iio/pressure/ms5611_spi.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * MS5611 pressure and temperature sensor driver (SPI bus)
0004  *
0005  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
0006  *
0007  */
0008
0009 #include <linux/delay.h>
0010 #include <linux/module.h>
0011 #include <linux/spi/spi.h>
0012 #include <linux/mod_devicetable.h>
0013
0014 #include <asm/unaligned.h>
0015
0016 #include "ms5611.h"
0017
0018 static int ms5611_spi_reset(struct ms5611_state *st)
0019 {
0020     u8 cmd = MS5611_RESET;
0021
0022     return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
0023 }
0024
0025 static int ms5611_spi_read_prom_word(struct ms5611_state *st, int index,
0026                      u16 *word)
0027 {
0028     int ret;
0029
0030     ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
0031     if (ret < 0)
0032         return ret;
0033
0034     *word = ret;
0035
0036     return 0;
0037 }
0038
0039 static int ms5611_spi_read_adc(struct ms5611_state *st, s32 *val)
0040 {
0041     int ret;
0042     u8 buf[3] = { MS5611_READ_ADC };
0043
0044     ret = spi_write_then_read(st->client, buf, 1, buf, 3);
0045     if (ret < 0)
0046         return ret;
0047
0048     *val = get_unaligned_be24(&buf[0]);
0049
0050     return 0;
0051 }
0052
0053 static int ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state *st,
0054                          s32 *temp, s32 *pressure)
0055 {
0056     int ret;
0057     const struct ms5611_osr *osr = st->temp_osr;
0058
0059     /*
0060      * Warning: &osr->cmd MUST be aligned on a word boundary since used as
0061      * 2nd argument (void*) of spi_write_then_read.
0062      */
0063     ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
0064     if (ret < 0)
0065         return ret;
0066
0067     usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
0068     ret = ms5611_spi_read_adc(st, temp);
0069     if (ret < 0)
0070         return ret;
0071
0072     osr = st->pressure_osr;
0073     ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
0074     if (ret < 0)
0075         return ret;
0076
0077     usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
0078     return ms5611_spi_read_adc(st, pressure);
0079 }
0080
0081 static int ms5611_spi_probe(struct spi_device *spi)
0082 {
0083     int ret;
0084     struct ms5611_state *st;
0085     struct iio_dev *indio_dev;
0086
0087     indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
0088     if (!indio_dev)
0089         return -ENOMEM;
0090
0091     spi_set_drvdata(spi, indio_dev);
0092
0093     spi->mode = SPI_MODE_0;
0094     spi->max_speed_hz = 20000000;
0095     spi->bits_per_word = 8;
0096     ret = spi_setup(spi);
0097     if (ret < 0)
0098         return ret;
0099
0100     st = iio_priv(indio_dev);
0101     st->reset = ms5611_spi_reset;
0102     st->read_prom_word = ms5611_spi_read_prom_word;
0103     st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
0104     st->client = spi;
0105
0106     return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
0107                 spi_get_device_id(spi)->driver_data);
0108 }
0109
0110 static void ms5611_spi_remove(struct spi_device *spi)
0111 {
0112     ms5611_remove(spi_get_drvdata(spi));
0113 }
0114
0115 static const struct of_device_id ms5611_spi_matches[] = {
0116     { .compatible = "meas,ms5611" },
0117     { .compatible = "meas,ms5607" },
0118     { }
0119 };
0120 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
0121
0122 static const struct spi_device_id ms5611_id[] = {
0123     { "ms5611", MS5611 },
0124     { "ms5607", MS5607 },
0125     { }
0126 };
0127 MODULE_DEVICE_TABLE(spi, ms5611_id);
0128
0129 static struct spi_driver ms5611_driver = {
0130     .driver = {
0131         .name = "ms5611",
0132         .of_match_table = ms5611_spi_matches
0133     },
0134     .id_table = ms5611_id,
0135     .probe = ms5611_spi_probe,
0136     .remove = ms5611_spi_remove,
0137 };
0138 module_spi_driver(ms5611_driver);
0139
0140 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
0141 MODULE_DESCRIPTION("MS5611 spi driver");
0142 MODULE_LICENSE("GPL v2");
0143 MODULE_IMPORT_NS(IIO_MS5611);