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/iio/iio.h>
  12 #include <linux/iio/trigger.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/regmap.h>
  15 #include <linux/iio/common/st_sensors.h>
  16 #include "st_sensors_core.h"
  17
  18 /**
  19  * st_sensors_new_samples_available() - check if more samples came in
  20  * @indio_dev: IIO device reference.
  21  * @sdata: Sensor data.
  22  *
  23  * returns:
  24  * false - no new samples available or read error
  25  * true - new samples available
  26  */
  27 static bool st_sensors_new_samples_available(struct iio_dev *indio_dev,
  28                                              struct st_sensor_data *sdata)
  29 {
  30         int ret, status;
  31
  32         /* How would I know if I can't check it? */
  33         if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr)
  34                 return true;
  35
  36         /* No scan mask, no interrupt */
  37         if (!indio_dev->active_scan_mask)
  38                 return false;
  39
  40         ret = regmap_read(sdata->regmap,
  41                           sdata->sensor_settings->drdy_irq.stat_drdy.addr,
  42                           &status);
  43         if (ret < 0) {
  44                 dev_err(indio_dev->dev.parent,
  45                         "error checking samples available\n");
  46                 return false;
  47         }
  48
  49         return !!(status & sdata->sensor_settings->drdy_irq.stat_drdy.mask);
  50 }
  51
  52 /**
  53  * st_sensors_irq_handler() - top half of the IRQ-based triggers
  54  * @irq: irq number
  55  * @p: private handler data
  56  */
  57 static irqreturn_t st_sensors_irq_handler(int irq, void *p)
  58 {
  59         struct iio_trigger *trig = p;
  60         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  61         struct st_sensor_data *sdata = iio_priv(indio_dev);
  62
  63         /* Get the time stamp as close in time as possible */
  64         sdata->hw_timestamp = iio_get_time_ns(indio_dev);
  65         return IRQ_WAKE_THREAD;
  66 }
  67
  68 /**
  69  * st_sensors_irq_thread() - bottom half of the IRQ-based triggers
  70  * @irq: irq number
  71  * @p: private handler data
  72  */
  73 static irqreturn_t st_sensors_irq_thread(int irq, void *p)
  74 {
  75         struct iio_trigger *trig = p;
  76         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  77         struct st_sensor_data *sdata = iio_priv(indio_dev);
  78
  79         /*
  80          * If this trigger is backed by a hardware interrupt and we have a
  81          * status register, check if this IRQ came from us. Notice that
  82          * we will process also if st_sensors_new_samples_available()
  83          * returns negative: if we can't check status, then poll
  84          * unconditionally.
  85          */
  86         if (sdata->hw_irq_trigger &&
  87             st_sensors_new_samples_available(indio_dev, sdata)) {
  88                 iio_trigger_poll_nested(p);
  89         } else {
  90                 dev_dbg(indio_dev->dev.parent, "spurious IRQ\n");
  91                 return IRQ_NONE;
  92         }
  93
  94         /*
  95          * If we have proper level IRQs the handler will be re-entered if
  96          * the line is still active, so return here and come back in through
  97          * the top half if need be.
  98          */
  99         if (!sdata->edge_irq)
 100                 return IRQ_HANDLED;
 101
 102         /*
 103          * If we are using edge IRQs, new samples arrived while processing
 104          * the IRQ and those may be missed unless we pick them here, so poll
 105          * again. If the sensor delivery frequency is very high, this thread
 106          * turns into a polled loop handler.
 107          */
 108         while (sdata->hw_irq_trigger &&
 109                st_sensors_new_samples_available(indio_dev, sdata)) {
 110                 dev_dbg(indio_dev->dev.parent,
 111                         "more samples came in during polling\n");
 112                 sdata->hw_timestamp = iio_get_time_ns(indio_dev);
 113                 iio_trigger_poll_nested(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         struct device *parent = indio_dev->dev.parent;
 124         unsigned long irq_trig;
 125         int err;
 126
 127         sdata->trig = devm_iio_trigger_alloc(parent, "%s-trigger",
 128                                              indio_dev->name);
 129         if (sdata->trig == NULL) {
 130                 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
 131                 return -ENOMEM;
 132         }
 133
 134         iio_trigger_set_drvdata(sdata->trig, indio_dev);
 135         sdata->trig->ops = trigger_ops;
 136
 137         irq_trig = irqd_get_trigger_type(irq_get_irq_data(sdata->irq));
 138         /*
 139          * If the IRQ is triggered on falling edge, we need to mark the
 140          * interrupt as active low, if the hardware supports this.
 141          */
 142         switch(irq_trig) {
 143         case IRQF_TRIGGER_FALLING:
 144         case IRQF_TRIGGER_LOW:
 145                 if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
 146                         dev_err(&indio_dev->dev,
 147                                 "falling/low specified for IRQ but hardware supports only rising/high: will request rising/high\n");
 148                         if (irq_trig == IRQF_TRIGGER_FALLING)
 149                                 irq_trig = IRQF_TRIGGER_RISING;
 150                         if (irq_trig == IRQF_TRIGGER_LOW)
 151                                 irq_trig = IRQF_TRIGGER_HIGH;
 152                 } else {
 153                         /* Set up INT active low i.e. falling edge */
 154                         err = st_sensors_write_data_with_mask(indio_dev,
 155                                 sdata->sensor_settings->drdy_irq.addr_ihl,
 156                                 sdata->sensor_settings->drdy_irq.mask_ihl, 1);
 157                         if (err < 0)
 158                                 return err;
 159                         dev_info(&indio_dev->dev,
 160                                  "interrupts on the falling edge or active low level\n");
 161                 }
 162                 break;
 163         case IRQF_TRIGGER_RISING:
 164                 dev_info(&indio_dev->dev,
 165                          "interrupts on the rising edge\n");
 166                 break;
 167         case IRQF_TRIGGER_HIGH:
 168                 dev_info(&indio_dev->dev,
 169                          "interrupts active high level\n");
 170                 break;
 171         default:
 172                 /* This is the most preferred mode, if possible */
 173                 dev_err(&indio_dev->dev,
 174                         "unsupported IRQ trigger specified (%lx), enforce rising edge\n", irq_trig);
 175                 irq_trig = IRQF_TRIGGER_RISING;
 176         }
 177
 178         /* Tell the interrupt handler that we're dealing with edges */
 179         if (irq_trig == IRQF_TRIGGER_FALLING ||
 180             irq_trig == IRQF_TRIGGER_RISING) {
 181                 if (!sdata->sensor_settings->drdy_irq.stat_drdy.addr) {
 182                         dev_err(&indio_dev->dev,
 183                                 "edge IRQ not supported w/o stat register.\n");
 184                         return -EOPNOTSUPP;
 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 = devm_request_threaded_irq(parent,
 210                                         sdata->irq,
 211                                         st_sensors_irq_handler,
 212                                         st_sensors_irq_thread,
 213                                         irq_trig,
 214                                         sdata->trig->name,
 215                                         sdata->trig);
 216         if (err) {
 217                 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
 218                 return err;
 219         }
 220
 221         err = devm_iio_trigger_register(parent, sdata->trig);
 222         if (err < 0) {
 223                 dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
 224                 return err;
 225         }
 226         indio_dev->trig = iio_trigger_get(sdata->trig);
 227
 228         return 0;
 229 }
 230 EXPORT_SYMBOL_NS(st_sensors_allocate_trigger, IIO_ST_SENSORS);
 231
 232 int st_sensors_validate_device(struct iio_trigger *trig,
 233                                struct iio_dev *indio_dev)
 234 {
 235         struct iio_dev *indio = iio_trigger_get_drvdata(trig);
 236
 237         if (indio != indio_dev)
 238                 return -EINVAL;
 239
 240         return 0;
 241 }
 242 EXPORT_SYMBOL_NS(st_sensors_validate_device, IIO_ST_SENSORS);