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 #include <linux/of_device.h>
  16
  17 #include "ms5611.h"
  18
  19 static int ms5611_spi_reset(struct device *dev)
  20 {
  21         u8 cmd = MS5611_RESET;
  22         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  23
  24         return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  25 }
  26
  27 static int ms5611_spi_read_prom_word(struct device *dev, int index, u16 *word)
  28 {
  29         int ret;
  30         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  31
  32         ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
  33         if (ret < 0)
  34                 return ret;
  35
  36         *word = ret;
  37
  38         return 0;
  39 }
  40
  41 static int ms5611_spi_read_adc(struct device *dev, s32 *val)
  42 {
  43         int ret;
  44         u8 buf[3] = { MS5611_READ_ADC };
  45         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  46
  47         ret = spi_write_then_read(st->client, buf, 1, buf, 3);
  48         if (ret < 0)
  49                 return ret;
  50
  51         *val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
  52
  53         return 0;
  54 }
  55
  56 static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev,
  57                                                  s32 *temp, s32 *pressure)
  58 {
  59         int ret;
  60         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  61         const struct ms5611_osr *osr = st->temp_osr;
  62
  63         /*
  64          * Warning: &osr->cmd MUST be aligned on a word boundary since used as
  65          * 2nd argument (void*) of spi_write_then_read.
  66          */
  67         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  68         if (ret < 0)
  69                 return ret;
  70
  71         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  72         ret = ms5611_spi_read_adc(dev, temp);
  73         if (ret < 0)
  74                 return ret;
  75
  76         osr = st->pressure_osr;
  77         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  78         if (ret < 0)
  79                 return ret;
  80
  81         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  82         return ms5611_spi_read_adc(dev, pressure);
  83 }
  84
  85 static int ms5611_spi_probe(struct spi_device *spi)
  86 {
  87         int ret;
  88         struct ms5611_state *st;
  89         struct iio_dev *indio_dev;
  90
  91         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  92         if (!indio_dev)
  93                 return -ENOMEM;
  94
  95         spi_set_drvdata(spi, indio_dev);
  96
  97         spi->mode = SPI_MODE_0;
  98         spi->max_speed_hz = 20000000;
  99         spi->bits_per_word = 8;
 100         ret = spi_setup(spi);
 101         if (ret < 0)
 102                 return ret;
 103
 104         st = iio_priv(indio_dev);
 105         st->reset = ms5611_spi_reset;
 106         st->read_prom_word = ms5611_spi_read_prom_word;
 107         st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
 108         st->client = spi;
 109
 110         return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
 111                             spi_get_device_id(spi)->driver_data);
 112 }
 113
 114 static int ms5611_spi_remove(struct spi_device *spi)
 115 {
 116         return ms5611_remove(spi_get_drvdata(spi));
 117 }
 118
 119 #if defined(CONFIG_OF)
 120 static const struct of_device_id ms5611_spi_matches[] = {
 121         { .compatible = "meas,ms5611" },
 122         { .compatible = "ms5611" },
 123         { .compatible = "meas,ms5607" },
 124         { .compatible = "ms5607" },
 125         { }
 126 };
 127 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
 128 #endif
 129
 130 static const struct spi_device_id ms5611_id[] = {
 131         { "ms5611", MS5611 },
 132         { "ms5607", MS5607 },
 133         { }
 134 };
 135 MODULE_DEVICE_TABLE(spi, ms5611_id);
 136
 137 static struct spi_driver ms5611_driver = {
 138         .driver = {
 139                 .name = "ms5611",
 140                 .of_match_table = of_match_ptr(ms5611_spi_matches)
 141         },
 142         .id_table = ms5611_id,
 143         .probe = ms5611_spi_probe,
 144         .remove = ms5611_spi_remove,
 145 };
 146 module_spi_driver(ms5611_driver);
 147
 148 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 149 MODULE_DESCRIPTION("MS5611 spi driver");
 150 MODULE_LICENSE("GPL v2");