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mpl115 driver currently supports i2c interface (MPL115A2). There is also SPI version (MPL115A1). The difference between them is only physical transport so we can easily support both while sharing most of the code. Split the driver into a core support module and one module each for I2C and SPI support. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Jonathan Cameron <jic23@kernel.org> Cc: Hartmut Knaack <knaack.h@gmx.de> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Peter Meerwald <pmeerw@pmeerw.net> Cc: linux-iio@vger.kernel.org Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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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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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.driver_module = THIS_MODULE,
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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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