USB: s3c2410 gadget: ensure vbus pin in input mode during read

Some CPUs in the S3C24XX series do not support readback of the
value of a pin when the pin has been configured to an IRQ.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/usb/gadget/s3c2410_udc.c b/drivers/usb/gadget/s3c2410_udc.c
index 5acaddabbe8f..4ce050c3d13f 100644
--- a/drivers/usb/gadget/s3c2410_udc.c
+++ b/drivers/usb/gadget/s3c2410_udc.c
@@ -1511,7 +1511,11 @@ static irqreturn_t s3c2410_udc_vbus_irq(int irq, void *_dev)
         unsigned int            value;
 
         dprintk(DEBUG_NORMAL, "%s()\n", __func__);
+
+        /* some cpus cannot read from an line configured to IRQ! */
+        s3c2410_gpio_cfgpin(udc_info->vbus_pin, S3C2410_GPIO_INPUT);
         value = s3c2410_gpio_getpin(udc_info->vbus_pin);
+        s3c2410_gpio_cfgpin(udc_info->vbus_pin, S3C2410_GPIO_SFN2);
 
         if (udc_info->vbus_pin_inverted)
                 value = !value;