diff options
Diffstat (limited to 'target/linux/generic-2.6/files')
| -rw-r--r-- | target/linux/generic-2.6/files/drivers/char/gpio_dev.c | 78 | ||||
| -rw-r--r-- | target/linux/generic-2.6/files/include/linux/gpio_dev.h | 35 |
2 files changed, 61 insertions, 52 deletions
diff --git a/target/linux/generic-2.6/files/drivers/char/gpio_dev.c b/target/linux/generic-2.6/files/drivers/char/gpio_dev.c index 8392fcf2d..e6d5b1d05 100644 --- a/target/linux/generic-2.6/files/drivers/char/gpio_dev.c +++ b/target/linux/generic-2.6/files/drivers/char/gpio_dev.c @@ -17,6 +17,7 @@ * * Feedback, Bugs... blogic@openwrt.org * + * dpg 20100106 */ #include <linux/module.h> @@ -36,54 +37,57 @@ #define DEVNAME "gpio" static int dev_major; -static unsigned int gpio_access_mask; static struct class *gpiodev_class; -/* Counter is 1, if the device is not opened and zero (or less) if opened. */ -static atomic_t gpio_open_cnt = ATOMIC_INIT(1); +/* third argument of user space ioctl ('arg' here) contains the <pin> */ static int -gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg) +gpio_ioctl(struct inode * inode, struct file * file, unsigned int cmd, + unsigned long arg) { int retval = 0; - if (((1 << arg) & gpio_access_mask) != (1 << arg)) - { - retval = -EINVAL; - goto out; - } - 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: - gpio_direction_input(arg); + retval = gpio_direction_input(arg); break; - case GPIO_DIR_OUT: - gpio_direction_output(arg, 0); + 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 <pin> */ + retval = gpio_request(arg, DRVNAME); + break; + case GPIO_FREE: + /* should be last ioctl operation on <pin> */ + /* 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; } - -out: return retval; } +/* Allow co-incident opens */ static int gpio_open(struct inode *inode, struct file *file) { @@ -96,19 +100,6 @@ gpio_open(struct inode *inode, struct file *file) result = -ENODEV; goto out; } - - /* FIXME: We should really allow multiple applications to open the device - * at the same time, as long as the apps access different IO pins. - * The generic gpio-registration functions can be used for that. - * Two new IOCTLs have to be introduced for that. Need to check userspace - * compatibility first. --mb */ - if (!atomic_dec_and_test(&gpio_open_cnt)) { - atomic_inc(&gpio_open_cnt); - printk(KERN_ERR DRVNAME ": Device with minor ID %d already in use\n", dev_minor); - result = -EBUSY; - goto out; - } - out: return result; } @@ -116,9 +107,9 @@ out: static int gpio_close(struct inode * inode, struct file * file) { - smp_mb__before_atomic_inc(); - atomic_inc(&gpio_open_cnt); - + /* could track all <pin>s requested by this fd and gpio_free() + * them here + */ return 0; } @@ -140,22 +131,9 @@ gpio_probe(struct platform_device *dev) 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); - - if (dev->num_resources != 1) - { - printk(KERN_ERR DRVNAME ": device may only have 1 resource\n"); - result = -ENODEV; - goto out; - } - - gpio_access_mask = dev->resource[0].start; - - printk(KERN_INFO DRVNAME ": gpio platform device registered with access mask %08X\n", gpio_access_mask); out: return result; } @@ -182,7 +160,7 @@ gpio_mod_init(void) { int ret = platform_driver_register(&gpio_driver); if (ret) - printk(KERN_INFO DRVNAME ": Error registering platfom driver!"); + printk(KERN_INFO DRVNAME ": Error registering platfom driver!\n"); return ret; } @@ -197,5 +175,5 @@ module_init (gpio_mod_init); module_exit (gpio_mod_exit); MODULE_LICENSE("GPL"); -MODULE_AUTHOR("John Crispin / OpenWrt"); +MODULE_AUTHOR("John Crispin / OpenWrt +"); MODULE_DESCRIPTION("Character device for for generic gpio api"); diff --git a/target/linux/generic-2.6/files/include/linux/gpio_dev.h b/target/linux/generic-2.6/files/include/linux/gpio_dev.h index 3f3c9c772..a2a4b51c7 100644 --- a/target/linux/generic-2.6/files/include/linux/gpio_dev.h +++ b/target/linux/generic-2.6/files/include/linux/gpio_dev.h @@ -1,11 +1,42 @@ -#ifndef _GPIODEV_H__ -#define _GPIODEV_H__ +#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, <pin>) should be called + * after the open("/dev/gpio", O_RDWR) to determine if the <pin> is + * already in use. If the ioctl is successful (i.e. returns 0 for not + * in use) then the <pin> is claimed by this driver and + * ioctl(fd, GPIO_FREE, <pin>) should be called prior to close(fd) . + * + * See <kernel_source>/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 <pin> (low) */ + +#define GPIO_DIR_HIGH _IO(IOC_GPIODEV_MAGIC, 15) + /* Sets the direction out and sets the <pin> (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 |