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a4fa6509 JW |
1 | /* |
2 | * IIO driver for the 3-axis accelerometer Domintech DMARD09. | |
3 | * | |
4 | * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms and conditions of the GNU General Public License, | |
8 | * version 2, as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | */ | |
15 | ||
16 | #include <asm/unaligned.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/i2c.h> | |
19 | #include <linux/iio/iio.h> | |
20 | ||
21 | #define DMARD09_DRV_NAME "dmard09" | |
22 | ||
23 | #define DMARD09_REG_CHIPID 0x18 | |
24 | #define DMARD09_REG_STAT 0x0A | |
25 | #define DMARD09_REG_X 0x0C | |
26 | #define DMARD09_REG_Y 0x0E | |
27 | #define DMARD09_REG_Z 0x10 | |
28 | #define DMARD09_CHIPID 0x95 | |
29 | ||
30 | #define DMARD09_BUF_LEN 8 | |
31 | #define DMARD09_AXIS_X 0 | |
32 | #define DMARD09_AXIS_Y 1 | |
33 | #define DMARD09_AXIS_Z 2 | |
34 | #define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2) | |
35 | #define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2) | |
36 | #define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2) | |
37 | ||
38 | struct dmard09_data { | |
39 | struct i2c_client *client; | |
40 | }; | |
41 | ||
42 | #define DMARD09_CHANNEL(_axis, offset) { \ | |
43 | .type = IIO_ACCEL, \ | |
44 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
45 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ | |
46 | .modified = 1, \ | |
47 | .address = offset, \ | |
48 | .channel2 = IIO_MOD_##_axis, \ | |
49 | } | |
50 | ||
51 | static const struct iio_chan_spec dmard09_channels[] = { | |
52 | DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET), | |
53 | DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET), | |
54 | DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET), | |
55 | }; | |
56 | ||
57 | static int dmard09_read_raw(struct iio_dev *indio_dev, | |
58 | struct iio_chan_spec const *chan, | |
59 | int *val, int *val2, long mask) | |
60 | { | |
61 | struct dmard09_data *data = iio_priv(indio_dev); | |
62 | u8 buf[DMARD09_BUF_LEN]; | |
63 | int ret; | |
64 | s16 accel; | |
65 | ||
66 | switch (mask) { | |
67 | case IIO_CHAN_INFO_RAW: | |
68 | /* | |
69 | * Read from the DMAR09_REG_STAT register, since the chip | |
70 | * caches reads from the individual X, Y, Z registers. | |
71 | */ | |
72 | ret = i2c_smbus_read_i2c_block_data(data->client, | |
73 | DMARD09_REG_STAT, | |
74 | DMARD09_BUF_LEN, buf); | |
75 | if (ret < 0) { | |
76 | dev_err(&data->client->dev, "Error reading reg %d\n", | |
77 | DMARD09_REG_STAT); | |
78 | return ret; | |
79 | } | |
80 | ||
81 | accel = get_unaligned_le16(&buf[chan->address]); | |
82 | ||
83 | /* Remove lower 3 bits and sign extend */ | |
84 | accel <<= 4; | |
85 | accel >>= 7; | |
86 | ||
87 | *val = accel; | |
88 | ||
89 | return IIO_VAL_INT; | |
90 | default: | |
91 | return -EINVAL; | |
92 | } | |
93 | } | |
94 | ||
95 | static const struct iio_info dmard09_info = { | |
96 | .driver_module = THIS_MODULE, | |
97 | .read_raw = dmard09_read_raw, | |
98 | }; | |
99 | ||
100 | static int dmard09_probe(struct i2c_client *client, | |
101 | const struct i2c_device_id *id) | |
102 | { | |
103 | int ret; | |
104 | struct iio_dev *indio_dev; | |
105 | struct dmard09_data *data; | |
106 | ||
107 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); | |
108 | if (!indio_dev) { | |
109 | dev_err(&client->dev, "iio allocation failed\n"); | |
110 | return -ENOMEM; | |
111 | } | |
112 | ||
113 | data = iio_priv(indio_dev); | |
114 | data->client = client; | |
115 | ||
116 | ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID); | |
117 | if (ret < 0) { | |
118 | dev_err(&client->dev, "Error reading chip id %d\n", ret); | |
119 | return ret; | |
120 | } | |
121 | ||
122 | if (ret != DMARD09_CHIPID) { | |
123 | dev_err(&client->dev, "Invalid chip id %d\n", ret); | |
124 | return -ENODEV; | |
125 | } | |
126 | ||
127 | i2c_set_clientdata(client, indio_dev); | |
128 | indio_dev->dev.parent = &client->dev; | |
129 | indio_dev->name = DMARD09_DRV_NAME; | |
130 | indio_dev->modes = INDIO_DIRECT_MODE; | |
131 | indio_dev->channels = dmard09_channels; | |
132 | indio_dev->num_channels = ARRAY_SIZE(dmard09_channels); | |
133 | indio_dev->info = &dmard09_info; | |
134 | ||
135 | return devm_iio_device_register(&client->dev, indio_dev); | |
136 | } | |
137 | ||
138 | static const struct i2c_device_id dmard09_id[] = { | |
139 | { "dmard09", 0}, | |
140 | { }, | |
141 | }; | |
142 | ||
143 | MODULE_DEVICE_TABLE(i2c, dmard09_id); | |
144 | ||
145 | static struct i2c_driver dmard09_driver = { | |
146 | .driver = { | |
147 | .name = DMARD09_DRV_NAME | |
148 | }, | |
149 | .probe = dmard09_probe, | |
150 | .id_table = dmard09_id, | |
151 | }; | |
152 | ||
153 | module_i2c_driver(dmard09_driver); | |
154 | ||
155 | MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>"); | |
156 | MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver"); | |
157 | MODULE_LICENSE("GPL"); |