release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/staging/iio/ring_generic.h

   1 /* The industrial I/O core - generic ring buffer interfaces.
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  */
   9
  10 #ifndef _IIO_RING_GENERIC_H_
  11 #define _IIO_RING_GENERIC_H_
  12 #include "iio.h"
  13
  14 #ifdef CONFIG_IIO_RING_BUFFER
  15
  16 struct iio_handler;
  17 struct iio_ring_buffer;
  18 struct iio_dev;
  19
  20 /**
  21  * iio_push_ring_event() - ring buffer specific push to event chrdev
  22  * @ring_buf:           ring buffer that is the event source
  23  * @event_code:         event indentification code
  24  * @timestamp:          time of event
  25  **/
  26 int iio_push_ring_event(struct iio_ring_buffer *ring_buf,
  27                         int event_code,
  28                         s64 timestamp);
  29 /**
  30  * iio_push_or_escallate_ring_event() - escalate or add as appropriate
  31  * @ring_buf:           ring buffer that is the event source
  32  * @event_code:         event indentification code
  33  * @timestamp:          time of event
  34  *
  35  * Typical usecase is to escalate a 50% ring full to 75% full if noone has yet
  36  * read the first event. Clearly the 50% full is no longer of interest in
  37  * typical use case.
  38  **/
  39 int iio_push_or_escallate_ring_event(struct iio_ring_buffer *ring_buf,
  40                                      int event_code,
  41                                      s64 timestamp);
  42
  43 /**
  44  * struct iio_ring_access_funcs - access functions for ring buffers.
  45  * @mark_in_use:        reference counting, typically to prevent module removal
  46  * @unmark_in_use:      reduce reference count when no longer using ring buffer
  47  * @store_to:           actually store stuff to the ring buffer
  48  * @read_last:          get the last element stored
  49  * @rip_lots:           try to get a specified number of elements (must exist)
  50  * @mark_param_change:  notify ring that some relevant parameter has changed
  51  *                      Often this means the underlying storage may need to
  52  *                      change.
  53  * @request_update:     if a parameter change has been marked, update underlying
  54  *                      storage.
  55  * @get_bpd:            get current bytes per datum
  56  * @set_bpd:            set number of bytes per datum
  57  * @get_length:         get number of datums in ring
  58  * @set_length:         set number of datums in ring
  59  * @is_enabled:         query if ring is currently being used
  60  * @enable:             enable the ring
  61  *
  62  * The purpose of this structure is to make the ring buffer element
  63  * modular as event for a given driver, different usecases may require
  64  * different ring designs (space efficiency vs speed for example).
  65  *
  66  * It is worth noting that a given ring implementation may only support a small
  67  * proportion of these functions.  The core code 'should' cope fine with any of
  68  * them not existing.
  69  **/
  70 struct iio_ring_access_funcs {
  71         void (*mark_in_use)(struct iio_ring_buffer *ring);
  72         void (*unmark_in_use)(struct iio_ring_buffer *ring);
  73
  74         int (*store_to)(struct iio_ring_buffer *ring, u8 *data, s64 timestamp);
  75         int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
  76         int (*rip_lots)(struct iio_ring_buffer *ring,
  77                         size_t count,
  78                         u8 **data,
  79                         int *dead_offset);
  80
  81         int (*mark_param_change)(struct iio_ring_buffer *ring);
  82         int (*request_update)(struct iio_ring_buffer *ring);
  83
  84         int (*get_bpd)(struct iio_ring_buffer *ring);
  85         int (*set_bpd)(struct iio_ring_buffer *ring, size_t bpd);
  86         int (*get_length)(struct iio_ring_buffer *ring);
  87         int (*set_length)(struct iio_ring_buffer *ring, int length);
  88
  89         int (*is_enabled)(struct iio_ring_buffer *ring);
  90         int (*enable)(struct iio_ring_buffer *ring);
  91 };
  92
  93 /**
  94  * struct iio_ring_buffer - general ring buffer structure
  95  * @dev:                ring buffer device struct
  96  * @access_dev:         system device struct for the chrdev
  97  * @indio_dev:          industrial I/O device structure
  98  * @owner:              module that owns the ring buffer (for ref counting)
  99  * @id:                 unique id number
 100  * @access_id:          device id number
 101  * @length:             [DEVICE] number of datums in ring
 102  * @bpd:                [DEVICE] size of individual datum including timestamp
 103  * @bpe:                [DEVICE] size of individual channel value
 104  * @loopcount:          [INTERN] number of times the ring has looped
 105  * @access_handler:     [INTERN] chrdev access handling
 106  * @ev_int:             [INTERN] chrdev interface for the event chrdev
 107  * @shared_ev_pointer:  [INTERN] the shared event pointer to allow escalation of
 108  *                      events
 109  * @access:             [DRIVER] ring access functions associated with the
 110  *                      implementation.
 111  * @preenable:          [DRIVER] function to run prior to marking ring enabled
 112  * @postenable:         [DRIVER] function to run after marking ring enabled
 113  * @predisable:         [DRIVER] function to run prior to marking ring disabled
 114  * @postdisable:        [DRIVER] function to run after marking ring disabled
 115   **/
 116 struct iio_ring_buffer {
 117         struct device dev;
 118         struct device access_dev;
 119         struct iio_dev *indio_dev;
 120         struct module *owner;
 121         int                             id;
 122         int                             access_id;
 123         int                             length;
 124         int                             bpd;
 125         int                             bpe;
 126         int                             loopcount;
 127         struct iio_handler              access_handler;
 128         struct iio_event_interface      ev_int;
 129         struct iio_shared_ev_pointer    shared_ev_pointer;
 130         struct iio_ring_access_funcs    access;
 131         int                             (*preenable)(struct iio_dev *);
 132         int                             (*postenable)(struct iio_dev *);
 133         int                             (*predisable)(struct iio_dev *);
 134         int                             (*postdisable)(struct iio_dev *);
 135
 136 };
 137 void iio_ring_buffer_init(struct iio_ring_buffer *ring,
 138                           struct iio_dev *dev_info);
 139
 140 /**
 141  * __iio_update_ring_buffer() - update common elements of ring buffers
 142  * @ring:               ring buffer that is the event source
 143  * @bytes_per_datum:    size of individual datum including timestamp
 144  * @length:             number of datums in ring
 145  **/
 146 static inline void __iio_update_ring_buffer(struct iio_ring_buffer *ring,
 147                                             int bytes_per_datum, int length)
 148 {
 149         ring->bpd = bytes_per_datum;
 150         ring->length = length;
 151         ring->loopcount = 0;
 152 }
 153
 154 /**
 155  * struct iio_scan_el - an individual element of a scan
 156  * @dev_attr:           control attribute (if directly controllable)
 157  * @number:             unique identifier of element (used for bit mask)
 158  * @bit_count:          number of bits in scan element
 159  * @label:              useful data for the scan el (often reg address)
 160  * @set_state:          for some devices datardy signals are generated
 161  *                      for any enabled lines.  This allows unwanted lines
 162  *                      to be disabled and hence not get in the way.
 163  **/
 164 struct iio_scan_el {
 165         struct device_attribute         dev_attr;
 166         unsigned int                    number;
 167         int                             bit_count;
 168         unsigned int                    label;
 169
 170         int (*set_state)(struct iio_scan_el *scanel,
 171                          struct iio_dev *dev_info,
 172                          bool state);
 173 };
 174
 175 #define to_iio_scan_el(_dev_attr)                               \
 176         container_of(_dev_attr, struct iio_scan_el, dev_attr);
 177
 178 /**
 179  * iio_scan_el_store() - sysfs scan element selection interface
 180  * @dev: the target device
 181  * @attr: the device attribute that is being processed
 182  * @buf: input from userspace
 183  * @len: length of input
 184  *
 185  * A generic function used to enable various scan elements.  In some
 186  * devices explicit read commands for each channel mean this is merely
 187  * a software switch.  In others this must actively disable the channel.
 188  * Complexities occur when this interacts with data ready type triggers
 189  * which may not reset unless every channel that is enabled is explicitly
 190  * read.
 191  **/
 192 ssize_t iio_scan_el_store(struct device *dev, struct device_attribute *attr,
 193                           const char *buf, size_t len);
 194 /**
 195  * iio_scal_el_show() - sysfs interface to query whether a scan element is
 196  *                      is enabled or not
 197  * @dev: the target device
 198  * @attr: the device attribute that is being processed
 199  * @buf: output buffer
 200  **/
 201 ssize_t iio_scan_el_show(struct device *dev, struct device_attribute *attr,
 202                          char *buf);
 203
 204 ssize_t iio_scan_el_ts_store(struct device *dev, struct device_attribute *attr,
 205                              const char *buf, size_t len);
 206
 207 ssize_t iio_scan_el_ts_show(struct device *dev, struct device_attribute *attr,
 208                             char *buf);
 209 /**
 210  * IIO_SCAN_EL_C - declare and initialize a scan element with a control func
 211  *
 212  * @_name:      identifying name. Resulting struct is iio_scan_el_##_name,
 213  *              sysfs element, _name##_en.
 214  * @_number:    unique id number for the scan element.
 215  * @_bits:      number of bits in the scan element result (used in mixed bit
 216  *              length devices).
 217  * @_label:     indentification variable used by drivers.  Often a reg address.
 218  * @_controlfunc: function used to notify hardware of whether state changes
 219  **/
 220 #define __IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc)    \
 221         struct iio_scan_el iio_scan_el_##_name = {                      \
 222                 .dev_attr = __ATTR(_number##_##_name##_en,              \
 223                                    S_IRUGO | S_IWUSR,                   \
 224                                    iio_scan_el_show,                    \
 225                                    iio_scan_el_store),                  \
 226                 .number =  _number,                                     \
 227                 .bit_count = _bits,                                     \
 228                 .label = _label,                                        \
 229                 .set_state = _controlfunc,                              \
 230         }
 231
 232 #define IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc)      \
 233         __IIO_SCAN_EL_C(_name, _number, _bits, _label, _controlfunc)
 234
 235 #define __IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \
 236         struct iio_scan_el iio_scan_el_##_name = {                      \
 237                 .dev_attr = __ATTR(_number##_##_string##_en,            \
 238                                    S_IRUGO | S_IWUSR,                   \
 239                                    iio_scan_el_show,                    \
 240                                    iio_scan_el_store),                  \
 241                 .number =  _number,                                     \
 242                 .bit_count = _bits,                                     \
 243                 .label = _label,                                        \
 244                 .set_state = _cf,                                       \
 245         }
 246 #define IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf) \
 247         __IIO_SCAN_NAMED_EL_C(_name, _string, _number, _bits, _label, _cf)
 248 /**
 249  * IIO_SCAN_EL_TIMESTAMP - declare a special scan element for timestamps
 250  *
 251  * Odd one out. Handled slightly differently from other scan elements.
 252  **/
 253 #define IIO_SCAN_EL_TIMESTAMP(number)                           \
 254         struct iio_scan_el iio_scan_el_timestamp = {            \
 255                 .dev_attr = __ATTR(number##_timestamp_en,       \
 256                                    S_IRUGO | S_IWUSR,           \
 257                                    iio_scan_el_ts_show,         \
 258                                    iio_scan_el_ts_store),       \
 259         }
 260
 261 static inline void iio_put_ring_buffer(struct iio_ring_buffer *ring)
 262 {
 263         put_device(&ring->dev);
 264 };
 265
 266 #define to_iio_ring_buffer(d)                   \
 267         container_of(d, struct iio_ring_buffer, dev)
 268 #define access_dev_to_iio_ring_buffer(d)                        \
 269         container_of(d, struct iio_ring_buffer, access_dev)
 270 int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id);
 271 void iio_ring_buffer_unregister(struct iio_ring_buffer *ring);
 272
 273 ssize_t iio_read_ring_length(struct device *dev,
 274                              struct device_attribute *attr,
 275                              char *buf);
 276 ssize_t iio_write_ring_length(struct device *dev,
 277                               struct device_attribute *attr,
 278                               const char *buf,
 279                               size_t len);
 280 ssize_t iio_read_ring_bps(struct device *dev,
 281                           struct device_attribute *attr,
 282                           char *buf);
 283 ssize_t iio_store_ring_enable(struct device *dev,
 284                               struct device_attribute *attr,
 285                               const char *buf,
 286                               size_t len);
 287 ssize_t iio_show_ring_enable(struct device *dev,
 288                              struct device_attribute *attr,
 289                              char *buf);
 290 #define IIO_RING_LENGTH_ATTR DEVICE_ATTR(length, S_IRUGO | S_IWUSR,     \
 291                                          iio_read_ring_length,          \
 292                                          iio_write_ring_length)
 293 #define IIO_RING_BPS_ATTR DEVICE_ATTR(bps, S_IRUGO | S_IWUSR,   \
 294                                       iio_read_ring_bps, NULL)
 295 #define IIO_RING_ENABLE_ATTR DEVICE_ATTR(ring_enable, S_IRUGO | S_IWUSR, \
 296                                          iio_show_ring_enable,          \
 297                                          iio_store_ring_enable)
 298 #else /* CONFIG_IIO_RING_BUFFER */
 299 static inline int iio_ring_buffer_register(struct iio_ring_buffer *ring, int id)
 300 {
 301         return 0;
 302 };
 303 static inline void iio_ring_buffer_unregister(struct iio_ring_buffer *ring)
 304 {};
 305
 306 #endif /* CONFIG_IIO_RING_BUFFER */
 307
 308 #endif /* _IIO_RING_GENERIC_H_ */