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39b2bbe3d7
The huge majority of GPIOs have their direction and initial value set right after being obtained by one of the gpiod_get() functions. The integer GPIO API had gpio_request_one() that took a convenience flags parameter allowing to specify an direction and value applied to the returned GPIO. This feature greatly simplifies client code and ensures errors are always handled properly. A similar feature has been requested for the gpiod API. Since setting the direction of a GPIO is so often the very next action done after obtaining its descriptor, we prefer to extend the existing functions instead of introducing new functions that would raise the number of gpiod getters to 16 (!). The drawback of this approach is that all gpiod clients need to be updated. To limit the pain, temporary macros are introduced that allow gpiod_get*() to be called with or without the extra flags argument. They will be removed once all consumer code has been updated. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Mark Brown <broonie@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
255 lines
6.8 KiB
C
255 lines
6.8 KiB
C
/*
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* drivers/gpio/devres.c - managed gpio resources
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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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 <blogic@openwrt.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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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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/**
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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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dr = devres_alloc(devm_gpiod_release, sizeof(struct gpiod_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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desc = gpiod_get_index(dev, con_id, idx, flags);
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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_gpiod_get_index);
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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_put - Resource-managed gpiod_put()
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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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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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