i2c: mux: gpio: Check gpio_direction_output return value

gpio_direction_output() may fail, check for that and deal with it
appropriately. Also log an error message if gpio_request() fails.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/muxes/i2c-mux-gpio.c

@@ -201,10 +201,21 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 
 	for (i = 0; i < mux->data.n_gpios; i++) {
 		ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
-		if (ret)
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to request GPIO %d\n",
+				mux->data.gpios[i]);
 			goto err_request_gpio;
-		gpio_direction_output(gpio_base + mux->data.gpios[i],
+		}
+
+		ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
 					    initial_state & (1 << i));
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to set direction of GPIO %d to output\n",
+				mux->data.gpios[i]);
+			i++;	/* gpio_request above succeeded, so must free */
+			goto err_request_gpio;
+		}
 	}
 
 	for (i = 0; i < mux->data.n_values; i++) {