drivers/iio/common/st_sensors/st_sensors_trigger.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics sensors trigger library driver
   4  *
   5  * Copyright 2012-2013 STMicroelectronics Inc.
   6  *
   7  * Denis Ciocca <denis.ciocca@st.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/iio/trigger.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/regmap.h>
  17 #include <linux/iio/common/st_sensors.h>
  18 #include "st_sensors_core.h"
  19
  20 /**
  21  * st_sensors_new_samples_available() - check if more samples came in
  22  * @indio_dev: IIO device reference.
  23  * @sdata: Sensor data.
  24  *
  25  * returns:
  26  * false - no new samples available or read error
  27  * true - new samples available
  28  */
  29 static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
  30                                              struct st_sensor_data *sdata)
  31 {
  32         int ret, status;
  33
  34         /* How would I know if I can't check it? */
  35         if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
  36                 return true;
  37
  38         /* No scan mask, no interrupt */
  39         if (!indio_dev->active_scan_mask)
  40                 return false;
  41
  42         ret = regmap_read(sdata->regmap,
  43                           sdata->sensor_settings->drdy_irq.stat_drdy.addr,
  44                           &status);
  45         if (ret < 0) {
  46                 dev_err(sdata->dev, "error checking samples available\n");
  47                 return false;
  48         }
  49
  50         return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
  51 }
  52
  53 /**
  54  * st_sensors_irq_handler() - top half of the IRQ-based triggers
  55  * @irq: irq number
  56  * @p: private handler data
  57  */
  58 static irqreturn_t st_sensors_irq_handler(int irq, void *p)
  59 {
  60         struct iio_trigger *trig = p;
  61         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  62         struct st_sensor_data *sdata = iio_priv(indio_dev);
  63
  64         /* Get the time stamp as close in time as possible */
  65         sdata->hw_timestamp = iio_get_time_ns(indio_dev);
  66         return IRQ_WAKE_THREAD;
  67 }
  68
  69 /**
  70  * st_sensors_irq_thread() - bottom half of the IRQ-based triggers
  71  * @irq: irq number
  72  * @p: private handler data
  73  */
  74 static irqreturn_t st_sensors_irq_thread(int irq, void *p)
  75 {
  76         struct iio_trigger *trig = p;
  77         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  78         struct st_sensor_data *sdata = iio_priv(indio_dev);
  79
  80         /*
  81          * If this trigger is backed by a hardware interrupt and we have a
  82          * status register, check if this IRQ came from us. Notice that
  83          * we will process also if st_sensors_new_samples_available()
  84          * returns negative: if we can't check status, then poll
  85          * unconditionally.
  86          */
  87         if (sdata->hw_irq_trigger &&
  88             st_sensors_new_samples_available(indio_dev, sdata)) {
  89                 iio_trigger_poll_chained(p);
  90         } else {
  91                 dev_dbg(sdata->dev, "spurious IRQ\n");
  92                 return IRQ_NONE;
  93         }
  94
  95         /*
  96          * If we have proper level IRQs the handler will be re-entered if
  97          * the line is still active, so return here and come back in through
  98          * the top half if need be.
  99          */
 100         if (!sdata->edge_irq)
 101                 return IRQ_HANDLED;
 102
 103         /*
 104          * If we are using edge IRQs, new samples arrived while processing
 105          * the IRQ and those may be missed unless we pick them here, so poll
 106          * again. If the sensor delivery frequency is very high, this thread
 107          * turns into a polled loop handler.
 108          */
 109         while (sdata->hw_irq_trigger &&
 110                st_sensors_new_samples_available(indio_dev, sdata)) {
 111                 dev_dbg(sdata->dev, "more samples came in during polling\n");
 112                 sdata->hw_timestamp = iio_get_time_ns(indio_dev);
 113                 iio_trigger_poll_chained(p);
 114         }
 115
 116         return IRQ_HANDLED;
 117 }
 118
 119 int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
 120                                 const struct iio_trigger_ops *trigger_ops)
 121 {
 122         struct st_sensor_data *sdata = iio_priv(indio_dev);
 123         unsigned long irq_trig;
 124         int err;
 125
 126         sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
 127         if (sdata->trig == NULL) {
 128                 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
 129                 return -ENOMEM;
 130         }
 131
 132         iio_trigger_set_drvdata(sdata->trig, indio_dev);
 133         sdata->trig->ops = trigger_ops;
 134         sdata->trig->dev.parent = sdata->dev;
 135
 136         irq_trig = irqd_get_trigger_type(irq_get_irq_data(sdata->irq));
 137         /*
 138          * If the IRQ is triggered on falling edge, we need to mark the
 139          * interrupt as active low, if the hardware supports this.
 140          */
 141         switch(irq_trig) {
 142         case IRQF_TRIGGER_FALLING:
 143         case IRQF_TRIGGER_LOW:
 144                 if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
 145                         dev_err(&indio_dev->dev,
 146                                 "falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n");
 147                         if (irq_trig == IRQF_TRIGGER_FALLING)
 148                                 irq_trig = IRQF_TRIGGER_RISING;
 149                         if (irq_trig == IRQF_TRIGGER_LOW)
 150                                 irq_trig = IRQF_TRIGGER_HIGH;
 151                 } else {
 152                         /* Set up INT active low i.e. falling edge */
 153                         err = st_sensors_write_data_with_mask(indio_dev,
 154                                 sdata->sensor_settings->drdy_irq.addr_ihl,
 155                                 sdata->sensor_settings->drdy_irq.mask_ihl, 1);
 156                         if (err < 0)
 157                                 goto iio_trigger_free;
 158                         dev_info(&indio_dev->dev,
 159                                  "interrupts on the falling edge or active low level\n");
 160                 }
 161                 break;
 162         case IRQF_TRIGGER_RISING:
 163                 dev_info(&indio_dev->dev,
 164                          "interrupts on the rising edge\n");
 165                 break;
 166         case IRQF_TRIGGER_HIGH:
 167                 dev_info(&indio_dev->dev,
 168                          "interrupts active high level\n");
 169                 break;
 170         default:
 171                 /* This is the most preferred mode, if possible */
 172                 dev_err(&indio_dev->dev,
 173                         "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
 174                 irq_trig = IRQF_TRIGGER_RISING;
 175         }
 176
 177         /* Tell the interrupt handler that we're dealing with edges */
 178         if (irq_trig == IRQF_TRIGGER_FALLING ||
 179             irq_trig == IRQF_TRIGGER_RISING) {
 180                 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
 181                         dev_err(&indio_dev->dev,
 182                                 "edge IRQ not supported w/o stat register.\n");
 183                         err = -EOPNOTSUPP;
 184                         goto iio_trigger_free;
 185                 }
 186                 sdata->edge_irq = true;
 187         } else {
 188                 /*
 189                  * If we're not using edges (i.e. level interrupts) we
 190                  * just mask off the IRQ, handle one interrupt, then
 191                  * if the line is still low, we return to the
 192                  * interrupt handler top half again and start over.
 193                  */
 194                 irq_trig |= IRQF_ONESHOT;
 195         }
 196
 197         /*
 198          * If the interrupt pin is Open Drain, by definition this
 199          * means that the interrupt line may be shared with other
 200          * peripherals. But to do this we also need to have a status
 201          * register and mask to figure out if this sensor was firing
 202          * the IRQ or not, so we can tell the interrupt handle that
 203          * it was "our" interrupt.
 204          */
 205         if (sdata->int_pin_open_drain &&
 206             sdata->sensor_settings->drdy_irq.stat_drdy.addr)
 207                 irq_trig |= IRQF_SHARED;
 208
 209         err = request_threaded_irq(sdata->irq,
 210                                    st_sensors_irq_handler,
 211                                    st_sensors_irq_thread,
 212                                    irq_trig,
 213                                    sdata->trig->name,
 214                                    sdata->trig);
 215         if (err) {
 216                 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
 217                 goto iio_trigger_free;
 218         }
 219
 220         err = iio_trigger_register(sdata->trig);
 221         if (err < 0) {
 222                 dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
 223                 goto iio_trigger_register_error;
 224         }
 225         indio_dev->trig = iio_trigger_get(sdata->trig);
 226
 227         return 0;
 228
 229 iio_trigger_register_error:
 230         free_irq(sdata->irq, sdata->trig);
 231 iio_trigger_free:
 232         iio_trigger_free(sdata->trig);
 233         return err;
 234 }
 235 EXPORT_SYMBOL(st_sensors_allocate_trigger);
 236
 237 void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
 238 {
 239         struct st_sensor_data *sdata = iio_priv(indio_dev);
 240
 241         iio_trigger_unregister(sdata->trig);
 242         free_irq(sdata->irq, sdata->trig);
 243         iio_trigger_free(sdata->trig);
 244 }
 245 EXPORT_SYMBOL(st_sensors_deallocate_trigger);
 246
 247 int st_sensors_validate_device(struct iio_trigger *trig,
 248                                struct iio_dev *indio_dev)
 249 {
 250         struct iio_dev *indio = iio_trigger_get_drvdata(trig);
 251
 252         if (indio != indio_dev)
 253                 return -EINVAL;
 254
 255         return 0;
 256 }
 257 EXPORT_SYMBOL(st_sensors_validate_device);
 258
 259 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 260 MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger");
 261 MODULE_LICENSE("GPL v2");