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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iqs624-pos.c (7178B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * Azoteq IQS624/625 Angular Position Sensors
      4 *
      5 * Copyright (C) 2019 Jeff LaBundy <jeff@labundy.com>
      6 */
      7
      8#include <linux/device.h>
      9#include <linux/iio/events.h>
     10#include <linux/iio/iio.h>
     11#include <linux/kernel.h>
     12#include <linux/mfd/iqs62x.h>
     13#include <linux/module.h>
     14#include <linux/mutex.h>
     15#include <linux/notifier.h>
     16#include <linux/platform_device.h>
     17#include <linux/regmap.h>
     18
     19#define IQS624_POS_DEG_OUT			0x16
     20
     21#define IQS624_POS_SCALE1			(314159 / 180)
     22#define IQS624_POS_SCALE2			100000
     23
     24struct iqs624_pos_private {
     25	struct iqs62x_core *iqs62x;
     26	struct iio_dev *indio_dev;
     27	struct notifier_block notifier;
     28	struct mutex lock;
     29	bool angle_en;
     30	u16 angle;
     31};
     32
     33static int iqs624_pos_angle_en(struct iqs62x_core *iqs62x, bool angle_en)
     34{
     35	unsigned int event_mask = IQS624_HALL_UI_WHL_EVENT;
     36
     37	/*
     38	 * The IQS625 reports angular position in the form of coarse intervals,
     39	 * so only interval change events are unmasked. Conversely, the IQS624
     40	 * reports angular position down to one degree of resolution, so wheel
     41	 * movement events are unmasked instead.
     42	 */
     43	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
     44		event_mask = IQS624_HALL_UI_INT_EVENT;
     45
     46	return regmap_update_bits(iqs62x->regmap, IQS624_HALL_UI, event_mask,
     47				  angle_en ? 0 : 0xFF);
     48}
     49
     50static int iqs624_pos_notifier(struct notifier_block *notifier,
     51			       unsigned long event_flags, void *context)
     52{
     53	struct iqs62x_event_data *event_data = context;
     54	struct iqs624_pos_private *iqs624_pos;
     55	struct iqs62x_core *iqs62x;
     56	struct iio_dev *indio_dev;
     57	u16 angle = event_data->ui_data;
     58	s64 timestamp;
     59	int ret;
     60
     61	iqs624_pos = container_of(notifier, struct iqs624_pos_private,
     62				  notifier);
     63	indio_dev = iqs624_pos->indio_dev;
     64	timestamp = iio_get_time_ns(indio_dev);
     65
     66	iqs62x = iqs624_pos->iqs62x;
     67	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
     68		angle = event_data->interval;
     69
     70	mutex_lock(&iqs624_pos->lock);
     71
     72	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
     73		ret = iqs624_pos_angle_en(iqs62x, iqs624_pos->angle_en);
     74		if (ret) {
     75			dev_err(indio_dev->dev.parent,
     76				"Failed to re-initialize device: %d\n", ret);
     77			ret = NOTIFY_BAD;
     78		} else {
     79			ret = NOTIFY_OK;
     80		}
     81	} else if (iqs624_pos->angle_en && (angle != iqs624_pos->angle)) {
     82		iio_push_event(indio_dev,
     83			       IIO_UNMOD_EVENT_CODE(IIO_ANGL, 0,
     84						    IIO_EV_TYPE_CHANGE,
     85						    IIO_EV_DIR_NONE),
     86			       timestamp);
     87
     88		iqs624_pos->angle = angle;
     89		ret = NOTIFY_OK;
     90	} else {
     91		ret = NOTIFY_DONE;
     92	}
     93
     94	mutex_unlock(&iqs624_pos->lock);
     95
     96	return ret;
     97}
     98
     99static void iqs624_pos_notifier_unregister(void *context)
    100{
    101	struct iqs624_pos_private *iqs624_pos = context;
    102	struct iio_dev *indio_dev = iqs624_pos->indio_dev;
    103	int ret;
    104
    105	ret = blocking_notifier_chain_unregister(&iqs624_pos->iqs62x->nh,
    106						 &iqs624_pos->notifier);
    107	if (ret)
    108		dev_err(indio_dev->dev.parent,
    109			"Failed to unregister notifier: %d\n", ret);
    110}
    111
    112static int iqs624_pos_angle_get(struct iqs62x_core *iqs62x, unsigned int *val)
    113{
    114	int ret;
    115	__le16 val_buf;
    116
    117	if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM)
    118		return regmap_read(iqs62x->regmap, iqs62x->dev_desc->interval,
    119				   val);
    120
    121	ret = regmap_raw_read(iqs62x->regmap, IQS624_POS_DEG_OUT, &val_buf,
    122			      sizeof(val_buf));
    123	if (ret)
    124		return ret;
    125
    126	*val = le16_to_cpu(val_buf);
    127
    128	return 0;
    129}
    130
    131static int iqs624_pos_read_raw(struct iio_dev *indio_dev,
    132			       struct iio_chan_spec const *chan,
    133			       int *val, int *val2, long mask)
    134{
    135	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
    136	struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
    137	unsigned int scale = 1;
    138	int ret;
    139
    140	switch (mask) {
    141	case IIO_CHAN_INFO_RAW:
    142		ret = iqs624_pos_angle_get(iqs62x, val);
    143		if (ret)
    144			return ret;
    145
    146		return IIO_VAL_INT;
    147
    148	case IIO_CHAN_INFO_SCALE:
    149		if (iqs62x->dev_desc->prod_num == IQS625_PROD_NUM) {
    150			ret = regmap_read(iqs62x->regmap, IQS624_INTERVAL_DIV,
    151					  &scale);
    152			if (ret)
    153				return ret;
    154		}
    155
    156		*val = scale * IQS624_POS_SCALE1;
    157		*val2 = IQS624_POS_SCALE2;
    158		return IIO_VAL_FRACTIONAL;
    159
    160	default:
    161		return -EINVAL;
    162	}
    163}
    164
    165static int iqs624_pos_read_event_config(struct iio_dev *indio_dev,
    166					const struct iio_chan_spec *chan,
    167					enum iio_event_type type,
    168					enum iio_event_direction dir)
    169{
    170	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
    171	int ret;
    172
    173	mutex_lock(&iqs624_pos->lock);
    174	ret = iqs624_pos->angle_en;
    175	mutex_unlock(&iqs624_pos->lock);
    176
    177	return ret;
    178}
    179
    180static int iqs624_pos_write_event_config(struct iio_dev *indio_dev,
    181					 const struct iio_chan_spec *chan,
    182					 enum iio_event_type type,
    183					 enum iio_event_direction dir,
    184					 int state)
    185{
    186	struct iqs624_pos_private *iqs624_pos = iio_priv(indio_dev);
    187	struct iqs62x_core *iqs62x = iqs624_pos->iqs62x;
    188	unsigned int val;
    189	int ret;
    190
    191	mutex_lock(&iqs624_pos->lock);
    192
    193	ret = iqs624_pos_angle_get(iqs62x, &val);
    194	if (ret)
    195		goto err_mutex;
    196
    197	ret = iqs624_pos_angle_en(iqs62x, state);
    198	if (ret)
    199		goto err_mutex;
    200
    201	iqs624_pos->angle = val;
    202	iqs624_pos->angle_en = state;
    203
    204err_mutex:
    205	mutex_unlock(&iqs624_pos->lock);
    206
    207	return ret;
    208}
    209
    210static const struct iio_info iqs624_pos_info = {
    211	.read_raw = &iqs624_pos_read_raw,
    212	.read_event_config = iqs624_pos_read_event_config,
    213	.write_event_config = iqs624_pos_write_event_config,
    214};
    215
    216static const struct iio_event_spec iqs624_pos_events[] = {
    217	{
    218		.type = IIO_EV_TYPE_CHANGE,
    219		.dir = IIO_EV_DIR_NONE,
    220		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
    221	},
    222};
    223
    224static const struct iio_chan_spec iqs624_pos_channels[] = {
    225	{
    226		.type = IIO_ANGL,
    227		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
    228				      BIT(IIO_CHAN_INFO_SCALE),
    229		.event_spec = iqs624_pos_events,
    230		.num_event_specs = ARRAY_SIZE(iqs624_pos_events),
    231	},
    232};
    233
    234static int iqs624_pos_probe(struct platform_device *pdev)
    235{
    236	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
    237	struct iqs624_pos_private *iqs624_pos;
    238	struct iio_dev *indio_dev;
    239	int ret;
    240
    241	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs624_pos));
    242	if (!indio_dev)
    243		return -ENOMEM;
    244
    245	iqs624_pos = iio_priv(indio_dev);
    246	iqs624_pos->iqs62x = iqs62x;
    247	iqs624_pos->indio_dev = indio_dev;
    248
    249	indio_dev->modes = INDIO_DIRECT_MODE;
    250	indio_dev->channels = iqs624_pos_channels;
    251	indio_dev->num_channels = ARRAY_SIZE(iqs624_pos_channels);
    252	indio_dev->name = iqs62x->dev_desc->dev_name;
    253	indio_dev->info = &iqs624_pos_info;
    254
    255	mutex_init(&iqs624_pos->lock);
    256
    257	iqs624_pos->notifier.notifier_call = iqs624_pos_notifier;
    258	ret = blocking_notifier_chain_register(&iqs624_pos->iqs62x->nh,
    259					       &iqs624_pos->notifier);
    260	if (ret) {
    261		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
    262		return ret;
    263	}
    264
    265	ret = devm_add_action_or_reset(&pdev->dev,
    266				       iqs624_pos_notifier_unregister,
    267				       iqs624_pos);
    268	if (ret)
    269		return ret;
    270
    271	return devm_iio_device_register(&pdev->dev, indio_dev);
    272}
    273
    274static struct platform_driver iqs624_pos_platform_driver = {
    275	.driver = {
    276		.name = "iqs624-pos",
    277	},
    278	.probe = iqs624_pos_probe,
    279};
    280module_platform_driver(iqs624_pos_platform_driver);
    281
    282MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
    283MODULE_DESCRIPTION("Azoteq IQS624/625 Angular Position Sensors");
    284MODULE_LICENSE("GPL");
    285MODULE_ALIAS("platform:iqs624-pos");