usb: dwc3: pci: make better use of gpiod API

Since 39b2bbe3d715 (gpio: add flags argument to gpiod_get*() functions)
which appeared in v3.17-rc1, the gpiod_get* functions take an additional
parameter that allows to specify direction and initial value for output.

Use this additional parameter and the _optional variant to simplify the
driver and improve error handling. Also expand the comment to explain
why it's not sensible to switch to devm_gpiod_get and why the gpiod_put
is also necessary.

Furthermore this is one caller less that stops us making the flags
argument to gpiod_get*() mandatory.

Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
index 27e4fc896e9d93572c44acef20e25c6cea3a7d10..f62617999f3c7fb093ff09d18088560a6ecb003e 100644 (file)
--- a/drivers/usb/dwc3/dwc3-pci.c
+++ b/drivers/usb/dwc3/dwc3-pci.c
@@ -83,17 +83,23 @@ static int dwc3_pci_quirks(struct pci_dev *pdev)
                acpi_dev_add_driver_gpios(ACPI_COMPANION(&pdev->dev),
                                          acpi_dwc3_byt_gpios);
 
-               /* These GPIOs will turn on the USB2 PHY */
-               gpio = gpiod_get(&pdev->dev, "cs");
-               if (!IS_ERR(gpio)) {
-                       gpiod_direction_output(gpio, 0);
-                       gpiod_set_value_cansleep(gpio, 1);
-                       gpiod_put(gpio);
-               }
+               /*
+                * These GPIOs will turn on the USB2 PHY. Note that we have to
+                * put the gpio descriptors again here because the phy driver
+                * might want to grab them, too.
+                */
+               gpio = gpiod_get_optional(&pdev->dev, "cs", GPIOD_OUT_LOW);
+               if (IS_ERR(gpio))
+                       return PTR_ERR(gpio);
+
+               gpiod_set_value_cansleep(gpio, 1);
+               gpiod_put(gpio);
+
+               gpio = gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
+               if (IS_ERR(gpio))
+                       return PTR_ERR(gpio);
 
-               gpio = gpiod_get(&pdev->dev, "reset");
-               if (!IS_ERR(gpio)) {
-                       gpiod_direction_output(gpio, 0);
+               if (gpio) {
                        gpiod_set_value_cansleep(gpio, 1);
                        gpiod_put(gpio);
                        usleep_range(10000, 11000);