[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,&regs->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,&regs->gpiodata[DATA_REG_ADDR(gpio)]);
> +	if (value)
> +		writel(1<<  gpio,&regs->gpiodata[DATA_REG_ADDR(gpio)]);
> +	else
> +		writel(0,&regs->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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