linux/drivers/iio/proximity/cros_ec_mkbp_proximity.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Driver for cros-ec proximity sensor exposed through MKBP switch
   4 *
   5 * Copyright 2021 Google LLC.
   6 */
   7
   8#include <linux/kernel.h>
   9#include <linux/module.h>
  10#include <linux/mutex.h>
  11#include <linux/notifier.h>
  12#include <linux/of.h>
  13#include <linux/platform_device.h>
  14#include <linux/slab.h>
  15#include <linux/types.h>
  16
  17#include <linux/platform_data/cros_ec_commands.h>
  18#include <linux/platform_data/cros_ec_proto.h>
  19
  20#include <linux/iio/events.h>
  21#include <linux/iio/iio.h>
  22#include <linux/iio/sysfs.h>
  23
  24#include <asm/unaligned.h>
  25
  26struct cros_ec_mkbp_proximity_data {
  27        struct cros_ec_device *ec;
  28        struct iio_dev *indio_dev;
  29        struct mutex lock;
  30        struct notifier_block notifier;
  31        int last_proximity;
  32        bool enabled;
  33};
  34
  35static const struct iio_event_spec cros_ec_mkbp_proximity_events[] = {
  36        {
  37                .type = IIO_EV_TYPE_THRESH,
  38                .dir = IIO_EV_DIR_EITHER,
  39                .mask_separate = BIT(IIO_EV_INFO_ENABLE),
  40        },
  41};
  42
  43static const struct iio_chan_spec cros_ec_mkbp_proximity_chan_spec[] = {
  44        {
  45                .type = IIO_PROXIMITY,
  46                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  47                .event_spec = cros_ec_mkbp_proximity_events,
  48                .num_event_specs = ARRAY_SIZE(cros_ec_mkbp_proximity_events),
  49        },
  50};
  51
  52static int cros_ec_mkbp_proximity_parse_state(const void *data)
  53{
  54        u32 switches = get_unaligned_le32(data);
  55
  56        return !!(switches & BIT(EC_MKBP_FRONT_PROXIMITY));
  57}
  58
  59static int cros_ec_mkbp_proximity_query(struct cros_ec_device *ec_dev,
  60                                        int *state)
  61{
  62        struct {
  63                struct cros_ec_command msg;
  64                union {
  65                        struct ec_params_mkbp_info params;
  66                        u32 switches;
  67                };
  68        } __packed buf = { };
  69        struct ec_params_mkbp_info *params = &buf.params;
  70        struct cros_ec_command *msg = &buf.msg;
  71        u32 *switches = &buf.switches;
  72        size_t insize = sizeof(*switches);
  73        int ret;
  74
  75        msg->command = EC_CMD_MKBP_INFO;
  76        msg->version = 1;
  77        msg->outsize = sizeof(*params);
  78        msg->insize = insize;
  79
  80        params->info_type = EC_MKBP_INFO_CURRENT;
  81        params->event_type = EC_MKBP_EVENT_SWITCH;
  82
  83        ret = cros_ec_cmd_xfer_status(ec_dev, msg);
  84        if (ret < 0)
  85                return ret;
  86
  87        if (ret != insize) {
  88                dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n", ret,
  89                         insize);
  90                return -EPROTO;
  91        }
  92
  93        *state = cros_ec_mkbp_proximity_parse_state(switches);
  94        return IIO_VAL_INT;
  95}
  96
  97static void cros_ec_mkbp_proximity_push_event(struct cros_ec_mkbp_proximity_data *data, int state)
  98{
  99        s64 timestamp;
 100        u64 ev;
 101        int dir;
 102        struct iio_dev *indio_dev = data->indio_dev;
 103        struct cros_ec_device *ec = data->ec;
 104
 105        mutex_lock(&data->lock);
 106        if (state != data->last_proximity) {
 107                if (data->enabled) {
 108                        timestamp = ktime_to_ns(ec->last_event_time);
 109                        if (iio_device_get_clock(indio_dev) != CLOCK_BOOTTIME)
 110                                timestamp = iio_get_time_ns(indio_dev);
 111
 112                        dir = state ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
 113                        ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
 114                                                  IIO_EV_TYPE_THRESH, dir);
 115                        iio_push_event(indio_dev, ev, timestamp);
 116                }
 117                data->last_proximity = state;
 118        }
 119        mutex_unlock(&data->lock);
 120}
 121
 122static int cros_ec_mkbp_proximity_notify(struct notifier_block *nb,
 123                                         unsigned long queued_during_suspend,
 124                                         void *_ec)
 125{
 126        struct cros_ec_mkbp_proximity_data *data;
 127        struct cros_ec_device *ec = _ec;
 128        u8 event_type = ec->event_data.event_type & EC_MKBP_EVENT_TYPE_MASK;
 129        void *switches;
 130        int state;
 131
 132        if (event_type == EC_MKBP_EVENT_SWITCH) {
 133                data = container_of(nb, struct cros_ec_mkbp_proximity_data,
 134                                    notifier);
 135
 136                switches = &ec->event_data.data.switches;
 137                state = cros_ec_mkbp_proximity_parse_state(switches);
 138                cros_ec_mkbp_proximity_push_event(data, state);
 139        }
 140
 141        return NOTIFY_OK;
 142}
 143
 144static int cros_ec_mkbp_proximity_read_raw(struct iio_dev *indio_dev,
 145                           const struct iio_chan_spec *chan, int *val,
 146                           int *val2, long mask)
 147{
 148        struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
 149        struct cros_ec_device *ec = data->ec;
 150
 151        if (chan->type == IIO_PROXIMITY && mask == IIO_CHAN_INFO_RAW)
 152                return cros_ec_mkbp_proximity_query(ec, val);
 153
 154        return -EINVAL;
 155}
 156
 157static int cros_ec_mkbp_proximity_read_event_config(struct iio_dev *indio_dev,
 158                                    const struct iio_chan_spec *chan,
 159                                    enum iio_event_type type,
 160                                    enum iio_event_direction dir)
 161{
 162        struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
 163
 164        return data->enabled;
 165}
 166
 167static int cros_ec_mkbp_proximity_write_event_config(struct iio_dev *indio_dev,
 168                                     const struct iio_chan_spec *chan,
 169                                     enum iio_event_type type,
 170                                     enum iio_event_direction dir, int state)
 171{
 172        struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
 173
 174        mutex_lock(&data->lock);
 175        data->enabled = state;
 176        mutex_unlock(&data->lock);
 177
 178        return 0;
 179}
 180
 181static const struct iio_info cros_ec_mkbp_proximity_info = {
 182        .read_raw = cros_ec_mkbp_proximity_read_raw,
 183        .read_event_config = cros_ec_mkbp_proximity_read_event_config,
 184        .write_event_config = cros_ec_mkbp_proximity_write_event_config,
 185};
 186
 187static __maybe_unused int cros_ec_mkbp_proximity_resume(struct device *dev)
 188{
 189        struct cros_ec_mkbp_proximity_data *data = dev_get_drvdata(dev);
 190        struct cros_ec_device *ec = data->ec;
 191        int ret, state;
 192
 193        ret = cros_ec_mkbp_proximity_query(ec, &state);
 194        if (ret < 0) {
 195                dev_warn(dev, "failed to fetch proximity state on resume: %d\n",
 196                         ret);
 197        } else {
 198                cros_ec_mkbp_proximity_push_event(data, state);
 199        }
 200
 201        return 0;
 202}
 203
 204static SIMPLE_DEV_PM_OPS(cros_ec_mkbp_proximity_pm_ops, NULL,
 205                         cros_ec_mkbp_proximity_resume);
 206
 207static int cros_ec_mkbp_proximity_probe(struct platform_device *pdev)
 208{
 209        struct device *dev = &pdev->dev;
 210        struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
 211        struct iio_dev *indio_dev;
 212        struct cros_ec_mkbp_proximity_data *data;
 213        int ret;
 214
 215        indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 216        if (!indio_dev)
 217                return -ENOMEM;
 218
 219        data = iio_priv(indio_dev);
 220        data->ec = ec;
 221        data->indio_dev = indio_dev;
 222        data->last_proximity = -1; /* Unknown to start */
 223        mutex_init(&data->lock);
 224        platform_set_drvdata(pdev, data);
 225
 226        indio_dev->name = dev->driver->name;
 227        indio_dev->info = &cros_ec_mkbp_proximity_info;
 228        indio_dev->modes = INDIO_DIRECT_MODE;
 229        indio_dev->channels = cros_ec_mkbp_proximity_chan_spec;
 230        indio_dev->num_channels = ARRAY_SIZE(cros_ec_mkbp_proximity_chan_spec);
 231
 232        ret = devm_iio_device_register(dev, indio_dev);
 233        if (ret)
 234                return ret;
 235
 236        data->notifier.notifier_call = cros_ec_mkbp_proximity_notify;
 237        blocking_notifier_chain_register(&ec->event_notifier, &data->notifier);
 238
 239        return 0;
 240}
 241
 242static int cros_ec_mkbp_proximity_remove(struct platform_device *pdev)
 243{
 244        struct cros_ec_mkbp_proximity_data *data = platform_get_drvdata(pdev);
 245        struct cros_ec_device *ec = data->ec;
 246
 247        blocking_notifier_chain_unregister(&ec->event_notifier,
 248                                           &data->notifier);
 249
 250        return 0;
 251}
 252
 253static const struct of_device_id cros_ec_mkbp_proximity_of_match[] = {
 254        { .compatible = "google,cros-ec-mkbp-proximity" },
 255        {}
 256};
 257MODULE_DEVICE_TABLE(of, cros_ec_mkbp_proximity_of_match);
 258
 259static struct platform_driver cros_ec_mkbp_proximity_driver = {
 260        .driver = {
 261                .name = "cros-ec-mkbp-proximity",
 262                .of_match_table = cros_ec_mkbp_proximity_of_match,
 263                .pm = &cros_ec_mkbp_proximity_pm_ops,
 264        },
 265        .probe = cros_ec_mkbp_proximity_probe,
 266        .remove = cros_ec_mkbp_proximity_remove,
 267};
 268module_platform_driver(cros_ec_mkbp_proximity_driver);
 269
 270MODULE_LICENSE("GPL v2");
 271MODULE_DESCRIPTION("ChromeOS EC MKBP proximity sensor driver");
 272