Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753471Ab1DQVrg (ORCPT ); Sun, 17 Apr 2011 17:47:36 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:51191 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751601Ab1DQVra (ORCPT ); Sun, 17 Apr 2011 17:47:30 -0400 Date: Sun, 17 Apr 2011 22:48:16 +0100 From: Alan Cox To: Linus Walleij Cc: Grant Likely , , , Lee Jones , Linus Walleij Subject: Re: [PATCH 1/2] gpio: add pin biasing and drive mode to gpiolib Message-ID: <20110417224816.38ddffee@lxorguk.ukuu.org.uk> In-Reply-To: <1303076273-8093-1-git-send-email-linus.walleij@stericsson.com> References: <1303076273-8093-1-git-send-email-linus.walleij@stericsson.com> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.0; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1267 Lines: 25 > + * enum gpio_drive - drive modes for GPIOs (output) > + * @GPIO_DRIVE_PUSH_PULL: the GPIO will be driven actively high and low, this > + * is the most typical case and is typically achieved with two active > + * transistors on the output > + * @GPIO_DRIVE_OPEN_DRAIN: the GPIO will be driven with open drain (open > + * collector) which means it is usually wired with other output ports > + * which are then pulled up with an external resistor > + * @GPIO_DRIVE_OPEN_SOURCE: the GPIO will be driven with open drain > + * (open emitter) which is the same as open drain mutatis mutandis but > + * pulled to ground How about "off". As I've pointed out at various times some devices have GPIO pins that may or may not be connected depending upon what other chip logic is doing. As I've also noted with various other previous suggestions for API additions you also need an "unknown" state so that a device can implement the methods but indicate for some pins the value is unknown due to hardware or firmware limitations. -- 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/