107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
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/*
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* Freescale MPL115A1 pressure/temperature sensor
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*
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* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
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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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* Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
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*/
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#include "mpl115.h"
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#define MPL115_SPI_WRITE(address) ((address) << 1)
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#define MPL115_SPI_READ(address) (0x80 | (address) << 1)
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struct mpl115_spi_buf {
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u8 tx[4];
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u8 rx[4];
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};
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static int mpl115_spi_init(struct device *dev)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf;
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buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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spi_set_drvdata(spi, buf);
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return 0;
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}
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static int mpl115_spi_read(struct device *dev, u8 address)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
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struct spi_transfer xfer = {
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.tx_buf = buf->tx,
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.rx_buf = buf->rx,
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.len = 4,
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};
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int ret;
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buf->tx[0] = MPL115_SPI_READ(address);
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buf->tx[2] = MPL115_SPI_READ(address + 1);
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ret = spi_sync_transfer(spi, &xfer, 1);
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if (ret)
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return ret;
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return (buf->rx[1] << 8) | buf->rx[3];
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}
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static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
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struct spi_transfer xfer = {
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.tx_buf = buf->tx,
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.len = 2,
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};
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buf->tx[0] = MPL115_SPI_WRITE(address);
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buf->tx[1] = value;
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return spi_sync_transfer(spi, &xfer, 1);
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}
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static const struct mpl115_ops mpl115_spi_ops = {
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.init = mpl115_spi_init,
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.read = mpl115_spi_read,
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.write = mpl115_spi_write,
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};
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static int mpl115_spi_probe(struct spi_device *spi)
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{
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const struct spi_device_id *id = spi_get_device_id(spi);
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return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
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}
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static const struct spi_device_id mpl115_spi_ids[] = {
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{ "mpl115", 0 },
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{}
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};
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MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
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static struct spi_driver mpl115_spi_driver = {
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.driver = {
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.name = "mpl115",
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},
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.probe = mpl115_spi_probe,
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.id_table = mpl115_spi_ids,
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};
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module_spi_driver(mpl115_spi_driver);
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MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
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MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
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MODULE_LICENSE("GPL");
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