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
18 struct mpl115_spi_buf {
19 u8 tx[4];
20 u8 rx[4];
21 };
22
mpl115_spi_init(struct device * dev)23 static 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
mpl115_spi_read(struct device * dev,u8 address)37 static 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
mpl115_spi_write(struct device * dev,u8 address,u8 value)58 static 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
73 static const struct mpl115_ops mpl115_spi_ops = {
74 .init = mpl115_spi_init,
75 .read = mpl115_spi_read,
76 .write = mpl115_spi_write,
77 };
78
mpl115_spi_probe(struct spi_device * spi)79 static 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
86 static const struct spi_device_id mpl115_spi_ids[] = {
87 { "mpl115", 0 },
88 {}
89 };
90 MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
91
92 static struct spi_driver mpl115_spi_driver = {
93 .driver = {
94 .name = "mpl115",
95 },
96 .probe = mpl115_spi_probe,
97 .id_table = mpl115_spi_ids,
98 };
99 module_spi_driver(mpl115_spi_driver);
100
101 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
102 MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
103 MODULE_LICENSE("GPL");
104