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authorHans J. Koch <hjk@linutronix.de>2008-05-23 15:50:14 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-07-22 08:54:55 +0400
commit328a14e70e7f46997cb50d4258dd93d5377f98c6 (patch)
tree7cc64b122fc45af454d4dde9f561b329d9f2b0c4 /drivers/uio/uio.c
parent934da4766e5f72797118f7c014efaef567a812fc (diff)
downloadlinux-328a14e70e7f46997cb50d4258dd93d5377f98c6.tar.xz
UIO: Add write function to allow irq masking
Sometimes it is necessary to enable/disable the interrupt of a UIO device from the userspace part of the driver. With this patch, the UIO kernel driver can implement an "irqcontrol()" function that does this. Userspace can write an s32 value to /dev/uioX (usually 0 or 1 to turn the irq off or on). The UIO core will then call the driver's irqcontrol function. Signed-off-by: Hans J. Koch <hjk@linutronix.de> Acked-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com> Acked-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/uio/uio.c')
-rw-r--r--drivers/uio/uio.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 5a7ca2e6094d..3a6934bf7131 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -427,6 +427,31 @@ static ssize_t uio_read(struct file *filep, char __user *buf,
return retval;
}
+static ssize_t uio_write(struct file *filep, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct uio_listener *listener = filep->private_data;
+ struct uio_device *idev = listener->dev;
+ ssize_t retval;
+ s32 irq_on;
+
+ if (idev->info->irq == UIO_IRQ_NONE)
+ return -EIO;
+
+ if (count != sizeof(s32))
+ return -EINVAL;
+
+ if (!idev->info->irqcontrol)
+ return -ENOSYS;
+
+ if (copy_from_user(&irq_on, buf, count))
+ return -EFAULT;
+
+ retval = idev->info->irqcontrol(idev->info, irq_on);
+
+ return retval ? retval : sizeof(s32);
+}
+
static int uio_find_mem_index(struct vm_area_struct *vma)
{
int mi;
@@ -546,6 +571,7 @@ static const struct file_operations uio_fops = {
.open = uio_open,
.release = uio_release,
.read = uio_read,
+ .write = uio_write,
.mmap = uio_mmap,
.poll = uio_poll,
.fasync = uio_fasync,