linux/include/media/v4l2-device.h
Hans Verkuil 0996517cf8 V4L/DVB: v4l2: Add new control handling framework
Add a new framework to handle controls which makes life for driver
developers much easier.

Note that this patch moves some of the control support that used to be in
v4l2-common.c to v4l2-ctrls.c. The tables were copied unchanged. The body
of v4l2_ctrl_query_fill() was copied to a new v4l2_ctrl_fill() function
in v4l2-ctrls.c. This new function doesn't use the v4l2_queryctrl
struct anymore, which makes it more general.

The remainder of v4l2-ctrls.c is all new. Highlights include:

- No need to implement VIDIOC_QUERYCTRL, QUERYMENU, S_CTRL, G_CTRL,
  S_EXT_CTRLS, G_EXT_CTRLS or TRY_EXT_CTRLS in either bridge drivers
  or subdevs. New wrapper functions are provided that can just be plugged in.
  Once everything has been converted these wrapper functions can be removed as well.

- When subdevices are added their controls can be automatically merged
  with the bridge driver's controls.

- Most drivers just need to implement s_ctrl to set the controls.
  The framework handles the locking and tries to be as 'atomic' as possible.

- Ready for the subdev device nodes: the same mechanism applies to subdevs
  and their device nodes as well. Sub-device drivers can make controls
  local, preventing them from being merged with bridge drivers.

- Takes care of backwards compatibility handling of VIDIOC_S_CTRL and
  VIDIOC_G_CTRL. Handling of V4L2_CID_PRIVATE_BASE is fully transparent.
  CTRL_CLASS controls are automatically added.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:43:03 -03:00

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5.8 KiB
C

/*
V4L2 device support header.
Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _V4L2_DEVICE_H
#define _V4L2_DEVICE_H
#include <media/v4l2-subdev.h>
/* Each instance of a V4L2 device should create the v4l2_device struct,
either stand-alone or embedded in a larger struct.
It allows easy access to sub-devices (see v4l2-subdev.h) and provides
basic V4L2 device-level support.
*/
#define V4L2_DEVICE_NAME_SIZE (20 + 16)
struct v4l2_ctrl_handler;
struct v4l2_device {
/* dev->driver_data points to this struct.
Note: dev might be NULL if there is no parent device
as is the case with e.g. ISA devices. */
struct device *dev;
/* used to keep track of the registered subdevs */
struct list_head subdevs;
/* lock this struct; can be used by the driver as well if this
struct is embedded into a larger struct. */
spinlock_t lock;
/* unique device name, by default the driver name + bus ID */
char name[V4L2_DEVICE_NAME_SIZE];
/* notify callback called by some sub-devices. */
void (*notify)(struct v4l2_subdev *sd,
unsigned int notification, void *arg);
/* The control handler. May be NULL. */
struct v4l2_ctrl_handler *ctrl_handler;
};
/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
dev may be NULL in rare cases (ISA devices). In that case you
must fill in the v4l2_dev->name field before calling this function. */
int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
/* Optional function to initialize the name field of struct v4l2_device using
the driver name and a driver-global atomic_t instance.
This function will increment the instance counter and returns the instance
value used in the name.
Example:
static atomic_t drv_instance = ATOMIC_INIT(0);
...
instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
The first time this is called the name field will be set to foo0 and
this function returns 0. If the name ends with a digit (e.g. cx18),
then the name will be set to cx18-0 since cx180 looks really odd. */
int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
atomic_t *instance);
/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
Since the parent disappears this ensures that v4l2_dev doesn't have an
invalid parent pointer. */
void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
/* Unregister all sub-devices and any other resources related to v4l2_dev. */
void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
/* Register a subdev with a v4l2 device. While registered the subdev module
is marked as in-use. An error is returned if the module is no longer
loaded when you attempt to register it. */
int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
struct v4l2_subdev *sd);
/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
wasn't registered. In that case it will do nothing. */
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
/* Iterate over all subdevs. */
#define v4l2_device_for_each_subdev(sd, v4l2_dev) \
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
/* Call the specified callback for all subdevs matching the condition.
Ignore any errors. Note that you cannot add or delete a subdev
while walking the subdevs list. */
#define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...) \
do { \
struct v4l2_subdev *sd; \
\
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) \
if ((cond) && sd->ops->o && sd->ops->o->f) \
sd->ops->o->f(sd , ##args); \
} while (0)
/* Call the specified callback for all subdevs matching the condition.
If the callback returns an error other than 0 or -ENOIOCTLCMD, then
return with that error code. Note that you cannot add or delete a
subdev while walking the subdevs list. */
#define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
({ \
struct v4l2_subdev *sd; \
long err = 0; \
\
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) { \
if ((cond) && sd->ops->o && sd->ops->o->f) \
err = sd->ops->o->f(sd , ##args); \
if (err && err != -ENOIOCTLCMD) \
break; \
} \
(err == -ENOIOCTLCMD) ? 0 : err; \
})
/* Call the specified callback for all subdevs matching grp_id (if 0, then
match them all). Ignore any errors. Note that you cannot add or delete
a subdev while walking the subdevs list. */
#define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs(v4l2_dev, \
!(grpid) || sd->grp_id == (grpid), o, f , ##args)
/* Call the specified callback for all subdevs matching grp_id (if 0, then
match them all). If the callback returns an error other than 0 or
-ENOIOCTLCMD, then return with that error code. Note that you cannot
add or delete a subdev while walking the subdevs list. */
#define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs_until_err(v4l2_dev, \
!(grpid) || sd->grp_id == (grpid), o, f , ##args)
#endif