[U-Boot] gpio: Question about gpio_set_value() implementation in spear_gpio.c

Otavio Salvador otavio at ossystems.com.br
Wed Jun 19 15:48:40 CEST 2013


On Wed, Jun 19, 2013 at 10:44 AM, Axel Lin <axel.lin at ingics.com> 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)]);
>
>         return 0;
>  }

writel(value << gpio, &regs->gpiodata[DATA_REG_ADDR(gpio)]);

Should do no? This would avoid the if block.

--
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://projetos.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750


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