drivers/iio/pressure/ms5611_spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MS5611 pressure and temperature sensor driver (SPI bus)
   4  *
   5  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   6  *
   7  */
   8
   9 #include <linux/delay.h>
  10 #include <linux/module.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/mod_devicetable.h>
  13
  14 #include <asm/unaligned.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 = get_unaligned_be24(&buf[0]);
  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         int ret;
  59         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  60         const struct ms5611_osr *osr = st->temp_osr;
  61
  62         /*
  63          * Warning: &osr->cmd MUST be aligned on a word boundary since used as
  64          * 2nd argument (void*) of spi_write_then_read.
  65          */
  66         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  67         if (ret < 0)
  68                 return ret;
  69
  70         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  71         ret = ms5611_spi_read_adc(dev, temp);
  72         if (ret < 0)
  73                 return ret;
  74
  75         osr = st->pressure_osr;
  76         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  77         if (ret < 0)
  78                 return ret;
  79
  80         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  81         return ms5611_spi_read_adc(dev, pressure);
  82 }
  83
  84 static int ms5611_spi_probe(struct spi_device *spi)
  85 {
  86         int ret;
  87         struct ms5611_state *st;
  88         struct iio_dev *indio_dev;
  89
  90         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  91         if (!indio_dev)
  92                 return -ENOMEM;
  93
  94         spi_set_drvdata(spi, indio_dev);
  95
  96         spi->mode = SPI_MODE_0;
  97         spi->max_speed_hz = 20000000;
  98         spi->bits_per_word = 8;
  99         ret = spi_setup(spi);
 100         if (ret < 0)
 101                 return ret;
 102
 103         st = iio_priv(indio_dev);
 104         st->reset = ms5611_spi_reset;
 105         st->read_prom_word = ms5611_spi_read_prom_word;
 106         st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
 107         st->client = spi;
 108
 109         return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
 110                             spi_get_device_id(spi)->driver_data);
 111 }
 112
 113 static int ms5611_spi_remove(struct spi_device *spi)
 114 {
 115         return ms5611_remove(spi_get_drvdata(spi));
 116 }
 117
 118 static const struct of_device_id ms5611_spi_matches[] = {
 119         { .compatible = "meas,ms5611" },
 120         { .compatible = "meas,ms5607" },
 121         { }
 122 };
 123 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
 124
 125 static const struct spi_device_id ms5611_id[] = {
 126         { "ms5611", MS5611 },
 127         { "ms5607", MS5607 },
 128         { }
 129 };
 130 MODULE_DEVICE_TABLE(spi, ms5611_id);
 131
 132 static struct spi_driver ms5611_driver = {
 133         .driver = {
 134                 .name = "ms5611",
 135                 .of_match_table = ms5611_spi_matches
 136         },
 137         .id_table = ms5611_id,
 138         .probe = ms5611_spi_probe,
 139         .remove = ms5611_spi_remove,
 140 };
 141 module_spi_driver(ms5611_driver);
 142
 143 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 144 MODULE_DESCRIPTION("MS5611 spi driver");
 145 MODULE_LICENSE("GPL v2");