[media] lirc_dev: allow bufferless driver registration

Transmitters don't necessarily need to have a FIFO managed buffer
for their transfers.

When registering the driver, before allocating the buffer, check
whether the device is a transmitter or receiver. Allocate the
buffer only for receivers.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c
index 571697811e4d50deb18c0e021c494f6f95d7a669..154e553b3b67e8a67414e9760c990ce2c77932d1 100644 (file)
--- a/drivers/media/rc/lirc_dev.c
+++ b/drivers/media/rc/lirc_dev.c
@@ -205,12 +205,14 @@ err_out:
 
 static int lirc_allocate_buffer(struct irctl *ir)
 {
-       int err;
+       int err = 0;
        int bytes_in_key;
        unsigned int chunk_size;
        unsigned int buffer_size;
        struct lirc_driver *d = &ir->d;
 
+       mutex_lock(&lirc_dev_lock);
+
        bytes_in_key = BITS_TO_LONGS(d->code_length) +
                                                (d->code_length % 8 ? 1 : 0);
        buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
@@ -220,21 +222,26 @@ static int lirc_allocate_buffer(struct irctl *ir)
                ir->buf = d->rbuf;
        } else {
                ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
-               if (!ir->buf)
-                       return -ENOMEM;
+               if (!ir->buf) {
+                       err = -ENOMEM;
+                       goto out;
+               }
 
                err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
                if (err) {
                        kfree(ir->buf);
-                       return err;
+                       goto out;
                }
        }
        ir->chunk_size = ir->buf->chunk_size;
 
-       return 0;
+out:
+       mutex_unlock(&lirc_dev_lock);
+
+       return err;
 }
 
-int lirc_register_driver(struct lirc_driver *d)
+static int lirc_allocate_driver(struct lirc_driver *d)
 {
        struct irctl *ir;
        int minor;
@@ -342,10 +349,6 @@ int lirc_register_driver(struct lirc_driver *d)
        /* some safety check 8-) */
        d->name[sizeof(d->name)-1] = '\0';
 
-       err = lirc_allocate_buffer(ir);
-       if (err)
-               goto out_lock;
-
        if (d->features == 0)
                d->features = LIRC_CAN_REC_LIRCCODE;
 
@@ -385,6 +388,23 @@ out_lock:
 out:
        return err;
 }
+
+int lirc_register_driver(struct lirc_driver *d)
+{
+       int minor, err = 0;
+
+       minor = lirc_allocate_driver(d);
+       if (minor < 0)
+               return minor;
+
+       if (LIRC_CAN_REC(d->features)) {
+               err = lirc_allocate_buffer(irctls[minor]);
+               if (err)
+                       lirc_unregister_driver(minor);
+       }
+
+       return err ? err : minor;
+}
 EXPORT_SYMBOL(lirc_register_driver);
 
 int lirc_unregister_driver(int minor)