cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mxc6255.c (4474B)

      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
     39enum mxc6255_axis {
     40	AXIS_X,
     41	AXIS_Y,
     42};
     43
     44struct mxc6255_data {
     45	struct i2c_client *client;
     46	struct regmap *regmap;
     47};
     48
     49static 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, &reg);
     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
     77static 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
     90static const struct iio_chan_spec mxc6255_channels[] = {
     91	MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
     92	MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
     93};
     94
     95static 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
    107static 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
    116static int mxc6255_probe(struct i2c_client *client,
    117			 const struct i2c_device_id *id)
    118{
    119	struct mxc6255_data *data;
    120	struct iio_dev *indio_dev;
    121	struct regmap *regmap;
    122	unsigned int chip_id;
    123	int ret;
    124
    125	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
    126	if (!indio_dev)
    127		return -ENOMEM;
    128
    129	regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
    130	if (IS_ERR(regmap)) {
    131		dev_err(&client->dev, "Error initializing regmap\n");
    132		return PTR_ERR(regmap);
    133	}
    134
    135	data = iio_priv(indio_dev);
    136	i2c_set_clientdata(client, indio_dev);
    137	data->client = client;
    138	data->regmap = regmap;
    139
    140	indio_dev->name = MXC6255_DRV_NAME;
    141	indio_dev->channels = mxc6255_channels;
    142	indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
    143	indio_dev->modes = INDIO_DIRECT_MODE;
    144	indio_dev->info = &mxc6255_info;
    145
    146	ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
    147	if (ret < 0) {
    148		dev_err(&client->dev, "Error reading chip id %d\n", ret);
    149		return ret;
    150	}
    151
    152	if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
    153		dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
    154		return -ENODEV;
    155	}
    156
    157	dev_dbg(&client->dev, "Chip id %x\n", chip_id);
    158
    159	ret = devm_iio_device_register(&client->dev, indio_dev);
    160	if (ret < 0) {
    161		dev_err(&client->dev, "Could not register IIO device\n");
    162		return ret;
    163	}
    164
    165	return 0;
    166}
    167
    168static const struct acpi_device_id mxc6255_acpi_match[] = {
    169	{"MXC6225",	0},
    170	{"MXC6255",	0},
    171	{ }
    172};
    173MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
    174
    175static const struct i2c_device_id mxc6255_id[] = {
    176	{"mxc6225",	0},
    177	{"mxc6255",	0},
    178	{ }
    179};
    180MODULE_DEVICE_TABLE(i2c, mxc6255_id);
    181
    182static struct i2c_driver mxc6255_driver = {
    183	.driver = {
    184		.name = MXC6255_DRV_NAME,
    185		.acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
    186	},
    187	.probe		= mxc6255_probe,
    188	.id_table	= mxc6255_id,
    189};
    190
    191module_i2c_driver(mxc6255_driver);
    192
    193MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
    194MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
    195MODULE_LICENSE("GPL v2");