include/media/v4l2-subdev.h - kernel/common - Git at Google


            
            /*

            
                V4L2 sub-device support header.


                Copyright (C) 2008  Hans Verkuil <[email protected]>


                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>

            
            #include <media/v4l2-mediabus.h>


            /* generic v4l2_device notify callback notification values */

            
            #define V4L2_SUBDEV_IR_RX_NOTIFY		_IOW('v', 0, u32)

            
            #define V4L2_SUBDEV_IR_RX_FIFO_SERVICE_REQ	0x00000001

            
            #define V4L2_SUBDEV_IR_RX_END_OF_RX_DETECTED	0x00000002

            
            #define V4L2_SUBDEV_IR_RX_HW_FIFO_OVERRUN	0x00000004

            
            #define V4L2_SUBDEV_IR_RX_SW_FIFO_OVERRUN	0x00000008


            #define V4L2_SUBDEV_IR_TX_NOTIFY		_IOW('v', 1, u32)

            
            #define V4L2_SUBDEV_IR_TX_FIFO_SERVICE_REQ	0x00000001


            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.

            
             */


            /* s_config: if set, then it is always called by the v4l2_i2c_new_subdev*

            
            	functions after the v4l2_subdev was registered. It is used to pass

            
            	platform data to the subdev which can be used during initialization.


               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.


               s_power: puts subdevice in power saving mode (on == 0) or normal operation

            
            	mode (on == 1).

            
             */

            
            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 (*s_config)(struct v4l2_subdev *sd, int irq, void *platform_data);

            
            	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

            
            	int (*s_power)(struct v4l2_subdev *sd, int on);

            
            };


            /* 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

            
             */

            
            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 (*g_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);

            
            	int (*s_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);

            
            	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);

            
            };


            /* 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.


               s_dv_preset: set dv (Digital Video) preset in the sub device. Similar to

            
            	s_std()


               query_dv_preset: query dv preset in the sub device. This is similar to

            
            	querystd()


               s_dv_timings(): Set custom dv timings in the sub device. This is used

            
            	when sub device is capable of setting detailed timing information

            
            	in the hardware to generate/detect the video signal.


               g_dv_timings(): Get custom dv timings in the sub device.


               enum_mbus_fmt: enumerate pixel formats, provided by a video data source


               g_mbus_fmt: get the current pixel format, provided by a video data source


               try_mbus_fmt: try to set a pixel format on a video data source


               s_mbus_fmt: set a pixel format on a video data source

            
             */

            
            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 (*cropcap)(struct v4l2_subdev *sd, struct v4l2_cropcap *cc);

            
            	int (*g_crop)(struct v4l2_subdev *sd, struct v4l2_crop *crop);

            
            	int (*s_crop)(struct v4l2_subdev *sd, struct v4l2_crop *crop);

            
            	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);

            
            	int (*s_dv_preset)(struct v4l2_subdev *sd,

            
            			struct v4l2_dv_preset *preset);

            
            	int (*query_dv_preset)(struct v4l2_subdev *sd,

            
            			struct v4l2_dv_preset *preset);

            
            	int (*s_dv_timings)(struct v4l2_subdev *sd,

            
            			struct v4l2_dv_timings *timings);

            
            	int (*g_dv_timings)(struct v4l2_subdev *sd,

            
            			struct v4l2_dv_timings *timings);

            
            	int (*enum_mbus_fmt)(struct v4l2_subdev *sd, int index,

            
            			     enum v4l2_mbus_pixelcode *code);

            
            	int (*g_mbus_fmt)(struct v4l2_subdev *sd,

            
            			  struct v4l2_mbus_framefmt *fmt);

            
            	int (*try_mbus_fmt)(struct v4l2_subdev *sd,

            
            			    struct v4l2_mbus_framefmt *fmt);

            
            	int (*s_mbus_fmt)(struct v4l2_subdev *sd,

            
            			  struct v4l2_mbus_framefmt *fmt);

            
            };


            /**

            
             * struct v4l2_subdev_sensor_ops - v4l2-subdev sensor operations

            
             * @g_skip_top_lines: number of lines at the top of the image to be skipped.

            
             *		      This is needed for some sensors, which always corrupt

            
             *		      several top lines of the output image, or which send their

            
             *		      metadata in them.

            
             */

            
            struct v4l2_subdev_sensor_ops {

            
            	int (*g_skip_top_lines)(struct v4l2_subdev *sd, u32 *lines);

            
            };


            /*

            
               interrupt_service_routine: Called by the bridge chip's interrupt service

            
            	handler, when an IR interrupt status has be raised due to this subdev,

            
            	so that this subdev can handle the details.  It may schedule work to be

            
            	performed later.  It must not sleep.  *Called from an IRQ context*.


               [rt]x_g_parameters: Get the current operating parameters and state of the

            
            	the IR receiver or transmitter.


               [rt]x_s_parameters: Set the current operating parameters and state of the

            
            	the IR receiver or transmitter.  It is recommended to call

            
            	[rt]x_g_parameters first to fill out the current state, and only change

            
            	the fields that need to be changed.  Upon return, the actual device

            
            	operating parameters and state will be returned.  Note that hardware

            
            	limitations may prevent the actual settings from matching the requested

            
            	settings - e.g. an actual carrier setting of 35,904 Hz when 36,000 Hz

            
            	was requested.  An exception is when the shutdown parameter is true.

            
            	The last used operational parameters will be returned, but the actual

            
            	state of the hardware be different to minimize power consumption and

            
            	processing when shutdown is true.


               rx_read: Reads received codes or pulse width data.

            
            	The semantics are similar to a non-blocking read() call.


               tx_write: Writes codes or pulse width data for transmission.

            
            	The semantics are similar to a non-blocking write() call.

            
             */


            enum v4l2_subdev_ir_mode {

            
            	V4L2_SUBDEV_IR_MODE_PULSE_WIDTH, /* space & mark widths in nanosecs */

            
            };


            /* Data format of data read or written for V4L2_SUBDEV_IR_MODE_PULSE_WIDTH */

            
            #define V4L2_SUBDEV_IR_PULSE_MAX_WIDTH_NS	0x7fffffff

            
            #define V4L2_SUBDEV_IR_PULSE_LEVEL_MASK		0x80000000

            
            #define V4L2_SUBDEV_IR_PULSE_RX_SEQ_END		0xffffffff


            struct v4l2_subdev_ir_parameters {

            
            	/* Either Rx or Tx */

            
            	unsigned int bytes_per_data_element; /* of data in read or write call */

            
            	enum v4l2_subdev_ir_mode mode;


            	bool enable;

            
            	bool interrupt_enable;

            
            	bool shutdown; /* true: set hardware to low/no power, false: normal */


            	bool modulation;           /* true: uses carrier, false: baseband */

            
            	u32 max_pulse_width;       /* ns,      valid only for baseband signal */

            
            	unsigned int carrier_freq; /* Hz,      valid only for modulated signal*/

            
            	unsigned int duty_cycle;   /* percent, valid only for modulated signal*/

            
            	bool invert;		   /* logically invert sense of mark/space */


            	/* Rx only */

            
            	u32 noise_filter_min_width;       /* ns, min time of a valid pulse */

            
            	unsigned int carrier_range_lower; /* Hz, valid only for modulated sig */

            
            	unsigned int carrier_range_upper; /* Hz, valid only for modulated sig */

            
            	u32 resolution;                   /* ns */

            
            };


            struct v4l2_subdev_ir_ops {

            
            	/* Common to receiver and transmitter */

            
            	int (*interrupt_service_routine)(struct v4l2_subdev *sd,

            
            						u32 status, bool *handled);


            	/* Receiver */

            
            	int (*rx_read)(struct v4l2_subdev *sd, u8 *buf, size_t count,

            
            				ssize_t *num);


            	int (*rx_g_parameters)(struct v4l2_subdev *sd,

            
            				struct v4l2_subdev_ir_parameters *params);

            
            	int (*rx_s_parameters)(struct v4l2_subdev *sd,

            
            				struct v4l2_subdev_ir_parameters *params);


            	/* Transmitter */

            
            	int (*tx_write)(struct v4l2_subdev *sd, u8 *buf, size_t count,

            
            				ssize_t *num);


            	int (*tx_g_parameters)(struct v4l2_subdev *sd,

            
            				struct v4l2_subdev_ir_parameters *params);

            
            	int (*tx_s_parameters)(struct v4l2_subdev *sd,

            
            				struct v4l2_subdev_ir_parameters *params);

            
            };


            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;

            
            	const struct v4l2_subdev_ir_ops		*ir;

            
            	const struct v4l2_subdev_sensor_ops	*sensor;

            
            };


            #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)->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 <[email protected]>

	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>
	#include <media/v4l2-mediabus.h>

	/* generic v4l2_device notify callback notification values */
	#define V4L2_SUBDEV_IR_RX_NOTIFY _IOW('v', 0, u32)
	#define V4L2_SUBDEV_IR_RX_FIFO_SERVICE_REQ 0x00000001
	#define V4L2_SUBDEV_IR_RX_END_OF_RX_DETECTED 0x00000002
	#define V4L2_SUBDEV_IR_RX_HW_FIFO_OVERRUN 0x00000004
	#define V4L2_SUBDEV_IR_RX_SW_FIFO_OVERRUN 0x00000008

	#define V4L2_SUBDEV_IR_TX_NOTIFY _IOW('v', 1, u32)
	#define V4L2_SUBDEV_IR_TX_FIFO_SERVICE_REQ 0x00000001

	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.
	*/

	/* s_config: if set, then it is always called by the v4l2_i2c_new_subdev*
	functions after the v4l2_subdev was registered. It is used to pass
	platform data to the subdev which can be used during initialization.

	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.

	s_power: puts subdevice in power saving mode (on == 0) or normal operation
	mode (on == 1).
	*/
	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 (s_config)(struct v4l2_subdev sd, int irq, void *platform_data);
	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
	int (s_power)(struct v4l2_subdev sd, int on);
	};

	/* 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
	*/
	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 (g_modulator)(struct v4l2_subdev sd, struct v4l2_modulator *vm);
	int (s_modulator)(struct v4l2_subdev sd, struct v4l2_modulator *vm);
	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);
	};

	/* 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.

	s_dv_preset: set dv (Digital Video) preset in the sub device. Similar to
	s_std()

	query_dv_preset: query dv preset in the sub device. This is similar to
	querystd()

	s_dv_timings(): Set custom dv timings in the sub device. This is used
	when sub device is capable of setting detailed timing information
	in the hardware to generate/detect the video signal.

	g_dv_timings(): Get custom dv timings in the sub device.

	enum_mbus_fmt: enumerate pixel formats, provided by a video data source

	g_mbus_fmt: get the current pixel format, provided by a video data source

	try_mbus_fmt: try to set a pixel format on a video data source

	s_mbus_fmt: set a pixel format on a video data source
	*/
	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 (cropcap)(struct v4l2_subdev sd, struct v4l2_cropcap *cc);
	int (g_crop)(struct v4l2_subdev sd, struct v4l2_crop *crop);
	int (s_crop)(struct v4l2_subdev sd, struct v4l2_crop *crop);
	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);
	int (s_dv_preset)(struct v4l2_subdev sd,
	struct v4l2_dv_preset *preset);
	int (query_dv_preset)(struct v4l2_subdev sd,
	struct v4l2_dv_preset *preset);
	int (s_dv_timings)(struct v4l2_subdev sd,
	struct v4l2_dv_timings *timings);
	int (g_dv_timings)(struct v4l2_subdev sd,
	struct v4l2_dv_timings *timings);
	int (enum_mbus_fmt)(struct v4l2_subdev sd, int index,
	enum v4l2_mbus_pixelcode *code);
	int (g_mbus_fmt)(struct v4l2_subdev sd,
	struct v4l2_mbus_framefmt *fmt);
	int (try_mbus_fmt)(struct v4l2_subdev sd,
	struct v4l2_mbus_framefmt *fmt);
	int (s_mbus_fmt)(struct v4l2_subdev sd,
	struct v4l2_mbus_framefmt *fmt);
	};

	/**
	* struct v4l2_subdev_sensor_ops - v4l2-subdev sensor operations
	* @g_skip_top_lines: number of lines at the top of the image to be skipped.
	* This is needed for some sensors, which always corrupt
	* several top lines of the output image, or which send their
	* metadata in them.
	*/
	struct v4l2_subdev_sensor_ops {
	int (g_skip_top_lines)(struct v4l2_subdev sd, u32 *lines);
	};

	/*
	interrupt_service_routine: Called by the bridge chip's interrupt service
	handler, when an IR interrupt status has be raised due to this subdev,
	so that this subdev can handle the details. It may schedule work to be
	performed later. It must not sleep. Called from an IRQ context.

	[rt]x_g_parameters: Get the current operating parameters and state of the
	the IR receiver or transmitter.

	[rt]x_s_parameters: Set the current operating parameters and state of the
	the IR receiver or transmitter. It is recommended to call
	[rt]x_g_parameters first to fill out the current state, and only change
	the fields that need to be changed. Upon return, the actual device
	operating parameters and state will be returned. Note that hardware
	limitations may prevent the actual settings from matching the requested
	settings - e.g. an actual carrier setting of 35,904 Hz when 36,000 Hz
	was requested. An exception is when the shutdown parameter is true.
	The last used operational parameters will be returned, but the actual
	state of the hardware be different to minimize power consumption and
	processing when shutdown is true.

	rx_read: Reads received codes or pulse width data.
	The semantics are similar to a non-blocking read() call.

	tx_write: Writes codes or pulse width data for transmission.
	The semantics are similar to a non-blocking write() call.
	*/

	enum v4l2_subdev_ir_mode {
	V4L2_SUBDEV_IR_MODE_PULSE_WIDTH, /* space & mark widths in nanosecs */
	};

	/* Data format of data read or written for V4L2_SUBDEV_IR_MODE_PULSE_WIDTH */
	#define V4L2_SUBDEV_IR_PULSE_MAX_WIDTH_NS 0x7fffffff
	#define V4L2_SUBDEV_IR_PULSE_LEVEL_MASK 0x80000000
	#define V4L2_SUBDEV_IR_PULSE_RX_SEQ_END 0xffffffff

	struct v4l2_subdev_ir_parameters {
	/* Either Rx or Tx */
	unsigned int bytes_per_data_element; /* of data in read or write call */
	enum v4l2_subdev_ir_mode mode;

	bool enable;
	bool interrupt_enable;
	bool shutdown; /* true: set hardware to low/no power, false: normal */

	bool modulation; /* true: uses carrier, false: baseband */
	u32 max_pulse_width; /* ns, valid only for baseband signal */
	unsigned int carrier_freq; /* Hz, valid only for modulated signal*/
	unsigned int duty_cycle; /* percent, valid only for modulated signal*/
	bool invert; /* logically invert sense of mark/space */

	/* Rx only */
	u32 noise_filter_min_width; /* ns, min time of a valid pulse */
	unsigned int carrier_range_lower; /* Hz, valid only for modulated sig */
	unsigned int carrier_range_upper; /* Hz, valid only for modulated sig */
	u32 resolution; /* ns */
	};

	struct v4l2_subdev_ir_ops {
	/* Common to receiver and transmitter */
	int (interrupt_service_routine)(struct v4l2_subdev sd,
	u32 status, bool *handled);

	/* Receiver */
	int (rx_read)(struct v4l2_subdev sd, u8 *buf, size_t count,
	ssize_t *num);

	int (rx_g_parameters)(struct v4l2_subdev sd,
	struct v4l2_subdev_ir_parameters *params);
	int (rx_s_parameters)(struct v4l2_subdev sd,
	struct v4l2_subdev_ir_parameters *params);

	/* Transmitter */
	int (tx_write)(struct v4l2_subdev sd, u8 *buf, size_t count,
	ssize_t *num);

	int (tx_g_parameters)(struct v4l2_subdev sd,
	struct v4l2_subdev_ir_parameters *params);
	int (tx_s_parameters)(struct v4l2_subdev sd,
	struct v4l2_subdev_ir_parameters *params);
	};

	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;
	const struct v4l2_subdev_ir_ops *ir;
	const struct v4l2_subdev_sensor_ops *sensor;
	};

	#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)->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