drivers/iio/proximity/cros_ec_mkbp_proximity.c

   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
  26 struct 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
  35 static 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
  43 static 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
  52 static 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
  59 static 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
  97 static 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
 122 static 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
 144 static 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
 157 static 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
 167 static 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
 181 static 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
 187 static __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
 204 static SIMPLE_DEV_PM_OPS(cros_ec_mkbp_proximity_pm_ops, NULL,
 205                          cros_ec_mkbp_proximity_resume);
 206
 207 static 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
 242 static 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
 253 static const struct of_device_id cros_ec_mkbp_proximity_of_match[] = {
 254         { .compatible = "google,cros-ec-mkbp-proximity" },
 255         {}
 256 };
 257 MODULE_DEVICE_TABLE(of, cros_ec_mkbp_proximity_of_match);
 258
 259 static 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 };
 268 module_platform_driver(cros_ec_mkbp_proximity_driver);
 269
 270 MODULE_LICENSE("GPL v2");
 271 MODULE_DESCRIPTION("ChromeOS EC MKBP proximity sensor driver");