[PATCH 2/4] gpio: sysfs: correct error handling on 'value' attribute read.

[Christophe Leroy]

'value' attribute is supposed to only return 0 or 1 according to
the documentation.
With today's implementation, if gpiod_get_value_cansleep() fails
the printed 'value' is a negative value.

This patch ensures that an error is returned on read instead.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
 drivers/gpio/gpiolib-sysfs.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 7a3f4271393b..1b0f415df03b 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -106,8 +106,12 @@ static ssize_t value_show(struct device *dev,
 
 	mutex_lock(&data->mutex);
 
-	status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
+	status = gpiod_get_value_cansleep(desc);
+	if (status < 0)
+		goto err;
 
+	status = sprintf(buf, "%d\n", status);
+err:
 	mutex_unlock(&data->mutex);
 
 	return status;
-- 
2.13.3