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/acpi.h>
16 #include <linux/regmap.h>
17 #include <linux/iio/sysfs.h>
18
19 #define MXC6255_DRV_NAME "mxc6255"
20 #define MXC6255_REGMAP_NAME "mxc6255_regmap"
21
22 #define MXC6255_REG_XOUT 0x00
23 #define MXC6255_REG_YOUT 0x01
24 #define MXC6255_REG_CHIP_ID 0x08
25
26 #define MXC6255_CHIP_ID 0x05
27
28 /*
29 * MXC6255 has only one measurement range: +/- 2G.
30 * The acceleration output is an 8-bit value.
31 *
32 * Scale is calculated as follows:
33 * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
34 *
35 * Scale value for +/- 2G measurement range
36 */
37 #define MXC6255_SCALE 153829
38
39 enum mxc6255_axis {
40 AXIS_X,
41 AXIS_Y,
42 };
43
44 struct mxc6255_data {
45 struct i2c_client *client;
46 struct regmap *regmap;
47 };
48
mxc6255_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)49 static int mxc6255_read_raw(struct iio_dev *indio_dev,
50 struct iio_chan_spec const *chan,
51 int *val, int *val2, long mask)
52 {
53 struct mxc6255_data *data = iio_priv(indio_dev);
54 unsigned int reg;
55 int ret;
56
57 switch (mask) {
58 case IIO_CHAN_INFO_RAW:
59 ret = regmap_read(data->regmap, chan->address, ®);
60 if (ret < 0) {
61 dev_err(&data->client->dev,
62 "Error reading reg %lu\n", chan->address);
63 return ret;
64 }
65
66 *val = sign_extend32(reg, 7);
67 return IIO_VAL_INT;
68 case IIO_CHAN_INFO_SCALE:
69 *val = 0;
70 *val2 = MXC6255_SCALE;
71 return IIO_VAL_INT_PLUS_MICRO;
72 default:
73 return -EINVAL;
74 }
75 }
76
77 static const struct iio_info mxc6255_info = {
78 .read_raw = mxc6255_read_raw,
79 };
80
81 #define MXC6255_CHANNEL(_axis, reg) { \
82 .type = IIO_ACCEL, \
83 .modified = 1, \
84 .channel2 = IIO_MOD_##_axis, \
85 .address = reg, \
86 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
87 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
88 }
89
90 static const struct iio_chan_spec mxc6255_channels[] = {
91 MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
92 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
93 };
94
mxc6255_is_readable_reg(struct device * dev,unsigned int reg)95 static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
96 {
97 switch (reg) {
98 case MXC6255_REG_XOUT:
99 case MXC6255_REG_YOUT:
100 case MXC6255_REG_CHIP_ID:
101 return true;
102 default:
103 return false;
104 }
105 }
106
107 static const struct regmap_config mxc6255_regmap_config = {
108 .name = MXC6255_REGMAP_NAME,
109
110 .reg_bits = 8,
111 .val_bits = 8,
112
113 .readable_reg = mxc6255_is_readable_reg,
114 };
115
mxc6255_probe(struct i2c_client * client)116 static int mxc6255_probe(struct i2c_client *client)
117 {
118 struct mxc6255_data *data;
119 struct iio_dev *indio_dev;
120 struct regmap *regmap;
121 unsigned int chip_id;
122 int ret;
123
124 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
125 if (!indio_dev)
126 return -ENOMEM;
127
128 regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
129 if (IS_ERR(regmap)) {
130 dev_err(&client->dev, "Error initializing regmap\n");
131 return PTR_ERR(regmap);
132 }
133
134 data = iio_priv(indio_dev);
135 i2c_set_clientdata(client, indio_dev);
136 data->client = client;
137 data->regmap = regmap;
138
139 indio_dev->name = MXC6255_DRV_NAME;
140 indio_dev->channels = mxc6255_channels;
141 indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
142 indio_dev->modes = INDIO_DIRECT_MODE;
143 indio_dev->info = &mxc6255_info;
144
145 ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
146 if (ret < 0) {
147 dev_err(&client->dev, "Error reading chip id %d\n", ret);
148 return ret;
149 }
150
151 if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
152 dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
153 return -ENODEV;
154 }
155
156 dev_dbg(&client->dev, "Chip id %x\n", chip_id);
157
158 ret = devm_iio_device_register(&client->dev, indio_dev);
159 if (ret < 0) {
160 dev_err(&client->dev, "Could not register IIO device\n");
161 return ret;
162 }
163
164 return 0;
165 }
166
167 static const struct acpi_device_id mxc6255_acpi_match[] = {
168 {"MXC6225", 0},
169 {"MXC6255", 0},
170 { }
171 };
172 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
173
174 static const struct i2c_device_id mxc6255_id[] = {
175 {"mxc6225", 0},
176 {"mxc6255", 0},
177 { }
178 };
179 MODULE_DEVICE_TABLE(i2c, mxc6255_id);
180
181 static struct i2c_driver mxc6255_driver = {
182 .driver = {
183 .name = MXC6255_DRV_NAME,
184 .acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
185 },
186 .probe = mxc6255_probe,
187 .id_table = mxc6255_id,
188 };
189
190 module_i2c_driver(mxc6255_driver);
191
192 MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
193 MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
194 MODULE_LICENSE("GPL v2");
195
