1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * MXC6255 - MEMSIC orientation sensing accelerometer
4 *
5 * Copyright (c) 2015, Intel Corporation.
6 *
7 * IIO driver for MXC6255 (7-bit I2C slave address 0x15).
8 */
9
10 #include <linux/module.h>
11 #include <linux/i2c.h>
12 #include <linux/init.h>
13 #include <linux/iio/iio.h>
14 #include <linux/delay.h>
15 #include <linux/regmap.h>
16 #include <linux/iio/sysfs.h>
17
18 #define MXC6255_DRV_NAME "mxc6255"
19
20 #define MXC6255_REG_XOUT 0x00
21 #define MXC6255_REG_YOUT 0x01
22 #define MXC6255_REG_CHIP_ID 0x08
23
24 #define MXC6255_CHIP_ID 0x05
25
26 /*
27 * MXC6255 has only one measurement range: +/- 2G.
28 * The acceleration output is an 8-bit value.
29 *
30 * Scale is calculated as follows:
31 * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
32 *
33 * Scale value for +/- 2G measurement range
34 */
35 #define MXC6255_SCALE 153829
36
37 enum mxc6255_axis {
38 AXIS_X,
39 AXIS_Y,
40 };
41
42 struct mxc6255_data {
43 struct i2c_client *client;
44 struct regmap *regmap;
45 };
46
mxc6255_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)47 static int mxc6255_read_raw(struct iio_dev *indio_dev,
48 struct iio_chan_spec const *chan,
49 int *val, int *val2, long mask)
50 {
51 struct mxc6255_data *data = iio_priv(indio_dev);
52 unsigned int reg;
53 int ret;
54
55 switch (mask) {
56 case IIO_CHAN_INFO_RAW:
57 ret = regmap_read(data->regmap, chan->address, ®);
58 if (ret < 0) {
59 dev_err(&data->client->dev,
60 "Error reading reg %lu\n", chan->address);
61 return ret;
62 }
63
64 *val = sign_extend32(reg, 7);
65 return IIO_VAL_INT;
66 case IIO_CHAN_INFO_SCALE:
67 *val = 0;
68 *val2 = MXC6255_SCALE;
69 return IIO_VAL_INT_PLUS_MICRO;
70 default:
71 return -EINVAL;
72 }
73 }
74
75 static const struct iio_info mxc6255_info = {
76 .read_raw = mxc6255_read_raw,
77 };
78
79 #define MXC6255_CHANNEL(_axis, reg) { \
80 .type = IIO_ACCEL, \
81 .modified = 1, \
82 .channel2 = IIO_MOD_##_axis, \
83 .address = reg, \
84 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
85 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
86 }
87
88 static const struct iio_chan_spec mxc6255_channels[] = {
89 MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
90 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
91 };
92
mxc6255_is_readable_reg(struct device * dev,unsigned int reg)93 static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
94 {
95 switch (reg) {
96 case MXC6255_REG_XOUT:
97 case MXC6255_REG_YOUT:
98 case MXC6255_REG_CHIP_ID:
99 return true;
100 default:
101 return false;
102 }
103 }
104
105 static const struct regmap_config mxc6255_regmap_config = {
106 .name = "mxc6255_regmap",
107
108 .reg_bits = 8,
109 .val_bits = 8,
110
111 .readable_reg = mxc6255_is_readable_reg,
112 };
113
mxc6255_probe(struct i2c_client * client)114 static int mxc6255_probe(struct i2c_client *client)
115 {
116 struct mxc6255_data *data;
117 struct iio_dev *indio_dev;
118 struct regmap *regmap;
119 unsigned int chip_id;
120 int ret;
121
122 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
123 if (!indio_dev)
124 return -ENOMEM;
125
126 regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
127 if (IS_ERR(regmap)) {
128 dev_err(&client->dev, "Error initializing regmap\n");
129 return PTR_ERR(regmap);
130 }
131
132 data = iio_priv(indio_dev);
133 i2c_set_clientdata(client, indio_dev);
134 data->client = client;
135 data->regmap = regmap;
136
137 indio_dev->name = MXC6255_DRV_NAME;
138 indio_dev->channels = mxc6255_channels;
139 indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
140 indio_dev->modes = INDIO_DIRECT_MODE;
141 indio_dev->info = &mxc6255_info;
142
143 ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
144 if (ret < 0) {
145 dev_err(&client->dev, "Error reading chip id %d\n", ret);
146 return ret;
147 }
148
149 if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
150 dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
151 return -ENODEV;
152 }
153
154 dev_dbg(&client->dev, "Chip id %x\n", chip_id);
155
156 ret = devm_iio_device_register(&client->dev, indio_dev);
157 if (ret < 0) {
158 dev_err(&client->dev, "Could not register IIO device\n");
159 return ret;
160 }
161
162 return 0;
163 }
164
165 static const struct acpi_device_id mxc6255_acpi_match[] = {
166 {"MXC6225", 0},
167 {"MXC6255", 0},
168 { }
169 };
170 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
171
172 static const struct i2c_device_id mxc6255_id[] = {
173 { .name = "mxc6225" },
174 { .name = "mxc6255" },
175 { }
176 };
177 MODULE_DEVICE_TABLE(i2c, mxc6255_id);
178
179 static struct i2c_driver mxc6255_driver = {
180 .driver = {
181 .name = MXC6255_DRV_NAME,
182 .acpi_match_table = mxc6255_acpi_match,
183 },
184 .probe = mxc6255_probe,
185 .id_table = mxc6255_id,
186 };
187
188 module_i2c_driver(mxc6255_driver);
189
190 MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
191 MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
192 MODULE_LICENSE("GPL v2");
193