drivers/iio/pressure/ms5611_spi.c

   1 /*
   2  * MS5611 pressure and temperature sensor driver (SPI bus)
   3  *
   4  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/delay.h>
  13 #include <linux/module.h>
  14 #include <linux/spi/spi.h>
  15
  16 #include "ms5611.h"
  17
  18 static int ms5611_spi_reset(struct device *dev)
  19 {
  20         u8 cmd = MS5611_RESET;
  21         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  22
  23         return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  24 }
  25
  26 static int ms5611_spi_read_prom_word(struct device *dev, int index, u16 *word)
  27 {
  28         int ret;
  29         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  30
  31         ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
  32         if (ret < 0)
  33                 return ret;
  34
  35         *word = ret;
  36
  37         return 0;
  38 }
  39
  40 static int ms5611_spi_read_adc(struct device *dev, s32 *val)
  41 {
  42         int ret;
  43         u8 buf[3] = { MS5611_READ_ADC };
  44         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  45
  46         ret = spi_write_then_read(st->client, buf, 1, buf, 3);
  47         if (ret < 0)
  48                 return ret;
  49
  50         *val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
  51
  52         return 0;
  53 }
  54
  55 static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev,
  56                                                  s32 *temp, s32 *pressure)
  57 {
  58         u8 cmd;
  59         int ret;
  60         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  61
  62         cmd = MS5611_START_TEMP_CONV;
  63         ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  64         if (ret < 0)
  65                 return ret;
  66
  67         usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
  68
  69         ret = ms5611_spi_read_adc(dev, temp);
  70         if (ret < 0)
  71                 return ret;
  72
  73         cmd = MS5611_START_PRESSURE_CONV;
  74         ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  75         if (ret < 0)
  76                 return ret;
  77
  78         usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
  79
  80         return ms5611_spi_read_adc(dev, pressure);
  81 }
  82
  83 static int ms5611_spi_probe(struct spi_device *spi)
  84 {
  85         int ret;
  86         struct ms5611_state *st;
  87         struct iio_dev *indio_dev;
  88
  89         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  90         if (!indio_dev)
  91                 return -ENOMEM;
  92
  93         spi->mode = SPI_MODE_0;
  94         spi->max_speed_hz = 20000000;
  95         spi->bits_per_word = 8;
  96         ret = spi_setup(spi);
  97         if (ret < 0)
  98                 return ret;
  99
 100         st = iio_priv(indio_dev);
 101         st->reset = ms5611_spi_reset;
 102         st->read_prom_word = ms5611_spi_read_prom_word;
 103         st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
 104         st->client = spi;
 105
 106         return ms5611_probe(indio_dev, &spi->dev,
 107                             spi_get_device_id(spi)->driver_data);
 108 }
 109
 110 static const struct spi_device_id ms5611_id[] = {
 111         { "ms5611", MS5611 },
 112         { "ms5607", MS5607 },
 113         { }
 114 };
 115 MODULE_DEVICE_TABLE(spi, ms5611_id);
 116
 117 static struct spi_driver ms5611_driver = {
 118         .driver = {
 119                 .name = "ms5611",
 120         },
 121         .id_table = ms5611_id,
 122         .probe = ms5611_spi_probe,
 123 };
 124 module_spi_driver(ms5611_driver);
 125
 126 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 127 MODULE_DESCRIPTION("MS5611 spi driver");
 128 MODULE_LICENSE("GPL v2");