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authorclaudio <claudio@3c298f89-4303-0410-b956-a3cf2f4a3e73>2010-06-13 13:27:06 +0000
committerclaudio <claudio@3c298f89-4303-0410-b956-a3cf2f4a3e73>2010-06-13 13:27:06 +0000
commit4f0d403f056957b064ddc5bc3cb37c45ba792223 (patch)
treeed26cbc988e7d712dcb64db00bf992402d5d9ef8 /target/linux/generic-2.6/files/drivers
parent17984c3bab278e1aed28dec6558943e4f445a2b4 (diff)
[kernel] Extend the gpio device driver (#5671)
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@21787 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/linux/generic-2.6/files/drivers')
-rw-r--r--target/linux/generic-2.6/files/drivers/char/gpio_dev.c78
1 files changed, 28 insertions, 50 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");