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 <linux/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
30 struct 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
43 static 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
dmard09_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)49 static 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
87 static const struct iio_info dmard09_info = {
88 .read_raw = dmard09_read_raw,
89 };
90
dmard09_probe(struct i2c_client * client)91 static int dmard09_probe(struct i2c_client *client)
92 {
93 int ret;
94 struct iio_dev *indio_dev;
95 struct dmard09_data *data;
96
97 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
98 if (!indio_dev) {
99 dev_err(&client->dev, "iio allocation failed\n");
100 return -ENOMEM;
101 }
102
103 data = iio_priv(indio_dev);
104 data->client = client;
105
106 ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
107 if (ret < 0) {
108 dev_err(&client->dev, "Error reading chip id %d\n", ret);
109 return ret;
110 }
111
112 if (ret != DMARD09_CHIPID) {
113 dev_err(&client->dev, "Invalid chip id %d\n", ret);
114 return -ENODEV;
115 }
116
117 i2c_set_clientdata(client, indio_dev);
118 indio_dev->name = DMARD09_DRV_NAME;
119 indio_dev->modes = INDIO_DIRECT_MODE;
120 indio_dev->channels = dmard09_channels;
121 indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
122 indio_dev->info = &dmard09_info;
123
124 return devm_iio_device_register(&client->dev, indio_dev);
125 }
126
127 static const struct i2c_device_id dmard09_id[] = {
128 { "dmard09" },
129 { }
130 };
131
132 MODULE_DEVICE_TABLE(i2c, dmard09_id);
133
134 static struct i2c_driver dmard09_driver = {
135 .driver = {
136 .name = DMARD09_DRV_NAME
137 },
138 .probe = dmard09_probe,
139 .id_table = dmard09_id,
140 };
141
142 module_i2c_driver(dmard09_driver);
143
144 MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
145 MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
146 MODULE_LICENSE("GPL");
147