From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Behme Subject: [PATCH] Documentation: gpio: consumer: describe the con_id parameter Date: Sat, 11 Jul 2015 07:46:02 +0200 Message-ID: <1436593562-5119-1-git-send-email-dirk.behme@gmail.com> Return-path: Received: from mail-wg0-f42.google.com ([74.125.82.42]:36072 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649AbbGKGQ5 (ORCPT ); Sat, 11 Jul 2015 02:16:57 -0400 Received: by wgxm20 with SMTP id m20so80015124wgx.3 for ; Fri, 10 Jul 2015 23:16:56 -0700 (PDT) Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: linux-gpio@vger.kernel.org Cc: Dirk Behme The con_id parameter has to match the GPIO description and is automatically extended by the GPIO suffix if not NULL. I had to look into the code to understand this and properly find the GPIO I've been looking for, so document this. Signed-off-by: Dirk Behme --- Documentation/gpio/consumer.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 75542b9..d0d1e47 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -39,6 +39,18 @@ device that displays digits), an additional index argument can be specified: const char *con_id, unsigned int idx, enum gpiod_flags flags) +The con_id string parameter has to be either NULL or the prefix of the GPIO +suffixes ("gpios" or "gpio"): + +* If the GPIO description is just named with one of the GPIO suffixes + ("gpios" or "gpio") use NULL. +* If the GPIO description is prefixed with anything, e.g. "reset-gpios", use the + prefix without the "-" as con_id parameter (in this example "reset"). + +In case con_id is not NULL, the gpiod subsystem prefixes the GPIO suffix +("gpios" or "gpio") with the string passed in con_id to get the resulting string +(snprintf(... "%s-%s", con_id, gpio_suffixes[]). + The flags parameter is used to optionally specify a direction and initial value for the GPIO. Values can be: -- 2.4.5