linux-kernel - Re: [PATCH v2] pinctrl: baytrail: show output gpio state correctly on Intel Baytrail

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Message-ID: <20141014181901.GD18747@saruman>
Date:	Tue, 14 Oct 2014 13:19:01 -0500
From:	Felipe Balbi <balbi@...com>
To:	David Cohen <david.a.cohen@...ux.intel.com>
CC:	<linus.walleij@...aro.org>, <linux-gpio@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <balbi@...com>,
	<stable@...r.kernel.org>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: Re: [PATCH v2] pinctrl: baytrail: show output gpio state correctly
 on Intel Baytrail

On Tue, Oct 14, 2014 at 10:54:37AM -0700, David Cohen wrote:
> Even if a gpio pin is set to output, we still need to set INPUT_EN
> functionality (by clearing INPUT_EN bit) to be able to read the pin's
> level.
> 
> E.g. without this change, we'll always read low level state from sysfs.
> 
> Cc: <stable@...r.kernel.org> # v3.14+
> Cc: Mathias Nyman <mathias.nyman@...ux.intel.com>
> Signed-off-by: David Cohen <david.a.cohen@...ux.intel.com>

Reviewed-by: Felipe Balbi <balbi@...com>

> ---
> 
> v1 to v2: improved patch's body description as requested by Felipe Balbi
> ---
> 
>  drivers/pinctrl/pinctrl-baytrail.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c
> index e12e5b07f6d7..c23d8ded936d 100644
> --- a/drivers/pinctrl/pinctrl-baytrail.c
> +++ b/drivers/pinctrl/pinctrl-baytrail.c
> @@ -318,7 +318,7 @@ static int byt_gpio_direction_output(struct gpio_chip *chip,
>  		"Potential Error: Setting GPIO with direct_irq_en to output");
>  
>  	reg_val = readl(reg) | BYT_DIR_MASK;
> -	reg_val &= ~BYT_OUTPUT_EN;
> +	reg_val &= ~(BYT_OUTPUT_EN | BYT_INPUT_EN);
>  
>  	if (value)
>  		writel(reg_val | BYT_LEVEL, reg);
> -- 
> 2.1.0
> 

-- 
balbi

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