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6a15fef2cb
The equivalent of both of these are now done via macro magic when the relevant register calls are made. The actual structure elements will shortly go away. Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
200 lines
4.5 KiB
C
200 lines
4.5 KiB
C
/*
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* mpl115.c - Support for Freescale MPL115A pressure/temperature sensor
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*
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* Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* TODO: shutdown pin
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*
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*/
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/delay.h>
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#include "mpl115.h"
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#define MPL115_PADC 0x00 /* pressure ADC output value, MSB first, 10 bit */
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#define MPL115_TADC 0x02 /* temperature ADC output value, MSB first, 10 bit */
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#define MPL115_A0 0x04 /* 12 bit integer, 3 bit fraction */
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#define MPL115_B1 0x06 /* 2 bit integer, 13 bit fraction */
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#define MPL115_B2 0x08 /* 1 bit integer, 14 bit fraction */
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#define MPL115_C12 0x0a /* 0 bit integer, 13 bit fraction */
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#define MPL115_CONVERT 0x12 /* convert temperature and pressure */
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struct mpl115_data {
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struct device *dev;
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struct mutex lock;
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s16 a0;
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s16 b1, b2;
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s16 c12;
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const struct mpl115_ops *ops;
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};
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static int mpl115_request(struct mpl115_data *data)
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{
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int ret = data->ops->write(data->dev, MPL115_CONVERT, 0);
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if (ret < 0)
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return ret;
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usleep_range(3000, 4000);
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return 0;
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}
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static int mpl115_comp_pressure(struct mpl115_data *data, int *val, int *val2)
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{
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int ret;
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u16 padc, tadc;
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int a1, y1, pcomp;
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unsigned kpa;
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mutex_lock(&data->lock);
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ret = mpl115_request(data);
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if (ret < 0)
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goto done;
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ret = data->ops->read(data->dev, MPL115_PADC);
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if (ret < 0)
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goto done;
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padc = ret >> 6;
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ret = data->ops->read(data->dev, MPL115_TADC);
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if (ret < 0)
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goto done;
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tadc = ret >> 6;
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/* see Freescale AN3785 */
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a1 = data->b1 + ((data->c12 * tadc) >> 11);
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y1 = (data->a0 << 10) + a1 * padc;
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/* compensated pressure with 4 fractional bits */
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pcomp = (y1 + ((data->b2 * (int) tadc) >> 1)) >> 9;
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kpa = pcomp * (115 - 50) / 1023 + (50 << 4);
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*val = kpa >> 4;
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*val2 = (kpa & 15) * (1000000 >> 4);
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done:
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mutex_unlock(&data->lock);
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return ret;
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}
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static int mpl115_read_temp(struct mpl115_data *data)
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{
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int ret;
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mutex_lock(&data->lock);
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ret = mpl115_request(data);
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if (ret < 0)
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goto done;
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ret = data->ops->read(data->dev, MPL115_TADC);
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done:
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mutex_unlock(&data->lock);
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return ret;
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}
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static int mpl115_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct mpl115_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_PROCESSED:
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ret = mpl115_comp_pressure(data, val, val2);
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if (ret < 0)
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return ret;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CHAN_INFO_RAW:
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/* temperature -5.35 C / LSB, 472 LSB is 25 C */
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ret = mpl115_read_temp(data);
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if (ret < 0)
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return ret;
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*val = ret >> 6;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_OFFSET:
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*val = -605;
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*val2 = 750000;
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CHAN_INFO_SCALE:
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*val = -186;
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*val2 = 915888;
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return IIO_VAL_INT_PLUS_MICRO;
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}
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return -EINVAL;
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}
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static const struct iio_chan_spec mpl115_channels[] = {
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{
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.type = IIO_PRESSURE,
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
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},
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{
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.type = IIO_TEMP,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type =
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BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),
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},
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};
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static const struct iio_info mpl115_info = {
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.read_raw = &mpl115_read_raw,
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};
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int mpl115_probe(struct device *dev, const char *name,
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const struct mpl115_ops *ops)
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{
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struct mpl115_data *data;
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struct iio_dev *indio_dev;
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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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data->dev = dev;
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data->ops = ops;
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mutex_init(&data->lock);
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indio_dev->info = &mpl115_info;
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indio_dev->name = name;
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indio_dev->dev.parent = dev;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = mpl115_channels;
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indio_dev->num_channels = ARRAY_SIZE(mpl115_channels);
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ret = data->ops->init(data->dev);
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if (ret)
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return ret;
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ret = data->ops->read(data->dev, MPL115_A0);
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if (ret < 0)
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return ret;
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data->a0 = ret;
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ret = data->ops->read(data->dev, MPL115_B1);
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if (ret < 0)
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return ret;
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data->b1 = ret;
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ret = data->ops->read(data->dev, MPL115_B2);
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if (ret < 0)
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return ret;
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data->b2 = ret;
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ret = data->ops->read(data->dev, MPL115_C12);
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if (ret < 0)
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return ret;
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data->c12 = ret;
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return devm_iio_device_register(dev, indio_dev);
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}
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EXPORT_SYMBOL_GPL(mpl115_probe);
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MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
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MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");
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MODULE_LICENSE("GPL");
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