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From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] gpio: Question about gpio_set_value() implementation in spear_gpio.c
Date: Wed, 19 Jun 2013 15:49:01 +0200	[thread overview]
Message-ID: <201306191549.01906.marex@denx.de> (raw)
In-Reply-To: <1371649453.2126.2.camel@phoenix>

Dear Axel Lin,

> 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)]);


You might want to use clrbits_le32() and setbits_le32() here, no?

>  	return 0;
>  }

Best regards,
Marek Vasut

  parent reply	other threads:[~2013-06-19 13:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-19 13:44 [U-Boot] gpio: Question about gpio_set_value() implementation in spear_gpio.c Axel Lin
2013-06-19 13:48 ` Otavio Salvador
2013-06-19 23:51   ` Marek Vasut
2013-06-19 13:49 ` Marek Vasut [this message]
2013-06-19 14:01   ` Axel Lin
2013-06-19 14:40     ` Stefan Roese
2013-06-20  3:52 ` Vipin Kumar

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