xref: /openbmc/linux/drivers/iio/accel/dmard09.c (revision 7cf15f42)
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 
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", 0 },
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