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Subject[PATCH v2 02/15] [media] lirc_dev: allow bufferless driver registration
Date
Some drivers don't necessarily need to have a FIFO managed buffer
for their transfers. Drivers now should call
lirc_register_bufferless_driver in order to handle the buffer
themselves.

The function works exaclty like lirc_register_driver except of
the buffer allocation.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
---
drivers/media/rc/lirc_dev.c | 44 ++++++++++++++++++++++++++++++++++----------
include/media/lirc_dev.h | 12 ++++++++++++
2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c
index 5716978..fa562a3 100644
--- 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;

@@ -385,8 +388,29 @@ out_lock:
out:
return err;
}
+
+int lirc_register_driver(struct lirc_driver *d)
+{
+ int err, minor;
+
+ minor = lirc_allocate_driver(d);
+ if (minor < 0)
+ return minor;
+
+ err = lirc_allocate_buffer(irctls[minor]);
+ if (err)
+ lirc_unregister_driver(minor);
+
+ return err ? err : minor;
+}
EXPORT_SYMBOL(lirc_register_driver);

+int lirc_register_bufferless_driver(struct lirc_driver *d)
+{
+ return lirc_allocate_driver(d);
+}
+EXPORT_SYMBOL(lirc_register_bufferless_driver);
+
int lirc_unregister_driver(int minor)
{
struct irctl *ir;
diff --git a/include/media/lirc_dev.h b/include/media/lirc_dev.h
index 0ab59a5..8bed57a 100644
--- a/include/media/lirc_dev.h
+++ b/include/media/lirc_dev.h
@@ -214,6 +214,18 @@ struct lirc_driver {
*/
extern int lirc_register_driver(struct lirc_driver *d);

+/* int lirc_register_bufferless_driver - allocates a lirc bufferless driver
+ * @d: reference to the lirc_driver to initialize
+ *
+ * The difference between lirc_register_driver and
+ * lirc_register_bufferless_driver is that the latter doesn't allocate any
+ * buffer, which means that the driver using the lirc_driver should take care of
+ * it by itself.
+ *
+ * returns 0 on success or a the negative errno number in case of failure.
+ */
+extern int lirc_register_bufferless_driver(struct lirc_driver *d);
+
/* returns negative value on error or 0 if success
*/
extern int lirc_unregister_driver(int minor);
--
2.8.1
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