From patchwork Thu Feb 7 16:28:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Petazzoni X-Patchwork-Id: 1038169 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bootlin.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43wP0B1Bjrz9s9G for ; Fri, 8 Feb 2019 03:29:14 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726844AbfBGQ3N (ORCPT ); Thu, 7 Feb 2019 11:29:13 -0500 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:40233 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726832AbfBGQ3M (ORCPT ); Thu, 7 Feb 2019 11:29:12 -0500 X-Originating-IP: 90.88.22.177 Received: from localhost (aaubervilliers-681-1-80-177.w90-88.abo.wanadoo.fr [90.88.22.177]) (Authenticated sender: thomas.petazzoni@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id B4ED81BF217; Thu, 7 Feb 2019 16:29:08 +0000 (UTC) From: Thomas Petazzoni To: Linus Walleij , Bartosz Golaszewski , Rob Herring , Mark Rutland , Frank Rowand Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Jan_Kundr=C3=A1t?= , Thomas Petazzoni Subject: [PATCH v2 1/5] dt-bindings: gpio: document the new pull-up/pull-down flags Date: Thu, 7 Feb 2019 17:28:55 +0100 Message-Id: <20190207162859.26252-2-thomas.petazzoni@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190207162859.26252-1-thomas.petazzoni@bootlin.com> References: <20190207162859.26252-1-thomas.petazzoni@bootlin.com> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This commit extends the flags that can be used in GPIO specifiers to indicate if a pull-up resistor or pull-down resistor should be enabled. While some pinctrl DT bindings already offer the capability of configuring pull-up/pull-down resistors at the pin level, a number of simple GPIO controllers don't have any pinmuxing capability, and therefore do not rely on the pinctrl DT bindings. Such simple GPIO controllers however sometimes allow to configure pull-up and pull-down resistors on a per-pin basis, and whether such resistors should be enabled or not is a highly board-specific HW characteristic. By using two additional bits of the GPIO flag specifier, we can easily allow the Device Tree to describe which GPIOs should have their pull-up or pull-down resistors enabled. Even though the two options are mutually exclusive, we still need two bits to encode at least three states: no pull-up/pull-down, pull-up, pull-down. Signed-off-by: Thomas Petazzoni --- Documentation/devicetree/bindings/gpio/gpio.txt | 12 ++++++++++++ include/dt-bindings/gpio/gpio.h | 6 ++++++ 2 files changed, 18 insertions(+) diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index f0ba154b5723..a8895d339bfe 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -67,6 +67,18 @@ Optional standard bitfield specifiers for the last cell: https://en.wikipedia.org/wiki/Open_collector - Bit 3: 0 means the output should be maintained during sleep/low-power mode 1 means the output state can be lost during sleep/low-power mode +- Bit 4: 0 means no pull-up resistor should be enabled + 1 means a pull-up resistor should be enabled + This setting only applies to hardware with a simple on/off + control for pull-up configuration. If the hardware has more + elaborate pull-up configuration, it should be represented + using a pin control binding. +- Bit 5: 0 means no pull-down resistor should be enabled + 1 means a pull-down resistor should be enabled + This setting only applies to hardware with a simple on/off + control for pull-down configuration. If the hardware has more + elaborate pull-down configuration, it should be represented + using a pin control binding. 1.1) GPIO specifier best practices ---------------------------------- diff --git a/include/dt-bindings/gpio/gpio.h b/include/dt-bindings/gpio/gpio.h index 2cc10ae4bbb7..c029467e828b 100644 --- a/include/dt-bindings/gpio/gpio.h +++ b/include/dt-bindings/gpio/gpio.h @@ -33,4 +33,10 @@ #define GPIO_PERSISTENT 0 #define GPIO_TRANSITORY 8 +/* Bit 4 express pull up */ +#define GPIO_PULL_UP 16 + +/* Bit 5 express pull down */ +#define GPIO_PULL_DOWN 32 + #endif From patchwork Thu Feb 7 16:28:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Petazzoni X-Patchwork-Id: 1038172 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bootlin.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43wP0V4wq8z9sMM for ; Fri, 8 Feb 2019 03:29:30 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727080AbfBGQ3U (ORCPT ); Thu, 7 Feb 2019 11:29:20 -0500 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:49185 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727021AbfBGQ3R (ORCPT ); Thu, 7 Feb 2019 11:29:17 -0500 X-Originating-IP: 90.88.22.177 Received: from localhost (aaubervilliers-681-1-80-177.w90-88.abo.wanadoo.fr [90.88.22.177]) (Authenticated sender: thomas.petazzoni@bootlin.com) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id E65FC20006; Thu, 7 Feb 2019 16:29:13 +0000 (UTC) From: Thomas Petazzoni To: Linus Walleij , Bartosz Golaszewski , Rob Herring , Mark Rutland , Frank Rowand Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Jan_Kundr=C3=A1t?= , Thomas Petazzoni Subject: [PATCH v2 4/5] gpio: add core support for pull-up/pull-down configuration Date: Thu, 7 Feb 2019 17:28:58 +0100 Message-Id: <20190207162859.26252-5-thomas.petazzoni@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190207162859.26252-1-thomas.petazzoni@bootlin.com> References: <20190207162859.26252-1-thomas.petazzoni@bootlin.com> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This commit adds support for configuring the pull-up and pull-down resistors available in some GPIO controllers. While configuring pull-up/pull-down is already possible through the pinctrl subsystem, some GPIO controllers, especially simple ones such as GPIO expanders on I2C, don't have any pinmuxing capability and therefore do not use the pinctrl subsystem. This commit implements the GPIO_PULL_UP and GPIO_PULL_DOWN flags, which can be used from the Device Tree, to enable a pull-up or pull-down resistor on a given GPIO. The flag is simply propagated all the way to the core GPIO subsystem, where it is used to call the gpio_chip ->set_config callback with the appropriate existing PIN_CONFIG_BIAS_* values. Signed-off-by: Thomas Petazzoni --- drivers/gpio/gpiolib-of.c | 5 +++++ drivers/gpio/gpiolib.c | 18 ++++++++++++++++++ drivers/gpio/gpiolib.h | 2 ++ include/linux/gpio/machine.h | 2 ++ include/linux/of_gpio.h | 2 ++ 5 files changed, 29 insertions(+) diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index a6e1891217e2..9a8b78477f79 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -345,6 +345,11 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id, if (of_flags & OF_GPIO_TRANSITORY) *flags |= GPIO_TRANSITORY; + if (of_flags & OF_GPIO_PULL_UP) + *flags |= GPIO_PULL_UP; + if (of_flags & OF_GPIO_PULL_DOWN) + *flags |= GPIO_PULL_DOWN; + return desc; } diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9762a836fec9..9be4c9401172 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2610,6 +2610,13 @@ int gpiod_direction_input(struct gpio_desc *desc) if (status == 0) clear_bit(FLAG_IS_OUT, &desc->flags); + if (test_bit(FLAG_PULL_UP, &desc->flags)) + gpio_set_config(chip, gpio_chip_hwgpio(desc), + PIN_CONFIG_BIAS_PULL_UP); + else if (test_bit(FLAG_PULL_DOWN, &desc->flags)) + gpio_set_config(chip, gpio_chip_hwgpio(desc), + PIN_CONFIG_BIAS_PULL_DOWN); + trace_gpio_direction(desc_to_gpio(desc), 1, status); return status; @@ -4087,6 +4094,17 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id, if (lflags & GPIO_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &desc->flags); + if ((lflags & GPIO_PULL_UP) && (lflags & GPIO_PULL_DOWN)) { + gpiod_err(desc, + "both pull-up and pull-down enabled, invalid configuration\n"); + return -EINVAL; + } + + if (lflags & GPIO_PULL_UP) + set_bit(FLAG_PULL_UP, &desc->flags); + else if (lflags & GPIO_PULL_DOWN) + set_bit(FLAG_PULL_DOWN, &desc->flags); + status = gpiod_set_transitory(desc, (lflags & GPIO_TRANSITORY)); if (status < 0) return status; diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index bc57f0dc5953..078ab17b96bf 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -219,6 +219,8 @@ struct gpio_desc { #define FLAG_IRQ_IS_ENABLED 10 /* GPIO is connected to an enabled IRQ */ #define FLAG_IS_HOGGED 11 /* GPIO is hogged */ #define FLAG_TRANSITORY 12 /* GPIO may lose value in sleep or reset */ +#define FLAG_PULL_UP 13 /* GPIO has pull up enabled */ +#define FLAG_PULL_DOWN 14 /* GPIO has pull down enabled */ /* Connection label */ const char *label; diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h index daa44eac9241..69673be10213 100644 --- a/include/linux/gpio/machine.h +++ b/include/linux/gpio/machine.h @@ -12,6 +12,8 @@ enum gpio_lookup_flags { GPIO_OPEN_SOURCE = (1 << 2), GPIO_PERSISTENT = (0 << 3), GPIO_TRANSITORY = (1 << 3), + GPIO_PULL_UP = (1 << 4), + GPIO_PULL_DOWN = (1 << 5), }; /** diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h index 163b79ecd01a..f9737dea9d1f 100644 --- a/include/linux/of_gpio.h +++ b/include/linux/of_gpio.h @@ -28,6 +28,8 @@ enum of_gpio_flags { OF_GPIO_SINGLE_ENDED = 0x2, OF_GPIO_OPEN_DRAIN = 0x4, OF_GPIO_TRANSITORY = 0x8, + OF_GPIO_PULL_UP = 0x10, + OF_GPIO_PULL_DOWN = 0x20, }; #ifdef CONFIG_OF_GPIO