include/media/v4l2-subdev.h

   1 /*
   2     V4L2 sub-device support header.
   3
   4     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #ifndef _V4L2_SUBDEV_H
  22 #define _V4L2_SUBDEV_H
  23
  24 #include <media/v4l2-common.h>
  25 #include <media/v4l2-mediabus.h>
  26
  27 /* generic v4l2_device notify callback notification values */
  28 #define V4L2_SUBDEV_IR_RX_NOTIFY                _IOW('v', 0, u32)
  29 #define V4L2_SUBDEV_IR_RX_FIFO_SERVICE_REQ      0x00000001
  30 #define V4L2_SUBDEV_IR_RX_END_OF_RX_DETECTED    0x00000002
  31 #define V4L2_SUBDEV_IR_RX_HW_FIFO_OVERRUN       0x00000004
  32 #define V4L2_SUBDEV_IR_RX_SW_FIFO_OVERRUN       0x00000008
  33
  34 #define V4L2_SUBDEV_IR_TX_NOTIFY                _IOW('v', 1, u32)
  35 #define V4L2_SUBDEV_IR_TX_FIFO_SERVICE_REQ      0x00000001
  36
  37 struct v4l2_device;
  38 struct v4l2_ctrl_handler;
  39 struct v4l2_subdev;
  40 struct tuner_setup;
  41
  42 /* decode_vbi_line */
  43 struct v4l2_decode_vbi_line {
  44         u32 is_second_field;    /* Set to 0 for the first (odd) field,
  45                                    set to 1 for the second (even) field. */
  46         u8 *p;                  /* Pointer to the sliced VBI data from the decoder.
  47                                    On exit points to the start of the payload. */
  48         u32 line;               /* Line number of the sliced VBI data (1-23) */
  49         u32 type;               /* VBI service type (V4L2_SLICED_*). 0 if no service found */
  50 };
  51
  52 /* Sub-devices are devices that are connected somehow to the main bridge
  53    device. These devices are usually audio/video muxers/encoders/decoders or
  54    sensors and webcam controllers.
  55
  56    Usually these devices are controlled through an i2c bus, but other busses
  57    may also be used.
  58
  59    The v4l2_subdev struct provides a way of accessing these devices in a
  60    generic manner. Most operations that these sub-devices support fall in
  61    a few categories: core ops, audio ops, video ops and tuner ops.
  62
  63    More categories can be added if needed, although this should remain a
  64    limited set (no more than approx. 8 categories).
  65
  66    Each category has its own set of ops that subdev drivers can implement.
  67
  68    A subdev driver can leave the pointer to the category ops NULL if
  69    it does not implement them (e.g. an audio subdev will generally not
  70    implement the video category ops). The exception is the core category:
  71    this must always be present.
  72
  73    These ops are all used internally so it is no problem to change, remove
  74    or add ops or move ops from one to another category. Currently these
  75    ops are based on the original ioctls, but since ops are not limited to
  76    one argument there is room for improvement here once all i2c subdev
  77    drivers are converted to use these ops.
  78  */
  79
  80 /* Core ops: it is highly recommended to implement at least these ops:
  81
  82    g_chip_ident
  83    log_status
  84    g_register
  85    s_register
  86
  87    This provides basic debugging support.
  88
  89    The ioctl ops is meant for generic ioctl-like commands. Depending on
  90    the use-case it might be better to use subdev-specific ops (currently
  91    not yet implemented) since ops provide proper type-checking.
  92  */
  93
  94 /* Subdevice external IO pin configuration */
  95 #define V4L2_SUBDEV_IO_PIN_DISABLE      (1 << 0) /* ENABLE assumed */
  96 #define V4L2_SUBDEV_IO_PIN_OUTPUT       (1 << 1)
  97 #define V4L2_SUBDEV_IO_PIN_INPUT        (1 << 2)
  98 #define V4L2_SUBDEV_IO_PIN_SET_VALUE    (1 << 3) /* Set output value */
  99 #define V4L2_SUBDEV_IO_PIN_ACTIVE_LOW   (1 << 4) /* ACTIVE HIGH assumed */
 100
 101 struct v4l2_subdev_io_pin_config {
 102         u32 flags;      /* V4L2_SUBDEV_IO_PIN_* flags for this pin's config */
 103         u8 pin;         /* Chip external IO pin to configure */
 104         u8 function;    /* Internal signal pad/function to route to IO pin */
 105         u8 value;       /* Initial value for pin - e.g. GPIO output value */
 106         u8 strength;    /* Pin drive strength */
 107 };
 108
 109 /*
 110    s_io_pin_config: configure one or more chip I/O pins for chips that
 111         multiplex different internal signal pads out to IO pins.  This function
 112         takes a pointer to an array of 'n' pin configuration entries, one for
 113         each pin being configured.  This function could be called at times
 114         other than just subdevice initialization.
 115
 116    init: initialize the sensor registors to some sort of reasonable default
 117         values. Do not use for new drivers and should be removed in existing
 118         drivers.
 119
 120    load_fw: load firmware.
 121
 122    reset: generic reset command. The argument selects which subsystems to
 123         reset. Passing 0 will always reset the whole chip. Do not use for new
 124         drivers without discussing this first on the linux-media mailinglist.
 125         There should be no reason normally to reset a device.
 126
 127    s_gpio: set GPIO pins. Very simple right now, might need to be extended with
 128         a direction argument if needed.
 129
 130    s_power: puts subdevice in power saving mode (on == 0) or normal operation
 131         mode (on == 1).
 132
 133    interrupt_service_routine: Called by the bridge chip's interrupt service
 134         handler, when an interrupt status has be raised due to this subdev,
 135         so that this subdev can handle the details.  It may schedule work to be
 136         performed later.  It must not sleep.  *Called from an IRQ context*.
 137  */
 138 struct v4l2_subdev_core_ops {
 139         int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_dbg_chip_ident *chip);
 140         int (*log_status)(struct v4l2_subdev *sd);
 141         int (*s_io_pin_config)(struct v4l2_subdev *sd, size_t n,
 142                                       struct v4l2_subdev_io_pin_config *pincfg);
 143         int (*init)(struct v4l2_subdev *sd, u32 val);
 144         int (*load_fw)(struct v4l2_subdev *sd);
 145         int (*reset)(struct v4l2_subdev *sd, u32 val);
 146         int (*s_gpio)(struct v4l2_subdev *sd, u32 val);
 147         int (*queryctrl)(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
 148         int (*g_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 149         int (*s_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 150         int (*g_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 151         int (*s_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 152         int (*try_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 153         int (*querymenu)(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
 154         int (*s_std)(struct v4l2_subdev *sd, v4l2_std_id norm);
 155         long (*ioctl)(struct v4l2_subdev *sd, unsigned int cmd, void *arg);
 156 #ifdef CONFIG_VIDEO_ADV_DEBUG
 157         int (*g_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 158         int (*s_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 159 #endif
 160         int (*s_power)(struct v4l2_subdev *sd, int on);
 161         int (*interrupt_service_routine)(struct v4l2_subdev *sd,
 162                                                 u32 status, bool *handled);
 163 };
 164
 165 /* s_mode: switch the tuner to a specific tuner mode. Replacement of s_radio.
 166
 167    s_radio: v4l device was opened in Radio mode, to be replaced by s_mode.
 168
 169    s_type_addr: sets tuner type and its I2C addr.
 170
 171    s_config: sets tda9887 specific stuff, like port1, port2 and qss
 172  */
 173 struct v4l2_subdev_tuner_ops {
 174         int (*s_mode)(struct v4l2_subdev *sd, enum v4l2_tuner_type);
 175         int (*s_radio)(struct v4l2_subdev *sd);
 176         int (*s_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 177         int (*g_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 178         int (*g_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 179         int (*s_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 180         int (*g_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);
 181         int (*s_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);
 182         int (*s_type_addr)(struct v4l2_subdev *sd, struct tuner_setup *type);
 183         int (*s_config)(struct v4l2_subdev *sd, const struct v4l2_priv_tun_config *config);
 184 };
 185
 186 /* s_clock_freq: set the frequency (in Hz) of the audio clock output.
 187         Used to slave an audio processor to the video decoder, ensuring that
 188         audio and video remain synchronized. Usual values for the frequency
 189         are 48000, 44100 or 32000 Hz. If the frequency is not supported, then
 190         -EINVAL is returned.
 191
 192    s_i2s_clock_freq: sets I2S speed in bps. This is used to provide a standard
 193         way to select I2S clock used by driving digital audio streams at some
 194         board designs. Usual values for the frequency are 1024000 and 2048000.
 195         If the frequency is not supported, then -EINVAL is returned.
 196
 197    s_routing: used to define the input and/or output pins of an audio chip,
 198         and any additional configuration data.
 199         Never attempt to use user-level input IDs (e.g. Composite, S-Video,
 200         Tuner) at this level. An i2c device shouldn't know about whether an
 201         input pin is connected to a Composite connector, become on another
 202         board or platform it might be connected to something else entirely.
 203         The calling driver is responsible for mapping a user-level input to
 204         the right pins on the i2c device.
 205  */
 206 struct v4l2_subdev_audio_ops {
 207         int (*s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 208         int (*s_i2s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 209         int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 210         int (*s_stream)(struct v4l2_subdev *sd, int enable);
 211 };
 212
 213 /*
 214    s_std_output: set v4l2_std_id for video OUTPUT devices. This is ignored by
 215         video input devices.
 216
 217    s_crystal_freq: sets the frequency of the crystal used to generate the
 218         clocks in Hz. An extra flags field allows device specific configuration
 219         regarding clock frequency dividers, etc. If not used, then set flags
 220         to 0. If the frequency is not supported, then -EINVAL is returned.
 221
 222    g_input_status: get input status. Same as the status field in the v4l2_input
 223         struct.
 224
 225    s_routing: see s_routing in audio_ops, except this version is for video
 226         devices.
 227
 228    s_dv_preset: set dv (Digital Video) preset in the sub device. Similar to
 229         s_std()
 230
 231    query_dv_preset: query dv preset in the sub device. This is similar to
 232         querystd()
 233
 234    s_dv_timings(): Set custom dv timings in the sub device. This is used
 235         when sub device is capable of setting detailed timing information
 236         in the hardware to generate/detect the video signal.
 237
 238    g_dv_timings(): Get custom dv timings in the sub device.
 239
 240    enum_mbus_fmt: enumerate pixel formats, provided by a video data source
 241
 242    g_mbus_fmt: get the current pixel format, provided by a video data source
 243
 244    try_mbus_fmt: try to set a pixel format on a video data source
 245
 246    s_mbus_fmt: set a pixel format on a video data source
 247  */
 248 struct v4l2_subdev_video_ops {
 249         int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 250         int (*s_crystal_freq)(struct v4l2_subdev *sd, u32 freq, u32 flags);
 251         int (*s_std_output)(struct v4l2_subdev *sd, v4l2_std_id std);
 252         int (*querystd)(struct v4l2_subdev *sd, v4l2_std_id *std);
 253         int (*g_input_status)(struct v4l2_subdev *sd, u32 *status);
 254         int (*s_stream)(struct v4l2_subdev *sd, int enable);
 255         int (*cropcap)(struct v4l2_subdev *sd, struct v4l2_cropcap *cc);
 256         int (*g_crop)(struct v4l2_subdev *sd, struct v4l2_crop *crop);
 257         int (*s_crop)(struct v4l2_subdev *sd, struct v4l2_crop *crop);
 258         int (*g_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm *param);
 259         int (*s_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm *param);
 260         int (*enum_framesizes)(struct v4l2_subdev *sd, struct v4l2_frmsizeenum *fsize);
 261         int (*enum_frameintervals)(struct v4l2_subdev *sd, struct v4l2_frmivalenum *fival);
 262         int (*enum_dv_presets) (struct v4l2_subdev *sd,
 263                         struct v4l2_dv_enum_preset *preset);
 264         int (*s_dv_preset)(struct v4l2_subdev *sd,
 265                         struct v4l2_dv_preset *preset);
 266         int (*query_dv_preset)(struct v4l2_subdev *sd,
 267                         struct v4l2_dv_preset *preset);
 268         int (*s_dv_timings)(struct v4l2_subdev *sd,
 269                         struct v4l2_dv_timings *timings);
 270         int (*g_dv_timings)(struct v4l2_subdev *sd,
 271                         struct v4l2_dv_timings *timings);
 272         int (*enum_mbus_fmt)(struct v4l2_subdev *sd, unsigned int index,
 273                              enum v4l2_mbus_pixelcode *code);
 274         int (*g_mbus_fmt)(struct v4l2_subdev *sd,
 275                           struct v4l2_mbus_framefmt *fmt);
 276         int (*try_mbus_fmt)(struct v4l2_subdev *sd,
 277                             struct v4l2_mbus_framefmt *fmt);
 278         int (*s_mbus_fmt)(struct v4l2_subdev *sd,
 279                           struct v4l2_mbus_framefmt *fmt);
 280 };
 281
 282 /*
 283    decode_vbi_line: video decoders that support sliced VBI need to implement
 284         this ioctl. Field p of the v4l2_sliced_vbi_line struct is set to the
 285         start of the VBI data that was generated by the decoder. The driver
 286         then parses the sliced VBI data and sets the other fields in the
 287         struct accordingly. The pointer p is updated to point to the start of
 288         the payload which can be copied verbatim into the data field of the
 289         v4l2_sliced_vbi_data struct. If no valid VBI data was found, then the
 290         type field is set to 0 on return.
 291
 292    s_vbi_data: used to generate VBI signals on a video signal.
 293         v4l2_sliced_vbi_data is filled with the data packets that should be
 294         output. Note that if you set the line field to 0, then that VBI signal
 295         is disabled. If no valid VBI data was found, then the type field is
 296         set to 0 on return.
 297
 298    g_vbi_data: used to obtain the sliced VBI packet from a readback register.
 299         Not all video decoders support this. If no data is available because
 300         the readback register contains invalid or erroneous data -EIO is
 301         returned. Note that you must fill in the 'id' member and the 'field'
 302         member (to determine whether CC data from the first or second field
 303         should be obtained).
 304
 305    s_raw_fmt: setup the video encoder/decoder for raw VBI.
 306
 307    g_sliced_fmt: retrieve the current sliced VBI settings.
 308
 309    s_sliced_fmt: setup the sliced VBI settings.
 310  */
 311 struct v4l2_subdev_vbi_ops {
 312         int (*decode_vbi_line)(struct v4l2_subdev *sd, struct v4l2_decode_vbi_line *vbi_line);
 313         int (*s_vbi_data)(struct v4l2_subdev *sd, const struct v4l2_sliced_vbi_data *vbi_data);
 314         int (*g_vbi_data)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_data *vbi_data);
 315         int (*g_sliced_vbi_cap)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_cap *cap);
 316         int (*s_raw_fmt)(struct v4l2_subdev *sd, struct v4l2_vbi_format *fmt);
 317         int (*g_sliced_fmt)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_format *fmt);
 318         int (*s_sliced_fmt)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_format *fmt);
 319 };
 320
 321 /**
 322  * struct v4l2_subdev_sensor_ops - v4l2-subdev sensor operations
 323  * @g_skip_top_lines: number of lines at the top of the image to be skipped.
 324  *                    This is needed for some sensors, which always corrupt
 325  *                    several top lines of the output image, or which send their
 326  *                    metadata in them.
 327  */
 328 struct v4l2_subdev_sensor_ops {
 329         int (*g_skip_top_lines)(struct v4l2_subdev *sd, u32 *lines);
 330 };
 331
 332 /*
 333    [rt]x_g_parameters: Get the current operating parameters and state of the
 334         the IR receiver or transmitter.
 335
 336    [rt]x_s_parameters: Set the current operating parameters and state of the
 337         the IR receiver or transmitter.  It is recommended to call
 338         [rt]x_g_parameters first to fill out the current state, and only change
 339         the fields that need to be changed.  Upon return, the actual device
 340         operating parameters and state will be returned.  Note that hardware
 341         limitations may prevent the actual settings from matching the requested
 342         settings - e.g. an actual carrier setting of 35,904 Hz when 36,000 Hz
 343         was requested.  An exception is when the shutdown parameter is true.
 344         The last used operational parameters will be returned, but the actual
 345         state of the hardware be different to minimize power consumption and
 346         processing when shutdown is true.
 347
 348    rx_read: Reads received codes or pulse width data.
 349         The semantics are similar to a non-blocking read() call.
 350
 351    tx_write: Writes codes or pulse width data for transmission.
 352         The semantics are similar to a non-blocking write() call.
 353  */
 354
 355 enum v4l2_subdev_ir_mode {
 356         V4L2_SUBDEV_IR_MODE_PULSE_WIDTH, /* uses struct ir_raw_event records */
 357 };
 358
 359 struct v4l2_subdev_ir_parameters {
 360         /* Either Rx or Tx */
 361         unsigned int bytes_per_data_element; /* of data in read or write call */
 362         enum v4l2_subdev_ir_mode mode;
 363
 364         bool enable;
 365         bool interrupt_enable;
 366         bool shutdown; /* true: set hardware to low/no power, false: normal */
 367
 368         bool modulation;           /* true: uses carrier, false: baseband */
 369         u32 max_pulse_width;       /* ns,      valid only for baseband signal */
 370         unsigned int carrier_freq; /* Hz,      valid only for modulated signal*/
 371         unsigned int duty_cycle;   /* percent, valid only for modulated signal*/
 372         bool invert_level;         /* invert signal level */
 373
 374         /* Tx only */
 375         bool invert_carrier_sense; /* Send 0/space as a carrier burst */
 376
 377         /* Rx only */
 378         u32 noise_filter_min_width;       /* ns, min time of a valid pulse */
 379         unsigned int carrier_range_lower; /* Hz, valid only for modulated sig */
 380         unsigned int carrier_range_upper; /* Hz, valid only for modulated sig */
 381         u32 resolution;                   /* ns */
 382 };
 383
 384 struct v4l2_subdev_ir_ops {
 385         /* Receiver */
 386         int (*rx_read)(struct v4l2_subdev *sd, u8 *buf, size_t count,
 387                                 ssize_t *num);
 388
 389         int (*rx_g_parameters)(struct v4l2_subdev *sd,
 390                                 struct v4l2_subdev_ir_parameters *params);
 391         int (*rx_s_parameters)(struct v4l2_subdev *sd,
 392                                 struct v4l2_subdev_ir_parameters *params);
 393
 394         /* Transmitter */
 395         int (*tx_write)(struct v4l2_subdev *sd, u8 *buf, size_t count,
 396                                 ssize_t *num);
 397
 398         int (*tx_g_parameters)(struct v4l2_subdev *sd,
 399                                 struct v4l2_subdev_ir_parameters *params);
 400         int (*tx_s_parameters)(struct v4l2_subdev *sd,
 401                                 struct v4l2_subdev_ir_parameters *params);
 402 };
 403
 404 struct v4l2_subdev_ops {
 405         const struct v4l2_subdev_core_ops       *core;
 406         const struct v4l2_subdev_tuner_ops      *tuner;
 407         const struct v4l2_subdev_audio_ops      *audio;
 408         const struct v4l2_subdev_video_ops      *video;
 409         const struct v4l2_subdev_vbi_ops        *vbi;
 410         const struct v4l2_subdev_ir_ops         *ir;
 411         const struct v4l2_subdev_sensor_ops     *sensor;
 412 };
 413
 414 /*
 415  * Internal ops. Never call this from drivers, only the v4l2 framework can call
 416  * these ops.
 417  *
 418  * registered: called when this subdev is registered. When called the v4l2_dev
 419  *      field is set to the correct v4l2_device.
 420  *
 421  * unregistered: called when this subdev is unregistered. When called the
 422  *      v4l2_dev field is still set to the correct v4l2_device.
 423  */
 424 struct v4l2_subdev_internal_ops {
 425         int (*registered)(struct v4l2_subdev *sd);
 426         void (*unregistered)(struct v4l2_subdev *sd);
 427 };
 428
 429 #define V4L2_SUBDEV_NAME_SIZE 32
 430
 431 /* Set this flag if this subdev is a i2c device. */
 432 #define V4L2_SUBDEV_FL_IS_I2C (1U << 0)
 433 /* Set this flag if this subdev is a spi device. */
 434 #define V4L2_SUBDEV_FL_IS_SPI (1U << 1)
 435
 436 /* Each instance of a subdev driver should create this struct, either
 437    stand-alone or embedded in a larger struct.
 438  */
 439 struct v4l2_subdev {
 440         struct list_head list;
 441         struct module *owner;
 442         u32 flags;
 443         struct v4l2_device *v4l2_dev;
 444         const struct v4l2_subdev_ops *ops;
 445         /* Never call these internal ops from within a driver! */
 446         const struct v4l2_subdev_internal_ops *internal_ops;
 447         /* The control handler of this subdev. May be NULL. */
 448         struct v4l2_ctrl_handler *ctrl_handler;
 449         /* name must be unique */
 450         char name[V4L2_SUBDEV_NAME_SIZE];
 451         /* can be used to group similar subdevs, value is driver-specific */
 452         u32 grp_id;
 453         /* pointer to private data */
 454         void *dev_priv;
 455         void *host_priv;
 456 };
 457
 458 static inline void v4l2_set_subdevdata(struct v4l2_subdev *sd, void *p)
 459 {
 460         sd->dev_priv = p;
 461 }
 462
 463 static inline void *v4l2_get_subdevdata(const struct v4l2_subdev *sd)
 464 {
 465         return sd->dev_priv;
 466 }
 467
 468 static inline void v4l2_set_subdev_hostdata(struct v4l2_subdev *sd, void *p)
 469 {
 470         sd->host_priv = p;
 471 }
 472
 473 static inline void *v4l2_get_subdev_hostdata(const struct v4l2_subdev *sd)
 474 {
 475         return sd->host_priv;
 476 }
 477
 478 static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
 479                                         const struct v4l2_subdev_ops *ops)
 480 {
 481         INIT_LIST_HEAD(&sd->list);
 482         /* ops->core MUST be set */
 483         BUG_ON(!ops || !ops->core);
 484         sd->ops = ops;
 485         sd->v4l2_dev = NULL;
 486         sd->flags = 0;
 487         sd->name[0] = '\0';
 488         sd->grp_id = 0;
 489         sd->dev_priv = NULL;
 490         sd->host_priv = NULL;
 491 }
 492
 493 /* Call an ops of a v4l2_subdev, doing the right checks against
 494    NULL pointers.
 495
 496    Example: err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
 497  */
 498 #define v4l2_subdev_call(sd, o, f, args...)                             \
 499         (!(sd) ? -ENODEV : (((sd)->ops->o && (sd)->ops->o->f) ? \
 500                 (sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))
 501
 502 /* Send a notification to v4l2_device. */
 503 #define v4l2_subdev_notify(sd, notification, arg)                          \
 504         ((!(sd) || !(sd)->v4l2_dev || !(sd)->v4l2_dev->notify) ? -ENODEV : \
 505          (sd)->v4l2_dev->notify((sd), (notification), (arg)))
 506
 507 #endif