LXR linux/drivers/iio/pressure/mpl115

   1/*
   2 * Freescale MPL115A1 pressure/temperature sensor
   3 *
   4 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
   5 *
   6 * This file is subject to the terms and conditions of version 2 of
   7 * the GNU General Public License.  See the file COPYING in the main
   8 * directory of this archive for more details.
   9 *
  10 * Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/spi/spi.h>
  15
  16#include "mpl115.h"
  17
  18#define MPL115_SPI_WRITE(address)       ((address) << 1)
  19#define MPL115_SPI_READ(address)        (0x80 | (address) << 1)
  20
  21struct mpl115_spi_buf {
  22        u8 tx[4];
  23        u8 rx[4];
  24};
  25
  26static int mpl115_spi_init(struct device *dev)
  27{
  28        struct spi_device *spi = to_spi_device(dev);
  29        struct mpl115_spi_buf *buf;
  30
  31        buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
  32        if (!buf)
  33                return -ENOMEM;
  34
  35        spi_set_drvdata(spi, buf);
  36
  37        return 0;
  38}
  39
  40static int mpl115_spi_read(struct device *dev, u8 address)
  41{
  42        struct spi_device *spi = to_spi_device(dev);
  43        struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
  44        struct spi_transfer xfer = {
  45                .tx_buf = buf->tx,
  46                .rx_buf = buf->rx,
  47                .len = 4,
  48        };
  49        int ret;
  50
  51        buf->tx[0] = MPL115_SPI_READ(address);
  52        buf->tx[2] = MPL115_SPI_READ(address + 1);
  53
  54        ret = spi_sync_transfer(spi, &xfer, 1);
  55        if (ret)
  56                return ret;
  57
  58        return (buf->rx[1] << 8) | buf->rx[3];
  59}
  60
  61static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
  62{
  63        struct spi_device *spi = to_spi_device(dev);
  64        struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
  65        struct spi_transfer xfer = {
  66                .tx_buf = buf->tx,
  67                .len = 2,
  68        };
  69
  70        buf->tx[0] = MPL115_SPI_WRITE(address);
  71        buf->tx[1] = value;
  72
  73        return spi_sync_transfer(spi, &xfer, 1);
  74}
  75
  76static const struct mpl115_ops mpl115_spi_ops = {
  77        .init = mpl115_spi_init,
  78        .read = mpl115_spi_read,
  79        .write = mpl115_spi_write,
  80};
  81
  82static int mpl115_spi_probe(struct spi_device *spi)
  83{
  84        const struct spi_device_id *id = spi_get_device_id(spi);
  85
  86        return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
  87}
  88
  89static const struct spi_device_id mpl115_spi_ids[] = {
  90        { "mpl115", 0 },
  91        {}
  92};
  93MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
  94
  95static struct spi_driver mpl115_spi_driver = {
  96        .driver = {
  97                .name   = "mpl115",
  98        },
  99        .probe = mpl115_spi_probe,
 100        .id_table = mpl115_spi_ids,
 101};
 102module_spi_driver(mpl115_spi_driver);
 103
 104MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 105MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
 106MODULE_LICENSE("GPL");
 107