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Teodora Baluta75b6548f2015-10-22 15:44:50 +03001/*
2 * MXC6255 - MEMSIC orientation sensing accelerometer
3 *
4 * Copyright (c) 2015, Intel Corporation.
5 *
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
9 *
10 * IIO driver for MXC6255 (7-bit I2C slave address 0x15).
11 */
12
13#include <linux/module.h>
14#include <linux/i2c.h>
15#include <linux/init.h>
16#include <linux/iio/iio.h>
17#include <linux/delay.h>
18#include <linux/acpi.h>
19#include <linux/regmap.h>
20#include <linux/iio/sysfs.h>
21
22#define MXC6255_DRV_NAME "mxc6255"
23#define MXC6255_REGMAP_NAME "mxc6255_regmap"
24
25#define MXC6255_REG_XOUT 0x00
26#define MXC6255_REG_YOUT 0x01
27#define MXC6255_REG_CHIP_ID 0x08
28
29#define MXC6255_CHIP_ID 0x05
30
31/*
32 * MXC6255 has only one measurement range: +/- 2G.
33 * The acceleration output is an 8-bit value.
34 *
35 * Scale is calculated as follows:
36 * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
37 *
38 * Scale value for +/- 2G measurement range
39 */
40#define MXC6255_SCALE 153829
41
42enum mxc6255_axis {
43 AXIS_X,
44 AXIS_Y,
45};
46
47struct mxc6255_data {
48 struct i2c_client *client;
49 struct regmap *regmap;
50};
51
52static int mxc6255_read_raw(struct iio_dev *indio_dev,
53 struct iio_chan_spec const *chan,
54 int *val, int *val2, long mask)
55{
56 struct mxc6255_data *data = iio_priv(indio_dev);
57 unsigned int reg;
58 int ret;
59
60 switch (mask) {
61 case IIO_CHAN_INFO_RAW:
62 ret = regmap_read(data->regmap, chan->address, &reg);
63 if (ret < 0) {
64 dev_err(&data->client->dev,
65 "Error reading reg %lu\n", chan->address);
66 return ret;
67 }
68
69 *val = sign_extend32(reg, 7);
70 return IIO_VAL_INT;
71 case IIO_CHAN_INFO_SCALE:
72 *val = 0;
73 *val2 = MXC6255_SCALE;
74 return IIO_VAL_INT_PLUS_MICRO;
75 default:
76 return -EINVAL;
77 }
78}
79
80static const struct iio_info mxc6255_info = {
81 .driver_module = THIS_MODULE,
82 .read_raw = mxc6255_read_raw,
83};
84
85#define MXC6255_CHANNEL(_axis, reg) { \
86 .type = IIO_ACCEL, \
87 .modified = 1, \
88 .channel2 = IIO_MOD_##_axis, \
89 .address = reg, \
90 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
91 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
92}
93
94static const struct iio_chan_spec mxc6255_channels[] = {
95 MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
96 MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
97};
98
99static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
100{
101 switch (reg) {
102 case MXC6255_REG_XOUT:
103 case MXC6255_REG_YOUT:
104 case MXC6255_REG_CHIP_ID:
105 return true;
106 default:
107 return false;
108 }
109}
110
111static const struct regmap_config mxc6255_regmap_config = {
112 .name = MXC6255_REGMAP_NAME,
113
114 .reg_bits = 8,
115 .val_bits = 8,
116
117 .readable_reg = mxc6255_is_readable_reg,
118};
119
120static int mxc6255_probe(struct i2c_client *client,
121 const struct i2c_device_id *id)
122{
123 struct mxc6255_data *data;
124 struct iio_dev *indio_dev;
125 struct regmap *regmap;
126 unsigned int chip_id;
127 int ret;
128
129 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
130 if (!indio_dev)
131 return -ENOMEM;
132
133 regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
134 if (IS_ERR(regmap)) {
135 dev_err(&client->dev, "Error initializing regmap\n");
136 return PTR_ERR(regmap);
137 }
138
139 data = iio_priv(indio_dev);
140 i2c_set_clientdata(client, indio_dev);
141 data->client = client;
142 data->regmap = regmap;
143
144 indio_dev->name = MXC6255_DRV_NAME;
145 indio_dev->dev.parent = &client->dev;
146 indio_dev->channels = mxc6255_channels;
147 indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
148 indio_dev->modes = INDIO_DIRECT_MODE;
149 indio_dev->info = &mxc6255_info;
150
151 ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
152 if (ret < 0) {
153 dev_err(&client->dev, "Error reading chip id %d\n", ret);
154 return ret;
155 }
156
Hans de Goede16965662016-09-11 18:29:16 +0200157 if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
Teodora Baluta75b6548f2015-10-22 15:44:50 +0300158 dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
159 return -ENODEV;
160 }
161
162 dev_dbg(&client->dev, "Chip id %x\n", chip_id);
163
164 ret = devm_iio_device_register(&client->dev, indio_dev);
165 if (ret < 0) {
166 dev_err(&client->dev, "Could not register IIO device\n");
167 return ret;
168 }
169
170 return 0;
171}
172
173static const struct acpi_device_id mxc6255_acpi_match[] = {
Hans de Goede06777c52016-09-04 19:35:32 +0200174 {"MXC6225", 0},
Teodora Baluta75b6548f2015-10-22 15:44:50 +0300175 {"MXC6255", 0},
176 { }
177};
178MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
179
180static const struct i2c_device_id mxc6255_id[] = {
Hans de Goede06777c52016-09-04 19:35:32 +0200181 {"mxc6225", 0},
Teodora Baluta75b6548f2015-10-22 15:44:50 +0300182 {"mxc6255", 0},
183 { }
184};
185MODULE_DEVICE_TABLE(i2c, mxc6255_id);
186
187static struct i2c_driver mxc6255_driver = {
188 .driver = {
189 .name = MXC6255_DRV_NAME,
190 .acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
191 },
192 .probe = mxc6255_probe,
193 .id_table = mxc6255_id,
194};
195
196module_i2c_driver(mxc6255_driver);
197
198MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
199MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
200MODULE_LICENSE("GPL v2");