1a0703ede4
This patch adds 2 functions that allow managed devices to request GPIOs. These GPIOs will then be managed by drivers/base/devres.c. Signed-off-by: John Crispin <blogic@openwrt.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
90 lines
2.4 KiB
C
90 lines
2.4 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/gpio.h>
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#include <linux/device.h>
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#include <linux/gfp.h>
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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_free - free an interrupt
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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_destroy(dev, devm_gpio_release, devm_gpio_match,
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&gpio));
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gpio_free(gpio);
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}
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EXPORT_SYMBOL(devm_gpio_free);
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