drivers/staging/iio/iio_simple_dummy_events.c

   1 /**
   2  * Copyright (c) 2011 Jonathan Cameron
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * Event handling elements of industrial I/O reference driver.
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/sysfs.h>
  17 #include <linux/iio/events.h>
  18 #include "iio_simple_dummy.h"
  19
  20 /* Evgen 'fakes' interrupt events for this example */
  21 #include "iio_dummy_evgen.h"
  22
  23 /**
  24  * iio_simple_dummy_read_event_config() - is event enabled?
  25  * @indio_dev: the device instance data
  26  * @chan: channel for the event whose state is being queried
  27  * @type: type of the event whose state is being queried
  28  * @dir: direction of the vent whose state is being queried
  29  *
  30  * This function would normally query the relevant registers or a cache to
  31  * discover if the event generation is enabled on the device.
  32  */
  33 int iio_simple_dummy_read_event_config(struct iio_dev *indio_dev,
  34                                        const struct iio_chan_spec *chan,
  35                                        enum iio_event_type type,
  36                                        enum iio_event_direction dir)
  37 {
  38         struct iio_dummy_state *st = iio_priv(indio_dev);
  39
  40         return st->event_en;
  41 }
  42
  43 /**
  44  * iio_simple_dummy_write_event_config() - set whether event is enabled
  45  * @indio_dev: the device instance data
  46  * @chan: channel for the event whose state is being set
  47  * @type: type of the event whose state is being set
  48  * @dir: direction of the vent whose state is being set
  49  * @state: whether to enable or disable the device.
  50  *
  51  * This function would normally set the relevant registers on the devices
  52  * so that it generates the specified event. Here it just sets up a cached
  53  * value.
  54  */
  55 int iio_simple_dummy_write_event_config(struct iio_dev *indio_dev,
  56                                         const struct iio_chan_spec *chan,
  57                                         enum iio_event_type type,
  58                                         enum iio_event_direction dir,
  59                                         int state)
  60 {
  61         struct iio_dummy_state *st = iio_priv(indio_dev);
  62
  63         /*
  64          *  Deliberately over the top code splitting to illustrate
  65          * how this is done when multiple events exist.
  66          */
  67         switch (chan->type) {
  68         case IIO_VOLTAGE:
  69                 switch (type) {
  70                 case IIO_EV_TYPE_THRESH:
  71                         if (dir == IIO_EV_DIR_RISING)
  72                                 st->event_en = state;
  73                         else
  74                                 return -EINVAL;
  75                 default:
  76                         return -EINVAL;
  77                 }
  78                 break;
  79         case IIO_ACTIVITY:
  80                 switch (type) {
  81                 case IIO_EV_TYPE_THRESH:
  82                         st->event_en = state;
  83                         break;
  84                 default:
  85                         return -EINVAL;
  86                 }
  87                 break;
  88         case IIO_STEPS:
  89                 switch (type) {
  90                 case IIO_EV_TYPE_CHANGE:
  91                         st->event_en = state;
  92                         break;
  93                 default:
  94                         return -EINVAL;
  95                 }
  96                 break;
  97         default:
  98                 return -EINVAL;
  99         }
 100
 101         return 0;
 102 }
 103
 104 /**
 105  * iio_simple_dummy_read_event_value() - get value associated with event
 106  * @indio_dev: device instance specific data
 107  * @chan: channel for the event whose value is being read
 108  * @type: type of the event whose value is being read
 109  * @dir: direction of the vent whose value is being read
 110  * @info: info type of the event whose value is being read
 111  * @val: value for the event code.
 112  *
 113  * Many devices provide a large set of events of which only a subset may
 114  * be enabled at a time, with value registers whose meaning changes depending
 115  * on the event enabled. This often means that the driver must cache the values
 116  * associated with each possible events so that the right value is in place when
 117  * the enabled event is changed.
 118  */
 119 int iio_simple_dummy_read_event_value(struct iio_dev *indio_dev,
 120                                       const struct iio_chan_spec *chan,
 121                                       enum iio_event_type type,
 122                                       enum iio_event_direction dir,
 123                                       enum iio_event_info info,
 124                                       int *val, int *val2)
 125 {
 126         struct iio_dummy_state *st = iio_priv(indio_dev);
 127
 128         *val = st->event_val;
 129
 130         return IIO_VAL_INT;
 131 }
 132
 133 /**
 134  * iio_simple_dummy_write_event_value() - set value associate with event
 135  * @indio_dev: device instance specific data
 136  * @chan: channel for the event whose value is being set
 137  * @type: type of the event whose value is being set
 138  * @dir: direction of the vent whose value is being set
 139  * @info: info type of the event whose value is being set
 140  * @val: the value to be set.
 141  */
 142 int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
 143                                        const struct iio_chan_spec *chan,
 144                                        enum iio_event_type type,
 145                                        enum iio_event_direction dir,
 146                                        enum iio_event_info info,
 147                                        int val, int val2)
 148 {
 149         struct iio_dummy_state *st = iio_priv(indio_dev);
 150
 151         st->event_val = val;
 152
 153         return 0;
 154 }
 155
 156 /**
 157  * iio_simple_dummy_event_handler() - identify and pass on event
 158  * @irq: irq of event line
 159  * @private: pointer to device instance state.
 160  *
 161  * This handler is responsible for querying the device to find out what
 162  * event occurred and for then pushing that event towards userspace.
 163  * Here only one event occurs so we push that directly on with locally
 164  * grabbed timestamp.
 165  */
 166 static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
 167 {
 168         struct iio_dev *indio_dev = private;
 169         struct iio_dummy_state *st = iio_priv(indio_dev);
 170
 171         dev_dbg(&indio_dev->dev, "id %x event %x\n",
 172                 st->regs->reg_id, st->regs->reg_data);
 173
 174         switch (st->regs->reg_data) {
 175         case 0:
 176                 iio_push_event(indio_dev,
 177                                IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
 178                                               IIO_EV_DIR_RISING,
 179                                               IIO_EV_TYPE_THRESH, 0, 0, 0),
 180                                iio_get_time_ns());
 181                 break;
 182         case 1:
 183                 if (st->activity_running > st->event_val)
 184                         iio_push_event(indio_dev,
 185                                        IIO_EVENT_CODE(IIO_ACTIVITY, 0,
 186                                                       IIO_MOD_RUNNING,
 187                                                       IIO_EV_DIR_RISING,
 188                                                       IIO_EV_TYPE_THRESH,
 189                                                       0, 0, 0),
 190                                        iio_get_time_ns());
 191                 break;
 192         case 2:
 193                 if (st->activity_walking < st->event_val)
 194                         iio_push_event(indio_dev,
 195                                        IIO_EVENT_CODE(IIO_ACTIVITY, 0,
 196                                                       IIO_MOD_WALKING,
 197                                                       IIO_EV_DIR_FALLING,
 198                                                       IIO_EV_TYPE_THRESH,
 199                                                       0, 0, 0),
 200                                        iio_get_time_ns());
 201                 break;
 202         case 3:
 203                 iio_push_event(indio_dev,
 204                                IIO_EVENT_CODE(IIO_STEPS, 0, IIO_NO_MOD,
 205                                               IIO_EV_DIR_NONE,
 206                                               IIO_EV_TYPE_CHANGE, 0, 0, 0),
 207                                iio_get_time_ns());
 208                 break;
 209         default:
 210                 break;
 211         }
 212
 213         return IRQ_HANDLED;
 214 }
 215
 216 /**
 217  * iio_simple_dummy_events_register() - setup interrupt handling for events
 218  * @indio_dev: device instance data
 219  *
 220  * This function requests the threaded interrupt to handle the events.
 221  * Normally the irq is a hardware interrupt and the number comes
 222  * from board configuration files.  Here we get it from a companion
 223  * module that fakes the interrupt for us. Note that module in
 224  * no way forms part of this example. Just assume that events magically
 225  * appear via the provided interrupt.
 226  */
 227 int iio_simple_dummy_events_register(struct iio_dev *indio_dev)
 228 {
 229         struct iio_dummy_state *st = iio_priv(indio_dev);
 230         int ret;
 231
 232         /* Fire up event source - normally not present */
 233         st->event_irq = iio_dummy_evgen_get_irq();
 234         if (st->event_irq < 0) {
 235                 ret = st->event_irq;
 236                 goto error_ret;
 237         }
 238         st->regs = iio_dummy_evgen_get_regs(st->event_irq);
 239
 240         ret = request_threaded_irq(st->event_irq,
 241                                    NULL,
 242                                    &iio_simple_dummy_event_handler,
 243                                    IRQF_ONESHOT,
 244                                    "iio_simple_event",
 245                                    indio_dev);
 246         if (ret < 0)
 247                 goto error_free_evgen;
 248         return 0;
 249
 250 error_free_evgen:
 251         iio_dummy_evgen_release_irq(st->event_irq);
 252 error_ret:
 253         return ret;
 254 }
 255
 256 /**
 257  * iio_simple_dummy_events_unregister() - tidy up interrupt handling on remove
 258  * @indio_dev: device instance data
 259  */
 260 void iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
 261 {
 262         struct iio_dummy_state *st = iio_priv(indio_dev);
 263
 264         free_irq(st->event_irq, indio_dev);
 265         /* Not part of normal driver */
 266         iio_dummy_evgen_release_irq(st->event_irq);
 267 }