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alistair23-linux/drivers/gpio/devres.c
Linus Walleij 92542edc42 gpio: Export devm_gpiod_get_from_of_node() for consumers 
We have been holding back on adding an API for fetching GPIO handles
directly from device nodes, strongly preferring to get it from the
spawn devices instead.

The fwnode interface however already contains an API for doing this,
as it is used for opaque device tree nodes or ACPI nodes for getting
handles to LEDs and keys that use GPIO: those are specified as one
child per LED/key in the device tree and are not individual devices.

However regulators present a special problem as they already have
helper functions to traverse the device tree from a regulator node
and two levels down to fill in data, and as it already traverses
GPIO nodes in its own way, and already holds a pointer to each
regulators device tree node, it makes most sense to export an
API to fetch the GPIO descriptor directly from the node.

We only support the devm_* version for now, hopefully no non-devres
version will be needed.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-01-12 11:05:24 +01:00

448 lines
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/*
* drivers/gpio/devres.c - managed gpio resources
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This file is based on kernel/irq/devres.c
*
* Copyright (c) 2011 John Crispin <john@phrozen.org>
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/device.h>
#include <linux/gfp.h>
#include "gpiolib.h"
static void devm_gpiod_release(struct device *dev, void *res)
{
struct gpio_desc **desc = res;
gpiod_put(*desc);
}
static int devm_gpiod_match(struct device *dev, void *res, void *data)
{
struct gpio_desc **this = res, **gpio = data;
return *this == *gpio;
}
static void devm_gpiod_release_array(struct device *dev, void *res)
{
struct gpio_descs **descs = res;
gpiod_put_array(*descs);
}
static int devm_gpiod_match_array(struct device *dev, void *res, void *data)
{
struct gpio_descs **this = res, **gpios = data;
return *this == *gpios;
}
/**
* devm_gpiod_get - Resource-managed gpiod_get()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get(). GPIO descriptors returned from this function are
* automatically disposed on driver detach. See gpiod_get() for detailed
* information about behavior and return values.
*/
struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
{
return devm_gpiod_get_index(dev, con_id, 0, flags);
}
EXPORT_SYMBOL(devm_gpiod_get);
/**
* devm_gpiod_get_optional - Resource-managed gpiod_get_optional()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get_optional(). GPIO descriptors returned from this function
* are automatically disposed on driver detach. See gpiod_get_optional() for
* detailed information about behavior and return values.
*/
struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
{
return devm_gpiod_get_index_optional(dev, con_id, 0, flags);
}
EXPORT_SYMBOL(devm_gpiod_get_optional);
/**
* devm_gpiod_get_index - Resource-managed gpiod_get_index()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @idx: index of the GPIO to obtain in the consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get_index(). GPIO descriptors returned from this function are
* automatically disposed on driver detach. See gpiod_get_index() for detailed
* information about behavior and return values.
*/
struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx,
enum gpiod_flags flags)
{
struct gpio_desc **dr;
struct gpio_desc *desc;
dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
GFP_KERNEL);
if (!dr)
return ERR_PTR(-ENOMEM);
desc = gpiod_get_index(dev, con_id, idx, flags);
if (IS_ERR(desc)) {
devres_free(dr);
return desc;
}
*dr = desc;
devres_add(dev, dr);
return desc;
}
EXPORT_SYMBOL(devm_gpiod_get_index);
/**
* devm_gpiod_get_from_of_node() - obtain a GPIO from an OF node
* @dev: device for lifecycle management
* @node: handle of the OF node
* @propname: name of the DT property representing the GPIO
* @index: index of the GPIO to obtain for the consumer
* @dflags: GPIO initialization flags
* @label: label to attach to the requested GPIO
*
* Returns:
* On successful request the GPIO pin is configured in accordance with
* provided @dflags.
*
* In case of error an ERR_PTR() is returned.
*/
struct gpio_desc *devm_gpiod_get_from_of_node(struct device *dev,
struct device_node *node,
const char *propname, int index,
enum gpiod_flags dflags,
const char *label)
{
struct gpio_desc **dr;
struct gpio_desc *desc;
dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
GFP_KERNEL);
if (!dr)
return ERR_PTR(-ENOMEM);
desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
if (IS_ERR(desc)) {
devres_free(dr);
return desc;
}
*dr = desc;
devres_add(dev, dr);
return desc;
}
EXPORT_SYMBOL(devm_gpiod_get_from_of_node);
/**
* devm_fwnode_get_index_gpiod_from_child - get a GPIO descriptor from a
* device's child node
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @index: index of the GPIO to obtain in the consumer
* @child: firmware node (child of @dev)
* @flags: GPIO initialization flags
* @label: label to attach to the requested GPIO
*
* GPIO descriptors returned from this function are automatically disposed on
* driver detach.
*
* On successful request the GPIO pin is configured in accordance with
* provided @flags.
*/
struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
const char *con_id, int index,
struct fwnode_handle *child,
enum gpiod_flags flags,
const char *label)
{
char prop_name[32]; /* 32 is max size of property name */
struct gpio_desc **dr;
struct gpio_desc *desc;
unsigned int i;
dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
GFP_KERNEL);
if (!dr)
return ERR_PTR(-ENOMEM);
for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
if (con_id)
snprintf(prop_name, sizeof(prop_name), "%s-%s",
con_id, gpio_suffixes[i]);
else
snprintf(prop_name, sizeof(prop_name), "%s",
gpio_suffixes[i]);
desc = fwnode_get_named_gpiod(child, prop_name, index, flags,
label);
if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
break;
}
if (IS_ERR(desc)) {
devres_free(dr);
return desc;
}
*dr = desc;
devres_add(dev, dr);
return desc;
}
EXPORT_SYMBOL(devm_fwnode_get_index_gpiod_from_child);
/**
* devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @index: index of the GPIO to obtain in the consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get_index_optional(). GPIO descriptors returned from this
* function are automatically disposed on driver detach. See
* gpiod_get_index_optional() for detailed information about behavior and
* return values.
*/
struct gpio_desc *__must_check devm_gpiod_get_index_optional(struct device *dev,
const char *con_id,
unsigned int index,
enum gpiod_flags flags)
{
struct gpio_desc *desc;
desc = devm_gpiod_get_index(dev, con_id, index, flags);
if (IS_ERR(desc)) {
if (PTR_ERR(desc) == -ENOENT)
return NULL;
}
return desc;
}
EXPORT_SYMBOL(devm_gpiod_get_index_optional);
/**
* devm_gpiod_get_array - Resource-managed gpiod_get_array()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get_array(). GPIO descriptors returned from this function are
* automatically disposed on driver detach. See gpiod_get_array() for detailed
* information about behavior and return values.
*/
struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
{
struct gpio_descs **dr;
struct gpio_descs *descs;
dr = devres_alloc(devm_gpiod_release_array,
sizeof(struct gpio_descs *), GFP_KERNEL);
if (!dr)
return ERR_PTR(-ENOMEM);
descs = gpiod_get_array(dev, con_id, flags);
if (IS_ERR(descs)) {
devres_free(dr);
return descs;
}
*dr = descs;
devres_add(dev, dr);
return descs;
}
EXPORT_SYMBOL(devm_gpiod_get_array);
/**
* devm_gpiod_get_array_optional - Resource-managed gpiod_get_array_optional()
* @dev: GPIO consumer
* @con_id: function within the GPIO consumer
* @flags: optional GPIO initialization flags
*
* Managed gpiod_get_array_optional(). GPIO descriptors returned from this
* function are automatically disposed on driver detach.
* See gpiod_get_array_optional() for detailed information about behavior and
* return values.
*/
struct gpio_descs *__must_check
devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
struct gpio_descs *descs;
descs = devm_gpiod_get_array(dev, con_id, flags);
if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
return NULL;
return descs;
}
EXPORT_SYMBOL(devm_gpiod_get_array_optional);
/**
* devm_gpiod_put - Resource-managed gpiod_put()
* @dev: GPIO consumer
* @desc: GPIO descriptor to dispose of
*
* Dispose of a GPIO descriptor obtained with devm_gpiod_get() or
* devm_gpiod_get_index(). Normally this function will not be called as the GPIO
* will be disposed of by the resource management code.
*/
void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
{
WARN_ON(devres_release(dev, devm_gpiod_release, devm_gpiod_match,
&desc));
}
EXPORT_SYMBOL(devm_gpiod_put);
/**
* devm_gpiod_put_array - Resource-managed gpiod_put_array()
* @dev: GPIO consumer
* @descs: GPIO descriptor array to dispose of
*
* Dispose of an array of GPIO descriptors obtained with devm_gpiod_get_array().
* Normally this function will not be called as the GPIOs will be disposed of
* by the resource management code.
*/
void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs)
{
WARN_ON(devres_release(dev, devm_gpiod_release_array,
devm_gpiod_match_array, &descs));
}
EXPORT_SYMBOL(devm_gpiod_put_array);
static void devm_gpio_release(struct device *dev, void *res)
{
unsigned *gpio = res;
gpio_free(*gpio);
}
static int devm_gpio_match(struct device *dev, void *res, void *data)
{
unsigned *this = res, *gpio = data;
return *this == *gpio;
}
/**
* devm_gpio_request - request a GPIO for a managed device
* @dev: device to request the GPIO for
* @gpio: GPIO to allocate
* @label: the name of the requested GPIO
*
* Except for the extra @dev argument, this function takes the
* same arguments and performs the same function as
* gpio_request(). GPIOs requested with this function will be
* automatically freed on driver detach.
*
* If an GPIO allocated with this function needs to be freed
* separately, devm_gpio_free() must be used.
*/
int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
{
unsigned *dr;
int rc;
dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
if (!dr)
return -ENOMEM;
rc = gpio_request(gpio, label);
if (rc) {
devres_free(dr);
return rc;
}
*dr = gpio;
devres_add(dev, dr);
return 0;
}
EXPORT_SYMBOL(devm_gpio_request);
/**
* devm_gpio_request_one - request a single GPIO with initial setup
* @dev: device to request for
* @gpio: the GPIO number
* @flags: GPIO configuration as specified by GPIOF_*
* @label: a literal description string of this GPIO
*/
int devm_gpio_request_one(struct device *dev, unsigned gpio,
unsigned long flags, const char *label)
{
unsigned *dr;
int rc;
dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
if (!dr)
return -ENOMEM;
rc = gpio_request_one(gpio, flags, label);
if (rc) {
devres_free(dr);
return rc;
}
*dr = gpio;
devres_add(dev, dr);
return 0;
}
EXPORT_SYMBOL(devm_gpio_request_one);
/**
* devm_gpio_free - free a GPIO
* @dev: device to free GPIO for
* @gpio: GPIO to free
*
* Except for the extra @dev argument, this function takes the
* same arguments and performs the same function as gpio_free().
* This function instead of gpio_free() should be used to manually
* free GPIOs allocated with devm_gpio_request().
*/
void devm_gpio_free(struct device *dev, unsigned int gpio)
{
WARN_ON(devres_release(dev, devm_gpio_release, devm_gpio_match,
&gpio));
}
EXPORT_SYMBOL(devm_gpio_free);
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