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 static irqreturn_t iio_simple_dummy_get_timestamp(int irq, void *private) 157 { 158 struct iio_dev *indio_dev = private; 159 struct iio_dummy_state *st = iio_priv(indio_dev); 160 161 st->event_timestamp = iio_get_time_ns(); 162 return IRQ_WAKE_THREAD; 163 } 164 165 /** 166 * iio_simple_dummy_event_handler() - identify and pass on event 167 * @irq: irq of event line 168 * @private: pointer to device instance state. 169 * 170 * This handler is responsible for querying the device to find out what 171 * event occurred and for then pushing that event towards userspace. 172 * Here only one event occurs so we push that directly on with locally 173 * grabbed timestamp. 174 */ 175 static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private) 176 { 177 struct iio_dev *indio_dev = private; 178 struct iio_dummy_state *st = iio_priv(indio_dev); 179 180 dev_dbg(&indio_dev->dev, "id %x event %x\n", 181 st->regs->reg_id, st->regs->reg_data); 182 183 switch (st->regs->reg_data) { 184 case 0: 185 iio_push_event(indio_dev, 186 IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0, 187 IIO_EV_DIR_RISING, 188 IIO_EV_TYPE_THRESH, 0, 0, 0), 189 st->event_timestamp); 190 break; 191 case 1: 192 if (st->activity_running > st->event_val) 193 iio_push_event(indio_dev, 194 IIO_EVENT_CODE(IIO_ACTIVITY, 0, 195 IIO_MOD_RUNNING, 196 IIO_EV_DIR_RISING, 197 IIO_EV_TYPE_THRESH, 198 0, 0, 0), 199 st->event_timestamp); 200 break; 201 case 2: 202 if (st->activity_walking < st->event_val) 203 iio_push_event(indio_dev, 204 IIO_EVENT_CODE(IIO_ACTIVITY, 0, 205 IIO_MOD_WALKING, 206 IIO_EV_DIR_FALLING, 207 IIO_EV_TYPE_THRESH, 208 0, 0, 0), 209 st->event_timestamp); 210 break; 211 case 3: 212 iio_push_event(indio_dev, 213 IIO_EVENT_CODE(IIO_STEPS, 0, IIO_NO_MOD, 214 IIO_EV_DIR_NONE, 215 IIO_EV_TYPE_CHANGE, 0, 0, 0), 216 st->event_timestamp); 217 break; 218 default: 219 break; 220 } 221 222 return IRQ_HANDLED; 223 } 224 225 /** 226 * iio_simple_dummy_events_register() - setup interrupt handling for events 227 * @indio_dev: device instance data 228 * 229 * This function requests the threaded interrupt to handle the events. 230 * Normally the irq is a hardware interrupt and the number comes 231 * from board configuration files. Here we get it from a companion 232 * module that fakes the interrupt for us. Note that module in 233 * no way forms part of this example. Just assume that events magically 234 * appear via the provided interrupt. 235 */ 236 int iio_simple_dummy_events_register(struct iio_dev *indio_dev) 237 { 238 struct iio_dummy_state *st = iio_priv(indio_dev); 239 int ret; 240 241 /* Fire up event source - normally not present */ 242 st->event_irq = iio_dummy_evgen_get_irq(); 243 if (st->event_irq < 0) { 244 ret = st->event_irq; 245 goto error_ret; 246 } 247 st->regs = iio_dummy_evgen_get_regs(st->event_irq); 248 249 ret = request_threaded_irq(st->event_irq, 250 &iio_simple_dummy_get_timestamp, 251 &iio_simple_dummy_event_handler, 252 IRQF_ONESHOT, 253 "iio_simple_event", 254 indio_dev); 255 if (ret < 0) 256 goto error_free_evgen; 257 return 0; 258 259 error_free_evgen: 260 iio_dummy_evgen_release_irq(st->event_irq); 261 error_ret: 262 return ret; 263 } 264 265 /** 266 * iio_simple_dummy_events_unregister() - tidy up interrupt handling on remove 267 * @indio_dev: device instance data 268 */ 269 void iio_simple_dummy_events_unregister(struct iio_dev *indio_dev) 270 { 271 struct iio_dummy_state *st = iio_priv(indio_dev); 272 273 free_irq(st->event_irq, indio_dev); 274 /* Not part of normal driver */ 275 iio_dummy_evgen_release_irq(st->event_irq); 276 } 277