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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>
This commit is contained in:
Adrian Hunter 2011-10-03 14:36:07 +03:00 committed by Grant Likely
parent 38eb18a6f9
commit 8c0f7b10f1
1 changed files with 27 additions and 0 deletions
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27
drivers/gpio/gpio-langwell.c
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@ -59,6 +59,7 @@ enum GPIO_REG {
GRER, /* rising edge detect */
GFER, /* falling edge detect */
GEDR, /* edge detect result */
GAFR, /* alt function */
};
struct lnw_gpio {
@ -81,6 +82,31 @@ static void __iomem *gpio_reg(struct gpio_chip *chip, unsigned offset,
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 @@ static int __devinit lnw_gpio_probe(struct pci_dev *pdev,
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;