| John Crispin | 1a0703e | 2011-12-20 21:40:21 +0100 | [diff] [blame] | 1 | /* |
| 2 | * drivers/gpio/devres.c - managed gpio resources |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 |
| 6 | * as published by the Free Software Foundation. |
| 7 | * |
| 8 | * You should have received a copy of the GNU General Public License |
| 9 | * along with this program; if not, write to the Free Software |
| 10 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 11 | * |
| 12 | * This file is based on kernel/irq/devres.c |
| 13 | * |
| 14 | * Copyright (c) 2011 John Crispin <blogic@openwrt.org> |
| 15 | */ |
| 16 | |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/gpio.h> |
| 19 | #include <linux/device.h> |
| 20 | #include <linux/gfp.h> |
| 21 | |
| 22 | static void devm_gpio_release(struct device *dev, void *res) |
| 23 | { |
| 24 | unsigned *gpio = res; |
| 25 | |
| 26 | gpio_free(*gpio); |
| 27 | } |
| 28 | |
| 29 | static int devm_gpio_match(struct device *dev, void *res, void *data) |
| 30 | { |
| 31 | unsigned *this = res, *gpio = data; |
| 32 | |
| 33 | return *this == *gpio; |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * devm_gpio_request - request a gpio for a managed device |
| 38 | * @dev: device to request the gpio for |
| 39 | * @gpio: gpio to allocate |
| 40 | * @label: the name of the requested gpio |
| 41 | * |
| 42 | * Except for the extra @dev argument, this function takes the |
| 43 | * same arguments and performs the same function as |
| 44 | * gpio_request(). GPIOs requested with this function will be |
| 45 | * automatically freed on driver detach. |
| 46 | * |
| 47 | * If an GPIO allocated with this function needs to be freed |
| 48 | * separately, devm_gpio_free() must be used. |
| 49 | */ |
| 50 | |
| 51 | int devm_gpio_request(struct device *dev, unsigned gpio, const char *label) |
| 52 | { |
| 53 | unsigned *dr; |
| 54 | int rc; |
| 55 | |
| 56 | dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL); |
| 57 | if (!dr) |
| 58 | return -ENOMEM; |
| 59 | |
| 60 | rc = gpio_request(gpio, label); |
| 61 | if (rc) { |
| 62 | devres_free(dr); |
| 63 | return rc; |
| 64 | } |
| 65 | |
| 66 | *dr = gpio; |
| 67 | devres_add(dev, dr); |
| 68 | |
| 69 | return 0; |
| 70 | } |
| 71 | EXPORT_SYMBOL(devm_gpio_request); |
| 72 | |
| 73 | /** |
| 74 | * devm_gpio_free - free an interrupt |
| 75 | * @dev: device to free gpio for |
| 76 | * @gpio: gpio to free |
| 77 | * |
| 78 | * Except for the extra @dev argument, this function takes the |
| 79 | * same arguments and performs the same function as gpio_free(). |
| 80 | * This function instead of gpio_free() should be used to manually |
| 81 | * free GPIOs allocated with devm_gpio_request(). |
| 82 | */ |
| 83 | void devm_gpio_free(struct device *dev, unsigned int gpio) |
| 84 | { |
| 85 | |
| 86 | WARN_ON(devres_destroy(dev, devm_gpio_release, devm_gpio_match, |
| 87 | &gpio)); |
| 88 | gpio_free(gpio); |
| 89 | } |
| 90 | EXPORT_SYMBOL(devm_gpio_free); |