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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dmard09.c (3573B)

      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
     30struct 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
     43static 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
     49static 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
     87static const struct iio_info dmard09_info = {
     88	.read_raw	= dmard09_read_raw,
     89};
     90
     91static int dmard09_probe(struct i2c_client *client,
     92			const struct i2c_device_id *id)
     93{
     94	int ret;
     95	struct iio_dev *indio_dev;
     96	struct dmard09_data *data;
     97
     98	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
     99	if (!indio_dev) {
    100		dev_err(&client->dev, "iio allocation failed\n");
    101		return -ENOMEM;
    102	}
    103
    104	data = iio_priv(indio_dev);
    105	data->client = client;
    106
    107	ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
    108	if (ret < 0) {
    109		dev_err(&client->dev, "Error reading chip id %d\n", ret);
    110		return ret;
    111	}
    112
    113	if (ret != DMARD09_CHIPID) {
    114		dev_err(&client->dev, "Invalid chip id %d\n", ret);
    115		return -ENODEV;
    116	}
    117
    118	i2c_set_clientdata(client, indio_dev);
    119	indio_dev->name = DMARD09_DRV_NAME;
    120	indio_dev->modes = INDIO_DIRECT_MODE;
    121	indio_dev->channels = dmard09_channels;
    122	indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
    123	indio_dev->info = &dmard09_info;
    124
    125	return devm_iio_device_register(&client->dev, indio_dev);
    126}
    127
    128static const struct i2c_device_id dmard09_id[] = {
    129	{ "dmard09", 0 },
    130	{ },
    131};
    132
    133MODULE_DEVICE_TABLE(i2c, dmard09_id);
    134
    135static struct i2c_driver dmard09_driver = {
    136	.driver = {
    137		.name = DMARD09_DRV_NAME
    138	},
    139	.probe = dmard09_probe,
    140	.id_table = dmard09_id,
    141};
    142
    143module_i2c_driver(dmard09_driver);
    144
    145MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
    146MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
    147MODULE_LICENSE("GPL");