Re: [PATCH] pinctrl: establish pull-up/pull-down terminology

From: Tony Prisk <linux@prisktech.co.nz>
To: Linus Walleij <linus.walleij@stericsson.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"James Hogan" <james.hogan@imgtec.com>,
	"Stephen Warren" <swarren@nvidia.com>, � <heiko@sntech.de>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Anmar Oueja" <anmar.oueja@linaro.org>,
	"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH] pinctrl: establish pull-up/pull-down terminology
Date: Mon, 17 Jun 2013 16:38:50 +1200	[thread overview]
Message-ID: <51BE92DA.30408@prisktech.co.nz> (raw)
In-Reply-To: <1371379548-6482-1-git-send-email-linus.walleij@stericsson.com>

On 16/06/13 22:45, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
>
> It is counter-intuitive to have "0" mean disable in a boolean
> manner for electronic properties of pins such as pull-up and
> pull-down. Therefore, define that a pull-up/pull-down argument
> of 0 to such a generic option means that the pin is
> short-circuited to VDD or GROUND. Pull disablement shall be
> done using PIN_CONFIG_BIAS_DISABLE.
>
> Cc: Heiko St�bner <heiko@sntech.de>
> Cc: James Hogan <james.hogan@imgtec.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>   include/linux/pinctrl/pinconf-generic.h | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
> index d414a77..67780f5 100644
> --- a/include/linux/pinctrl/pinconf-generic.h
> +++ b/include/linux/pinctrl/pinconf-generic.h
> @@ -36,14 +36,15 @@
>    *	tristate. The argument is ignored.
>    * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high
>    *	impedance to VDD). If the argument is != 0 pull-up is enabled,
> - *	if it is 0, pull-up is disabled.
> + *	if it is 0, pull-up it total, i.e. the pin is connected to VDD.
s/it/is
>    * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with high
>    *	impedance to GROUND). If the argument is != 0 pull-down is enabled,
> - *	if it is 0, pull-down is disabled.
> + *	if it is 0, pull-down is total, i.e. the pin is connected to GROUND.
>    * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down based
>    *	on embedded knowledge of the controller, like current mux function.
> - *	If the argument is != 0 pull up/down is enabled, if it is 0,
> - *	the pull is disabled.
> + *	If the argument is != 0 pull up/down is enabled, if it is 0, the
> + *	configuration is ignored. The proper way to disable it is to use
> + *	@PIN_CONFIG_BIAS_DISABLE.
>    * @PIN_CONFIG_DRIVE_PUSH_PULL: the pin will be driven actively high and
>    *	low, this is the most typical case and is typically achieved with two
>    *	active transistors on the output. Setting this config will enable
> @@ -72,8 +73,8 @@
>    *	supplies, the argument to this parameter (on a custom format) tells
>    *	the driver which alternative power source to use.
>    * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
> - * 	this parameter (on a custom format) tells the driver which alternative
> - * 	slew rate to use.
> + *	this parameter (on a custom format) tells the driver which alternative
> + *	slew rate to use.
>    * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power
>    *	operation, if several modes of operation are supported these can be
>    *	passed in the argument on a custom form, else just use argument 1
>
>
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