linux-kernel - Re: [PATCH] pinctrl: sunxi: set pin function as input on export

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160208172031.GJ31506@lukather>
Date:	Mon, 8 Feb 2016 18:20:31 +0100
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Krzysztof Adamski <krzysztof.adamski@...to.com>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Chen-Yu Tsai <wens@...e.org>,
	Hans de Goede <hdegoede@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Lee Jones <lee.jones@...aro.org>,
	Jonas Gorski <jogo@...nwrt.org>, linux-gpio@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-sunxi@...glegroups.com
Subject: Re: [PATCH] pinctrl: sunxi: set pin function as input on export

Hi,

On Mon, Feb 08, 2016 at 03:37:22PM +0100, Krzysztof Adamski wrote:
> Default function of a pin in sunxi SoCs is "disabled". By default gpios
> exported by sysfs are set as input and indeed, when reading "direction"
> file you will get "in". The "value" pin won't return proper value,
> though, confusing user of this interface.
> 
> This patch sets direction of a GPIO as input when exporting it.
> 
> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@...to.com>
> ---
>  drivers/pinctrl/sunxi/pinctrl-sunxi.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> index 7a2465f..905a9fb 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> @@ -452,6 +452,16 @@ static int sunxi_pinctrl_gpio_direction_input(struct gpio_chip *chip,
>  	return pinctrl_gpio_direction_input(chip->base + offset);
>  }
>  
> +int sunxi_pinctrl_gpio_request(struct gpio_chip *chip, unsigned offset)
> +{
> +	int ret = pinctrl_gpio_direction_input(chip->base + offset);
> +
> +	if (ret)
> +		return ret;
> +
> +	return pinctrl_request_gpio(chip->base + offset);
> +}
> +
>  static int sunxi_pinctrl_gpio_get(struct gpio_chip *chip, unsigned offset)
>  {
>  	struct sunxi_pinctrl *pctl = gpiochip_get_data(chip);
> @@ -946,7 +956,7 @@ int sunxi_pinctrl_init(struct platform_device *pdev,
>  
>  	last_pin = pctl->desc->pins[pctl->desc->npins - 1].pin.number;
>  	pctl->chip->owner = THIS_MODULE;
> -	pctl->chip->request = gpiochip_generic_request,
> +	pctl->chip->request = sunxi_pinctrl_gpio_request,
>  	pctl->chip->free = gpiochip_generic_free,
>  	pctl->chip->direction_input = sunxi_pinctrl_gpio_direction_input,
>  	pctl->chip->direction_output = sunxi_pinctrl_gpio_direction_output,
> -- 
> 2.4.2
> 

It seems to me that it's something that should be enforced in the
core, there's nothing sunxi specific here.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Download attachment "signature.asc" of type "application/pgp-signature" (820 bytes)