From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Behme Subject: [PATCH 2/2 v2] Documentation: gpio: board: describe the con_id parameter Date: Sun, 30 Aug 2015 11:15:55 +0200 Message-ID: <1440926155-7183-2-git-send-email-dirk.behme@gmail.com> References: <1440926155-7183-1-git-send-email-dirk.behme@gmail.com> Return-path: Received: from mail-wi0-f172.google.com ([209.85.212.172]:38799 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088AbbH3JQB (ORCPT ); Sun, 30 Aug 2015 05:16:01 -0400 Received: by wicpl12 with SMTP id pl12so3181154wic.1 for ; Sun, 30 Aug 2015 02:16:00 -0700 (PDT) In-Reply-To: <1440926155-7183-1-git-send-email-dirk.behme@gmail.com> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Alexandre Courbot Cc: linux-gpio@vger.kernel.org, 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 --- Changes in v2: Using the "gpios" property without prefix is considered deprecated, therefore don't describe it. Documentation/gpio/board.txt | 9 +++++++++ Documentation/gpio/consumer.txt | 3 +++ 2 files changed, 12 insertions(+) diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt index 7605773..0bfc455 100644 --- a/Documentation/gpio/board.txt +++ b/Documentation/gpio/board.txt @@ -48,6 +48,15 @@ This property will make GPIOs 15, 16 and 17 available to the driver under the The led GPIOs will be active-high, while the power GPIO will be active-low (i.e. gpiod_is_active_low(power) will be true). +The second parameter of the gpiod_get() functions, the con_id string, has to be +the -prefix of the GPIO suffixes ("gpios" or "gpio", automatically +looked up by the gpiod functions internally) used in the device tree. With above +"led-gpios" example, use the prefix without the "-" as con_id parameter: "led". + +Internally, the GPIO 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[]). + ACPI ---- ACPI also supports function names for GPIOs in a similar fashion to DT. diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 75542b9..47ce4fd 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -39,6 +39,9 @@ device that displays digits), an additional index argument can be specified: const char *con_id, unsigned int idx, enum gpiod_flags flags) +For a more detailed description of the con_id parameter in the DeviceTree case +see Documentation/gpio/board.txt + The flags parameter is used to optionally specify a direction and initial value for the GPIO. Values can be: -- 2.5.1