include/media/v4l2-subdev.h - kernel/msm - Gitiles

 /*
     V4L2 sub-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_SUBDEV_H
 #define _V4L2_SUBDEV_H

 #include <media/v4l2-common.h>

 struct v4l2_device;
 struct v4l2_subdev;
 struct tuner_setup;

 /* decode_vbi_line */
 struct v4l2_decode_vbi_line {
 	u32 is_second_field;	/* Set to 0 for the first (odd) field,
 				   set to 1 for the second (even) field. */
 	u8 *p; 			/* Pointer to the sliced VBI data from the decoder.
 				   On exit points to the start of the payload. */
 	u32 line;		/* Line number of the sliced VBI data (1-23) */
 	u32 type;		/* VBI service type (V4L2_SLICED_*). 0 if no service found */
 };

 /* Sub-devices are devices that are connected somehow to the main bridge
    device. These devices are usually audio/video muxers/encoders/decoders or
    sensors and webcam controllers.

    Usually these devices are controlled through an i2c bus, but other busses
    may also be used.

    The v4l2_subdev struct provides a way of accessing these devices in a
    generic manner. Most operations that these sub-devices support fall in
    a few categories: core ops, audio ops, video ops and tuner ops.

    More categories can be added if needed, although this should remain a
    limited set (no more than approx. 8 categories).

    Each category has its own set of ops that subdev drivers can implement.

    A subdev driver can leave the pointer to the category ops NULL if
    it does not implement them (e.g. an audio subdev will generally not
    implement the video category ops). The exception is the core category:
    this must always be present.

    These ops are all used internally so it is no problem to change, remove
    or add ops or move ops from one to another category. Currently these
    ops are based on the original ioctls, but since ops are not limited to
    one argument there is room for improvement here once all i2c subdev
    drivers are converted to use these ops.
  */

 /* Core ops: it is highly recommended to implement at least these ops:

    g_chip_ident
    log_status
    g_register
    s_register

    This provides basic debugging support.

    The ioctl ops is meant for generic ioctl-like commands. Depending on
    the use-case it might be better to use subdev-specific ops (currently
    not yet implemented) since ops provide proper type-checking.
  */

 /* init: initialize the sensor registors to some sort of reasonable default
 	values. Do not use for new drivers and should be removed in existing
 	drivers.

    load_fw: load firmware.

    reset: generic reset command. The argument selects which subsystems to
 	reset. Passing 0 will always reset the whole chip. Do not use for new
 	drivers without discussing this first on the linux-media mailinglist.
 	There should be no reason normally to reset a device.

    s_gpio: set GPIO pins. Very simple right now, might need to be extended with
 	a direction argument if needed.
  */
 struct v4l2_subdev_core_ops {
 	int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_dbg_chip_ident *chip);
 	int (*log_status)(struct v4l2_subdev *sd);
 	int (*init)(struct v4l2_subdev *sd, u32 val);
 	int (*load_fw)(struct v4l2_subdev *sd);
 	int (*reset)(struct v4l2_subdev *sd, u32 val);
 	int (*s_gpio)(struct v4l2_subdev *sd, u32 val);
 	int (*queryctrl)(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
 	int (*g_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 	int (*s_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 	int (*g_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 	int (*s_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 	int (*try_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 	int (*querymenu)(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
 	int (*s_std)(struct v4l2_subdev *sd, v4l2_std_id norm);
 	long (*ioctl)(struct v4l2_subdev *sd, unsigned int cmd, void *arg);
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 	int (*g_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 	int (*s_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 #endif
 };

 /* s_mode: switch the tuner to a specific tuner mode. Replacement of s_radio.

    s_radio: v4l device was opened in Radio mode, to be replaced by s_mode.

    s_type_addr: sets tuner type and its I2C addr.

    s_config: sets tda9887 specific stuff, like port1, port2 and qss

    s_standby: puts tuner on powersaving state, disabling it, except for i2c.
  */
 struct v4l2_subdev_tuner_ops {
 	int (*s_mode)(struct v4l2_subdev *sd, enum v4l2_tuner_type);
 	int (*s_radio)(struct v4l2_subdev *sd);
 	int (*s_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 	int (*g_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 	int (*g_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 	int (*s_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 	int (*s_type_addr)(struct v4l2_subdev *sd, struct tuner_setup *type);
 	int (*s_config)(struct v4l2_subdev *sd, const struct v4l2_priv_tun_config *config);
 	int (*s_standby)(struct v4l2_subdev *sd);
 };

 /* s_clock_freq: set the frequency (in Hz) of the audio clock output.
 	Used to slave an audio processor to the video decoder, ensuring that
 	audio and video remain synchronized. Usual values for the frequency
 	are 48000, 44100 or 32000 Hz. If the frequency is not supported, then
 	-EINVAL is returned.

    s_i2s_clock_freq: sets I2S speed in bps. This is used to provide a standard
 	way to select I2S clock used by driving digital audio streams at some
 	board designs. Usual values for the frequency are 1024000 and 2048000.
 	If the frequency is not supported, then -EINVAL is returned.

    s_routing: used to define the input and/or output pins of an audio chip,
 	and any additional configuration data.
 	Never attempt to use user-level input IDs (e.g. Composite, S-Video,
 	Tuner) at this level. An i2c device shouldn't know about whether an
 	input pin is connected to a Composite connector, become on another
 	board or platform it might be connected to something else entirely.
 	The calling driver is responsible for mapping a user-level input to
 	the right pins on the i2c device.
  */
 struct v4l2_subdev_audio_ops {
 	int (*s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 	int (*s_i2s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 	int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 };

 /*
    decode_vbi_line: video decoders that support sliced VBI need to implement
 	this ioctl. Field p of the v4l2_sliced_vbi_line struct is set to the
 	start of the VBI data that was generated by the decoder. The driver
 	then parses the sliced VBI data and sets the other fields in the
 	struct accordingly. The pointer p is updated to point to the start of
 	the payload which can be copied verbatim into the data field of the
 	v4l2_sliced_vbi_data struct. If no valid VBI data was found, then the
 	type field is set to 0 on return.

    s_vbi_data: used to generate VBI signals on a video signal.
 	v4l2_sliced_vbi_data is filled with the data packets that should be
 	output. Note that if you set the line field to 0, then that VBI signal
 	is disabled. If no valid VBI data was found, then the type field is
 	set to 0 on return.

    g_vbi_data: used to obtain the sliced VBI packet from a readback register.
 	Not all video decoders support this. If no data is available because
 	the readback register contains invalid or erroneous data -EIO is
 	returned. Note that you must fill in the 'id' member and the 'field'
 	member (to determine whether CC data from the first or second field
 	should be obtained).

    s_std_output: set v4l2_std_id for video OUTPUT devices. This is ignored by
 	video input devices.

   s_crystal_freq: sets the frequency of the crystal used to generate the
 	clocks in Hz. An extra flags field allows device specific configuration
 	regarding clock frequency dividers, etc. If not used, then set flags
 	to 0. If the frequency is not supported, then -EINVAL is returned.

    g_input_status: get input status. Same as the status field in the v4l2_input
 	struct.

    s_routing: see s_routing in audio_ops, except this version is for video
 	devices.
  */
 struct v4l2_subdev_video_ops {
 	int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 	int (*s_crystal_freq)(struct v4l2_subdev *sd, u32 freq, u32 flags);
 	int (*decode_vbi_line)(struct v4l2_subdev *sd, struct v4l2_decode_vbi_line *vbi_line);
 	int (*s_vbi_data)(struct v4l2_subdev *sd, const struct v4l2_sliced_vbi_data *vbi_data);
 	int (*g_vbi_data)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_data *vbi_data);
 	int (*g_sliced_vbi_cap)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_cap *cap);
 	int (*s_std_output)(struct v4l2_subdev *sd, v4l2_std_id std);
 	int (*querystd)(struct v4l2_subdev *sd, v4l2_std_id *std);
 	int (*g_input_status)(struct v4l2_subdev *sd, u32 *status);
 	int (*s_stream)(struct v4l2_subdev *sd, int enable);
 	int (*enum_fmt)(struct v4l2_subdev *sd, struct v4l2_fmtdesc *fmtdesc);
 	int (*g_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 	int (*try_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 	int (*s_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 	int (*g_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm *param);
 	int (*s_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm *param);
 	int (*enum_framesizes)(struct v4l2_subdev *sd, struct v4l2_frmsizeenum *fsize);
 	int (*enum_frameintervals)(struct v4l2_subdev *sd, struct v4l2_frmivalenum *fival);
 };

 struct v4l2_subdev_ops {
 	const struct v4l2_subdev_core_ops  *core;
 	const struct v4l2_subdev_tuner_ops *tuner;
 	const struct v4l2_subdev_audio_ops *audio;
 	const struct v4l2_subdev_video_ops *video;
 };

 #define V4L2_SUBDEV_NAME_SIZE 32

 /* Set this flag if this subdev is a i2c device. */
 #define V4L2_SUBDEV_FL_IS_I2C (1U << 0)

 /* Each instance of a subdev driver should create this struct, either
    stand-alone or embedded in a larger struct.
  */
 struct v4l2_subdev {
 	struct list_head list;
 	struct module *owner;
 	u32 flags;
 	struct v4l2_device *v4l2_dev;
 	const struct v4l2_subdev_ops *ops;
 	/* name must be unique */
 	char name[V4L2_SUBDEV_NAME_SIZE];
 	/* can be used to group similar subdevs, value is driver-specific */
 	u32 grp_id;
 	/* pointer to private data */
 	void *priv;
 };

 static inline void v4l2_set_subdevdata(struct v4l2_subdev *sd, void *p)
 {
 	sd->priv = p;
 }

 static inline void *v4l2_get_subdevdata(const struct v4l2_subdev *sd)
 {
 	return sd->priv;
 }

 static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
 					const struct v4l2_subdev_ops *ops)
 {
 	INIT_LIST_HEAD(&sd->list);
 	/* ops->core MUST be set */
 	BUG_ON(!ops || !ops->core);
 	sd->ops = ops;
 	sd->v4l2_dev = NULL;
 	sd->flags = 0;
 	sd->name[0] = '\0';
 	sd->grp_id = 0;
 	sd->priv = NULL;
 }

 /* Call an ops of a v4l2_subdev, doing the right checks against
    NULL pointers.

    Example: err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
  */
 #define v4l2_subdev_call(sd, o, f, args...)				\
 	(!(sd) ? -ENODEV : (((sd) && (sd)->ops->o && (sd)->ops->o->f) ?	\
 		(sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))

 /* Send a notification to v4l2_device. */
 #define v4l2_subdev_notify(sd, notification, arg)			   \
 	((!(sd) || !(sd)->v4l2_dev || !(sd)->v4l2_dev->notify) ? -ENODEV : \
 	 (sd)->v4l2_dev->notify((sd), (notification), (arg)))

 #endif
	/*
	V4L2 sub-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_SUBDEV_H
	#define _V4L2_SUBDEV_H

	#include <media/v4l2-common.h>

	struct v4l2_device;
	struct v4l2_subdev;
	struct tuner_setup;

	/* decode_vbi_line */
	struct v4l2_decode_vbi_line {
	u32 is_second_field; /* Set to 0 for the first (odd) field,
	set to 1 for the second (even) field. */
	u8 p; / Pointer to the sliced VBI data from the decoder.
	On exit points to the start of the payload. */
	u32 line; /* Line number of the sliced VBI data (1-23) */
	u32 type; /* VBI service type (V4L2_SLICED_). 0 if no service found /
	};

	/* Sub-devices are devices that are connected somehow to the main bridge
	device. These devices are usually audio/video muxers/encoders/decoders or
	sensors and webcam controllers.

	Usually these devices are controlled through an i2c bus, but other busses
	may also be used.

	The v4l2_subdev struct provides a way of accessing these devices in a
	generic manner. Most operations that these sub-devices support fall in
	a few categories: core ops, audio ops, video ops and tuner ops.

	More categories can be added if needed, although this should remain a
	limited set (no more than approx. 8 categories).

	Each category has its own set of ops that subdev drivers can implement.

	A subdev driver can leave the pointer to the category ops NULL if
	it does not implement them (e.g. an audio subdev will generally not
	implement the video category ops). The exception is the core category:
	this must always be present.

	These ops are all used internally so it is no problem to change, remove
	or add ops or move ops from one to another category. Currently these
	ops are based on the original ioctls, but since ops are not limited to
	one argument there is room for improvement here once all i2c subdev
	drivers are converted to use these ops.
	*/

	/* Core ops: it is highly recommended to implement at least these ops:

	g_chip_ident
	log_status
	g_register
	s_register

	This provides basic debugging support.

	The ioctl ops is meant for generic ioctl-like commands. Depending on
	the use-case it might be better to use subdev-specific ops (currently
	not yet implemented) since ops provide proper type-checking.
	*/

	/* init: initialize the sensor registors to some sort of reasonable default
	values. Do not use for new drivers and should be removed in existing
	drivers.

	load_fw: load firmware.

	reset: generic reset command. The argument selects which subsystems to
	reset. Passing 0 will always reset the whole chip. Do not use for new
	drivers without discussing this first on the linux-media mailinglist.
	There should be no reason normally to reset a device.

	s_gpio: set GPIO pins. Very simple right now, might need to be extended with
	a direction argument if needed.
	*/
	struct v4l2_subdev_core_ops {
	int (g_chip_ident)(struct v4l2_subdev sd, struct v4l2_dbg_chip_ident *chip);
	int (log_status)(struct v4l2_subdev sd);
	int (init)(struct v4l2_subdev sd, u32 val);
	int (load_fw)(struct v4l2_subdev sd);
	int (reset)(struct v4l2_subdev sd, u32 val);
	int (s_gpio)(struct v4l2_subdev sd, u32 val);
	int (queryctrl)(struct v4l2_subdev sd, struct v4l2_queryctrl *qc);
	int (g_ctrl)(struct v4l2_subdev sd, struct v4l2_control *ctrl);
	int (s_ctrl)(struct v4l2_subdev sd, struct v4l2_control *ctrl);
	int (g_ext_ctrls)(struct v4l2_subdev sd, struct v4l2_ext_controls *ctrls);
	int (s_ext_ctrls)(struct v4l2_subdev sd, struct v4l2_ext_controls *ctrls);
	int (try_ext_ctrls)(struct v4l2_subdev sd, struct v4l2_ext_controls *ctrls);
	int (querymenu)(struct v4l2_subdev sd, struct v4l2_querymenu *qm);
	int (s_std)(struct v4l2_subdev sd, v4l2_std_id norm);
	long (ioctl)(struct v4l2_subdev sd, unsigned int cmd, void *arg);
	#ifdef CONFIG_VIDEO_ADV_DEBUG
	int (g_register)(struct v4l2_subdev sd, struct v4l2_dbg_register *reg);
	int (s_register)(struct v4l2_subdev sd, struct v4l2_dbg_register *reg);
	#endif
	};

	/* s_mode: switch the tuner to a specific tuner mode. Replacement of s_radio.

	s_radio: v4l device was opened in Radio mode, to be replaced by s_mode.

	s_type_addr: sets tuner type and its I2C addr.

	s_config: sets tda9887 specific stuff, like port1, port2 and qss

	s_standby: puts tuner on powersaving state, disabling it, except for i2c.
	*/
	struct v4l2_subdev_tuner_ops {
	int (s_mode)(struct v4l2_subdev sd, enum v4l2_tuner_type);
	int (s_radio)(struct v4l2_subdev sd);
	int (s_frequency)(struct v4l2_subdev sd, struct v4l2_frequency *freq);
	int (g_frequency)(struct v4l2_subdev sd, struct v4l2_frequency *freq);
	int (g_tuner)(struct v4l2_subdev sd, struct v4l2_tuner *vt);
	int (s_tuner)(struct v4l2_subdev sd, struct v4l2_tuner *vt);
	int (s_type_addr)(struct v4l2_subdev sd, struct tuner_setup *type);
	int (s_config)(struct v4l2_subdev sd, const struct v4l2_priv_tun_config *config);
	int (s_standby)(struct v4l2_subdev sd);
	};

	/* s_clock_freq: set the frequency (in Hz) of the audio clock output.
	Used to slave an audio processor to the video decoder, ensuring that
	audio and video remain synchronized. Usual values for the frequency
	are 48000, 44100 or 32000 Hz. If the frequency is not supported, then
	-EINVAL is returned.

	s_i2s_clock_freq: sets I2S speed in bps. This is used to provide a standard
	way to select I2S clock used by driving digital audio streams at some
	board designs. Usual values for the frequency are 1024000 and 2048000.
	If the frequency is not supported, then -EINVAL is returned.

	s_routing: used to define the input and/or output pins of an audio chip,
	and any additional configuration data.
	Never attempt to use user-level input IDs (e.g. Composite, S-Video,
	Tuner) at this level. An i2c device shouldn't know about whether an
	input pin is connected to a Composite connector, become on another
	board or platform it might be connected to something else entirely.
	The calling driver is responsible for mapping a user-level input to
	the right pins on the i2c device.
	*/
	struct v4l2_subdev_audio_ops {
	int (s_clock_freq)(struct v4l2_subdev sd, u32 freq);
	int (s_i2s_clock_freq)(struct v4l2_subdev sd, u32 freq);
	int (s_routing)(struct v4l2_subdev sd, u32 input, u32 output, u32 config);
	};

	/*
	decode_vbi_line: video decoders that support sliced VBI need to implement
	this ioctl. Field p of the v4l2_sliced_vbi_line struct is set to the
	start of the VBI data that was generated by the decoder. The driver
	then parses the sliced VBI data and sets the other fields in the
	struct accordingly. The pointer p is updated to point to the start of
	the payload which can be copied verbatim into the data field of the
	v4l2_sliced_vbi_data struct. If no valid VBI data was found, then the
	type field is set to 0 on return.

	s_vbi_data: used to generate VBI signals on a video signal.
	v4l2_sliced_vbi_data is filled with the data packets that should be
	output. Note that if you set the line field to 0, then that VBI signal
	is disabled. If no valid VBI data was found, then the type field is
	set to 0 on return.

	g_vbi_data: used to obtain the sliced VBI packet from a readback register.
	Not all video decoders support this. If no data is available because
	the readback register contains invalid or erroneous data -EIO is
	returned. Note that you must fill in the 'id' member and the 'field'
	member (to determine whether CC data from the first or second field
	should be obtained).

	s_std_output: set v4l2_std_id for video OUTPUT devices. This is ignored by
	video input devices.

	s_crystal_freq: sets the frequency of the crystal used to generate the
	clocks in Hz. An extra flags field allows device specific configuration
	regarding clock frequency dividers, etc. If not used, then set flags
	to 0. If the frequency is not supported, then -EINVAL is returned.

	g_input_status: get input status. Same as the status field in the v4l2_input
	struct.

	s_routing: see s_routing in audio_ops, except this version is for video
	devices.
	*/
	struct v4l2_subdev_video_ops {
	int (s_routing)(struct v4l2_subdev sd, u32 input, u32 output, u32 config);
	int (s_crystal_freq)(struct v4l2_subdev sd, u32 freq, u32 flags);
	int (decode_vbi_line)(struct v4l2_subdev sd, struct v4l2_decode_vbi_line *vbi_line);
	int (s_vbi_data)(struct v4l2_subdev sd, const struct v4l2_sliced_vbi_data *vbi_data);
	int (g_vbi_data)(struct v4l2_subdev sd, struct v4l2_sliced_vbi_data *vbi_data);
	int (g_sliced_vbi_cap)(struct v4l2_subdev sd, struct v4l2_sliced_vbi_cap *cap);
	int (s_std_output)(struct v4l2_subdev sd, v4l2_std_id std);
	int (querystd)(struct v4l2_subdev sd, v4l2_std_id *std);
	int (g_input_status)(struct v4l2_subdev sd, u32 *status);
	int (s_stream)(struct v4l2_subdev sd, int enable);
	int (enum_fmt)(struct v4l2_subdev sd, struct v4l2_fmtdesc *fmtdesc);
	int (g_fmt)(struct v4l2_subdev sd, struct v4l2_format *fmt);
	int (try_fmt)(struct v4l2_subdev sd, struct v4l2_format *fmt);
	int (s_fmt)(struct v4l2_subdev sd, struct v4l2_format *fmt);
	int (g_parm)(struct v4l2_subdev sd, struct v4l2_streamparm *param);
	int (s_parm)(struct v4l2_subdev sd, struct v4l2_streamparm *param);
	int (enum_framesizes)(struct v4l2_subdev sd, struct v4l2_frmsizeenum *fsize);
	int (enum_frameintervals)(struct v4l2_subdev sd, struct v4l2_frmivalenum *fival);
	};

	struct v4l2_subdev_ops {
	const struct v4l2_subdev_core_ops *core;
	const struct v4l2_subdev_tuner_ops *tuner;
	const struct v4l2_subdev_audio_ops *audio;
	const struct v4l2_subdev_video_ops *video;
	};

	#define V4L2_SUBDEV_NAME_SIZE 32

	/* Set this flag if this subdev is a i2c device. */
	#define V4L2_SUBDEV_FL_IS_I2C (1U << 0)

	/* Each instance of a subdev driver should create this struct, either
	stand-alone or embedded in a larger struct.
	*/
	struct v4l2_subdev {
	struct list_head list;
	struct module *owner;
	u32 flags;
	struct v4l2_device *v4l2_dev;
	const struct v4l2_subdev_ops *ops;
	/* name must be unique */
	char name[V4L2_SUBDEV_NAME_SIZE];
	/* can be used to group similar subdevs, value is driver-specific */
	u32 grp_id;
	/* pointer to private data */
	void *priv;
	};

	static inline void v4l2_set_subdevdata(struct v4l2_subdev sd, void p)
	{
	sd->priv = p;
	}

	static inline void v4l2_get_subdevdata(const struct v4l2_subdev sd)
	{
	return sd->priv;
	}

	static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
	const struct v4l2_subdev_ops *ops)
	{
	INIT_LIST_HEAD(&sd->list);
	/* ops->core MUST be set */
	BUG_ON(!ops \|\| !ops->core);
	sd->ops = ops;
	sd->v4l2_dev = NULL;
	sd->flags = 0;
	sd->name[0] = '\0';
	sd->grp_id = 0;
	sd->priv = NULL;
	}

	/* Call an ops of a v4l2_subdev, doing the right checks against
	NULL pointers.

	Example: err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
	*/
	#define v4l2_subdev_call(sd, o, f, args...) \
	(!(sd) ? -ENODEV : (((sd) && (sd)->ops->o && (sd)->ops->o->f) ? \
	(sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))

	/* Send a notification to v4l2_device. */
	#define v4l2_subdev_notify(sd, notification, arg) \
	((!(sd) \|\| !(sd)->v4l2_dev \|\| !(sd)->v4l2_dev->notify) ? -ENODEV : \
	(sd)->v4l2_dev->notify((sd), (notification), (arg)))

	#endif