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 int st_sensors_allocate_trigger(struct iio_dev *indio_dev,
  21                                 const struct iio_trigger_ops *trigger_ops)
  22 {
  23         int err, irq;
  24         struct st_sensor_data *sdata = iio_priv(indio_dev);
  25         unsigned long irq_trig;
  26
  27         sdata->trig = iio_trigger_alloc("%s-trigger", indio_dev->name);
  28         if (sdata->trig == NULL) {
  29                 dev_err(&indio_dev->dev, "failed to allocate iio trigger.\n");
  30                 return -ENOMEM;
  31         }
  32
  33         irq = sdata->get_irq_data_ready(indio_dev);
  34         irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
  35         /*
  36          * If the IRQ is triggered on falling edge, we need to mark the
  37          * interrupt as active low, if the hardware supports this.
  38          */
  39         if (irq_trig == IRQF_TRIGGER_FALLING) {
  40                 if (!sdata->sensor_settings->drdy_irq.addr_ihl) {
  41                         dev_err(&indio_dev->dev,
  42                                 "falling edge specified for IRQ but hardware "
  43                                 "only support rising edge, will request "
  44                                 "rising edge\n");
  45                         irq_trig = IRQF_TRIGGER_RISING;
  46                 } else {
  47                         /* Set up INT active low i.e. falling edge */
  48                         err = st_sensors_write_data_with_mask(indio_dev,
  49                                 sdata->sensor_settings->drdy_irq.addr_ihl,
  50                                 sdata->sensor_settings->drdy_irq.mask_ihl, 1);
  51                         if (err < 0)
  52                                 goto iio_trigger_free;
  53                         dev_info(&indio_dev->dev,
  54                                  "interrupts on the falling edge\n");
  55                 }
  56         } else if (irq_trig == IRQF_TRIGGER_RISING) {
  57                 dev_info(&indio_dev->dev,
  58                          "interrupts on the rising edge\n");
  59
  60         } else {
  61                 dev_err(&indio_dev->dev,
  62                 "unsupported IRQ trigger specified (%lx), only "
  63                         "rising and falling edges supported, enforce "
  64                         "rising edge\n", irq_trig);
  65                 irq_trig = IRQF_TRIGGER_RISING;
  66         }
  67
  68         /*
  69          * If the interrupt pin is Open Drain, by definition this
  70          * means that the interrupt line may be shared with other
  71          * peripherals. But to do this we also need to have a status
  72          * register and mask to figure out if this sensor was firing
  73          * the IRQ or not, so we can tell the interrupt handle that
  74          * it was "our" interrupt.
  75          */
  76         if (sdata->int_pin_open_drain &&
  77             sdata->sensor_settings->drdy_irq.addr_stat_drdy)
  78                 irq_trig |= IRQF_SHARED;
  79
  80         err = request_threaded_irq(irq,
  81                         iio_trigger_generic_data_rdy_poll,
  82                         NULL,
  83                         irq_trig,
  84                         sdata->trig->name,
  85                         sdata->trig);
  86         if (err) {
  87                 dev_err(&indio_dev->dev, "failed to request trigger IRQ.\n");
  88                 goto iio_trigger_free;
  89         }
  90
  91         iio_trigger_set_drvdata(sdata->trig, indio_dev);
  92         sdata->trig->ops = trigger_ops;
  93         sdata->trig->dev.parent = sdata->dev;
  94
  95         err = iio_trigger_register(sdata->trig);
  96         if (err < 0) {
  97                 dev_err(&indio_dev->dev, "failed to register iio trigger.\n");
  98                 goto iio_trigger_register_error;
  99         }
 100         indio_dev->trig = iio_trigger_get(sdata->trig);
 101
 102         return 0;
 103
 104 iio_trigger_register_error:
 105         free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
 106 iio_trigger_free:
 107         iio_trigger_free(sdata->trig);
 108         return err;
 109 }
 110 EXPORT_SYMBOL(st_sensors_allocate_trigger);
 111
 112 void st_sensors_deallocate_trigger(struct iio_dev *indio_dev)
 113 {
 114         struct st_sensor_data *sdata = iio_priv(indio_dev);
 115
 116         iio_trigger_unregister(sdata->trig);
 117         free_irq(sdata->get_irq_data_ready(indio_dev), sdata->trig);
 118         iio_trigger_free(sdata->trig);
 119 }
 120 EXPORT_SYMBOL(st_sensors_deallocate_trigger);
 121
 122 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 123 MODULE_DESCRIPTION("STMicroelectronics ST-sensors trigger");
 124 MODULE_LICENSE("GPL v2");