void free_used_gpio_if_valid(unsigned int gpio,
-					   struct led_classdev *led)
+static inline void free_used_gpio_if_valid(int gpio, struct led_classdev *led)
 {
-	if (gpio == 0)
+	if (!gpio_is_valid(gpio))
 		return;
 
 	free_irq(gpio_to_irq(gpio), led);
@@ -144,12 +143,6 @@ static ssize_t gpio_trig_gpio_store(struct device *dev,
 	if (gpio_data->gpio == gpio)
 		return n;
 
-	if (!gpio) {
-		free_used_gpio_if_valid(gpio_data->gpio, led);
-		gpio_data->gpio = 0;
-		return n;
-	}
-
 	ret = gpio_request(gpio, "ledtrig-gpio");
 	if (ret) {
 		dev_err(dev, "gpio_request failed with error %d\n", ret);
@@ -195,6 +188,7 @@ static int gpio_trig_activate(struct led_classdev *led)
 		return -ENOMEM;
 
 	gpio_data->led = led;
+	gpio_data->gpio = -1;
 	led_set_trigger_data(led, gpio_data);
 
 	return 0;
-- 
2.21.0.1020.gf2820cf01a-goog