linux-kernel - [PATCH v1 1/1] leds: trigger: gpio: Convert to use kstrtox()

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Date:   Thu,  9 Jun 2022 19:18:29 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Pavel Machek <pavel@....cz>
Subject: [PATCH v1 1/1] leds: trigger: gpio: Convert to use kstrtox()

sscanf() is a heavy one and moreover requires additional boundary checks.
Convert driver to use kstrtox() and replace kstrtoul() by kstrtobool()
in gpio_trig_inverted_store().

While here, check the desired brightness against maximum defined for
a certain LED.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/leds/trigger/ledtrig-gpio.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c
index 0120faa3dafa..19e43333457a 100644
--- a/drivers/leds/trigger/ledtrig-gpio.c
+++ b/drivers/leds/trigger/ledtrig-gpio.c
@@ -60,10 +60,10 @@ static ssize_t gpio_trig_brightness_store(struct device *dev,
 	unsigned desired_brightness;
 	int ret;
 
-	ret = sscanf(buf, "%u", &desired_brightness);
-	if (ret < 1 || desired_brightness > 255) {
+	ret = kstrtouint(buf, 10, &desired_brightness);
+	if (ret || desired_brightness > gpio_data->led->max_brightness) {
 		dev_err(dev, "invalid value\n");
-		return -EINVAL;
+		return ret ?: -EINVAL;
 	}
 
 	gpio_data->desired_brightness = desired_brightness;
@@ -86,16 +86,13 @@ static ssize_t gpio_trig_inverted_store(struct device *dev,
 {
 	struct led_classdev *led = led_trigger_get_led(dev);
 	struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
-	unsigned long inverted;
+	bool inverted;
 	int ret;
 
-	ret = kstrtoul(buf, 10, &inverted);
-	if (ret < 0)
+	ret = kstrtobool(buf, &inverted);
+	if (ret)
 		return ret;
 
-	if (inverted > 1)
-		return -EINVAL;
-
 	gpio_data->inverted = inverted;
 
 	/* After inverting, we need to update the LED. */
@@ -123,10 +120,10 @@ static ssize_t gpio_trig_gpio_store(struct device *dev,
 	unsigned gpio;
 	int ret;
 
-	ret = sscanf(buf, "%u", &gpio);
-	if (ret < 1) {
+	ret = kstrtouint(buf, 10, &gpio);
+	if (ret) {
 		dev_err(dev, "couldn't read gpio number\n");
-		return -EINVAL;
+		return ret;
 	}
 
 	if (gpio_data->gpio == gpio)
-- 
2.35.1