drivers/iio/humidity/hts221_buffer.c

   1 /*
   2  * STMicroelectronics hts221 sensor driver
   3  *
   4  * Copyright 2016 STMicroelectronics Inc.
   5  *
   6  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irqreturn.h>
  15
  16 #include <linux/iio/iio.h>
  17 #include <linux/iio/trigger.h>
  18 #include <linux/iio/events.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/iio/triggered_buffer.h>
  21 #include <linux/iio/buffer.h>
  22
  23 #include "hts221.h"
  24
  25 #define HTS221_REG_STATUS_ADDR          0x27
  26 #define HTS221_RH_DRDY_MASK             BIT(1)
  27 #define HTS221_TEMP_DRDY_MASK           BIT(0)
  28
  29 static int hts221_trig_set_state(struct iio_trigger *trig, bool state)
  30 {
  31         struct iio_dev *iio_dev = iio_trigger_get_drvdata(trig);
  32         struct hts221_hw *hw = iio_priv(iio_dev);
  33
  34         return hts221_config_drdy(hw, state);
  35 }
  36
  37 static const struct iio_trigger_ops hts221_trigger_ops = {
  38         .owner = THIS_MODULE,
  39         .set_trigger_state = hts221_trig_set_state,
  40 };
  41
  42 static irqreturn_t hts221_trigger_handler_thread(int irq, void *private)
  43 {
  44         struct hts221_hw *hw = private;
  45         u8 status;
  46         int err;
  47
  48         err = hw->tf->read(hw->dev, HTS221_REG_STATUS_ADDR, sizeof(status),
  49                            &status);
  50         if (err < 0)
  51                 return IRQ_HANDLED;
  52
  53         /*
  54          * H_DA bit (humidity data available) is routed to DRDY line.
  55          * Humidity sample is computed after temperature one.
  56          * Here we can assume data channels are both available if H_DA bit
  57          * is set in status register
  58          */
  59         if (!(status & HTS221_RH_DRDY_MASK))
  60                 return IRQ_NONE;
  61
  62         iio_trigger_poll_chained(hw->trig);
  63
  64         return IRQ_HANDLED;
  65 }
  66
  67 int hts221_allocate_trigger(struct hts221_hw *hw)
  68 {
  69         struct iio_dev *iio_dev = iio_priv_to_dev(hw);
  70         unsigned long irq_type;
  71         int err;
  72
  73         irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
  74
  75         switch (irq_type) {
  76         case IRQF_TRIGGER_HIGH:
  77         case IRQF_TRIGGER_RISING:
  78                 break;
  79         default:
  80                 dev_info(hw->dev,
  81                          "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
  82                          irq_type);
  83                 irq_type = IRQF_TRIGGER_RISING;
  84                 break;
  85         }
  86
  87         err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
  88                                         hts221_trigger_handler_thread,
  89                                         irq_type | IRQF_ONESHOT,
  90                                         hw->name, hw);
  91         if (err) {
  92                 dev_err(hw->dev, "failed to request trigger irq %d\n",
  93                         hw->irq);
  94                 return err;
  95         }
  96
  97         hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
  98                                           iio_dev->name);
  99         if (!hw->trig)
 100                 return -ENOMEM;
 101
 102         iio_trigger_set_drvdata(hw->trig, iio_dev);
 103         hw->trig->ops = &hts221_trigger_ops;
 104         hw->trig->dev.parent = hw->dev;
 105         iio_dev->trig = iio_trigger_get(hw->trig);
 106
 107         return devm_iio_trigger_register(hw->dev, hw->trig);
 108 }
 109
 110 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
 111 {
 112         return hts221_power_on(iio_priv(iio_dev));
 113 }
 114
 115 static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
 116 {
 117         return hts221_power_off(iio_priv(iio_dev));
 118 }
 119
 120 static const struct iio_buffer_setup_ops hts221_buffer_ops = {
 121         .preenable = hts221_buffer_preenable,
 122         .postenable = iio_triggered_buffer_postenable,
 123         .predisable = iio_triggered_buffer_predisable,
 124         .postdisable = hts221_buffer_postdisable,
 125 };
 126
 127 static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
 128 {
 129         u8 buffer[ALIGN(2 * HTS221_DATA_SIZE, sizeof(s64)) + sizeof(s64)];
 130         struct iio_poll_func *pf = p;
 131         struct iio_dev *iio_dev = pf->indio_dev;
 132         struct hts221_hw *hw = iio_priv(iio_dev);
 133         struct iio_chan_spec const *ch;
 134         int err;
 135
 136         /* humidity data */
 137         ch = &iio_dev->channels[HTS221_SENSOR_H];
 138         err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
 139                            buffer);
 140         if (err < 0)
 141                 goto out;
 142
 143         /* temperature data */
 144         ch = &iio_dev->channels[HTS221_SENSOR_T];
 145         err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
 146                            buffer + HTS221_DATA_SIZE);
 147         if (err < 0)
 148                 goto out;
 149
 150         iio_push_to_buffers_with_timestamp(iio_dev, buffer,
 151                                            iio_get_time_ns(iio_dev));
 152
 153 out:
 154         iio_trigger_notify_done(hw->trig);
 155
 156         return IRQ_HANDLED;
 157 }
 158
 159 int hts221_allocate_buffers(struct hts221_hw *hw)
 160 {
 161         return devm_iio_triggered_buffer_setup(hw->dev, iio_priv_to_dev(hw),
 162                                         NULL, hts221_buffer_handler_thread,
 163                                         &hts221_buffer_ops);
 164 }
 165
 166 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 167 MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
 168 MODULE_LICENSE("GPL v2");