[REVIEW,01/14] V4L: Int if: Dummy slave
Commit Message
This patch implements a dummy slave that has no functionality. Helps
managing slaves in the OMAP 3 camera driver; no need to check for NULL
pointers.
Signed-off-by: Sakari Ailus <sakari.ailus@nokia.com>
Signed-off-by: Sergio Aguirre <saaguirre@ti.com>
---
drivers/media/video/v4l2-int-device.c | 19 +++++++++++++++++++
include/media/v4l2-int-device.h | 2 ++
2 files changed, 21 insertions(+), 0 deletions(-)
Comments
Mauro Carvalho Chehab wrote:
> On Mon, 12 Jan 2009 20:03:08 -0600
> "Aguirre Rodriguez, Sergio Alberto" <saaguirre@ti.com> wrote:
>
>> +static struct v4l2_int_slave dummy_slave = {
>> + /* Dummy pointer to avoid underflow in find_ioctl. */
>> + .ioctls = (void *)0x80000000,
>
> Why are you using here a magic number?
Not really a reason. It could be or actually perhaps anything equal to
or bigger than sizeof(struct v4l2_int_ioctl_desc) so that last doesn't
underflow:
const struct v4l2_int_ioctl_desc *first = slave->ioctls;
const struct v4l2_int_ioctl_desc *last =
first + slave->num_ioctls - 1;
num_ioctls is zero. See find_ioctl in drivers/media/video/v4l2-int-device.c.
I guess that should be changed to sizeof(struct v4l2_int_ioctl_desc).
@@ -32,6 +32,25 @@
static DEFINE_MUTEX(mutex);
static LIST_HEAD(int_list);
+static struct v4l2_int_slave dummy_slave = {
+ /* Dummy pointer to avoid underflow in find_ioctl. */
+ .ioctls = (void *)0x80000000,
+ .num_ioctls = 0,
+};
+
+static struct v4l2_int_device dummy = {
+ .type = v4l2_int_type_slave,
+ .u = {
+ .slave = &dummy_slave,
+ },
+};
+
+struct v4l2_int_device *v4l2_int_device_dummy()
+{
+ return &dummy;
+}
+EXPORT_SYMBOL_GPL(v4l2_int_device_dummy);
+
void v4l2_int_device_try_attach_all(void)
{
struct v4l2_int_device *m, *s;
@@ -84,6 +84,8 @@ struct v4l2_int_device {
void *priv;
};
+struct v4l2_int_device *v4l2_int_device_dummy(void);
+
void v4l2_int_device_try_attach_all(void);
int v4l2_int_device_register(struct v4l2_int_device *d);