hwmon: (gpio-fan) Prevent overflow problem when writing large limits

commit 2565fb05d1e9fc0831f7b1c083bcfcb1cba1f020 upstream.

On platforms with sizeof(int) < sizeof(unsigned long), writing a rpm value
larger than MAXINT will result in unpredictable limit values written to the
chip. Avoid auto-conversion from unsigned long to int to fix the problem.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index 9ba38f318ffb458247dd66b58b77c3c03e203727..05c4f473f46878a978a28c8570c10f79faf13ee4 100644 (file)
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -195,7 +195,7 @@ static int get_fan_speed_index(struct gpio_fan_data *fan_data)
        return -EINVAL;
 }
 
-static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
+static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
 {
        struct gpio_fan_speed *speed = fan_data->speed;
        int i;