mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-01-25 13:09:38 +07:00
033691a9a1
Add support for setting and retrieving OverSampling Rate independently for each of the temperature and pressure channels. This allows userspace to fine tune hardware sampling process according to the following tradeoffs : * the higher the OSR, the finer the resolution ; * the higher the OSR, the lower the noise ; BUT: * the higher the OSR, the larger the drift ; * the higher the OSR, the longer the response time, i.e. less samples per unit of time. Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
151 lines
3.6 KiB
C
151 lines
3.6 KiB
C
/*
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* MS5611 pressure and temperature sensor driver (SPI bus)
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*
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* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#include <linux/of_device.h>
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#include "ms5611.h"
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static int ms5611_spi_reset(struct device *dev)
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{
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u8 cmd = MS5611_RESET;
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struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
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return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
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}
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static int ms5611_spi_read_prom_word(struct device *dev, int index, u16 *word)
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{
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int ret;
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struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
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ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
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if (ret < 0)
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return ret;
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*word = ret;
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return 0;
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}
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static int ms5611_spi_read_adc(struct device *dev, s32 *val)
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{
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int ret;
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u8 buf[3] = { MS5611_READ_ADC };
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struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
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ret = spi_write_then_read(st->client, buf, 1, buf, 3);
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if (ret < 0)
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return ret;
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*val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
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return 0;
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}
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static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev,
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s32 *temp, s32 *pressure)
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{
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int ret;
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struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
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const struct ms5611_osr *osr = st->temp_osr;
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/*
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* Warning: &osr->cmd MUST be aligned on a word boundary since used as
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* 2nd argument (void*) of spi_write_then_read.
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*/
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ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
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if (ret < 0)
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return ret;
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usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
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ret = ms5611_spi_read_adc(dev, temp);
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if (ret < 0)
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return ret;
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osr = st->pressure_osr;
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ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
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if (ret < 0)
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return ret;
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usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
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return ms5611_spi_read_adc(dev, pressure);
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}
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static int ms5611_spi_probe(struct spi_device *spi)
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{
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int ret;
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struct ms5611_state *st;
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struct iio_dev *indio_dev;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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spi_set_drvdata(spi, indio_dev);
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spi->mode = SPI_MODE_0;
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spi->max_speed_hz = 20000000;
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spi->bits_per_word = 8;
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ret = spi_setup(spi);
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if (ret < 0)
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return ret;
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st = iio_priv(indio_dev);
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st->reset = ms5611_spi_reset;
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st->read_prom_word = ms5611_spi_read_prom_word;
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st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
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st->client = spi;
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return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
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spi_get_device_id(spi)->driver_data);
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}
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static int ms5611_spi_remove(struct spi_device *spi)
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{
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return ms5611_remove(spi_get_drvdata(spi));
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}
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#if defined(CONFIG_OF)
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static const struct of_device_id ms5611_spi_matches[] = {
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{ .compatible = "meas,ms5611" },
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{ .compatible = "ms5611" },
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{ .compatible = "meas,ms5607" },
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{ .compatible = "ms5607" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
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#endif
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static const struct spi_device_id ms5611_id[] = {
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{ "ms5611", MS5611 },
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{ "ms5607", MS5607 },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, ms5611_id);
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static struct spi_driver ms5611_driver = {
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.driver = {
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.name = "ms5611",
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.of_match_table = of_match_ptr(ms5611_spi_matches)
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},
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.id_table = ms5611_id,
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.probe = ms5611_spi_probe,
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.remove = ms5611_spi_remove,
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};
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module_spi_driver(ms5611_driver);
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MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
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MODULE_DESCRIPTION("MS5611 spi driver");
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MODULE_LICENSE("GPL v2");
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