gpio: langwell: ensure alternate function is cleared
Alternate function must be zero for the pin to act as
a GPIO.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/gpio/gpio-langwell.c b/drivers/gpio/gpio-langwell.c
index d2eb57c..00692e8 100644
--- a/drivers/gpio/gpio-langwell.c
+++ b/drivers/gpio/gpio-langwell.c
@@ -59,6 +59,7 @@
GRER, /* rising edge detect */
GFER, /* falling edge detect */
GEDR, /* edge detect result */
+ GAFR, /* alt function */
};
struct lnw_gpio {
@@ -81,6 +82,31 @@
return ptr;
}
+static void __iomem *gpio_reg_2bit(struct gpio_chip *chip, unsigned offset,
+ enum GPIO_REG reg_type)
+{
+ struct lnw_gpio *lnw = container_of(chip, struct lnw_gpio, chip);
+ unsigned nreg = chip->ngpio / 32;
+ u8 reg = offset / 16;
+ void __iomem *ptr;
+
+ ptr = (void __iomem *)(lnw->reg_base + reg_type * nreg * 4 + reg * 4);
+ return ptr;
+}
+
+static int lnw_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+ void __iomem *gafr = gpio_reg_2bit(chip, offset, GAFR);
+ u32 value = readl(gafr);
+ int shift = (offset % 16) << 1, af = (value >> shift) & 3;
+
+ if (af) {
+ value &= ~(3 << shift);
+ writel(value, gafr);
+ }
+ return 0;
+}
+
static int lnw_gpio_get(struct gpio_chip *chip, unsigned offset)
{
void __iomem *gplr = gpio_reg(chip, offset, GPLR);
@@ -321,6 +347,7 @@
lnw->reg_base = base;
lnw->irq_base = irq_base;
lnw->chip.label = dev_name(&pdev->dev);
+ lnw->chip.request = lnw_gpio_request;
lnw->chip.direction_input = lnw_gpio_direction_input;
lnw->chip.direction_output = lnw_gpio_direction_output;
lnw->chip.get = lnw_gpio_get;