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>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
index 27e4fc896e9d..f62617999f3c 100644
--- 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);