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 <linux/unaligned.h>
  15
  16 #include "ms5611.h"
  17
  18 static int ms5611_spi_reset(struct ms5611_state *st)
  19 {
  20         u8 cmd = MS5611_RESET;
  21
  22         return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  23 }
  24
  25 static int ms5611_spi_read_prom_word(struct ms5611_state *st, int index,
  26                                      u16 *word)
  27 {
  28         int ret;
  29
  30         ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
  31         if (ret < 0)
  32                 return ret;
  33
  34         *word = ret;
  35
  36         return 0;
  37 }
  38
  39 static int ms5611_spi_read_adc(struct ms5611_state *st, s32 *val)
  40 {
  41         int ret;
  42         u8 buf[3] = { MS5611_READ_ADC };
  43
  44         ret = spi_write_then_read(st->client, buf, 1, buf, 3);
  45         if (ret < 0)
  46                 return ret;
  47
  48         *val = get_unaligned_be24(&buf[0]);
  49
  50         return 0;
  51 }
  52
  53 static int ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state *st,
  54                                                  s32 *temp, s32 *pressure)
  55 {
  56         int ret;
  57         const struct ms5611_osr *osr = st->temp_osr;
  58
  59         /*
  60          * Warning: &osr->cmd MUST be aligned on a word boundary since used as
  61          * 2nd argument (void*) of spi_write_then_read.
  62          */
  63         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  64         if (ret < 0)
  65                 return ret;
  66
  67         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  68         ret = ms5611_spi_read_adc(st, temp);
  69         if (ret < 0)
  70                 return ret;
  71
  72         osr = st->pressure_osr;
  73         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  74         if (ret < 0)
  75                 return ret;
  76
  77         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  78         return ms5611_spi_read_adc(st, pressure);
  79 }
  80
  81 static int ms5611_spi_probe(struct spi_device *spi)
  82 {
  83         int ret;
  84         struct ms5611_state *st;
  85         struct iio_dev *indio_dev;
  86
  87         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  88         if (!indio_dev)
  89                 return -ENOMEM;
  90
  91         spi_set_drvdata(spi, indio_dev);
  92
  93         spi->mode = SPI_MODE_0;
  94         spi->max_speed_hz = min(spi->max_speed_hz, 20000000U);
  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, spi_get_device_id(spi)->name,
 107                             spi_get_device_id(spi)->driver_data);
 108 }
 109
 110 static const struct of_device_id ms5611_spi_matches[] = {
 111         { .compatible = "meas,ms5611" },
 112         { .compatible = "meas,ms5607" },
 113         { }
 114 };
 115 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
 116
 117 static const struct spi_device_id ms5611_id[] = {
 118         { "ms5611", MS5611 },
 119         { "ms5607", MS5607 },
 120         { }
 121 };
 122 MODULE_DEVICE_TABLE(spi, ms5611_id);
 123
 124 static struct spi_driver ms5611_driver = {
 125         .driver = {
 126                 .name = "ms5611",
 127                 .of_match_table = ms5611_spi_matches
 128         },
 129         .id_table = ms5611_id,
 130         .probe = ms5611_spi_probe,
 131 };
 132 module_spi_driver(ms5611_driver);
 133
 134 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 135 MODULE_DESCRIPTION("MS5611 spi driver");
 136 MODULE_LICENSE("GPL v2");
 137 MODULE_IMPORT_NS(IIO_MS5611);