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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ams-iaq-core.c (4334B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * ams-iaq-core.c - Support for AMS iAQ-Core VOC sensors
      4 *
      5 * Copyright (C) 2015, 2018
      6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
      7 */
      8
      9#include <linux/module.h>
     10#include <linux/mod_devicetable.h>
     11#include <linux/mutex.h>
     12#include <linux/init.h>
     13#include <linux/i2c.h>
     14#include <linux/iio/iio.h>
     15
     16#define AMS_IAQCORE_DATA_SIZE		9
     17
     18#define AMS_IAQCORE_VOC_CO2_IDX		0
     19#define AMS_IAQCORE_VOC_RESISTANCE_IDX	1
     20#define AMS_IAQCORE_VOC_TVOC_IDX	2
     21
     22struct ams_iaqcore_reading {
     23	__be16 co2_ppm;
     24	u8 status;
     25	__be32 resistance;
     26	__be16 voc_ppb;
     27} __attribute__((__packed__));
     28
     29struct ams_iaqcore_data {
     30	struct i2c_client *client;
     31	struct mutex lock;
     32	unsigned long last_update;
     33
     34	struct ams_iaqcore_reading buffer;
     35};
     36
     37static const struct iio_chan_spec ams_iaqcore_channels[] = {
     38	{
     39		.type = IIO_CONCENTRATION,
     40		.channel2 = IIO_MOD_CO2,
     41		.modified = 1,
     42		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
     43		.address = AMS_IAQCORE_VOC_CO2_IDX,
     44	},
     45	{
     46		.type = IIO_RESISTANCE,
     47		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
     48		.address = AMS_IAQCORE_VOC_RESISTANCE_IDX,
     49	},
     50	{
     51		.type = IIO_CONCENTRATION,
     52		.channel2 = IIO_MOD_VOC,
     53		.modified = 1,
     54		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
     55		.address = AMS_IAQCORE_VOC_TVOC_IDX,
     56	},
     57};
     58
     59static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data)
     60{
     61	struct i2c_client *client = data->client;
     62	int ret;
     63
     64	struct i2c_msg msg = {
     65		.addr = client->addr,
     66		.flags = client->flags | I2C_M_RD,
     67		.len = AMS_IAQCORE_DATA_SIZE,
     68		.buf = (char *) &data->buffer,
     69	};
     70
     71	ret = i2c_transfer(client->adapter, &msg, 1);
     72
     73	return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret;
     74}
     75
     76static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data)
     77{
     78	int ret;
     79
     80	/* sensor can only be polled once a second max per datasheet */
     81	if (!time_after(jiffies, data->last_update + HZ))
     82		return 0;
     83
     84	ret = ams_iaqcore_read_measurement(data);
     85	if (ret < 0)
     86		return ret;
     87
     88	data->last_update = jiffies;
     89
     90	return 0;
     91}
     92
     93static int ams_iaqcore_read_raw(struct iio_dev *indio_dev,
     94				struct iio_chan_spec const *chan, int *val,
     95				int *val2, long mask)
     96{
     97	struct ams_iaqcore_data *data = iio_priv(indio_dev);
     98	int ret;
     99
    100	if (mask != IIO_CHAN_INFO_PROCESSED)
    101		return -EINVAL;
    102
    103	mutex_lock(&data->lock);
    104	ret = ams_iaqcore_get_measurement(data);
    105
    106	if (ret)
    107		goto err_out;
    108
    109	switch (chan->address) {
    110	case AMS_IAQCORE_VOC_CO2_IDX:
    111		*val = 0;
    112		*val2 = be16_to_cpu(data->buffer.co2_ppm);
    113		ret = IIO_VAL_INT_PLUS_MICRO;
    114		break;
    115	case AMS_IAQCORE_VOC_RESISTANCE_IDX:
    116		*val = be32_to_cpu(data->buffer.resistance);
    117		ret = IIO_VAL_INT;
    118		break;
    119	case AMS_IAQCORE_VOC_TVOC_IDX:
    120		*val = 0;
    121		*val2 = be16_to_cpu(data->buffer.voc_ppb);
    122		ret = IIO_VAL_INT_PLUS_NANO;
    123		break;
    124	default:
    125		ret = -EINVAL;
    126	}
    127
    128err_out:
    129	mutex_unlock(&data->lock);
    130
    131	return ret;
    132}
    133
    134static const struct iio_info ams_iaqcore_info = {
    135	.read_raw	= ams_iaqcore_read_raw,
    136};
    137
    138static int ams_iaqcore_probe(struct i2c_client *client,
    139			     const struct i2c_device_id *id)
    140{
    141	struct iio_dev *indio_dev;
    142	struct ams_iaqcore_data *data;
    143
    144	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
    145	if (!indio_dev)
    146		return -ENOMEM;
    147
    148	data = iio_priv(indio_dev);
    149	i2c_set_clientdata(client, indio_dev);
    150	data->client = client;
    151
    152	/* so initial reading will complete */
    153	data->last_update = jiffies - HZ;
    154	mutex_init(&data->lock);
    155
    156	indio_dev->info = &ams_iaqcore_info;
    157	indio_dev->name = dev_name(&client->dev);
    158	indio_dev->modes = INDIO_DIRECT_MODE;
    159
    160	indio_dev->channels = ams_iaqcore_channels;
    161	indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels);
    162
    163	return devm_iio_device_register(&client->dev, indio_dev);
    164}
    165
    166static const struct i2c_device_id ams_iaqcore_id[] = {
    167	{ "ams-iaq-core", 0 },
    168	{ }
    169};
    170MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id);
    171
    172static const struct of_device_id ams_iaqcore_dt_ids[] = {
    173	{ .compatible = "ams,iaq-core" },
    174	{ }
    175};
    176MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids);
    177
    178static struct i2c_driver ams_iaqcore_driver = {
    179	.driver = {
    180		.name	= "ams-iaq-core",
    181		.of_match_table = ams_iaqcore_dt_ids,
    182	},
    183	.probe = ams_iaqcore_probe,
    184	.id_table = ams_iaqcore_id,
    185};
    186module_i2c_driver(ams_iaqcore_driver);
    187
    188MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
    189MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors");
    190MODULE_LICENSE("GPL v2");