--- ORIG/drivers/gpio/gpio_dev.c 2009-12-18 12:41:18.861575861 -0500 +++ NEW/drivers/gpio/gpio_dev.c 2010-01-06 23:59:16.000000000 -0500 @@ -0,0 +1,196 @@ +/* + * character device wrapper for generic gpio layer + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * 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, MA02111-1307USA + * + * Feedback, Bugs... blogic@openwrt.org + * + * dpg 20100106 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRVNAME "gpiodev" +#define DEVNAME "gpio" + +static int dev_major; +static struct class *gpiodev_class; + + +/* third argument of user space ioctl ('arg' here) contains the */ +static int +gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, + unsigned long arg) +{ + int retval = 0; + + switch (cmd) + { + case GPIO_GET: + retval = gpio_get_value(arg); + break; + case GPIO_SET: + gpio_set_value(arg, 1); + break; + case GPIO_CLEAR: + gpio_set_value(arg, 0); + break; + case GPIO_DIR_IN: + retval = gpio_direction_input(arg); + break; + case GPIO_DIR_OUT: + retval = gpio_direction_output(arg, 0); + break; + case GPIO_DIR_HIGH: + retval = gpio_direction_output(arg, 1); + break; + case GPIO_REQUEST: + /* should be first ioctl operation on */ + retval = gpio_request(arg, DRVNAME); + break; + case GPIO_FREE: + /* should be last ioctl operation on */ + /* may be needed first if previous user missed this ioctl */ + gpio_free(arg); + break; + case GPIO_CAN_SLEEP: + retval = gpio_cansleep(arg); + break; + default: + retval = -EINVAL; + /* = -ENOTTY; // correct return but ... */ + break; + } + return retval; +} + +/* Allow co-incident opens */ +static int +gpio_open(struct inode *inode, struct file *file) +{ + int result = 0; + unsigned int dev_minor = MINOR(inode->i_rdev); + + if (dev_minor != 0) + { + printk(KERN_ERR DRVNAME ": trying to access unknown minor device -> %d\n", dev_minor); + result = -ENODEV; + goto out; + } +out: + return result; +} + +static int +gpio_close(struct inode * inode, struct file * file) +{ + /* could track all s requested by this fd and gpio_free() + * them here + */ + return 0; +} + +struct file_operations gpio_fops = { + ioctl: gpio_ioctl, + open: gpio_open, + release: gpio_close +}; + +static int +gpio_probe(struct platform_device *dev) +{ + int result = 0; + + dev_major = register_chrdev(0, DEVNAME, &gpio_fops); + if (!dev_major) + { + printk(KERN_ERR DRVNAME ": Error whilst opening %s \n", DEVNAME); + result = -ENODEV; + goto out; + } + gpiodev_class = class_create(THIS_MODULE, DRVNAME); + device_create(gpiodev_class, NULL, MKDEV(dev_major, 0), dev, DEVNAME); + printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major); +out: + return result; +} + +static int +gpio_remove(struct platform_device *dev) +{ + unregister_chrdev(dev_major, DEVNAME); + return 0; +} + +static struct platform_device * gpiodev_platform_device; + +static struct +platform_driver gpio_driver = { + .probe = gpio_probe, + .remove = gpio_remove, + .driver = { + .name = "GPIODEV", + .owner = THIS_MODULE, + }, +}; + +static int __init +gpio_mod_init(void) +{ + int ret; + + gpiodev_platform_device = platform_device_alloc("GPIODEV", -1); + if (!gpiodev_platform_device) + return -ENOMEM; + + ret = platform_device_add(gpiodev_platform_device); + if (ret < 0) { + printk(KERN_INFO DRVNAME ": Error platform_device_add()\n"); + platform_device_put(gpiodev_platform_device); + return ret; + } + ret = platform_driver_register(&gpio_driver); + if (ret) { + printk(KERN_INFO DRVNAME ": Error registering platfom driver!\n"); + platform_device_unregister(gpiodev_platform_device); + } + + return ret; +} + +static void __exit +gpio_mod_exit(void) +{ + platform_driver_unregister(&gpio_driver); + platform_device_unregister(gpiodev_platform_device); +} + +module_init (gpio_mod_init); +module_exit (gpio_mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("John Crispin / OpenWrt +"); +MODULE_DESCRIPTION("Character device for for generic gpio api"); --- ORIG/include/linux/gpio_dev.h 2009-12-18 12:41:18.861575861 -0500 +++ NEW/include/linux/gpio_dev.h 2010-01-01 09:24:33.000000000 -0500 @@ -0,0 +1,42 @@ +#ifndef _GPIO_DEV_H__ +#define _GPIO_DEV_H__ + +/********************************************************************* + * + * This Linux kernel header is expanded from the original driver + * (gpio_dev) by John Crispin. It provides an ioctl based interface to + * GPIO pins via the /dev/gpio char device and gpiolib within the kernel. + * The third argument to each ioctl is the GPIO pin number. + * + * This driver has been tested with lk 2.6.31 and works. The original + * driver fails quietly with this version. The protocol is now a bit + * different: the ioctl(fd, GPIO_REQUEST, ) should be called + * after the open("/dev/gpio", O_RDWR) to determine if the is + * already in use. If the ioctl is successful (i.e. returns 0 for not + * in use) then the is claimed by this driver and + * ioctl(fd, GPIO_FREE, ) should be called prior to close(fd) . + * + * See /Documentation/gpio.txt + * Note that kernel designers prefer the use of the sysfs gpio interface. + * This char driver is easier to use from code and faster. + ********************************************************************/ + +/* This header can be included in both the user and kernel spaces */ +/* The _IO macro is defined in sys/ioctl.h */ + +#define IOC_GPIODEV_MAGIC 'B' + +#define GPIO_GET _IO(IOC_GPIODEV_MAGIC, 10) +#define GPIO_SET _IO(IOC_GPIODEV_MAGIC, 11) +#define GPIO_CLEAR _IO(IOC_GPIODEV_MAGIC, 12) +#define GPIO_DIR_IN _IO(IOC_GPIODEV_MAGIC, 13) +#define GPIO_DIR_OUT _IO(IOC_GPIODEV_MAGIC, 14) + /* Sets the direction out and clears the (low) */ + +#define GPIO_DIR_HIGH _IO(IOC_GPIODEV_MAGIC, 15) + /* Sets the direction out and sets the (high) */ +#define GPIO_REQUEST _IO(IOC_GPIODEV_MAGIC, 16) +#define GPIO_FREE _IO(IOC_GPIODEV_MAGIC, 17) +#define GPIO_CAN_SLEEP _IO(IOC_GPIODEV_MAGIC, 18) + +#endif --- linux-2.6.35.4/drivers/gpio/Kconfig 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/gpio/Kconfig_gpiodev 2010-11-08 20:41:22.092387006 -0500 @@ -63,6 +63,15 @@ Kernel drivers may also request that a particular GPIO be exported to userspace; this can be useful when debugging. +config GPIO_DEVICE + tristate "GPIO device support" + depends on GPIOLIB + help + Say Y to enable Linux GPIO device support. This allows control of + GPIO pins using a character device (typically /dev/gpio) typically + from a program. See linux/gpio_dev.h header file. + + # put expanders in the right section, in alphabetical order config GPIO_MAX730X --- linux-2.6.35.4/drivers/gpio/Makefile 2010-08-26 19:47:12.000000000 -0400 +++ linux-2.6.35.4/drivers/gpio/Makefile_gpiodev 2010-11-08 20:43:05.444387006 -0500 @@ -8,6 +8,8 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o +obj-$(CONFIG_GPIO_DEVICE) += gpio_dev.o + obj-$(CONFIG_GPIO_ADP5520) += adp5520-gpio.o obj-$(CONFIG_GPIO_ADP5588) += adp5588-gpio.o obj-$(CONFIG_GPIO_LANGWELL) += langwell_gpio.o