mirror of https://github.com/hak5/openwrt-owl.git
Claudio Mignanti
parent
fb94196462
commit
35ff4c9aa8
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@ -17,6 +17,7 @@
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*
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* Feedback, Bugs... blogic@openwrt.org
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*
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* dpg 20100106
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*/
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#include <linux/module.h>
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@ -36,54 +37,57 @@
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#define DEVNAME "gpio"
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static int dev_major;
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static unsigned int gpio_access_mask;
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static struct class *gpiodev_class;
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/* Counter is 1, if the device is not opened and zero (or less) if opened. */
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static atomic_t gpio_open_cnt = ATOMIC_INIT(1);
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/* third argument of user space ioctl ('arg' here) contains the <pin> */
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static int
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gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg)
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gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd,
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unsigned long arg)
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{
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int retval = 0;
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if (((1 << arg) & gpio_access_mask) != (1 << arg))
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{
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retval = -EINVAL;
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goto out;
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}
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switch (cmd)
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{
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case GPIO_GET:
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retval = gpio_get_value(arg);
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break;
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case GPIO_SET:
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gpio_set_value(arg, 1);
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break;
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case GPIO_CLEAR:
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gpio_set_value(arg, 0);
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break;
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case GPIO_DIR_IN:
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gpio_direction_input(arg);
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retval = gpio_direction_input(arg);
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break;
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case GPIO_DIR_OUT:
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gpio_direction_output(arg, 0);
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retval = gpio_direction_output(arg, 0);
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break;
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case GPIO_DIR_HIGH:
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retval = gpio_direction_output(arg, 1);
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break;
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case GPIO_REQUEST:
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/* should be first ioctl operation on <pin> */
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retval = gpio_request(arg, DRVNAME);
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break;
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case GPIO_FREE:
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/* should be last ioctl operation on <pin> */
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/* may be needed first if previous user missed this ioctl */
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gpio_free(arg);
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break;
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case GPIO_CAN_SLEEP:
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retval = gpio_cansleep(arg);
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break;
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default:
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retval = -EINVAL;
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/* = -ENOTTY; // correct return but ... */
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break;
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}
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out:
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return retval;
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}
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/* Allow co-incident opens */
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static int
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gpio_open(struct inode *inode, struct file *file)
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{
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@ -96,19 +100,6 @@ gpio_open(struct inode *inode, struct file *file)
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result = -ENODEV;
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goto out;
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}
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/* FIXME: We should really allow multiple applications to open the device
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* at the same time, as long as the apps access different IO pins.
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* The generic gpio-registration functions can be used for that.
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* Two new IOCTLs have to be introduced for that. Need to check userspace
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* compatibility first. --mb */
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if (!atomic_dec_and_test(&gpio_open_cnt)) {
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atomic_inc(&gpio_open_cnt);
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printk(KERN_ERR DRVNAME ": Device with minor ID %d already in use\n", dev_minor);
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result = -EBUSY;
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goto out;
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}
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out:
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return result;
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}
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@ -116,9 +107,9 @@ out:
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static int
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gpio_close(struct inode * inode, struct file * file)
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{
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smp_mb__before_atomic_inc();
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atomic_inc(&gpio_open_cnt);
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/* could track all <pin>s requested by this fd and gpio_free()
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* them here
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*/
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return 0;
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}
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@ -140,22 +131,9 @@ gpio_probe(struct platform_device *dev)
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result = -ENODEV;
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goto out;
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}
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gpiodev_class = class_create(THIS_MODULE, DRVNAME);
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device_create(gpiodev_class, NULL, MKDEV(dev_major, 0), dev, DEVNAME);
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printk(KERN_INFO DRVNAME ": gpio device registered with major %d\n", dev_major);
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if (dev->num_resources != 1)
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{
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printk(KERN_ERR DRVNAME ": device may only have 1 resource\n");
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result = -ENODEV;
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goto out;
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}
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gpio_access_mask = dev->resource[0].start;
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printk(KERN_INFO DRVNAME ": gpio platform device registered with access mask %08X\n", gpio_access_mask);
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out:
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return result;
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}
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@ -182,7 +160,7 @@ gpio_mod_init(void)
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{
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int ret = platform_driver_register(&gpio_driver);
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if (ret)
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printk(KERN_INFO DRVNAME ": Error registering platfom driver!");
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printk(KERN_INFO DRVNAME ": Error registering platfom driver!\n");
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return ret;
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}
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@ -197,5 +175,5 @@ module_init (gpio_mod_init);
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module_exit (gpio_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("John Crispin / OpenWrt");
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MODULE_AUTHOR("John Crispin / OpenWrt +");
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MODULE_DESCRIPTION("Character device for for generic gpio api");
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@ -1,11 +1,42 @@
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#ifndef _GPIODEV_H__
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#define _GPIODEV_H__
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#ifndef _GPIO_DEV_H__
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#define _GPIO_DEV_H__
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/*********************************************************************
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*
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* This Linux kernel header is expanded from the original driver
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* (gpio_dev) by John Crispin. It provides an ioctl based interface to
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* GPIO pins via the /dev/gpio char device and gpiolib within the kernel.
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* The third argument to each ioctl is the GPIO pin number.
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*
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* This driver has been tested with lk 2.6.31 and works. The original
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* driver fails quietly with this version. The protocol is now a bit
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* different: the ioctl(fd, GPIO_REQUEST, <pin>) should be called
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* after the open("/dev/gpio", O_RDWR) to determine if the <pin> is
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* already in use. If the ioctl is successful (i.e. returns 0 for not
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* in use) then the <pin> is claimed by this driver and
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* ioctl(fd, GPIO_FREE, <pin>) should be called prior to close(fd) .
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*
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* See <kernel_source>/Documentation/gpio.txt
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* Note that kernel designers prefer the use of the sysfs gpio interface.
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* This char driver is easier to use from code and faster.
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********************************************************************/
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/* This header can be included in both the user and kernel spaces */
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/* The _IO macro is defined in sys/ioctl.h */
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#define IOC_GPIODEV_MAGIC 'B'
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#define GPIO_GET _IO(IOC_GPIODEV_MAGIC, 10)
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#define GPIO_SET _IO(IOC_GPIODEV_MAGIC, 11)
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#define GPIO_CLEAR _IO(IOC_GPIODEV_MAGIC, 12)
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#define GPIO_DIR_IN _IO(IOC_GPIODEV_MAGIC, 13)
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#define GPIO_DIR_OUT _IO(IOC_GPIODEV_MAGIC, 14)
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/* Sets the direction out and clears the <pin> (low) */
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#define GPIO_DIR_HIGH _IO(IOC_GPIODEV_MAGIC, 15)
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/* Sets the direction out and sets the <pin> (high) */
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#define GPIO_REQUEST _IO(IOC_GPIODEV_MAGIC, 16)
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#define GPIO_FREE _IO(IOC_GPIODEV_MAGIC, 17)
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#define GPIO_CAN_SLEEP _IO(IOC_GPIODEV_MAGIC, 18)
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#endif
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