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>
149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
/*
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* MS5611 pressure and temperature sensor driver (I2C 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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* 7-bit I2C slave addresses:
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*
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* 0x77 (CSB pin low)
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* 0x76 (CSB pin high)
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*
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*/
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include "ms5611.h"
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static int ms5611_i2c_reset(struct device *dev)
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{
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struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
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return i2c_smbus_write_byte(st->client, MS5611_RESET);
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}
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static int ms5611_i2c_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 = i2c_smbus_read_word_swapped(st->client,
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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_i2c_read_adc(struct ms5611_state *st, s32 *val)
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{
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int ret;
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u8 buf[3];
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ret = i2c_smbus_read_i2c_block_data(st->client, MS5611_READ_ADC,
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3, buf);
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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_i2c_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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ret = i2c_smbus_write_byte(st->client, osr->cmd);
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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_i2c_read_adc(st, 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 = i2c_smbus_write_byte(st->client, osr->cmd);
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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_i2c_read_adc(st, pressure);
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}
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static int ms5611_i2c_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct ms5611_state *st;
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struct iio_dev *indio_dev;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_WRITE_BYTE |
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I2C_FUNC_SMBUS_READ_WORD_DATA |
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I2C_FUNC_SMBUS_READ_I2C_BLOCK))
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return -EOPNOTSUPP;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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st->reset = ms5611_i2c_reset;
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st->read_prom_word = ms5611_i2c_read_prom_word;
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st->read_adc_temp_and_pressure = ms5611_i2c_read_adc_temp_and_pressure;
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st->client = client;
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return ms5611_probe(indio_dev, &client->dev, id->name, id->driver_data);
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}
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static int ms5611_i2c_remove(struct i2c_client *client)
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{
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return ms5611_remove(i2c_get_clientdata(client));
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}
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#if defined(CONFIG_OF)
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static const struct of_device_id ms5611_i2c_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_i2c_matches);
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#endif
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static const struct i2c_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(i2c, ms5611_id);
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static struct i2c_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_i2c_matches)
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},
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.id_table = ms5611_id,
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.probe = ms5611_i2c_probe,
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.remove = ms5611_i2c_remove,
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};
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module_i2c_driver(ms5611_driver);
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MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
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MODULE_DESCRIPTION("MS5611 i2c driver");
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MODULE_LICENSE("GPL v2");
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