Similar to read() you can only write() a single event with one call to an
uhid device. To write multiple events use writev() which is supported by
uhid.
We currently always return -EOPNOTSUPP but other events will be added in
later patches.
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
---
drivers/hid/uhid.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 9386082..31e8379 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -30,6 +30,7 @@
struct uhid_device {
struct mutex devlock;
struct hid_device *hid;
+ struct uhid_event input_buf;
wait_queue_head_t waitq;
spinlock_t qlock;
@@ -156,7 +157,35 @@ try_again:
static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
- return 0;
+ struct uhid_device *uhid = file->private_data;
+ int ret;
+ size_t len;
+
+ /* we need at least the "type" member of uhid_event */
+ if (count < sizeof(__u32))
+ return -EINVAL;
+
+ ret = mutex_lock_interruptible(&uhid->devlock);
+ if (ret)
+ return ret;
+
+ memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
+ len = min(count, sizeof(uhid->input_buf));
+ if (copy_from_user(&uhid->input_buf, buffer, len)) {
+ ret = -EFAULT;
+ goto unlock;
+ }
+
+ switch (uhid->input_buf.type) {
+ default:
+ ret = -EOPNOTSUPP;
+ }
+
+unlock:
+ mutex_unlock(&uhid->devlock);
+
+ /* return "count" not "len" to not confuse the caller */
+ return ret ? ret : count;
}
static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
--
1.7.10.4
--
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