From patchwork Thu Apr 21 11:08:21 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 66375 Delivered-To: patch@linaro.org Received: by 10.140.93.198 with SMTP id d64csp75088qge; Thu, 21 Apr 2016 04:08:33 -0700 (PDT) X-Received: by 10.66.66.42 with SMTP id c10mr19479620pat.119.1461236913530; Thu, 21 Apr 2016 04:08:33 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f7si145503pfb.182.2016.04.21.04.08.33; Thu, 21 Apr 2016 04:08:33 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-gpio-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-gpio-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-gpio-owner@vger.kernel.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752340AbcDULIc (ORCPT + 4 others); Thu, 21 Apr 2016 07:08:32 -0400 Received: from mail-lb0-f178.google.com ([209.85.217.178]:33309 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752400AbcDULI2 (ORCPT ); Thu, 21 Apr 2016 07:08:28 -0400 Received: by mail-lb0-f178.google.com with SMTP id u8so24997780lbk.0 for ; Thu, 21 Apr 2016 04:08:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=kasNHQcoaW9jNv8pfINMkP+jcDS/xaIdpHmXF/x3HkA=; b=aourMPfZHqwcBC0503O3LIoP0Hmqq0mgMFQ5fOPHVv4AIUYbmGdRgik4enkaxrn5JL uuz6NQq6mlbLifdfEUT1AeWUgkdWW9V4vrasJVy0DNEutHFErlBN9yNyo2FHu24EwT4j 1UulmmPlwq3G0JoVSuxmKvrpT5136BlACJVSg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=kasNHQcoaW9jNv8pfINMkP+jcDS/xaIdpHmXF/x3HkA=; b=Fz/Klz6eyZmI8mylmyGna7f8/+Pz3j5b8ueyZU3bAWF20lXX4gJ/JirfsJVHarzUAW VtNDSIhV/wqrGePq7qVAH5QVh5fwVjlxl+i3mBRpVo0FR2KgzpFkqDr4/G0nGwKptSAU ZkNGA9j1bMhsJ/Rt9Eu2XHnTIQhN4sOxE3Vs2ol7BMpVPNy3SjlrWMhz1Lzdm4ka/MLx 7LX0N/jiJL5QLwaIJBGEeVIASKWjIzZH9sSDLrvMZPUXaPIUHr2HaqYANwQ1RunE/Xzh s3I5RPvLNRa76xCm4VrcackJqpQ/u/C4mhwieuL4Qky+OGLUMoWOHF0WsTE4ZIE479PK zZ2Q== X-Gm-Message-State: AOPr4FVRksnGqy4DMcGHzZ2FjnHB1FNvY+8TH/aUT+TDJKNtR2NKbaeDCsKrXFKtzSp2c6IL X-Received: by 10.112.43.140 with SMTP id w12mr6003685lbl.51.1461236906688; Thu, 21 Apr 2016 04:08:26 -0700 (PDT) Received: from localhost.localdomain ([85.235.10.227]) by smtp.gmail.com with ESMTPSA id a134sm462999lfb.1.2016.04.21.04.08.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Apr 2016 04:08:25 -0700 (PDT) From: Linus Walleij To: linux-gpio@vger.kernel.org, Alexandre Courbot , Johan Hovold , Michael Welling , Markus Pargmann , Lee Campbell Cc: Bamvor Jian Zhang , Grant Likely , Arnd Bergmann , Mark Brown , Greg Kroah-Hartman , Dmitry Torokhov , Linus Walleij , Rob Herring , Amit Kucheria , David Mandala , devicetree@vger.kernel.org Subject: [PATCH v3] gpio: of: make it possible to name GPIO lines Date: Thu, 21 Apr 2016 13:08:21 +0200 Message-Id: <1461236901-28626-1-git-send-email-linus.walleij@linaro.org> X-Mailer: git-send-email 2.4.11 Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Make it possible to name the producer side of a GPIO line using a "gpio-line-names" property array, modeled on the "clock-output-names" property from the clock bindings. This naming is especially useful for: - Debugging: lines are named after function, not just opaque offset numbers. - Exploration: systems where some or all GPIO lines are available to end users, such as prototyping, one-off's "makerspace usecases" users are helped by the names of the GPIO lines when tinkering. This usecase has been surfacing recently. The gpio-line-names attribute is completely optional. Example output from lsgpio on a patched Snowball tree: GPIO chip: gpiochip6, "8000e180.gpio", 32 GPIO lines line 0: unnamed unused line 1: "AP_GPIO161" "extkb3" [kernel] line 2: "AP_GPIO162" "extkb4" [kernel] line 3: "ACCELEROMETER_INT1_RDY" unused [kernel] line 4: "ACCELEROMETER_INT2" unused line 5: "MAG_DRDY" unused [kernel] line 6: "GYRO_DRDY" unused [kernel] line 7: "RSTn_MLC" unused line 8: "RSTn_SLC" unused line 9: "GYRO_INT" unused line 10: "UART_WAKE" unused line 11: "GBF_RESET" unused line 12: unnamed unused Cc: Rob Herring Cc: Grant Likely Cc: Amit Kucheria Cc: David Mandala Cc: Lee Campbell Cc: devicetree@vger.kernel.org Reviewed-by: Michael Welling Signed-off-by: Linus Walleij --- ChangeLog v2->v3: - Swap "gpio-names" for "gpio-line-names" as "gpio-names" indicate a consumer endpoint in DT terminology. - Index to either: (A) The end of the gpio-names array or (B) ngpios So we don't risk going out of bounds on either ChangeLog v1->v2: - Make the naming function return void: we continue at all times and always return 0 anyway. - Fix a return value check. This has been discussed at some length now. Why we are not using hogs: these are consumer side, not producer side. The gpio-controller in DT (gpio_chip in Linux) is a producer, not a consumer. This patch is not about assigning initial values to GPIO lines. That is an orthogonal usecase. This is just about naming lines. --- Documentation/devicetree/bindings/gpio/gpio.txt | 19 +++++++++++ drivers/gpio/gpiolib-of.c | 43 +++++++++++++++++++++++++ 2 files changed, 62 insertions(+) -- 2.4.11 -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index c88d2ccb05ca..68d28f62a6f4 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -152,6 +152,21 @@ additional bitmask is needed to specify which GPIOs are actually in use, and which are dummies. The bindings for this case has not yet been specified, but should be specified if/when such hardware appears. +Optionally, a GPIO controller may have a "gpio-line-names" property. This is +an array of strings defining the names of the GPIO lines going out of the +GPIO controller. This name should be the most meaningful producer name +for the system, such as a rail name indicating the usage. Package names +such as pin name are discouraged: such lines have opaque names (since they +are by definition generic purpose) and such names are usually not very +helpful. For example "MMC-CD", "Red LED Vdd" and "ethernet reset" are +reasonable line names as they describe what the line is used for. "GPIO0" +is not a good name to give to a GPIO line. Placeholders are discouraged: +rather use the "" (blank string) if the use of the GPIO line is undefined +in your design. The names are assigned starting from line offset 0 from +left to right from the passed array. An incomplete array (where the number +of passed named are less than ngpios) will still be used up until the last +provided valid line index. + Example: gpio-controller@00000000 { @@ -160,6 +175,10 @@ gpio-controller@00000000 { gpio-controller; #gpio-cells = <2>; ngpios = <18>; + gpio-line-names = "MMC-CD", "MMC-WP", "VDD eth", "RST eth", "LED R", + "LED G", "LED B", "Col A", "Col B", "Col C", "Col D", + "Row A", "Row B", "Row C", "Row D", "NMI button", + "poweroff", "reset"; } The GPIO chip may contain GPIO hog definitions. GPIO hogging is a mechanism diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index d81dbd8e90d9..d43eaca803e3 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -196,6 +196,45 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np, } /** + * of_gpiochip_set_names() - set up the names of the lines + * @chip: GPIO chip whose lines should be named, if possible + */ +static void of_gpiochip_set_names(struct gpio_chip *gc) +{ + struct gpio_device *gdev = gc->gpiodev; + struct device_node *np = gc->of_node; + int i; + int nstrings; + + /* Do we even have the "gpio-line-names" property */ + if (!of_property_read_bool(np, "gpio-line-names")) + return; + + nstrings = of_property_count_strings(np, "gpio-line-names"); + /* + * Make sure to not index beyond either the end of the + * "gpio-names" array nor the number of descriptors of + * the GPIO device. + */ + for (i = 0; i < nstrings && i < gdev->ngpio; i++) { + const char *name; + int ret; + + ret = of_property_read_string_index(np, + "gpio-line-names", + i, + &name); + if (!ret) + gdev->descs[i].name = name; + + /* Empty strings are OK */ + if (ret < 0 && ret != -ENODATA) + dev_err(&gdev->dev, "unable to name line %d\n", + i); + } +} + +/** * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions * @chip: gpio chip to act on * @@ -445,6 +484,10 @@ int of_gpiochip_add(struct gpio_chip *chip) if (status) return status; + /* If the chip defines names itself, these take precedence */ + if (!chip->names) + of_gpiochip_set_names(chip); + of_node_get(chip->of_node); return of_gpiochip_scan_gpios(chip);