drivers/iio/humidity/hts221_buffer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics hts221 sensor driver
   4  *
   5  * Copyright 2016 STMicroelectronics Inc.
   6  *
   7  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/device.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irqreturn.h>
  14 #include <linux/property.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_nested(hw->trig);
  72
  73         return IRQ_HANDLED;
  74 }
  75
  76 int hts221_allocate_trigger(struct iio_dev *iio_dev)
  77 {
  78         struct hts221_hw *hw = iio_priv(iio_dev);
  79         struct st_sensors_platform_data *pdata = dev_get_platdata(hw->dev);
  80         bool irq_active_low = false, open_drain = false;
  81         unsigned long irq_type;
  82         int err;
  83
  84         irq_type = irq_get_trigger_type(hw->irq);
  85         switch (irq_type) {
  86         case IRQF_TRIGGER_HIGH:
  87         case IRQF_TRIGGER_RISING:
  88                 break;
  89         case IRQF_TRIGGER_LOW:
  90         case IRQF_TRIGGER_FALLING:
  91                 irq_active_low = true;
  92                 break;
  93         default:
  94                 dev_info(hw->dev,
  95                          "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
  96                          irq_type);
  97                 irq_type = IRQF_TRIGGER_RISING;
  98                 break;
  99         }
 100
 101         err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_HL_ADDR,
 102                                  HTS221_REG_DRDY_HL_MASK,
 103                                  FIELD_PREP(HTS221_REG_DRDY_HL_MASK,
 104                                             irq_active_low));
 105         if (err < 0)
 106                 return err;
 107
 108         if (device_property_read_bool(hw->dev, "drive-open-drain") ||
 109             (pdata && pdata->open_drain)) {
 110                 irq_type |= IRQF_SHARED;
 111                 open_drain = true;
 112         }
 113
 114         err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_PP_OD_ADDR,
 115                                  HTS221_REG_DRDY_PP_OD_MASK,
 116                                  FIELD_PREP(HTS221_REG_DRDY_PP_OD_MASK,
 117                                             open_drain));
 118         if (err < 0)
 119                 return err;
 120
 121         err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
 122                                         hts221_trigger_handler_thread,
 123                                         irq_type | IRQF_ONESHOT,
 124                                         hw->name, hw);
 125         if (err) {
 126                 dev_err(hw->dev, "failed to request trigger irq %d\n",
 127                         hw->irq);
 128                 return err;
 129         }
 130
 131         hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
 132                                           iio_dev->name);
 133         if (!hw->trig)
 134                 return -ENOMEM;
 135
 136         iio_trigger_set_drvdata(hw->trig, iio_dev);
 137         hw->trig->ops = &hts221_trigger_ops;
 138
 139         err = devm_iio_trigger_register(hw->dev, hw->trig);
 140
 141         iio_dev->trig = iio_trigger_get(hw->trig);
 142
 143         return err;
 144 }
 145
 146 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
 147 {
 148         return hts221_set_enable(iio_priv(iio_dev), true);
 149 }
 150
 151 static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
 152 {
 153         return hts221_set_enable(iio_priv(iio_dev), false);
 154 }
 155
 156 static const struct iio_buffer_setup_ops hts221_buffer_ops = {
 157         .preenable = hts221_buffer_preenable,
 158         .postdisable = hts221_buffer_postdisable,
 159 };
 160
 161 static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
 162 {
 163         struct iio_poll_func *pf = p;
 164         struct iio_dev *iio_dev = pf->indio_dev;
 165         struct hts221_hw *hw = iio_priv(iio_dev);
 166         struct iio_chan_spec const *ch;
 167         int err;
 168
 169         /* humidity data */
 170         ch = &iio_dev->channels[HTS221_SENSOR_H];
 171         err = regmap_bulk_read(hw->regmap, ch->address,
 172                                &hw->scan.channels[0],
 173                                sizeof(hw->scan.channels[0]));
 174         if (err < 0)
 175                 goto out;
 176
 177         /* temperature data */
 178         ch = &iio_dev->channels[HTS221_SENSOR_T];
 179         err = regmap_bulk_read(hw->regmap, ch->address,
 180                                &hw->scan.channels[1],
 181                                sizeof(hw->scan.channels[1]));
 182         if (err < 0)
 183                 goto out;
 184
 185         iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
 186                                            iio_get_time_ns(iio_dev));
 187
 188 out:
 189         iio_trigger_notify_done(hw->trig);
 190
 191         return IRQ_HANDLED;
 192 }
 193
 194 int hts221_allocate_buffers(struct iio_dev *iio_dev)
 195 {
 196         struct hts221_hw *hw = iio_priv(iio_dev);
 197         return devm_iio_triggered_buffer_setup(hw->dev, iio_dev,
 198                                         NULL, hts221_buffer_handler_thread,
 199                                         &hts221_buffer_ops);
 200 }
 201
 202 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 203 MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
 204 MODULE_LICENSE("GPL v2");