drivers/iio/common/st_sensors/st_sensors_trigger.c

   1 /*
   2  * STMicroelectronics sensors trigger library driver
   3  *
   4  * Copyright 2012-2013 STMicroelectronics Inc.
   5  *
   6  * Denis Ciocca <denis.ciocca@st.com>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/trigger.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/iio/common/st_sensors.h>
  18 #include "st_sensors_core.h"
  19
  20 /**
  21  * st_sensors_irq_handler() - top half of the IRQ-based triggers
  22  * @irq: irq number
  23  * @p: private handler data
  24  */
  25 irqreturn_t st_sensors_irq_handler(int irq, void *p)
  26 {
  27         struct iio_trigger *trig = p;
  28         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  29         struct st_sensor_data *sdata = iio_priv(indio_dev);
  30
  31         /* Get the time stamp as close in time as possible */
  32         sdata->hw_timestamp = iio_get_time_ns();
  33         return IRQ_WAKE_THREAD;
  34 }
  35
  36 /**
  37  * st_sensors_irq_thread() - bottom half of the IRQ-based triggers
  38  * @irq: irq number
  39  * @p: private handler data
  40  */
  41 irqreturn_t st_sensors_irq_thread(int irq, void *p)
  42 {
  43         struct iio_trigger *trig = p;
  44         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
  45         struct st_sensor_data *sdata = iio_priv(indio_dev);
  46         int ret;
  47
  48         /*
  49          * If this trigger is backed by a hardware interrupt and we have a
  50          * status register, check if this IRQ came from us
  51          */
  52         if (sdata->sensor_settings->drdy_irq.addr_stat_drdy) {
  53                 u8 status;
  54
  55                 ret = sdata->tf->read_byte(&sdata->tb, sdata->dev,
  56                            sdata->sensor_settings->drdy_irq.addr_stat_drdy,
  57                            &status);
  58                 if (ret < 0) {
  59                         dev_err(sdata->dev, "could not read channel status\n");
  60                         goto out_poll;
  61                 }
  62                 /*
  63                  * the lower bits of .active_scan_mask[0] is directly mapped
  64                  * to the channels on the sensor: either bit 0 for
  65                  * one-dimensional sensors, or e.g. x,y,z for accelerometers,
  66                  * gyroscopes or magnetometers. No sensor use more than 3
  67                  * channels, so cut the other status bits here.
  68                  */
  69                 status &= 0x07;
  70
  71                 /*
  72                  * If this was not caused by any channels on this sensor,
  73                  * return IRQ_NONE
  74                  */
  75                 if (!indio_dev->active_scan_mask)
  76                         return IRQ_NONE;
  77                 if (!(status & (u8)indio_dev->active_scan_mask[0]))
  78                         return IRQ_NONE;
  79         }
  80
  81 out_poll:
  82         /* It's our IRQ: proceed to handle the register polling */
  83         iio_trigger_poll_chained(p);
  84         return IRQ_HANDLED;
  85 }
  86
  87 int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
  88                                 const struct iio_trigger_ops *trigger_ops)
  89 {
  90         int err, irq;
  91         struct st_sensor_data *sdata = iio_priv(indio_dev);
  92         unsigned long irq_trig;
  93
  94         sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
  95         if (sdata->trig == NULL) {
  96                 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
  97                 return -ENOMEM;
  98         }
  99
 100         iio_trigger_set_drvdata(sdata->trig, indio_dev);
 101         sdata->trig->ops = trigger_ops;
 102         sdata->trig->dev.parent = sdata->dev;
 103
 104         irq = sdata->get_irq_data_ready(indio_dev);
 105         irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
 106         /*
 107          * If the IRQ is triggered on falling edge, we need to mark the
 108          * interrupt as active low, if the hardware supports this.
 109          */
 110         if (irq_trig == IRQF_TRIGGER_FALLING) {
 111                 if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
 112                         dev_err(&indio_dev->dev,
 113                                 "falling edge specified for IRQ but hardware "
 114                                 "only support rising edge, will request "
 115                                 "rising edge\n");
 116                         irq_trig = IRQF_TRIGGER_RISING;
 117                 } else {
 118                         /* Set up INT active low i.e. falling edge */
 119                         err = st_sensors_write_data_with_mask(indio_dev,
 120                                 sdata->sensor_settings->drdy_irq.addr_ihl,
 121                                 sdata->sensor_settings->drdy_irq.mask_ihl, 1);
 122                         if (err < 0)
 123                                 goto iio_trigger_free;
 124                         dev_info(&indio_dev->dev,
 125                                  "interrupts on the falling edge\n");
 126                 }
 127         } else if (irq_trig == IRQF_TRIGGER_RISING) {
 128                 dev_info(&indio_dev->dev,
 129                          "interrupts on the rising edge\n");
 130
 131         } else {
 132                 dev_err(&indio_dev->dev,
 133                 "unsupported IRQ trigger specified (%lx), only "
 134                         "rising and falling edges supported, enforce "
 135                         "rising edge\n", irq_trig);
 136                 irq_trig = IRQF_TRIGGER_RISING;
 137         }
 138
 139         /*
 140          * If the interrupt pin is Open Drain, by definition this
 141          * means that the interrupt line may be shared with other
 142          * peripherals. But to do this we also need to have a status
 143          * register and mask to figure out if this sensor was firing
 144          * the IRQ or not, so we can tell the interrupt handle that
 145          * it was "our" interrupt.
 146          */
 147         if (sdata->int_pin_open_drain &&
 148             sdata->sensor_settings->drdy_irq.addr_stat_drdy)
 149                 irq_trig |= IRQF_SHARED;
 150
 151         /* Let's create an interrupt thread masking the hard IRQ here */
 152         irq_trig |= IRQF_ONESHOT;
 153
 154         err = request_threaded_irq(sdata->get_irq_data_ready(indio_dev),
 155                         st_sensors_irq_handler,
 156                         st_sensors_irq_thread,
 157                         irq_trig,
 158                         sdata->trig->name,
 159                         sdata->trig);
 160         if (err) {
 161                 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
 162                 goto iio_trigger_free;
 163         }
 164
 165         err = iio_trigger_register(sdata->trig);
 166         if (err < 0) {
 167                 dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
 168                 goto iio_trigger_register_error;
 169         }
 170         indio_dev->trig = iio_trigger_get(sdata->trig);
 171
 172         return 0;
 173
 174 iio_trigger_register_error:
 175         free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
 176 iio_trigger_free:
 177         iio_trigger_free(sdata->trig);
 178         return err;
 179 }
 180 EXPORT_SYMBOL(st_sensors_allocate_trigger);
 181
 182 void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
 183 {
 184         struct st_sensor_data *sdata = iio_priv(indio_dev);
 185
 186         iio_trigger_unregister(sdata->trig);
 187         free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
 188         iio_trigger_free(sdata->trig);
 189 }
 190 EXPORT_SYMBOL(st_sensors_deallocate_trigger);
 191
 192 int st_sensors_validate_device(struct iio_trigger *trig,
 193                                struct iio_dev *indio_dev)
 194 {
 195         struct iio_dev *indio = iio_trigger_get_drvdata(trig);
 196
 197         if (indio != indio_dev)
 198                 return -EINVAL;
 199
 200         return 0;
 201 }
 202 EXPORT_SYMBOL(st_sensors_validate_device);
 203
 204 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 205 MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger");
 206 MODULE_LICENSE("GPL v2");