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![Linus Walleij](/assets/img/avatar_default.png)
This adds a function named devm_gpiod_unhinge() that removes the resource management from a GPIO descriptor. I am not sure if this is the best anglosaxon name for the function, no other managed resources have an equivalent currently, but I chose "unhinge" as the closest intuitive thing I could imagine that fits Rusty Russell's API design criterions "the obvious use is the correct one" and "the name tells you how to use it". The idea came out of a remark from Mark Brown that it should be possible to handle over management of a resource from devres to the regulator core, and indeed we can do that. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com> Signed-off-by: Mark Brown <broonie@kernel.org>
495 lines
13 KiB
C
495 lines
13 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* devres.c - managed gpio resources
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* This file is based on kernel/irq/devres.c
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*
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* Copyright (c) 2011 John Crispin <john@phrozen.org>
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*/
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/gpio.h>
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#include <linux/gpio/consumer.h>
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#include <linux/device.h>
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#include <linux/gfp.h>
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#include "gpiolib.h"
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static void devm_gpiod_release(struct device *dev, void *res)
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{
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struct gpio_desc **desc = res;
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gpiod_put(*desc);
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}
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static int devm_gpiod_match(struct device *dev, void *res, void *data)
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{
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struct gpio_desc **this = res, **gpio = data;
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return *this == *gpio;
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}
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static void devm_gpiod_release_array(struct device *dev, void *res)
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{
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struct gpio_descs **descs = res;
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gpiod_put_array(*descs);
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}
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static int devm_gpiod_match_array(struct device *dev, void *res, void *data)
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{
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struct gpio_descs **this = res, **gpios = data;
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return *this == *gpios;
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}
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/**
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* devm_gpiod_get - Resource-managed gpiod_get()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get(). GPIO descriptors returned from this function are
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* automatically disposed on driver detach. See gpiod_get() for detailed
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* information about behavior and return values.
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*/
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struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
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const char *con_id,
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enum gpiod_flags flags)
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{
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return devm_gpiod_get_index(dev, con_id, 0, flags);
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}
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EXPORT_SYMBOL(devm_gpiod_get);
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/**
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* devm_gpiod_get_optional - Resource-managed gpiod_get_optional()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get_optional(). GPIO descriptors returned from this function
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* are automatically disposed on driver detach. See gpiod_get_optional() for
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* detailed information about behavior and return values.
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*/
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struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev,
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const char *con_id,
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enum gpiod_flags flags)
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{
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return devm_gpiod_get_index_optional(dev, con_id, 0, flags);
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}
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EXPORT_SYMBOL(devm_gpiod_get_optional);
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/**
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* devm_gpiod_get_index - Resource-managed gpiod_get_index()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @idx: index of the GPIO to obtain in the consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get_index(). GPIO descriptors returned from this function are
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* automatically disposed on driver detach. See gpiod_get_index() for detailed
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* information about behavior and return values.
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*/
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struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
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const char *con_id,
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unsigned int idx,
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enum gpiod_flags flags)
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{
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struct gpio_desc **dr;
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struct gpio_desc *desc;
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desc = gpiod_get_index(dev, con_id, idx, flags);
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if (IS_ERR(desc))
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return desc;
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/*
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* For non-exclusive GPIO descriptors, check if this descriptor is
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* already under resource management by this device.
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*/
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if (flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
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struct devres *dres;
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dres = devres_find(dev, devm_gpiod_release,
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devm_gpiod_match, &desc);
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if (dres)
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return desc;
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}
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dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
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GFP_KERNEL);
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if (!dr) {
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gpiod_put(desc);
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return ERR_PTR(-ENOMEM);
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}
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*dr = desc;
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devres_add(dev, dr);
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return desc;
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}
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EXPORT_SYMBOL(devm_gpiod_get_index);
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/**
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* devm_gpiod_get_from_of_node() - obtain a GPIO from an OF node
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* @dev: device for lifecycle management
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* @node: handle of the OF node
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* @propname: name of the DT property representing the GPIO
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* @index: index of the GPIO to obtain for the consumer
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* @dflags: GPIO initialization flags
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* @label: label to attach to the requested GPIO
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*
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* Returns:
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* On successful request the GPIO pin is configured in accordance with
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* provided @dflags.
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*
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* In case of error an ERR_PTR() is returned.
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*/
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struct gpio_desc *devm_gpiod_get_from_of_node(struct device *dev,
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struct device_node *node,
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const char *propname, int index,
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enum gpiod_flags dflags,
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const char *label)
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{
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struct gpio_desc **dr;
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struct gpio_desc *desc;
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desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
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if (IS_ERR(desc))
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return desc;
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/*
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* For non-exclusive GPIO descriptors, check if this descriptor is
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* already under resource management by this device.
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*/
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if (dflags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
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struct devres *dres;
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dres = devres_find(dev, devm_gpiod_release,
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devm_gpiod_match, &desc);
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if (dres)
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return desc;
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}
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dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
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GFP_KERNEL);
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if (!dr) {
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gpiod_put(desc);
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return ERR_PTR(-ENOMEM);
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}
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*dr = desc;
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devres_add(dev, dr);
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return desc;
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}
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EXPORT_SYMBOL(devm_gpiod_get_from_of_node);
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/**
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* devm_fwnode_get_index_gpiod_from_child - get a GPIO descriptor from a
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* device's child node
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @index: index of the GPIO to obtain in the consumer
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* @child: firmware node (child of @dev)
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* @flags: GPIO initialization flags
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* @label: label to attach to the requested GPIO
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*
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* GPIO descriptors returned from this function are automatically disposed on
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* driver detach.
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*
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* On successful request the GPIO pin is configured in accordance with
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* provided @flags.
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*/
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struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
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const char *con_id, int index,
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struct fwnode_handle *child,
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enum gpiod_flags flags,
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const char *label)
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{
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char prop_name[32]; /* 32 is max size of property name */
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struct gpio_desc **dr;
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struct gpio_desc *desc;
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unsigned int i;
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dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
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GFP_KERNEL);
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if (!dr)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
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if (con_id)
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snprintf(prop_name, sizeof(prop_name), "%s-%s",
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con_id, gpio_suffixes[i]);
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else
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snprintf(prop_name, sizeof(prop_name), "%s",
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gpio_suffixes[i]);
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desc = fwnode_get_named_gpiod(child, prop_name, index, flags,
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label);
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if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
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break;
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}
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if (IS_ERR(desc)) {
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devres_free(dr);
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return desc;
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}
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*dr = desc;
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devres_add(dev, dr);
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return desc;
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}
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EXPORT_SYMBOL(devm_fwnode_get_index_gpiod_from_child);
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/**
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* devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @index: index of the GPIO to obtain in the consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get_index_optional(). GPIO descriptors returned from this
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* function are automatically disposed on driver detach. See
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* gpiod_get_index_optional() for detailed information about behavior and
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* return values.
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*/
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struct gpio_desc *__must_check devm_gpiod_get_index_optional(struct device *dev,
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const char *con_id,
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unsigned int index,
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enum gpiod_flags flags)
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{
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struct gpio_desc *desc;
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desc = devm_gpiod_get_index(dev, con_id, index, flags);
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if (IS_ERR(desc)) {
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if (PTR_ERR(desc) == -ENOENT)
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return NULL;
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}
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return desc;
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}
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EXPORT_SYMBOL(devm_gpiod_get_index_optional);
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/**
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* devm_gpiod_get_array - Resource-managed gpiod_get_array()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get_array(). GPIO descriptors returned from this function are
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* automatically disposed on driver detach. See gpiod_get_array() for detailed
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* information about behavior and return values.
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*/
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struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
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const char *con_id,
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enum gpiod_flags flags)
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{
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struct gpio_descs **dr;
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struct gpio_descs *descs;
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dr = devres_alloc(devm_gpiod_release_array,
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sizeof(struct gpio_descs *), GFP_KERNEL);
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if (!dr)
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return ERR_PTR(-ENOMEM);
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descs = gpiod_get_array(dev, con_id, flags);
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if (IS_ERR(descs)) {
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devres_free(dr);
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return descs;
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}
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*dr = descs;
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devres_add(dev, dr);
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return descs;
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}
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EXPORT_SYMBOL(devm_gpiod_get_array);
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/**
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* devm_gpiod_get_array_optional - Resource-managed gpiod_get_array_optional()
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* @dev: GPIO consumer
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* @con_id: function within the GPIO consumer
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* @flags: optional GPIO initialization flags
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*
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* Managed gpiod_get_array_optional(). GPIO descriptors returned from this
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* function are automatically disposed on driver detach.
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* See gpiod_get_array_optional() for detailed information about behavior and
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* return values.
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*/
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struct gpio_descs *__must_check
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devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
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enum gpiod_flags flags)
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{
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struct gpio_descs *descs;
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descs = devm_gpiod_get_array(dev, con_id, flags);
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if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
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return NULL;
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return descs;
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}
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EXPORT_SYMBOL(devm_gpiod_get_array_optional);
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/**
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* devm_gpiod_put - Resource-managed gpiod_put()
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* @dev: GPIO consumer
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* @desc: GPIO descriptor to dispose of
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*
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* Dispose of a GPIO descriptor obtained with devm_gpiod_get() or
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* devm_gpiod_get_index(). Normally this function will not be called as the GPIO
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* will be disposed of by the resource management code.
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*/
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void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
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{
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WARN_ON(devres_release(dev, devm_gpiod_release, devm_gpiod_match,
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&desc));
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}
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EXPORT_SYMBOL(devm_gpiod_put);
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/**
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* devm_gpiod_unhinge - Remove resource management from a gpio descriptor
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* @dev: GPIO consumer
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* @desc: GPIO descriptor to remove resource management from
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*
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* Remove resource management from a GPIO descriptor. This is needed when
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* you want to hand over lifecycle management of a descriptor to another
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* mechanism.
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*/
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void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc)
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{
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int ret;
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if (IS_ERR_OR_NULL(desc))
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return;
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ret = devres_destroy(dev, devm_gpiod_release,
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devm_gpiod_match, &desc);
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/*
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* If the GPIO descriptor is requested as nonexclusive, we
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* may call this function several times on the same descriptor
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* so it is OK if devres_destroy() returns -ENOENT.
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*/
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if (ret == -ENOENT)
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return;
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/* Anything else we should warn about */
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WARN_ON(ret);
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}
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EXPORT_SYMBOL(devm_gpiod_unhinge);
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/**
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* devm_gpiod_put_array - Resource-managed gpiod_put_array()
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* @dev: GPIO consumer
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* @descs: GPIO descriptor array to dispose of
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*
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* Dispose of an array of GPIO descriptors obtained with devm_gpiod_get_array().
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* Normally this function will not be called as the GPIOs will be disposed of
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* by the resource management code.
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*/
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void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs)
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{
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WARN_ON(devres_release(dev, devm_gpiod_release_array,
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devm_gpiod_match_array, &descs));
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}
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EXPORT_SYMBOL(devm_gpiod_put_array);
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static void devm_gpio_release(struct device *dev, void *res)
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{
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unsigned *gpio = res;
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gpio_free(*gpio);
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}
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static int devm_gpio_match(struct device *dev, void *res, void *data)
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{
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unsigned *this = res, *gpio = data;
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return *this == *gpio;
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}
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/**
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* devm_gpio_request - request a GPIO for a managed device
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* @dev: device to request the GPIO for
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* @gpio: GPIO to allocate
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* @label: the name of the requested GPIO
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*
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* Except for the extra @dev argument, this function takes the
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* same arguments and performs the same function as
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* gpio_request(). GPIOs requested with this function will be
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* automatically freed on driver detach.
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*
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* If an GPIO allocated with this function needs to be freed
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* separately, devm_gpio_free() must be used.
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*/
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int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
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{
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unsigned *dr;
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int rc;
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dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
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if (!dr)
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return -ENOMEM;
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rc = gpio_request(gpio, label);
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if (rc) {
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devres_free(dr);
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return rc;
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}
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*dr = gpio;
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devres_add(dev, dr);
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return 0;
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}
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EXPORT_SYMBOL(devm_gpio_request);
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/**
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* devm_gpio_request_one - request a single GPIO with initial setup
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* @dev: device to request for
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* @gpio: the GPIO number
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* @flags: GPIO configuration as specified by GPIOF_*
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* @label: a literal description string of this GPIO
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*/
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int devm_gpio_request_one(struct device *dev, unsigned gpio,
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unsigned long flags, const char *label)
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{
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unsigned *dr;
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int rc;
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dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
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if (!dr)
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return -ENOMEM;
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rc = gpio_request_one(gpio, flags, label);
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if (rc) {
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devres_free(dr);
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return rc;
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}
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*dr = gpio;
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devres_add(dev, dr);
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return 0;
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}
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EXPORT_SYMBOL(devm_gpio_request_one);
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/**
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* devm_gpio_free - free a GPIO
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* @dev: device to free GPIO for
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* @gpio: GPIO to free
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*
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* Except for the extra @dev argument, this function takes the
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* same arguments and performs the same function as gpio_free().
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* This function instead of gpio_free() should be used to manually
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* free GPIOs allocated with devm_gpio_request().
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*/
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void devm_gpio_free(struct device *dev, unsigned int gpio)
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{
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WARN_ON(devres_release(dev, devm_gpio_release, devm_gpio_match,
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&gpio));
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}
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EXPORT_SYMBOL(devm_gpio_free);
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