1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * IIO driver for the 3-axis accelerometer Domintech DMARD09.
4 *
5 * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
6 */
7
8#include <asm/unaligned.h>
9#include <linux/module.h>
10#include <linux/i2c.h>
11#include <linux/iio/iio.h>
12
13#define DMARD09_DRV_NAME	"dmard09"
14
15#define DMARD09_REG_CHIPID      0x18
16#define DMARD09_REG_STAT	0x0A
17#define DMARD09_REG_X		0x0C
18#define DMARD09_REG_Y		0x0E
19#define DMARD09_REG_Z		0x10
20#define DMARD09_CHIPID		0x95
21
22#define DMARD09_BUF_LEN 8
23#define DMARD09_AXIS_X 0
24#define DMARD09_AXIS_Y 1
25#define DMARD09_AXIS_Z 2
26#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
27#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2)
28#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
29
30struct dmard09_data {
31	struct i2c_client *client;
32};
33
34#define DMARD09_CHANNEL(_axis, offset) {			\
35	.type = IIO_ACCEL,					\
36	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
37	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
38	.modified = 1,						\
39	.address = offset,					\
40	.channel2 = IIO_MOD_##_axis,				\
41}
42
43static const struct iio_chan_spec dmard09_channels[] = {
44	DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
45	DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
46	DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
47};
48
49static int dmard09_read_raw(struct iio_dev *indio_dev,
50			    struct iio_chan_spec const *chan,
51			    int *val, int *val2, long mask)
52{
53	struct dmard09_data *data = iio_priv(indio_dev);
54	u8 buf[DMARD09_BUF_LEN];
55	int ret;
56	s16 accel;
57
58	switch (mask) {
59	case IIO_CHAN_INFO_RAW:
60		/*
61		 * Read from the DMAR09_REG_STAT register, since the chip
62		 * caches reads from the individual X, Y, Z registers.
63		 */
64		ret = i2c_smbus_read_i2c_block_data(data->client,
65						    DMARD09_REG_STAT,
66						    DMARD09_BUF_LEN, buf);
67		if (ret < 0) {
68			dev_err(&data->client->dev, "Error reading reg %d\n",
69				DMARD09_REG_STAT);
70			return ret;
71		}
72
73		accel = get_unaligned_le16(&buf[chan->address]);
74
75		/* Remove lower 3 bits and sign extend */
76		accel <<= 4;
77		accel >>= 7;
78
79		*val = accel;
80
81		return IIO_VAL_INT;
82	default:
83		return -EINVAL;
84	}
85}
86
87static const struct iio_info dmard09_info = {
88	.read_raw	= dmard09_read_raw,
89};
90
91static int dmard09_probe(struct i2c_client *client,
92			const struct i2c_device_id *id)
93{
94	int ret;
95	struct iio_dev *indio_dev;
96	struct dmard09_data *data;
97
98	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
99	if (!indio_dev) {
100		dev_err(&client->dev, "iio allocation failed\n");
101		return -ENOMEM;
102	}
103
104	data = iio_priv(indio_dev);
105	data->client = client;
106
107	ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
108	if (ret < 0) {
109		dev_err(&client->dev, "Error reading chip id %d\n", ret);
110		return ret;
111	}
112
113	if (ret != DMARD09_CHIPID) {
114		dev_err(&client->dev, "Invalid chip id %d\n", ret);
115		return -ENODEV;
116	}
117
118	i2c_set_clientdata(client, indio_dev);
119	indio_dev->name = DMARD09_DRV_NAME;
120	indio_dev->modes = INDIO_DIRECT_MODE;
121	indio_dev->channels = dmard09_channels;
122	indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
123	indio_dev->info = &dmard09_info;
124
125	return devm_iio_device_register(&client->dev, indio_dev);
126}
127
128static const struct i2c_device_id dmard09_id[] = {
129	{ "dmard09", 0},
130	{ },
131};
132
133MODULE_DEVICE_TABLE(i2c, dmard09_id);
134
135static struct i2c_driver dmard09_driver = {
136	.driver = {
137		.name = DMARD09_DRV_NAME
138	},
139	.probe = dmard09_probe,
140	.id_table = dmard09_id,
141};
142
143module_i2c_driver(dmard09_driver);
144
145MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
146MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
147MODULE_LICENSE("GPL");
148