include/linux/iio/iio.h

   1
   2 /* The industrial I/O core
   3  *
   4  * Copyright (c) 2008 Jonathan Cameron
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10 #ifndef _INDUSTRIAL_IO_H_
  11 #define _INDUSTRIAL_IO_H_
  12
  13 #include <linux/device.h>
  14 #include <linux/cdev.h>
  15 #include <linux/iio/types.h>
  16 /* IIO TODO LIST */
  17 /*
  18  * Provide means of adjusting timer accuracy.
  19  * Currently assumes nano seconds.
  20  */
  21
  22 enum iio_chan_info_enum {
  23         IIO_CHAN_INFO_RAW = 0,
  24         IIO_CHAN_INFO_PROCESSED,
  25         IIO_CHAN_INFO_SCALE,
  26         IIO_CHAN_INFO_OFFSET,
  27         IIO_CHAN_INFO_CALIBSCALE,
  28         IIO_CHAN_INFO_CALIBBIAS,
  29         IIO_CHAN_INFO_PEAK,
  30         IIO_CHAN_INFO_PEAK_SCALE,
  31         IIO_CHAN_INFO_QUADRATURE_CORRECTION_RAW,
  32         IIO_CHAN_INFO_AVERAGE_RAW,
  33         IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY,
  34         IIO_CHAN_INFO_SAMP_FREQ,
  35         IIO_CHAN_INFO_FREQUENCY,
  36         IIO_CHAN_INFO_PHASE,
  37         IIO_CHAN_INFO_HARDWAREGAIN,
  38         IIO_CHAN_INFO_HYSTERESIS,
  39 };
  40
  41 enum iio_endian {
  42         IIO_CPU,
  43         IIO_BE,
  44         IIO_LE,
  45 };
  46
  47 struct iio_chan_spec;
  48 struct iio_dev;
  49
  50 /**
  51  * struct iio_chan_spec_ext_info - Extended channel info attribute
  52  * @name:       Info attribute name
  53  * @shared:     Whether this attribute is shared between all channels.
  54  * @read:       Read callback for this info attribute, may be NULL.
  55  * @write:      Write callback for this info attribute, may be NULL.
  56  * @private:    Data private to the driver.
  57  */
  58 struct iio_chan_spec_ext_info {
  59         const char *name;
  60         bool shared;
  61         ssize_t (*read)(struct iio_dev *, uintptr_t private,
  62                         struct iio_chan_spec const *, char *buf);
  63         ssize_t (*write)(struct iio_dev *, uintptr_t private,
  64                          struct iio_chan_spec const *, const char *buf,
  65                          size_t len);
  66         uintptr_t private;
  67 };
  68
  69 /**
  70  * struct iio_enum - Enum channel info attribute
  71  * @items:      An array of strings.
  72  * @num_items:  Length of the item array.
  73  * @set:        Set callback function, may be NULL.
  74  * @get:        Get callback function, may be NULL.
  75  *
  76  * The iio_enum struct can be used to implement enum style channel attributes.
  77  * Enum style attributes are those which have a set of strings which map to
  78  * unsigned integer values. The IIO enum helper code takes care of mapping
  79  * between value and string as well as generating a "_available" file which
  80  * contains a list of all available items. The set callback will be called when
  81  * the attribute is updated. The last parameter is the index to the newly
  82  * activated item. The get callback will be used to query the currently active
  83  * item and is supposed to return the index for it.
  84  */
  85 struct iio_enum {
  86         const char * const *items;
  87         unsigned int num_items;
  88         int (*set)(struct iio_dev *, const struct iio_chan_spec *, unsigned int);
  89         int (*get)(struct iio_dev *, const struct iio_chan_spec *);
  90 };
  91
  92 ssize_t iio_enum_available_read(struct iio_dev *indio_dev,
  93         uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
  94 ssize_t iio_enum_read(struct iio_dev *indio_dev,
  95         uintptr_t priv, const struct iio_chan_spec *chan, char *buf);
  96 ssize_t iio_enum_write(struct iio_dev *indio_dev,
  97         uintptr_t priv, const struct iio_chan_spec *chan, const char *buf,
  98         size_t len);
  99
 100 /**
 101  * IIO_ENUM() - Initialize enum extended channel attribute
 102  * @_name:      Attribute name
 103  * @_shared:    Whether the attribute is shared between all channels
 104  * @_e:         Pointer to an iio_enum struct
 105  *
 106  * This should usually be used together with IIO_ENUM_AVAILABLE()
 107  */
 108 #define IIO_ENUM(_name, _shared, _e) \
 109 { \
 110         .name = (_name), \
 111         .shared = (_shared), \
 112         .read = iio_enum_read, \
 113         .write = iio_enum_write, \
 114         .private = (uintptr_t)(_e), \
 115 }
 116
 117 /**
 118  * IIO_ENUM_AVAILABLE() - Initialize enum available extended channel attribute
 119  * @_name:      Attribute name ("_available" will be appended to the name)
 120  * @_e:         Pointer to an iio_enum struct
 121  *
 122  * Creates a read only attribute which lists all the available enum items in a
 123  * space separated list. This should usually be used together with IIO_ENUM()
 124  */
 125 #define IIO_ENUM_AVAILABLE(_name, _e) \
 126 { \
 127         .name = (_name "_available"), \
 128         .shared = true, \
 129         .read = iio_enum_available_read, \
 130         .private = (uintptr_t)(_e), \
 131 }
 132
 133 /**
 134  * struct iio_chan_spec - specification of a single channel
 135  * @type:               What type of measurement is the channel making.
 136  * @channel:            What number do we wish to assign the channel.
 137  * @channel2:           If there is a second number for a differential
 138  *                      channel then this is it. If modified is set then the
 139  *                      value here specifies the modifier.
 140  * @address:            Driver specific identifier.
 141  * @scan_index:         Monotonic index to give ordering in scans when read
 142  *                      from a buffer.
 143  * @scan_type:          Sign:           's' or 'u' to specify signed or unsigned
 144  *                      realbits:       Number of valid bits of data
 145  *                      storage_bits:   Realbits + padding
 146  *                      shift:          Shift right by this before masking out
 147  *                                      realbits.
 148  *                      endianness:     little or big endian
 149  * @info_mask:          What information is to be exported about this channel.
 150  *                      This includes calibbias, scale etc.
 151  * @info_mask_separate: What information is to be exported that is specific to
 152  *                      this channel.
 153  * @info_mask_shared_by_type: What information is to be exported that is shared
 154 *                       by all channels of the same type.
 155  * @event_mask:         What events can this channel produce.
 156  * @ext_info:           Array of extended info attributes for this channel.
 157  *                      The array is NULL terminated, the last element should
 158  *                      have its name field set to NULL.
 159  * @extend_name:        Allows labeling of channel attributes with an
 160  *                      informative name. Note this has no effect codes etc,
 161  *                      unlike modifiers.
 162  * @datasheet_name:     A name used in in-kernel mapping of channels. It should
 163  *                      correspond to the first name that the channel is referred
 164  *                      to by in the datasheet (e.g. IND), or the nearest
 165  *                      possible compound name (e.g. IND-INC).
 166  * @modified:           Does a modifier apply to this channel. What these are
 167  *                      depends on the channel type.  Modifier is set in
 168  *                      channel2. Examples are IIO_MOD_X for axial sensors about
 169  *                      the 'x' axis.
 170  * @indexed:            Specify the channel has a numerical index. If not,
 171  *                      the channel index number will be suppressed for sysfs
 172  *                      attributes but not for event codes.
 173  * @output:             Channel is output.
 174  * @differential:       Channel is differential.
 175  */
 176 struct iio_chan_spec {
 177         enum iio_chan_type      type;
 178         int                     channel;
 179         int                     channel2;
 180         unsigned long           address;
 181         int                     scan_index;
 182         struct {
 183                 char    sign;
 184                 u8      realbits;
 185                 u8      storagebits;
 186                 u8      shift;
 187                 enum iio_endian endianness;
 188         } scan_type;
 189         long                    info_mask;
 190         long                    info_mask_separate;
 191         long                    info_mask_shared_by_type;
 192         long                    event_mask;
 193         const struct iio_chan_spec_ext_info *ext_info;
 194         const char              *extend_name;
 195         const char              *datasheet_name;
 196         unsigned                modified:1;
 197         unsigned                indexed:1;
 198         unsigned                output:1;
 199         unsigned                differential:1;
 200 };
 201
 202
 203 /**
 204  * iio_channel_has_info() - Checks whether a channel supports a info attribute
 205  * @chan: The channel to be queried
 206  * @type: Type of the info attribute to be checked
 207  *
 208  * Returns true if the channels supports reporting values for the given info
 209  * attribute type, false otherwise.
 210  */
 211 static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
 212         enum iio_chan_info_enum type)
 213 {
 214         return (chan->info_mask_separate & type) |
 215                (chan->info_mask_shared_by_type & type);
 216 }
 217
 218 #define IIO_ST(si, rb, sb, sh)                                          \
 219         { .sign = si, .realbits = rb, .storagebits = sb, .shift = sh }
 220
 221 #define IIO_CHAN_SOFT_TIMESTAMP(_si)                                    \
 222         { .type = IIO_TIMESTAMP, .channel = -1,                         \
 223                         .scan_index = _si, .scan_type = IIO_ST('s', 64, 64, 0) }
 224
 225 /**
 226  * iio_get_time_ns() - utility function to get a time stamp for events etc
 227  **/
 228 static inline s64 iio_get_time_ns(void)
 229 {
 230         struct timespec ts;
 231         /*
 232          * calls getnstimeofday.
 233          * If hrtimers then up to ns accurate, if not microsecond.
 234          */
 235         ktime_get_real_ts(&ts);
 236
 237         return timespec_to_ns(&ts);
 238 }
 239
 240 /* Device operating modes */
 241 #define INDIO_DIRECT_MODE               0x01
 242 #define INDIO_BUFFER_TRIGGERED          0x02
 243 #define INDIO_BUFFER_HARDWARE           0x08
 244
 245 #define INDIO_ALL_BUFFER_MODES                                  \
 246         (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE)
 247
 248 struct iio_trigger; /* forward declaration */
 249 struct iio_dev;
 250
 251 /**
 252  * struct iio_info - constant information about device
 253  * @driver_module:      module structure used to ensure correct
 254  *                      ownership of chrdevs etc
 255  * @event_attrs:        event control attributes
 256  * @attrs:              general purpose device attributes
 257  * @read_raw:           function to request a value from the device.
 258  *                      mask specifies which value. Note 0 means a reading of
 259  *                      the channel in question.  Return value will specify the
 260  *                      type of value returned by the device. val and val2 will
 261  *                      contain the elements making up the returned value.
 262  * @write_raw:          function to write a value to the device.
 263  *                      Parameters are the same as for read_raw.
 264  * @write_raw_get_fmt:  callback function to query the expected
 265  *                      format/precision. If not set by the driver, write_raw
 266  *                      returns IIO_VAL_INT_PLUS_MICRO.
 267  * @read_event_config:  find out if the event is enabled.
 268  * @write_event_config: set if the event is enabled.
 269  * @read_event_value:   read a value associated with the event. Meaning
 270  *                      is event dependant. event_code specifies which event.
 271  * @write_event_value:  write the value associated with the event.
 272  *                      Meaning is event dependent.
 273  * @validate_trigger:   function to validate the trigger when the
 274  *                      current trigger gets changed.
 275  * @update_scan_mode:   function to configure device and scan buffer when
 276  *                      channels have changed
 277  * @debugfs_reg_access: function to read or write register value of device
 278  **/
 279 struct iio_info {
 280         struct module                   *driver_module;
 281         struct attribute_group          *event_attrs;
 282         const struct attribute_group    *attrs;
 283
 284         int (*read_raw)(struct iio_dev *indio_dev,
 285                         struct iio_chan_spec const *chan,
 286                         int *val,
 287                         int *val2,
 288                         long mask);
 289
 290         int (*write_raw)(struct iio_dev *indio_dev,
 291                          struct iio_chan_spec const *chan,
 292                          int val,
 293                          int val2,
 294                          long mask);
 295
 296         int (*write_raw_get_fmt)(struct iio_dev *indio_dev,
 297                          struct iio_chan_spec const *chan,
 298                          long mask);
 299
 300         int (*read_event_config)(struct iio_dev *indio_dev,
 301                                  u64 event_code);
 302
 303         int (*write_event_config)(struct iio_dev *indio_dev,
 304                                   u64 event_code,
 305                                   int state);
 306
 307         int (*read_event_value)(struct iio_dev *indio_dev,
 308                                 u64 event_code,
 309                                 int *val);
 310         int (*write_event_value)(struct iio_dev *indio_dev,
 311                                  u64 event_code,
 312                                  int val);
 313         int (*validate_trigger)(struct iio_dev *indio_dev,
 314                                 struct iio_trigger *trig);
 315         int (*update_scan_mode)(struct iio_dev *indio_dev,
 316                                 const unsigned long *scan_mask);
 317         int (*debugfs_reg_access)(struct iio_dev *indio_dev,
 318                                   unsigned reg, unsigned writeval,
 319                                   unsigned *readval);
 320 };
 321
 322 /**
 323  * struct iio_buffer_setup_ops - buffer setup related callbacks
 324  * @preenable:          [DRIVER] function to run prior to marking buffer enabled
 325  * @postenable:         [DRIVER] function to run after marking buffer enabled
 326  * @predisable:         [DRIVER] function to run prior to marking buffer
 327  *                      disabled
 328  * @postdisable:        [DRIVER] function to run after marking buffer disabled
 329  * @validate_scan_mask: [DRIVER] function callback to check whether a given
 330  *                      scan mask is valid for the device.
 331  */
 332 struct iio_buffer_setup_ops {
 333         int (*preenable)(struct iio_dev *);
 334         int (*postenable)(struct iio_dev *);
 335         int (*predisable)(struct iio_dev *);
 336         int (*postdisable)(struct iio_dev *);
 337         bool (*validate_scan_mask)(struct iio_dev *indio_dev,
 338                                    const unsigned long *scan_mask);
 339 };
 340
 341 /**
 342  * struct iio_dev - industrial I/O device
 343  * @id:                 [INTERN] used to identify device internally
 344  * @modes:              [DRIVER] operating modes supported by device
 345  * @currentmode:        [DRIVER] current operating mode
 346  * @dev:                [DRIVER] device structure, should be assigned a parent
 347  *                      and owner
 348  * @event_interface:    [INTERN] event chrdevs associated with interrupt lines
 349  * @buffer:             [DRIVER] any buffer present
 350  * @buffer_list:        [INTERN] list of all buffers currently attached
 351  * @scan_bytes:         [INTERN] num bytes captured to be fed to buffer demux
 352  * @mlock:              [INTERN] lock used to prevent simultaneous device state
 353  *                      changes
 354  * @available_scan_masks: [DRIVER] optional array of allowed bitmasks
 355  * @masklength:         [INTERN] the length of the mask established from
 356  *                      channels
 357  * @active_scan_mask:   [INTERN] union of all scan masks requested by buffers
 358  * @scan_timestamp:     [INTERN] set if any buffers have requested timestamp
 359  * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
 360  * @trig:               [INTERN] current device trigger (buffer modes)
 361  * @pollfunc:           [DRIVER] function run on trigger being received
 362  * @channels:           [DRIVER] channel specification structure table
 363  * @num_channels:       [DRIVER] number of channels specified in @channels.
 364  * @channel_attr_list:  [INTERN] keep track of automatically created channel
 365  *                      attributes
 366  * @chan_attr_group:    [INTERN] group for all attrs in base directory
 367  * @name:               [DRIVER] name of the device.
 368  * @info:               [DRIVER] callbacks and constant info from driver
 369  * @info_exist_lock:    [INTERN] lock to prevent use during removal
 370  * @setup_ops:          [DRIVER] callbacks to call before and after buffer
 371  *                      enable/disable
 372  * @chrdev:             [INTERN] associated character device
 373  * @groups:             [INTERN] attribute groups
 374  * @groupcounter:       [INTERN] index of next attribute group
 375  * @flags:              [INTERN] file ops related flags including busy flag.
 376  * @debugfs_dentry:     [INTERN] device specific debugfs dentry.
 377  * @cached_reg_addr:    [INTERN] cached register address for debugfs reads.
 378  */
 379 struct iio_dev {
 380         int                             id;
 381
 382         int                             modes;
 383         int                             currentmode;
 384         struct device                   dev;
 385
 386         struct iio_event_interface      *event_interface;
 387
 388         struct iio_buffer               *buffer;
 389         struct list_head                buffer_list;
 390         int                             scan_bytes;
 391         struct mutex                    mlock;
 392
 393         const unsigned long             *available_scan_masks;
 394         unsigned                        masklength;
 395         const unsigned long             *active_scan_mask;
 396         bool                            scan_timestamp;
 397         unsigned                        scan_index_timestamp;
 398         struct iio_trigger              *trig;
 399         struct iio_poll_func            *pollfunc;
 400
 401         struct iio_chan_spec const      *channels;
 402         int                             num_channels;
 403
 404         struct list_head                channel_attr_list;
 405         struct attribute_group          chan_attr_group;
 406         const char                      *name;
 407         const struct iio_info           *info;
 408         struct mutex                    info_exist_lock;
 409         const struct iio_buffer_setup_ops       *setup_ops;
 410         struct cdev                     chrdev;
 411 #define IIO_MAX_GROUPS 6
 412         const struct attribute_group    *groups[IIO_MAX_GROUPS + 1];
 413         int                             groupcounter;
 414
 415         unsigned long                   flags;
 416 #if defined(CONFIG_DEBUG_FS)
 417         struct dentry                   *debugfs_dentry;
 418         unsigned                        cached_reg_addr;
 419 #endif
 420 };
 421
 422 /**
 423  * iio_find_channel_from_si() - get channel from its scan index
 424  * @indio_dev:          device
 425  * @si:                 scan index to match
 426  */
 427 const struct iio_chan_spec
 428 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si);
 429
 430 /**
 431  * iio_device_register() - register a device with the IIO subsystem
 432  * @indio_dev:          Device structure filled by the device driver
 433  **/
 434 int iio_device_register(struct iio_dev *indio_dev);
 435
 436 /**
 437  * iio_device_unregister() - unregister a device from the IIO subsystem
 438  * @indio_dev:          Device structure representing the device.
 439  **/
 440 void iio_device_unregister(struct iio_dev *indio_dev);
 441
 442 /**
 443  * iio_push_event() - try to add event to the list for userspace reading
 444  * @indio_dev:          IIO device structure
 445  * @ev_code:            What event
 446  * @timestamp:          When the event occurred
 447  **/
 448 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);
 449
 450 extern struct bus_type iio_bus_type;
 451
 452 /**
 453  * iio_device_put() - reference counted deallocation of struct device
 454  * @indio_dev:          IIO device structure containing the device
 455  **/
 456 static inline void iio_device_put(struct iio_dev *indio_dev)
 457 {
 458         if (indio_dev)
 459                 put_device(&indio_dev->dev);
 460 };
 461
 462 /**
 463  * dev_to_iio_dev() - Get IIO device struct from a device struct
 464  * @dev:                The device embedded in the IIO device
 465  *
 466  * Note: The device must be a IIO device, otherwise the result is undefined.
 467  */
 468 static inline struct iio_dev *dev_to_iio_dev(struct device *dev)
 469 {
 470         return container_of(dev, struct iio_dev, dev);
 471 }
 472
 473 /**
 474  * iio_device_get() - increment reference count for the device
 475  * @indio_dev:          IIO device structure
 476  *
 477  * Returns: The passed IIO device
 478  **/
 479 static inline struct iio_dev *iio_device_get(struct iio_dev *indio_dev)
 480 {
 481         return indio_dev ? dev_to_iio_dev(get_device(&indio_dev->dev)) : NULL;
 482 }
 483
 484
 485 /**
 486  * iio_device_set_drvdata() - Set device driver data
 487  * @indio_dev: IIO device structure
 488  * @data: Driver specific data
 489  *
 490  * Allows to attach an arbitrary pointer to an IIO device, which can later be
 491  * retrieved by iio_device_get_drvdata().
 492  */
 493 static inline void iio_device_set_drvdata(struct iio_dev *indio_dev, void *data)
 494 {
 495         dev_set_drvdata(&indio_dev->dev, data);
 496 }
 497
 498 /**
 499  * iio_device_get_drvdata() - Get device driver data
 500  * @indio_dev: IIO device structure
 501  *
 502  * Returns the data previously set with iio_device_set_drvdata()
 503  */
 504 static inline void *iio_device_get_drvdata(struct iio_dev *indio_dev)
 505 {
 506         return dev_get_drvdata(&indio_dev->dev);
 507 }
 508
 509 /* Can we make this smaller? */
 510 #define IIO_ALIGN L1_CACHE_BYTES
 511 /**
 512  * iio_device_alloc() - allocate an iio_dev from a driver
 513  * @sizeof_priv:        Space to allocate for private structure.
 514  **/
 515 struct iio_dev *iio_device_alloc(int sizeof_priv);
 516
 517 static inline void *iio_priv(const struct iio_dev *indio_dev)
 518 {
 519         return (char *)indio_dev + ALIGN(sizeof(struct iio_dev), IIO_ALIGN);
 520 }
 521
 522 static inline struct iio_dev *iio_priv_to_dev(void *priv)
 523 {
 524         return (struct iio_dev *)((char *)priv -
 525                                   ALIGN(sizeof(struct iio_dev), IIO_ALIGN));
 526 }
 527
 528 /**
 529  * iio_device_free() - free an iio_dev from a driver
 530  * @indio_dev:          the iio_dev associated with the device
 531  **/
 532 void iio_device_free(struct iio_dev *indio_dev);
 533
 534 /**
 535  * iio_buffer_enabled() - helper function to test if the buffer is enabled
 536  * @indio_dev:          IIO device structure for device
 537  **/
 538 static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
 539 {
 540         return indio_dev->currentmode
 541                 & (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
 542 };
 543
 544 /**
 545  * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
 546  * @indio_dev:          IIO device structure for device
 547  **/
 548 #if defined(CONFIG_DEBUG_FS)
 549 static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
 550 {
 551         return indio_dev->debugfs_dentry;
 552 };
 553 #else
 554 static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
 555 {
 556         return NULL;
 557 };
 558 #endif
 559
 560 int iio_str_to_fixpoint(const char *str, int fract_mult, int *integer,
 561         int *fract);
 562
 563 /**
 564  * IIO_DEGREE_TO_RAD() - Convert degree to rad
 565  * @deg: A value in degree
 566  *
 567  * Returns the given value converted from degree to rad
 568  */
 569 #define IIO_DEGREE_TO_RAD(deg) (((deg) * 314159ULL + 9000000ULL) / 18000000ULL)
 570
 571 /**
 572  * IIO_G_TO_M_S_2() - Convert g to meter / second**2
 573  * @g: A value in g
 574  *
 575  * Returns the given value converted from g to meter / second**2
 576  */
 577 #define IIO_G_TO_M_S_2(g) ((g) * 980665ULL / 100000ULL)
 578
 579 #endif /* _INDUSTRIAL_IO_H_ */