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 #include <linux/regmap.h>
  16 #include <linux/bitfield.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/trigger.h>
  20 #include <linux/iio/events.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/iio/buffer.h>
  24
  25 #include <linux/platform_data/st_sensors_pdata.h>
  26
  27 #include "hts221.h"
  28
  29 #define HTS221_REG_DRDY_HL_ADDR         0x22
  30 #define HTS221_REG_DRDY_HL_MASK         BIT(7)
  31 #define HTS221_REG_DRDY_PP_OD_ADDR      0x22
  32 #define HTS221_REG_DRDY_PP_OD_MASK      BIT(6)
  33 #define HTS221_REG_DRDY_EN_ADDR         0x22
  34 #define HTS221_REG_DRDY_EN_MASK         BIT(2)
  35 #define HTS221_REG_STATUS_ADDR          0x27
  36 #define HTS221_RH_DRDY_MASK             BIT(1)
  37 #define HTS221_TEMP_DRDY_MASK           BIT(0)
  38
  39 static int hts221_trig_set_state(struct iio_trigger *trig, bool state)
  40 {
  41         struct iio_dev *iio_dev = iio_trigger_get_drvdata(trig);
  42         struct hts221_hw *hw = iio_priv(iio_dev);
  43
  44         return regmap_update_bits(hw->regmap, HTS221_REG_DRDY_EN_ADDR,
  45                                   HTS221_REG_DRDY_EN_MASK,
  46                                   FIELD_PREP(HTS221_REG_DRDY_EN_MASK, state));
  47 }
  48
  49 static const struct iio_trigger_ops hts221_trigger_ops = {
  50         .set_trigger_state = hts221_trig_set_state,
  51 };
  52
  53 static irqreturn_t hts221_trigger_handler_thread(int irq, void *private)
  54 {
  55         struct hts221_hw *hw = private;
  56         int err, status;
  57
  58         err = regmap_read(hw->regmap, HTS221_REG_STATUS_ADDR, &status);
  59         if (err < 0)
  60                 return IRQ_HANDLED;
  61
  62         /*
  63          * H_DA bit (humidity data available) is routed to DRDY line.
  64          * Humidity sample is computed after temperature one.
  65          * Here we can assume data channels are both available if H_DA bit
  66          * is set in status register
  67          */
  68         if (!(status & HTS221_RH_DRDY_MASK))
  69                 return IRQ_NONE;
  70
  71         iio_trigger_poll_chained(hw->trig);
  72
  73         return IRQ_HANDLED;
  74 }
  75
  76 int hts221_allocate_trigger(struct hts221_hw *hw)
  77 {
  78         struct iio_dev *iio_dev = iio_priv_to_dev(hw);
  79         bool irq_active_low = false, open_drain = false;
  80         struct device_node *np = hw->dev->of_node;
  81         struct st_sensors_platform_data *pdata;
  82         unsigned long irq_type;
  83         int err;
  84
  85         irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
  86
  87         switch (irq_type) {
  88         case IRQF_TRIGGER_HIGH:
  89         case IRQF_TRIGGER_RISING:
  90                 break;
  91         case IRQF_TRIGGER_LOW:
  92         case IRQF_TRIGGER_FALLING:
  93                 irq_active_low = true;
  94                 break;
  95         default:
  96                 dev_info(hw->dev,
  97                          "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
  98                          irq_type);
  99                 irq_type = IRQF_TRIGGER_RISING;
 100                 break;
 101         }
 102
 103         err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_HL_ADDR,
 104                                  HTS221_REG_DRDY_HL_MASK,
 105                                  FIELD_PREP(HTS221_REG_DRDY_HL_MASK,
 106                                             irq_active_low));
 107         if (err < 0)
 108                 return err;
 109
 110         pdata = (struct st_sensors_platform_data *)hw->dev->platform_data;
 111         if ((np && of_property_read_bool(np, "drive-open-drain")) ||
 112             (pdata && pdata->open_drain)) {
 113                 irq_type |= IRQF_SHARED;
 114                 open_drain = true;
 115         }
 116
 117         err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_PP_OD_ADDR,
 118                                  HTS221_REG_DRDY_PP_OD_MASK,
 119                                  FIELD_PREP(HTS221_REG_DRDY_PP_OD_MASK,
 120                                             open_drain));
 121         if (err < 0)
 122                 return err;
 123
 124         err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
 125                                         hts221_trigger_handler_thread,
 126                                         irq_type | IRQF_ONESHOT,
 127                                         hw->name, hw);
 128         if (err) {
 129                 dev_err(hw->dev, "failed to request trigger irq %d\n",
 130                         hw->irq);
 131                 return err;
 132         }
 133
 134         hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
 135                                           iio_dev->name);
 136         if (!hw->trig)
 137                 return -ENOMEM;
 138
 139         iio_trigger_set_drvdata(hw->trig, iio_dev);
 140         hw->trig->ops = &hts221_trigger_ops;
 141         hw->trig->dev.parent = hw->dev;
 142         iio_dev->trig = iio_trigger_get(hw->trig);
 143
 144         return devm_iio_trigger_register(hw->dev, hw->trig);
 145 }
 146
 147 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
 148 {
 149         return hts221_set_enable(iio_priv(iio_dev), true);
 150 }
 151
 152 static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
 153 {
 154         return hts221_set_enable(iio_priv(iio_dev), false);
 155 }
 156
 157 static const struct iio_buffer_setup_ops hts221_buffer_ops = {
 158         .preenable = hts221_buffer_preenable,
 159         .postenable = iio_triggered_buffer_postenable,
 160         .predisable = iio_triggered_buffer_predisable,
 161         .postdisable = hts221_buffer_postdisable,
 162 };
 163
 164 static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
 165 {
 166         struct iio_poll_func *pf = p;
 167         struct iio_dev *iio_dev = pf->indio_dev;
 168         struct hts221_hw *hw = iio_priv(iio_dev);
 169         struct iio_chan_spec const *ch;
 170         int err;
 171
 172         /* humidity data */
 173         ch = &iio_dev->channels[HTS221_SENSOR_H];
 174         err = regmap_bulk_read(hw->regmap, ch->address,
 175                                &hw->scan.channels[0],
 176                                sizeof(hw->scan.channels[0]));
 177         if (err < 0)
 178                 goto out;
 179
 180         /* temperature data */
 181         ch = &iio_dev->channels[HTS221_SENSOR_T];
 182         err = regmap_bulk_read(hw->regmap, ch->address,
 183                                &hw->scan.channels[1],
 184                                sizeof(hw->scan.channels[1]));
 185         if (err < 0)
 186                 goto out;
 187
 188         iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
 189                                            iio_get_time_ns(iio_dev));
 190
 191 out:
 192         iio_trigger_notify_done(hw->trig);
 193
 194         return IRQ_HANDLED;
 195 }
 196
 197 int hts221_allocate_buffers(struct hts221_hw *hw)
 198 {
 199         return devm_iio_triggered_buffer_setup(hw->dev, iio_priv_to_dev(hw),
 200                                         NULL, hts221_buffer_handler_thread,
 201                                         &hts221_buffer_ops);
 202 }
 203
 204 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 205 MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
 206 MODULE_LICENSE("GPL v2");