Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752476Ab2FLLN1 (ORCPT ); Tue, 12 Jun 2012 07:13:27 -0400 Received: from mail-qa0-f49.google.com ([209.85.216.49]:46166 "EHLO mail-qa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354Ab2FLLN0 (ORCPT ); Tue, 12 Jun 2012 07:13:26 -0400 MIME-Version: 1.0 In-Reply-To: References: <4FBCF9F0.1010901@wwwdotorg.org> <4FBD01A6.4080807@wwwdotorg.org> Date: Tue, 12 Jun 2012 13:13:25 +0200 Message-ID: Subject: Re: [PATCH] pinctrl: add a pinctrl_mux_group_selected() function From: Linus Walleij To: Guennadi Liakhovetski Cc: Stephen Warren , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1726 Lines: 41 On Thu, Jun 7, 2012 at 5:14 PM, Guennadi Liakhovetski wrote: > On Thu, 7 Jun 2012, Linus Walleij wrote: >> Isn't the card detection and write protect GPIO lines that >> will be requested with gpio_request()? This is usually the case, >> so I need to ask. GPIOs are usually muxed in on a per-pin basis >> as a result of the gpio_request() call. > > They can be, but they don't have to be. On some SDHI implementations CD is > a dedicated pin, belonging to the controller, but in those cases it is > usually preferable to configure it as a GPIO. On some boards it is just a > GPIO, on others yet it is just missing. Similarly, WP can be a GPIO or > absent. Sorry just to be clear on what we mean here: "Configuring it as GPIO" in Linux means that you use the GPIO subsystem and gpiolib to access it. If you mean that you set some electrical properties that are named as "the GPIO configuration" in the datasheet that is something else. So that you mux it in as "gpio" (a name of the function from the datasheet) does not make it into a GPIO in the Linux sense if it's not handled by gpiolib. In the case where such a pin is used by e.g. the MMC driver while put into what the datasheet calls "gpio mode" this is still just one pin in the MMC pinctrl function from the Linux point of view. But I guess this was what you meant all the time, I'm probably just confused by names being the same for similar but unrelated things ... :-) Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/