LXR linux/drivers/iio/pressure/mpl115

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Freescale MPL115A1 pressure/temperature sensor
   4 *
   5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
   6 *
   7 * Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/spi/spi.h>
  12
  13#include "mpl115.h"
  14
  15#define MPL115_SPI_WRITE(address)       ((address) << 1)
  16#define MPL115_SPI_READ(address)        (0x80 | (address) << 1)
  17
  18struct mpl115_spi_buf {
  19        u8 tx[4];
  20        u8 rx[4];
  21};
  22
  23static int mpl115_spi_init(struct device *dev)
  24{
  25        struct spi_device *spi = to_spi_device(dev);
  26        struct mpl115_spi_buf *buf;
  27
  28        buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
  29        if (!buf)
  30                return -ENOMEM;
  31
  32        spi_set_drvdata(spi, buf);
  33
  34        return 0;
  35}
  36
  37static int mpl115_spi_read(struct device *dev, u8 address)
  38{
  39        struct spi_device *spi = to_spi_device(dev);
  40        struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
  41        struct spi_transfer xfer = {
  42                .tx_buf = buf->tx,
  43                .rx_buf = buf->rx,
  44                .len = 4,
  45        };
  46        int ret;
  47
  48        buf->tx[0] = MPL115_SPI_READ(address);
  49        buf->tx[2] = MPL115_SPI_READ(address + 1);
  50
  51        ret = spi_sync_transfer(spi, &xfer, 1);
  52        if (ret)
  53                return ret;
  54
  55        return (buf->rx[1] << 8) | buf->rx[3];
  56}
  57
  58static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
  59{
  60        struct spi_device *spi = to_spi_device(dev);
  61        struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
  62        struct spi_transfer xfer = {
  63                .tx_buf = buf->tx,
  64                .len = 2,
  65        };
  66
  67        buf->tx[0] = MPL115_SPI_WRITE(address);
  68        buf->tx[1] = value;
  69
  70        return spi_sync_transfer(spi, &xfer, 1);
  71}
  72
  73static const struct mpl115_ops mpl115_spi_ops = {
  74        .init = mpl115_spi_init,
  75        .read = mpl115_spi_read,
  76        .write = mpl115_spi_write,
  77};
  78
  79static int mpl115_spi_probe(struct spi_device *spi)
  80{
  81        const struct spi_device_id *id = spi_get_device_id(spi);
  82
  83        return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
  84}
  85
  86static const struct spi_device_id mpl115_spi_ids[] = {
  87        { "mpl115", 0 },
  88        {}
  89};
  90MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
  91
  92static struct spi_driver mpl115_spi_driver = {
  93        .driver = {
  94                .name   = "mpl115",
  95        },
  96        .probe = mpl115_spi_probe,
  97        .id_table = mpl115_spi_ids,
  98};
  99module_spi_driver(mpl115_spi_driver);
 100
 101MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 102MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
 103MODULE_LICENSE("GPL");
 104