--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * cros_ec_activity - Driver for activities/gesture recognition.
+ *
+ * Copyright 2025 Google, Inc
+ *
+ * This driver uses the cros-ec interface to communicate with the ChromeOS
+ * EC about activity data.
+ */
+
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+
+#include <linux/iio/common/cros_ec_sensors_core.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define DRV_NAME "cros-ec-activity"
+
+/* state data for ec_sensors iio driver. */
+struct cros_ec_sensors_state {
+ /* Shared by all sensors */
+ struct cros_ec_sensors_core_state core;
+
+ struct iio_chan_spec *channels;
+
+ int body_detection_channel_index;
+ int sig_motion_channel_index;
+};
+
+static const struct iio_event_spec cros_ec_activity_single_shot[] = {
+ {
+ .type = IIO_EV_TYPE_CHANGE,
+ /* significant motion trigger when we get out of still. */
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
+static const struct iio_event_spec cros_ec_body_detect_events[] = {
+ {
+ .type = IIO_EV_TYPE_CHANGE,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
+static int cros_ec_activity_sensors_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (chan->type != IIO_PROXIMITY || mask != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ guard(mutex)(&st->core.cmd_lock);
+ st->core.param.cmd = MOTIONSENSE_CMD_GET_ACTIVITY;
+ st->core.param.get_activity.activity =
+ MOTIONSENSE_ACTIVITY_BODY_DETECTION;
+ ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * EC actually report if a body is near (1) or far (0).
+ * Units for proximity sensor after scale is in meter,
+ * so invert the result to return 0m when near and 1m when far.
+ */
+ *val = !st->core.resp->get_activity.state;
+ return IIO_VAL_INT;
+}
+
+static int cros_ec_activity_read_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir)
+{
+ struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (chan->type != IIO_ACTIVITY && chan->type != IIO_PROXIMITY)
+ return -EINVAL;
+
+ guard(mutex)(&st->core.cmd_lock);
+ st->core.param.cmd = MOTIONSENSE_CMD_LIST_ACTIVITIES;
+ ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+ if (ret)
+ return ret;
+
+ switch (chan->type) {
+ case IIO_PROXIMITY:
+ return !!(st->core.resp->list_activities.enabled &
+ (1 << MOTIONSENSE_ACTIVITY_BODY_DETECTION));
+ case IIO_ACTIVITY:
+ if (chan->channel2 == IIO_MOD_STILL) {
+ return !!(st->core.resp->list_activities.enabled &
+ (1 << MOTIONSENSE_ACTIVITY_SIG_MOTION));
+ }
+
+ dev_warn(&indio_dev->dev, "Unknown activity: %d\n",
+ chan->channel2);
+ return -EINVAL;
+ default:
+ dev_warn(&indio_dev->dev, "Unknown channel type: %d\n",
+ chan->type);
+ return -EINVAL;
+ }
+}
+
+static int cros_ec_activity_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ bool state)
+{
+ struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+
+ guard(mutex)(&st->core.cmd_lock);
+ st->core.param.cmd = MOTIONSENSE_CMD_SET_ACTIVITY;
+ switch (chan->type) {
+ case IIO_PROXIMITY:
+ st->core.param.set_activity.activity =
+ MOTIONSENSE_ACTIVITY_BODY_DETECTION;
+ break;
+ case IIO_ACTIVITY:
+ if (chan->channel2 == IIO_MOD_STILL) {
+ st->core.param.set_activity.activity =
+ MOTIONSENSE_ACTIVITY_SIG_MOTION;
+ break;
+ }
+ dev_warn(&indio_dev->dev, "Unknown activity: %d\n",
+ chan->channel2);
+ return -EINVAL;
+ default:
+ dev_warn(&indio_dev->dev, "Unknown channel type: %d\n",
+ chan->type);
+ return -EINVAL;
+ }
+ st->core.param.set_activity.enable = state;
+ return cros_ec_motion_send_host_cmd(&st->core, 0);
+}
+
+static int cros_ec_activity_push_data(struct iio_dev *indio_dev,
+ s16 *data, s64 timestamp)
+{
+ struct ec_response_activity_data *activity_data =
+ (struct ec_response_activity_data *)data;
+ enum motionsensor_activity activity = activity_data->activity;
+ u8 state = activity_data->state;
+ const struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+ const struct iio_chan_spec *chan;
+ enum iio_event_direction dir;
+ int index;
+
+ switch (activity) {
+ case MOTIONSENSE_ACTIVITY_BODY_DETECTION:
+ index = st->body_detection_channel_index;
+ dir = state ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
+ break;
+ case MOTIONSENSE_ACTIVITY_SIG_MOTION:
+ index = st->sig_motion_channel_index;
+ dir = IIO_EV_DIR_FALLING;
+ break;
+ default:
+ dev_warn(&indio_dev->dev, "Unknown activity: %d\n", activity);
+ return 0;
+ }
+ chan = &st->channels[index];
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(chan->type, index, chan->event_spec[0].type, dir),
+ timestamp);
+ return 0;
+}
+
+static irqreturn_t cros_ec_activity_capture(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+
+ /*
+ * This callback would be called when a software trigger is
+ * used. But when this virtual sensor is present, it is guaranteed
+ * the sensor hub is advanced enough to not need a software trigger.
+ */
+ dev_warn(&indio_dev->dev, "%s: Not Expected\n", __func__);
+ return IRQ_NONE;
+}
+
+static const struct iio_info ec_sensors_info = {
+ .read_raw = &cros_ec_activity_sensors_read_raw,
+ .read_event_config = cros_ec_activity_read_event_config,
+ .write_event_config = cros_ec_activity_write_event_config,
+};
+
+static int cros_ec_sensors_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cros_ec_device *ec_device = dev_get_drvdata(dev->parent);
+ struct iio_dev *indio_dev;
+ struct cros_ec_sensors_state *st;
+ struct iio_chan_spec *channel;
+ unsigned long activities;
+ int i, index, ret, nb_activities;
+
+ if (!ec_device) {
+ dev_warn(dev, "No CROS EC device found.\n");
+ return -EINVAL;
+ }
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
+ cros_ec_activity_capture);
+ if (ret)
+ return ret;
+
+ indio_dev->info = &ec_sensors_info;
+ st = iio_priv(indio_dev);
+ st->core.type = st->core.resp->info.type;
+ st->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
+
+ st->core.param.cmd = MOTIONSENSE_CMD_LIST_ACTIVITIES;
+ ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+ if (ret)
+ return ret;
+
+ activities = st->core.resp->list_activities.enabled |
+ st->core.resp->list_activities.disabled;
+ if (!activities)
+ return -ENODEV;
+
+ /* Allocate a channel per activity and one for timestamp */
+ nb_activities = hweight_long(activities) + 1;
+ st->channels = devm_kcalloc(dev, nb_activities,
+ sizeof(*st->channels), GFP_KERNEL);
+ if (!st->channels)
+ return -ENOMEM;
+
+ channel = &st->channels[0];
+ index = 0;
+ for_each_set_bit(i, &activities, BITS_PER_LONG) {
+ /* List all available triggers */
+ if (i == MOTIONSENSE_ACTIVITY_BODY_DETECTION) {
+ channel->type = IIO_PROXIMITY;
+ channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+ channel->event_spec = cros_ec_body_detect_events;
+ channel->num_event_specs =
+ ARRAY_SIZE(cros_ec_body_detect_events);
+ st->body_detection_channel_index = index;
+ } else {
+ channel->type = IIO_ACTIVITY;
+ channel->modified = 1;
+ channel->event_spec = cros_ec_activity_single_shot;
+ channel->num_event_specs =
+ ARRAY_SIZE(cros_ec_activity_single_shot);
+ if (i == MOTIONSENSE_ACTIVITY_SIG_MOTION) {
+ channel->channel2 = IIO_MOD_STILL;
+ st->sig_motion_channel_index = index;
+ } else {
+ dev_warn(dev, "Unknown activity: %d\n", i);
+ continue;
+ }
+ }
+ channel->ext_info = cros_ec_sensors_limited_info;
+ channel->scan_index = index++;
+ channel++;
+ }
+
+ /* Timestamp */
+ channel->scan_index = index;
+ channel->type = IIO_TIMESTAMP;
+ channel->channel = -1;
+ channel->scan_type.sign = 's';
+ channel->scan_type.realbits = 64;
+ channel->scan_type.storagebits = 64;
+
+ indio_dev->channels = st->channels;
+ indio_dev->num_channels = index + 1;
+
+ return cros_ec_sensors_core_register(dev, indio_dev,
+ cros_ec_activity_push_data);
+}
+
+static struct platform_driver cros_ec_sensors_platform_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ },
+ .probe = cros_ec_sensors_probe,
+};
+module_platform_driver(cros_ec_sensors_platform_driver);
+
+MODULE_DESCRIPTION("ChromeOS EC activity sensors driver");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_LICENSE("GPL v2");
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