HID: cp2112: fix setter callbacks return value

Since commit 6485543 ("HID: cp2112: use new line value setter
callbacks"), setting a GPIO value always fails with error -EBADE.

That's because the returned value by the setter callbacks is the
returned value by the hid_hw_raw_request() function which is the number of
bytes sent on success or a negative value on error. The function
gpiochip_set() returns -EBADE if the setter callbacks return a value >
0.

Fix this by making the setter callbacks return 0 on success or a negative
value on error.

While at it, use the returned value by cp2112_gpio_set_unlocked() in the
direction_output callback.

Fixes: 6485543 ("HID: cp2112: use new line value setter callbacks")
Signed-off-by: Sébastien Szymanski <[email protected]>
Reviewed-by: Bartosz Golaszewski <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Author: sebszymanski

drivers/hid/hid-cp2112.c

@@ -229,10 +229,12 @@ static int cp2112_gpio_set_unlocked(struct cp2112_device *dev,
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf,
 				 CP2112_GPIO_SET_LENGTH, HID_FEATURE_REPORT,
 				 HID_REQ_SET_REPORT);
-	if (ret < 0)
+	if (ret != CP2112_GPIO_SET_LENGTH) {
 		hid_err(hdev, "error setting GPIO values: %d\n", ret);
+		return ret < 0 ? ret : -EIO;
+	}
 
-	return ret;
+	return 0;
 }
 
 static int cp2112_gpio_set(struct gpio_chip *chip, unsigned int offset,
@@ -309,9 +311,7 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 	 * Set gpio value when output direction is already set,
 	 * as specified in AN495, Rev. 0.2, cpt. 4.4
 	 */
-	cp2112_gpio_set_unlocked(dev, offset, value);
-
-	return 0;
+	return cp2112_gpio_set_unlocked(dev, offset, value);
 }
 
 static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,