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/of_device.h>
  13
  14 #include "ms5611.h"
  15
  16 static int ms5611_spi_reset(struct device *dev)
  17 {
  18         u8 cmd = MS5611_RESET;
  19         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  20
  21         return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
  22 }
  23
  24 static int ms5611_spi_read_prom_word(struct device *dev, int index, u16 *word)
  25 {
  26         int ret;
  27         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  28
  29         ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
  30         if (ret < 0)
  31                 return ret;
  32
  33         *word = ret;
  34
  35         return 0;
  36 }
  37
  38 static int ms5611_spi_read_adc(struct device *dev, s32 *val)
  39 {
  40         int ret;
  41         u8 buf[3] = { MS5611_READ_ADC };
  42         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  43
  44         ret = spi_write_then_read(st->client, buf, 1, buf, 3);
  45         if (ret < 0)
  46                 return ret;
  47
  48         *val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
  49
  50         return 0;
  51 }
  52
  53 static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev,
  54                                                  s32 *temp, s32 *pressure)
  55 {
  56         int ret;
  57         struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
  58         const struct ms5611_osr *osr = st->temp_osr;
  59
  60         /*
  61          * Warning: &osr->cmd MUST be aligned on a word boundary since used as
  62          * 2nd argument (void*) of spi_write_then_read.
  63          */
  64         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  65         if (ret < 0)
  66                 return ret;
  67
  68         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  69         ret = ms5611_spi_read_adc(dev, temp);
  70         if (ret < 0)
  71                 return ret;
  72
  73         osr = st->pressure_osr;
  74         ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
  75         if (ret < 0)
  76                 return ret;
  77
  78         usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
  79         return ms5611_spi_read_adc(dev, pressure);
  80 }
  81
  82 static int ms5611_spi_probe(struct spi_device *spi)
  83 {
  84         int ret;
  85         struct ms5611_state *st;
  86         struct iio_dev *indio_dev;
  87
  88         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
  89         if (!indio_dev)
  90                 return -ENOMEM;
  91
  92         spi_set_drvdata(spi, indio_dev);
  93
  94         spi->mode = SPI_MODE_0;
  95         spi->max_speed_hz = 20000000;
  96         spi->bits_per_word = 8;
  97         ret = spi_setup(spi);
  98         if (ret < 0)
  99                 return ret;
 100
 101         st = iio_priv(indio_dev);
 102         st->reset = ms5611_spi_reset;
 103         st->read_prom_word = ms5611_spi_read_prom_word;
 104         st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
 105         st->client = spi;
 106
 107         return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
 108                             spi_get_device_id(spi)->driver_data);
 109 }
 110
 111 static int ms5611_spi_remove(struct spi_device *spi)
 112 {
 113         return ms5611_remove(spi_get_drvdata(spi));
 114 }
 115
 116 #if defined(CONFIG_OF)
 117 static const struct of_device_id ms5611_spi_matches[] = {
 118         { .compatible = "meas,ms5611" },
 119         { .compatible = "meas,ms5607" },
 120         { }
 121 };
 122 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
 123 #endif
 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 = of_match_ptr(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");