mpl115_spi.c (2319B)
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"); 104MODULE_IMPORT_NS(IIO_MPL115);