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[82.242.157.225]) by smtp.gmail.com with ESMTPSA id x140sm32382073wme.19.2016.12.11.14.22.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 11 Dec 2016 14:22:53 -0800 (PST) From: Bartosz Golaszewski To: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Mark Rutland Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Kevin Hilman , Patrick Titiano , Neil Armstrong , Linus Walleij , Alexandre Courbot , linux-gpio@vger.kernel.org, Sebastian Reichel , linux-pm@vger.kernel.org, Mark Brown , Liam Girdwood , Bartosz Golaszewski Subject: [PATCH 2/2] iio: misc: add support for GPIO power switches Date: Sun, 11 Dec 2016 23:21:45 +0100 Message-Id: <1481494905-18037-3-git-send-email-bgolaszewski@baylibre.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1481494905-18037-1-git-send-email-bgolaszewski@baylibre.com> References: <1481494905-18037-1-git-send-email-bgolaszewski@baylibre.com> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Some power-measuring ADCs work together with power load switches which allow to power-cycle measured devices. An example use case would be measuring the power consumption of a development board during boot using a power monitor such as TI INA226 and power-cycling the board remotely using a TPS229* power switch. Add an iio driver for simple GPIO power switches and expose a sysfs attribute allowing to toggle their state. Signed-off-by: Bartosz Golaszewski --- drivers/iio/Kconfig | 1 + drivers/iio/Makefile | 1 + drivers/iio/misc/Kconfig | 17 +++++ drivers/iio/misc/Makefile | 6 ++ drivers/iio/misc/gpio-power-switch.c | 127 +++++++++++++++++++++++++++++++++++ 5 files changed, 152 insertions(+) create mode 100644 drivers/iio/misc/Kconfig create mode 100644 drivers/iio/misc/Makefile create mode 100644 drivers/iio/misc/gpio-power-switch.c -- 2.9.3 -- 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/drivers/iio/Kconfig b/drivers/iio/Kconfig index 6743b18..2e896e0 100644 --- a/drivers/iio/Kconfig +++ b/drivers/iio/Kconfig @@ -80,6 +80,7 @@ source "drivers/iio/gyro/Kconfig" source "drivers/iio/health/Kconfig" source "drivers/iio/humidity/Kconfig" source "drivers/iio/imu/Kconfig" +source "drivers/iio/misc/Kconfig" source "drivers/iio/light/Kconfig" source "drivers/iio/magnetometer/Kconfig" source "drivers/iio/orientation/Kconfig" diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile index 87e4c43..4008d5a 100644 --- a/drivers/iio/Makefile +++ b/drivers/iio/Makefile @@ -25,6 +25,7 @@ obj-y += frequency/ obj-y += health/ obj-y += humidity/ obj-y += imu/ +obj-y += misc/ obj-y += light/ obj-y += magnetometer/ obj-y += orientation/ diff --git a/drivers/iio/misc/Kconfig b/drivers/iio/misc/Kconfig new file mode 100644 index 0000000..8d73751 --- /dev/null +++ b/drivers/iio/misc/Kconfig @@ -0,0 +1,17 @@ +# +# Miscellaneous iio drivers +# +# When adding new entries keep the list in alphabetical order + +menu "Miscellaneous iio drivers" + +config GPIO_POWER_SWITCH + tristate "GPIO power switch driver" + depends on GPIOLIB + help + Say yes here to build support for gpio power switches. + + To compile this driver as a module, choose M here: the module will + be called gpio-power-switch. + +endmenu diff --git a/drivers/iio/misc/Makefile b/drivers/iio/misc/Makefile new file mode 100644 index 0000000..cebd0c4 --- /dev/null +++ b/drivers/iio/misc/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for IIO misc drivers +# + +# When adding new entries keep the list in alphabetical order +obj-$(CONFIG_GPIO_POWER_SWITCH) += gpio-power-switch.o diff --git a/drivers/iio/misc/gpio-power-switch.c b/drivers/iio/misc/gpio-power-switch.c new file mode 100644 index 0000000..25fbeb7 --- /dev/null +++ b/drivers/iio/misc/gpio-power-switch.c @@ -0,0 +1,127 @@ +/* + * GPIO power switch driver using the industrial IO framework. + * + * Copyright (C) 2016 BayLibre SAS + * + * Author: + * Bartosz Golaszewski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include + +struct gpio_pwrsw_context { + struct gpio_desc *gpio; +}; + +static ssize_t gpio_pwrsw_enable_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gpio_pwrsw_context *ctx = iio_priv(dev_to_iio_dev(dev)); + int val; + + val = gpiod_get_value_cansleep(ctx->gpio); + if (val < 0) + return val; + + return sprintf(buf, "%d\n", val); +} + +static ssize_t gpio_pwrsw_enable_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct gpio_pwrsw_context *ctx = iio_priv(dev_to_iio_dev(dev)); + bool val; + int ret; + + ret = strtobool(buf, &val); + if (ret) + return ret; + + gpiod_set_value_cansleep(ctx->gpio, val ? 1 : 0); + + return len; +} + +static IIO_DEVICE_ATTR(in_active, 0644, + gpio_pwrsw_enable_show, + gpio_pwrsw_enable_store, 0); + +static struct attribute *gpio_pwrsw_attributes[] = { + &iio_dev_attr_in_active.dev_attr.attr, + NULL, +}; + +static const struct attribute_group gpio_pwrsw_attribute_group = { + .attrs = gpio_pwrsw_attributes, +}; + +static const struct iio_info gpio_pwrsw_info = { + .driver_module = THIS_MODULE, + .attrs = &gpio_pwrsw_attribute_group, +}; + +static int gpio_pwrsw_probe(struct platform_device *pdev) +{ + struct gpio_pwrsw_context *ctx; + struct iio_dev *iio_dev; + const char *name = NULL; + struct device *dev; + bool init_state; + int gpio_flags; + + dev = &pdev->dev; + + iio_dev = devm_iio_device_alloc(dev, sizeof(*ctx)); + if (!iio_dev) + return -ENOMEM; + + ctx = iio_priv(iio_dev); + + init_state = of_property_read_bool(dev->of_node, "power-switch-on"); + gpio_flags = init_state ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; + + ctx->gpio = devm_gpiod_get(dev, "power", gpio_flags); + if (IS_ERR(ctx->gpio)) { + dev_err(dev, "unable to get the power switch gpio: %ld\n", + PTR_ERR(ctx->gpio)); + return PTR_ERR(ctx->gpio); + } + + of_property_read_string(dev->of_node, "power-switch-name", &name); + + iio_dev->dev.parent = dev; + iio_dev->dev.of_node = dev->of_node; + iio_dev->name = name ? name : dev->driver->name; + iio_dev->info = &gpio_pwrsw_info; + + return devm_iio_device_register(dev, iio_dev); +} + +static const struct of_device_id gpio_pwrsw_of_match[] = { + { .compatible = "gpio-power-switch", }, + { }, +}; + +static struct platform_driver gpio_pwrsw_platform_driver = { + .probe = gpio_pwrsw_probe, + .driver = { + .name = "gpio-power-switch", + .of_match_table = gpio_pwrsw_of_match, + }, +}; +module_platform_driver(gpio_pwrsw_platform_driver); + +MODULE_AUTHOR("Bartosz Golaszewski "); +MODULE_DESCRIPTION("GPIO power switch driver for iio"); +MODULE_LICENSE("GPL v2");