[U-Boot] gpio: Question about gpio_set_value() implementation in spear_gpio.c
Vipin Kumar
vipin.kumar at st.com
Thu Jun 20 05:52:04 CEST 2013
On 6/19/2013 7:14 PM, Axel Lin wrote:
> Current code looks strange because no matter the value argument is 0 or 1
> it always calls
> writel(1<< gpio,®s->gpiodata[DATA_REG_ADDR(gpio)]);
>
> And then gpio_get_value() always return 1.
>
> I'm wondering if it needs to be fixed, something like below change:
>
> diff --git a/drivers/gpio/spear_gpio.c b/drivers/gpio/spear_gpio.c
> index d3c728e..8878608 100644
> --- a/drivers/gpio/spear_gpio.c
> +++ b/drivers/gpio/spear_gpio.c
> @@ -52,7 +52,10 @@ int gpio_set_value(unsigned gpio, int value)
> {
> struct gpio_regs *regs = (struct gpio_regs *)CONFIG_GPIO_BASE;
>
> - writel(1<< gpio,®s->gpiodata[DATA_REG_ADDR(gpio)]);
> + if (value)
> + writel(1<< gpio,®s->gpiodata[DATA_REG_ADDR(gpio)]);
> + else
> + writel(0,®s->gpiodata[DATA_REG_ADDR(gpio)]);
>
Yes, this is the right way. It was a blunder. I am wondering no one ever
tried to set a ZERO on any GPIO..
Thanks for pointing out
Regards
Vipin
> return 0;
> }
>
>
>
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