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_subdev;
  39 struct tuner_setup;
  40
  41 /* decode_vbi_line */
  42 struct v4l2_decode_vbi_line {
  43         u32 is_second_field;    /* Set to 0 for the first (odd) field,
  44                                    set to 1 for the second (even) field. */
  45         u8 *p;                  /* Pointer to the sliced VBI data from the decoder.
  46                                    On exit points to the start of the payload. */
  47         u32 line;               /* Line number of the sliced VBI data (1-23) */
  48         u32 type;               /* VBI service type (V4L2_SLICED_*). 0 if no service found */
  49 };
  50
  51 /* Sub-devices are devices that are connected somehow to the main bridge
  52    device. These devices are usually audio/video muxers/encoders/decoders or
  53    sensors and webcam controllers.
  54
  55    Usually these devices are controlled through an i2c bus, but other busses
  56    may also be used.
  57
  58    The v4l2_subdev struct provides a way of accessing these devices in a
  59    generic manner. Most operations that these sub-devices support fall in
  60    a few categories: core ops, audio ops, video ops and tuner ops.
  61
  62    More categories can be added if needed, although this should remain a
  63    limited set (no more than approx. 8 categories).
  64
  65    Each category has its own set of ops that subdev drivers can implement.
  66
  67    A subdev driver can leave the pointer to the category ops NULL if
  68    it does not implement them (e.g. an audio subdev will generally not
  69    implement the video category ops). The exception is the core category:
  70    this must always be present.
  71
  72    These ops are all used internally so it is no problem to change, remove
  73    or add ops or move ops from one to another category. Currently these
  74    ops are based on the original ioctls, but since ops are not limited to
  75    one argument there is room for improvement here once all i2c subdev
  76    drivers are converted to use these ops.
  77  */
  78
  79 /* Core ops: it is highly recommended to implement at least these ops:
  80
  81    g_chip_ident
  82    log_status
  83    g_register
  84    s_register
  85
  86    This provides basic debugging support.
  87
  88    The ioctl ops is meant for generic ioctl-like commands. Depending on
  89    the use-case it might be better to use subdev-specific ops (currently
  90    not yet implemented) since ops provide proper type-checking.
  91  */
  92
  93 /* Subdevice external IO pin configuration */
  94 #define V4L2_SUBDEV_IO_PIN_DISABLE      (1 << 0) /* ENABLE assumed */
  95 #define V4L2_SUBDEV_IO_PIN_OUTPUT       (1 << 1)
  96 #define V4L2_SUBDEV_IO_PIN_INPUT        (1 << 2)
  97 #define V4L2_SUBDEV_IO_PIN_SET_VALUE    (1 << 3) /* Set output value */
  98 #define V4L2_SUBDEV_IO_PIN_ACTIVE_LOW   (1 << 4) /* ACTIVE HIGH assumed */
  99
 100 struct v4l2_subdev_io_pin_config {
 101         u32 flags;      /* V4L2_SUBDEV_IO_PIN_* flags for this pin's config */
 102         u8 pin;         /* Chip external IO pin to configure */
 103         u8 function;    /* Internal signal pad/function to route to IO pin */
 104         u8 value;       /* Initial value for pin - e.g. GPIO output value */
 105         u8 strength;    /* Pin drive strength */
 106 };
 107
 108 /* s_config: if set, then it is always called by the v4l2_i2c_new_subdev*
 109         functions after the v4l2_subdev was registered. It is used to pass
 110         platform data to the subdev which can be used during initialization.
 111
 112    s_io_pin_config: configure one or more chip I/O pins for chips that
 113         multiplex different internal signal pads out to IO pins.  This function
 114         takes a pointer to an array of 'n' pin configuration entries, one for
 115         each pin being configured.  This function could be called at times
 116         other than just subdevice initialization.
 117
 118    init: initialize the sensor registors to some sort of reasonable default
 119         values. Do not use for new drivers and should be removed in existing
 120         drivers.
 121
 122    load_fw: load firmware.
 123
 124    reset: generic reset command. The argument selects which subsystems to
 125         reset. Passing 0 will always reset the whole chip. Do not use for new
 126         drivers without discussing this first on the linux-media mailinglist.
 127         There should be no reason normally to reset a device.
 128
 129    s_gpio: set GPIO pins. Very simple right now, might need to be extended with
 130         a direction argument if needed.
 131
 132    s_power: puts subdevice in power saving mode (on == 0) or normal operation
 133         mode (on == 1).
 134  */
 135 struct v4l2_subdev_core_ops {
 136         int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_dbg_chip_ident *chip);
 137         int (*log_status)(struct v4l2_subdev *sd);
 138         int (*s_config)(struct v4l2_subdev *sd, int irq, void *platform_data);
 139         int (*s_io_pin_config)(struct v4l2_subdev *sd, size_t n,
 140                                       struct v4l2_subdev_io_pin_config *pincfg);
 141         int (*init)(struct v4l2_subdev *sd, u32 val);
 142         int (*load_fw)(struct v4l2_subdev *sd);
 143         int (*reset)(struct v4l2_subdev *sd, u32 val);
 144         int (*s_gpio)(struct v4l2_subdev *sd, u32 val);
 145         int (*queryctrl)(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
 146         int (*g_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 147         int (*s_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
 148         int (*g_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 149         int (*s_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 150         int (*try_ext_ctrls)(struct v4l2_subdev *sd, struct v4l2_ext_controls *ctrls);
 151         int (*querymenu)(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
 152         int (*s_std)(struct v4l2_subdev *sd, v4l2_std_id norm);
 153         long (*ioctl)(struct v4l2_subdev *sd, unsigned int cmd, void *arg);
 154 #ifdef CONFIG_VIDEO_ADV_DEBUG
 155         int (*g_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 156         int (*s_register)(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg);
 157 #endif
 158         int (*s_power)(struct v4l2_subdev *sd, int on);
 159 };
 160
 161 /* s_mode: switch the tuner to a specific tuner mode. Replacement of s_radio.
 162
 163    s_radio: v4l device was opened in Radio mode, to be replaced by s_mode.
 164
 165    s_type_addr: sets tuner type and its I2C addr.
 166
 167    s_config: sets tda9887 specific stuff, like port1, port2 and qss
 168  */
 169 struct v4l2_subdev_tuner_ops {
 170         int (*s_mode)(struct v4l2_subdev *sd, enum v4l2_tuner_type);
 171         int (*s_radio)(struct v4l2_subdev *sd);
 172         int (*s_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 173         int (*g_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
 174         int (*g_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 175         int (*s_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
 176         int (*g_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);
 177         int (*s_modulator)(struct v4l2_subdev *sd, struct v4l2_modulator *vm);
 178         int (*s_type_addr)(struct v4l2_subdev *sd, struct tuner_setup *type);
 179         int (*s_config)(struct v4l2_subdev *sd, const struct v4l2_priv_tun_config *config);
 180 };
 181
 182 /* s_clock_freq: set the frequency (in Hz) of the audio clock output.
 183         Used to slave an audio processor to the video decoder, ensuring that
 184         audio and video remain synchronized. Usual values for the frequency
 185         are 48000, 44100 or 32000 Hz. If the frequency is not supported, then
 186         -EINVAL is returned.
 187
 188    s_i2s_clock_freq: sets I2S speed in bps. This is used to provide a standard
 189         way to select I2S clock used by driving digital audio streams at some
 190         board designs. Usual values for the frequency are 1024000 and 2048000.
 191         If the frequency is not supported, then -EINVAL is returned.
 192
 193    s_routing: used to define the input and/or output pins of an audio chip,
 194         and any additional configuration data.
 195         Never attempt to use user-level input IDs (e.g. Composite, S-Video,
 196         Tuner) at this level. An i2c device shouldn't know about whether an
 197         input pin is connected to a Composite connector, become on another
 198         board or platform it might be connected to something else entirely.
 199         The calling driver is responsible for mapping a user-level input to
 200         the right pins on the i2c device.
 201  */
 202 struct v4l2_subdev_audio_ops {
 203         int (*s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 204         int (*s_i2s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
 205         int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 206         int (*s_stream)(struct v4l2_subdev *sd, int enable);
 207 };
 208
 209 /*
 210    s_std_output: set v4l2_std_id for video OUTPUT devices. This is ignored by
 211         video input devices.
 212
 213    s_crystal_freq: sets the frequency of the crystal used to generate the
 214         clocks in Hz. An extra flags field allows device specific configuration
 215         regarding clock frequency dividers, etc. If not used, then set flags
 216         to 0. If the frequency is not supported, then -EINVAL is returned.
 217
 218    g_input_status: get input status. Same as the status field in the v4l2_input
 219         struct.
 220
 221    s_routing: see s_routing in audio_ops, except this version is for video
 222         devices.
 223
 224    s_dv_preset: set dv (Digital Video) preset in the sub device. Similar to
 225         s_std()
 226
 227    query_dv_preset: query dv preset in the sub device. This is similar to
 228         querystd()
 229
 230    s_dv_timings(): Set custom dv timings in the sub device. This is used
 231         when sub device is capable of setting detailed timing information
 232         in the hardware to generate/detect the video signal.
 233
 234    g_dv_timings(): Get custom dv timings in the sub device.
 235
 236    enum_mbus_fmt: enumerate pixel formats, provided by a video data source
 237
 238    g_mbus_fmt: get the current pixel format, provided by a video data source
 239
 240    try_mbus_fmt: try to set a pixel format on a video data source
 241
 242    s_mbus_fmt: set a pixel format on a video data source
 243  */
 244 struct v4l2_subdev_video_ops {
 245         int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32 config);
 246         int (*s_crystal_freq)(struct v4l2_subdev *sd, u32 freq, u32 flags);
 247         int (*s_std_output)(struct v4l2_subdev *sd, v4l2_std_id std);
 248         int (*querystd)(struct v4l2_subdev *sd, v4l2_std_id *std);
 249         int (*g_input_status)(struct v4l2_subdev *sd, u32 *status);
 250         int (*s_stream)(struct v4l2_subdev *sd, int enable);
 251         int (*enum_fmt)(struct v4l2_subdev *sd, struct v4l2_fmtdesc *fmtdesc);
 252         int (*g_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 253         int (*try_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 254         int (*s_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
 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    interrupt_service_routine: Called by the bridge chip's interrupt service
 334         handler, when an IR interrupt status has be raised due to this subdev,
 335         so that this subdev can handle the details.  It may schedule work to be
 336         performed later.  It must not sleep.  *Called from an IRQ context*.
 337
 338    [rt]x_g_parameters: Get the current operating parameters and state of the
 339         the IR receiver or transmitter.
 340
 341    [rt]x_s_parameters: Set the current operating parameters and state of the
 342         the IR receiver or transmitter.  It is recommended to call
 343         [rt]x_g_parameters first to fill out the current state, and only change
 344         the fields that need to be changed.  Upon return, the actual device
 345         operating parameters and state will be returned.  Note that hardware
 346         limitations may prevent the actual settings from matching the requested
 347         settings - e.g. an actual carrier setting of 35,904 Hz when 36,000 Hz
 348         was requested.  An exception is when the shutdown parameter is true.
 349         The last used operational parameters will be returned, but the actual
 350         state of the hardware be different to minimize power consumption and
 351         processing when shutdown is true.
 352
 353    rx_read: Reads received codes or pulse width data.
 354         The semantics are similar to a non-blocking read() call.
 355
 356    tx_write: Writes codes or pulse width data for transmission.
 357         The semantics are similar to a non-blocking write() call.
 358  */
 359
 360 enum v4l2_subdev_ir_mode {
 361         V4L2_SUBDEV_IR_MODE_PULSE_WIDTH, /* space & mark widths in nanosecs */
 362 };
 363
 364 /* Data format of data read or written for V4L2_SUBDEV_IR_MODE_PULSE_WIDTH */
 365 #define V4L2_SUBDEV_IR_PULSE_MAX_WIDTH_NS       0x7fffffff
 366 #define V4L2_SUBDEV_IR_PULSE_LEVEL_MASK         0x80000000
 367 #define V4L2_SUBDEV_IR_PULSE_RX_SEQ_END         0xffffffff
 368
 369 struct v4l2_subdev_ir_parameters {
 370         /* Either Rx or Tx */
 371         unsigned int bytes_per_data_element; /* of data in read or write call */
 372         enum v4l2_subdev_ir_mode mode;
 373
 374         bool enable;
 375         bool interrupt_enable;
 376         bool shutdown; /* true: set hardware to low/no power, false: normal */
 377
 378         bool modulation;           /* true: uses carrier, false: baseband */
 379         u32 max_pulse_width;       /* ns,      valid only for baseband signal */
 380         unsigned int carrier_freq; /* Hz,      valid only for modulated signal*/
 381         unsigned int duty_cycle;   /* percent, valid only for modulated signal*/
 382         bool invert;               /* logically invert sense of mark/space */
 383
 384         /* Rx only */
 385         u32 noise_filter_min_width;       /* ns, min time of a valid pulse */
 386         unsigned int carrier_range_lower; /* Hz, valid only for modulated sig */
 387         unsigned int carrier_range_upper; /* Hz, valid only for modulated sig */
 388         u32 resolution;                   /* ns */
 389 };
 390
 391 struct v4l2_subdev_ir_ops {
 392         /* Common to receiver and transmitter */
 393         int (*interrupt_service_routine)(struct v4l2_subdev *sd,
 394                                                 u32 status, bool *handled);
 395
 396         /* Receiver */
 397         int (*rx_read)(struct v4l2_subdev *sd, u8 *buf, size_t count,
 398                                 ssize_t *num);
 399
 400         int (*rx_g_parameters)(struct v4l2_subdev *sd,
 401                                 struct v4l2_subdev_ir_parameters *params);
 402         int (*rx_s_parameters)(struct v4l2_subdev *sd,
 403                                 struct v4l2_subdev_ir_parameters *params);
 404
 405         /* Transmitter */
 406         int (*tx_write)(struct v4l2_subdev *sd, u8 *buf, size_t count,
 407                                 ssize_t *num);
 408
 409         int (*tx_g_parameters)(struct v4l2_subdev *sd,
 410                                 struct v4l2_subdev_ir_parameters *params);
 411         int (*tx_s_parameters)(struct v4l2_subdev *sd,
 412                                 struct v4l2_subdev_ir_parameters *params);
 413 };
 414
 415 struct v4l2_subdev_ops {
 416         const struct v4l2_subdev_core_ops       *core;
 417         const struct v4l2_subdev_tuner_ops      *tuner;
 418         const struct v4l2_subdev_audio_ops      *audio;
 419         const struct v4l2_subdev_video_ops      *video;
 420         const struct v4l2_subdev_vbi_ops        *vbi;
 421         const struct v4l2_subdev_ir_ops         *ir;
 422         const struct v4l2_subdev_sensor_ops     *sensor;
 423 };
 424
 425 #define V4L2_SUBDEV_NAME_SIZE 32
 426
 427 /* Set this flag if this subdev is a i2c device. */
 428 #define V4L2_SUBDEV_FL_IS_I2C (1U << 0)
 429 /* Set this flag if this subdev is a spi device. */
 430 #define V4L2_SUBDEV_FL_IS_SPI (1U << 1)
 431
 432 /* Each instance of a subdev driver should create this struct, either
 433    stand-alone or embedded in a larger struct.
 434  */
 435 struct v4l2_subdev {
 436         struct list_head list;
 437         struct module *owner;
 438         u32 flags;
 439         struct v4l2_device *v4l2_dev;
 440         const struct v4l2_subdev_ops *ops;
 441         /* name must be unique */
 442         char name[V4L2_SUBDEV_NAME_SIZE];
 443         /* can be used to group similar subdevs, value is driver-specific */
 444         u32 grp_id;
 445         /* pointer to private data */
 446         void *priv;
 447 };
 448
 449 static inline void v4l2_set_subdevdata(struct v4l2_subdev *sd, void *p)
 450 {
 451         sd->priv = p;
 452 }
 453
 454 static inline void *v4l2_get_subdevdata(const struct v4l2_subdev *sd)
 455 {
 456         return sd->priv;
 457 }
 458
 459 static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
 460                                         const struct v4l2_subdev_ops *ops)
 461 {
 462         INIT_LIST_HEAD(&sd->list);
 463         /* ops->core MUST be set */
 464         BUG_ON(!ops || !ops->core);
 465         sd->ops = ops;
 466         sd->v4l2_dev = NULL;
 467         sd->flags = 0;
 468         sd->name[0] = '\0';
 469         sd->grp_id = 0;
 470         sd->priv = NULL;
 471 }
 472
 473 /* Call an ops of a v4l2_subdev, doing the right checks against
 474    NULL pointers.
 475
 476    Example: err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
 477  */
 478 #define v4l2_subdev_call(sd, o, f, args...)                             \
 479         (!(sd) ? -ENODEV : (((sd)->ops->o && (sd)->ops->o->f) ? \
 480                 (sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))
 481
 482 /* Send a notification to v4l2_device. */
 483 #define v4l2_subdev_notify(sd, notification, arg)                          \
 484         ((!(sd) || !(sd)->v4l2_dev || !(sd)->v4l2_dev->notify) ? -ENODEV : \
 485          (sd)->v4l2_dev->notify((sd), (notification), (arg)))
 486
 487 #endif