[PATCH v7 02/12] platform: chrome: sensorhub: Add FIFO support

From: Gwendal Grignou
Date: Fri Mar 27 2020 - 18:35:28 EST

cros_ec_sensorhub registers a listener and query motion sense FIFO,
spread to iio sensors registers.

To test, we can use libiio:
iiod&
iio_readdev -u ip:localhost -T 10000 -s 25 -b 16 cros-ec-gyro | od -x

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
---
Changes in v7:
- Use the number of sensors present to create the right number of
callback slots and to collect the right amount of FIFO information
when sensor events are lost.
- Report the number of lost events for sensors that lost all their
events.
Changes in v6:
- Unify function naming in cros_ec_sensorhub: cros_ec_sensorhub_ring_...
- Kernel module name is now cros-ec-sensorhub
- Remove unneceassary warning messages.

Changes in v5:
- Use a goto in cros_ec_sensorhub_ring_handler to centralize error
handling
- Use devm_add_action_or_reset to not need a .remove entry point for
cros_sensor_hub.
- Fix logic error in cros_ec_sensorhub_register_push_data.
- Update kernel_doc documentation.
- Remve the need for comments in variable declaration section.
Changes in v4:
- Keep defining cros_ec_sensorhub in kernel-doc format
- Fix logic error when checking if sensor index outside array.
- Check patch with --strict option
Use sizeof(*obj) instead of sizeof(struct ...obj)
Alignement
Use uX instead of uintX_t
Use !ptr instead of ptr != NULL
Changes in v3:
- Do not use ret !=
- Simplfy errpr handling by removing a goto
- Fix doxygen comments
- Replace suspend/resume entry points with regular driver entry point;
There was an issue in the past where the sensor stack was preventing
device to suspend, but the proper fix has been implemented in cros_ec
code (6ad16b78a039b "platform/chrome: don't report
EC_MKBP_EVENT_SENSOR_FIFO as wakeup")
- Reduce mutex scope by checking return code outside of it.
Changes in v2:
- Do not register a .remove routinge in plaform_driver. A
devm_action_add is added later patch IIO driver register their
callback.
- Remove double lines, add lines before return calls.
- Handle FLUSH flag from EC.

- Use ktime_t for most timestamp measurements.
- Add doxygen comments
- Cleanup timestamp collection when processing FIFO.
- Rename fifo_toggle to fifo_enable


drivers/platform/chrome/Makefile | 4 +-
drivers/platform/chrome/cros_ec_sensorhub.c | 107 +++--
.../platform/chrome/cros_ec_sensorhub_ring.c | 439 ++++++++++++++++++
.../linux/platform_data/cros_ec_sensorhub.h | 76 +++
4 files changed, 598 insertions(+), 28 deletions(-)
create mode 100644 drivers/platform/chrome/cros_ec_sensorhub_ring.c

diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 198c155c7c4d4..1223b028cefa0 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -20,7 +20,9 @@ obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_chardev.o
obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o
obj-$(CONFIG_CROS_EC_VBC) += cros_ec_vbc.o
obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o
-obj-$(CONFIG_CROS_EC_SENSORHUB) += cros_ec_sensorhub.o
+obj-$(CONFIG_CROS_EC_SENSORHUB) += cros-ec-sensorhub.o
+cros-ec-sensorhub-objs := cros_ec_sensorhub.o
+cros-ec-sensorhub-objs += cros_ec_sensorhub_ring.o
obj-$(CONFIG_CROS_EC_SYSFS) += cros_ec_sysfs.o
obj-$(CONFIG_CROS_USBPD_LOGGER) += cros_usbpd_logger.o
obj-$(CONFIG_CROS_USBPD_NOTIFY) += cros_usbpd_notify.o
diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
index 134ee5e460472..b7f2c00db5e1e 100644
--- a/drivers/platform/chrome/cros_ec_sensorhub.c
+++ b/drivers/platform/chrome/cros_ec_sensorhub.c
@@ -50,10 +50,8 @@ static int cros_ec_sensorhub_register(struct device *dev,
struct cros_ec_sensorhub *sensorhub)
{
int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
+ struct cros_ec_command *msg = sensorhub->msg;
struct cros_ec_dev *ec = sensorhub->ec;
- struct ec_params_motion_sense *params;
- struct ec_response_motion_sense *resp;
- struct cros_ec_command *msg;
int ret, i, sensor_num;
char *name;

@@ -71,22 +69,13 @@ static int cros_ec_sensorhub_register(struct device *dev,
return -EINVAL;
}

- /* Prepare a message to send INFO command to each sensor. */
- msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
- GFP_KERNEL);
- if (!msg)
- return -ENOMEM;
-
msg->version = 1;
- msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
- msg->outsize = sizeof(*params);
- msg->insize = sizeof(*resp);
- params = (struct ec_params_motion_sense *)msg->data;
- resp = (struct ec_response_motion_sense *)msg->data;
+ msg->insize = sizeof(struct ec_response_motion_sense);
+ msg->outsize = sizeof(struct ec_params_motion_sense);

for (i = 0; i < sensor_num; i++) {
- params->cmd = MOTIONSENSE_CMD_INFO;
- params->info.sensor_num = i;
+ sensorhub->params->cmd = MOTIONSENSE_CMD_INFO;
+ sensorhub->params->info.sensor_num = i;

ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
if (ret < 0) {
@@ -95,7 +84,7 @@ static int cros_ec_sensorhub_register(struct device *dev,
continue;
}

- switch (resp->info.type) {
+ switch (sensorhub->resp->info.type) {
case MOTIONSENSE_TYPE_ACCEL:
name = "cros-ec-accel";
break;
@@ -118,15 +107,16 @@ static int cros_ec_sensorhub_register(struct device *dev,
name = "cros-ec-activity";
break;
default:
- dev_warn(dev, "unknown type %d\n", resp->info.type);
+ dev_warn(dev, "unknown type %d\n",
+ sensorhub->resp->info.type);
continue;
}

ret = cros_ec_sensorhub_allocate_sensor(dev, name, i);
if (ret)
- goto error;
+ return ret;

- sensor_type[resp->info.type]++;
+ sensor_type[sensorhub->resp->info.type]++;
}

if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
@@ -138,29 +128,41 @@ static int cros_ec_sensorhub_register(struct device *dev,
"cros-ec-lid-angle",
0);
if (ret)
- goto error;
+ return ret;
}

- kfree(msg);
return 0;
-
-error:
- kfree(msg);
- return ret;
}

static int cros_ec_sensorhub_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
+ struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
struct cros_ec_sensorhub *data;
+ struct cros_ec_command *msg;
int ret;
int i;

+ msg = devm_kzalloc(dev, sizeof(struct cros_ec_command) +
+ max((u16)sizeof(struct ec_params_motion_sense),
+ ec->ec_dev->max_response), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
+
data = devm_kzalloc(dev, sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
if (!data)
return -ENOMEM;

- data->ec = dev_get_drvdata(dev->parent);
+ mutex_init(&data->cmd_lock);
+
+ data->dev = dev;
+ data->ec = ec;
+ data->msg = msg;
+ data->params = (struct ec_params_motion_sense *)msg->data;
+ data->resp = (struct ec_response_motion_sense *)msg->data;
+
dev_set_drvdata(dev, data);

/* Check whether this EC is a sensor hub. */
@@ -182,12 +184,63 @@ static int cros_ec_sensorhub_probe(struct platform_device *pdev)
}
}

+ /*
+ * If the EC does not have a FIFO, the sensors will query their data
+ * themselves via sysfs or a software trigger.
+ */
+ if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
+ ret = cros_ec_sensorhub_ring_add(data);
+ if (ret)
+ return ret;
+ /*
+ * The msg and its data is not under the control of the ring
+ * handler.
+ */
+ return devm_add_action_or_reset(dev,
+ cros_ec_sensorhub_ring_remove,
+ data);
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * When the EC is suspending, we must stop sending interrupt,
+ * we may use the same interrupt line for waking up the device.
+ * Tell the EC to stop sending non-interrupt event on the iio ring.
+ */
+static int cros_ec_sensorhub_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
+ struct cros_ec_dev *ec = sensorhub->ec;
+
+ if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
+ return cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
return 0;
}

+static int cros_ec_sensorhub_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
+ struct cros_ec_dev *ec = sensorhub->ec;
+
+ if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
+ return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(cros_ec_sensorhub_pm_ops,
+ cros_ec_sensorhub_suspend,
+ cros_ec_sensorhub_resume);
+
static struct platform_driver cros_ec_sensorhub_driver = {
.driver = {
.name = DRV_NAME,
+ .pm = &cros_ec_sensorhub_pm_ops,
},
.probe = cros_ec_sensorhub_probe,
};
diff --git a/drivers/platform/chrome/cros_ec_sensorhub_ring.c b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
new file mode 100644
index 0000000000000..da73757529ca5
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
@@ -0,0 +1,439 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Chrome OS EC Sensor hub FIFO.
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_data/cros_ec_sensorhub.h>
+#include <linux/platform_device.h>
+#include <linux/sort.h>
+#include <linux/slab.h>
+
+static inline int
+cros_sensorhub_send_sample(struct cros_ec_sensorhub *sensorhub,
+ struct cros_ec_sensors_ring_sample *sample)
+{
+ cros_ec_sensorhub_push_data_cb_t cb;
+ int id = sample->sensor_id;
+ struct iio_dev *indio_dev;
+
+ if (id > sensorhub->sensor_num)
+ return -EINVAL;
+
+ cb = sensorhub->push_data[id].push_data_cb;
+ if (!cb)
+ return 0;
+
+ indio_dev = sensorhub->push_data[id].indio_dev;
+
+ if (sample->flag & MOTIONSENSE_SENSOR_FLAG_FLUSH)
+ return 0;
+
+ return cb(indio_dev, sample->vector, sample->timestamp);
+}
+
+/**
+ * cros_ec_sensorhub_register_push_data() - register the callback to the hub.
+ *
+ * @sensorhub : Sensor Hub object
+ * @sensor_num : The sensor the caller is interested in.
+ * @indio_dev : The iio device to use when a sample arrives.
+ * @cb : The callback to call when a sample arrives.
+ *
+ * The callback cb will be used by cros_ec_sensorhub_ring to distribute events
+ * from the EC.
+ *
+ * Return: 0 when callback is registered.
+ * EINVAL is the sensor number is invalid or the slot already used.
+ */
+int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
+ u8 sensor_num,
+ struct iio_dev *indio_dev,
+ cros_ec_sensorhub_push_data_cb_t cb)
+{
+ if (sensor_num >= sensorhub->sensor_num)
+ return -EINVAL;
+ if (sensorhub->push_data[sensor_num].indio_dev)
+ return -EINVAL;
+
+ sensorhub->push_data[sensor_num].indio_dev = indio_dev;
+ sensorhub->push_data[sensor_num].push_data_cb = cb;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensorhub_register_push_data);
+
+void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
+ u8 sensor_num)
+{
+ sensorhub->push_data[sensor_num].indio_dev = NULL;
+ sensorhub->push_data[sensor_num].push_data_cb = NULL;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensorhub_unregister_push_data);
+
+/**
+ * cros_ec_sensorhub_ring_fifo_enable() - Enable or disable interrupt generation
+ * for FIFO events.
+ * @sensorhub: Sensor Hub object
+ * @on: true when events are requested.
+ *
+ * To be called before sleeping or when noone is listening.
+ * Return: 0 on success, or an error when we can not communicate with the EC.
+ *
+ */
+int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
+ bool on)
+{
+ int ret;
+
+ mutex_lock(&sensorhub->cmd_lock);
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INT_ENABLE;
+ sensorhub->params->fifo_int_enable.enable = on;
+
+ sensorhub->msg->outsize = sizeof(struct ec_params_motion_sense);
+ sensorhub->msg->insize = sizeof(struct ec_response_motion_sense);
+
+ ret = cros_ec_cmd_xfer_status(sensorhub->ec->ec_dev, sensorhub->msg);
+ mutex_unlock(&sensorhub->cmd_lock);
+
+ /* We expect to receive a payload of 4 bytes, ignore. */
+ if (ret > 0)
+ ret = 0;
+
+ return ret;
+}
+
+/**
+ * cros_ec_sensor_ring_process_event() - process one EC FIFO event
+ *
+ * @sensorhub: Sensor Hub object.
+ * @fifo_info: FIFO information from the EC (includes b point, EC timebase).
+ * @fifo_timestamp: EC IRQ, kernel timebase (aka c).
+ * @current_timestamp: calculated event timestamp, kernel timebase (aka a').
+ * @in: incoming FIFO event from EC (includes a point, EC timebase).
+ * @out: outgoing event to user space (includes a').
+ *
+ * Process one EC event, add it in the ring if necessary.
+ *
+ * Return: true if out event has been populated.
+ */
+static bool
+cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
+ const struct ec_response_motion_sense_fifo_info
+ *fifo_info,
+ const ktime_t fifo_timestamp,
+ ktime_t *current_timestamp,
+ struct ec_response_motion_sensor_data *in,
+ struct cros_ec_sensors_ring_sample *out)
+{
+ const s64 now = cros_ec_get_time_ns();
+ int axis, async_flags;
+
+ /* Do not populate the filter based on asynchronous events. */
+ async_flags = in->flags &
+ (MOTIONSENSE_SENSOR_FLAG_ODR | MOTIONSENSE_SENSOR_FLAG_FLUSH);
+
+ if (in->flags & MOTIONSENSE_SENSOR_FLAG_TIMESTAMP && !async_flags) {
+ s64 new_timestamp;
+
+ /*
+ * Disable filtering since we might add more jitter
+ * if b is in a random point in time.
+ */
+ new_timestamp = fifo_timestamp -
+ fifo_info->timestamp * 1000 +
+ in->timestamp * 1000;
+
+ /*
+ * The timestamp can be stale if we had to use the fifo
+ * info timestamp.
+ */
+ if (new_timestamp - *current_timestamp > 0)
+ *current_timestamp = new_timestamp;
+ }
+
+ if (in->flags & MOTIONSENSE_SENSOR_FLAG_FLUSH) {
+ out->sensor_id = in->sensor_num;
+ out->timestamp = *current_timestamp;
+ out->flag = in->flags;
+ /*
+ * No other payload information provided with
+ * flush ack.
+ */
+ return true;
+ }
+
+ if (in->flags & MOTIONSENSE_SENSOR_FLAG_TIMESTAMP)
+ /* If we just have a timestamp, skip this entry. */
+ return false;
+
+ /* Regular sample */
+ out->sensor_id = in->sensor_num;
+ if (*current_timestamp - now > 0)
+ /* If the timestamp is in the future. */
+ out->timestamp = now;
+ else
+ out->timestamp = *current_timestamp;
+
+ out->flag = in->flags;
+ for (axis = 0; axis < 3; axis++)
+ out->vector[axis] = in->data[axis];
+
+ return true;
+}
+
+/**
+ * cros_ec_sensorhub_ring_handler() - The trigger handler function
+ *
+ * @sensorhub: Sensor Hub object.
+ *
+ * Called by the notifier, process the EC sensor FIFO queue.
+ */
+static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
+{
+ struct ec_response_motion_sense_fifo_info *fifo_info =
+ sensorhub->fifo_info;
+ struct cros_ec_dev *ec = sensorhub->ec;
+ ktime_t fifo_timestamp, current_timestamp;
+ int i, j, number_data, ret;
+ struct ec_response_motion_sensor_data *in;
+ struct cros_ec_sensors_ring_sample *out, *last_out;
+
+ mutex_lock(&sensorhub->cmd_lock);
+
+ /* Get FIFO information if there are lost vectors. */
+ if (fifo_info->total_lost) {
+ int fifo_info_length =
+ sizeof(struct ec_response_motion_sense_fifo_info) +
+ sizeof(u16) * sensorhub->sensor_num;
+
+ /* Need to retrieve the number of lost vectors per sensor */
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
+ sensorhub->msg->outsize = 1;
+ sensorhub->msg->insize = fifo_info_length;
+
+ if (cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg) < 0)
+ goto error;
+
+ memcpy(fifo_info, &sensorhub->resp->fifo_info,
+ fifo_info_length);
+
+ /*
+ * Update collection time, will not be as precise as the
+ * non-error case.
+ */
+ fifo_timestamp = cros_ec_get_time_ns();
+ } else {
+ fifo_timestamp = sensorhub->fifo_timestamp[
+ CROS_EC_SENSOR_NEW_TS];
+ }
+
+ if (fifo_info->count > sensorhub->fifo_size ||
+ fifo_info->size != sensorhub->fifo_size) {
+ dev_warn(sensorhub->dev,
+ "Mismatch EC data: count %d, size %d - expected %d",
+ fifo_info->count, fifo_info->size,
+ sensorhub->fifo_size);
+ goto error;
+ }
+
+ /* Copy elements in the main fifo */
+ current_timestamp = sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS];
+ out = sensorhub->ring;
+ for (i = 0; i < fifo_info->count; i += number_data) {
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_READ;
+ sensorhub->params->fifo_read.max_data_vector =
+ fifo_info->count - i;
+ sensorhub->msg->outsize =
+ sizeof(struct ec_params_motion_sense);
+ sensorhub->msg->insize =
+ sizeof(sensorhub->resp->fifo_read) +
+ sensorhub->params->fifo_read.max_data_vector *
+ sizeof(struct ec_response_motion_sensor_data);
+ ret = cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg);
+ if (ret < 0) {
+ dev_warn(sensorhub->dev, "Fifo error: %d\n", ret);
+ break;
+ }
+ number_data = sensorhub->resp->fifo_read.number_data;
+ if (number_data == 0) {
+ dev_dbg(sensorhub->dev, "Unexpected empty FIFO\n");
+ break;
+ }
+ if (number_data > fifo_info->count - i) {
+ dev_warn(sensorhub->dev,
+ "Invalid EC data: too many entry received: %d, expected %d",
+ number_data, fifo_info->count - i);
+ break;
+ }
+ if (out + number_data >
+ sensorhub->ring + fifo_info->count) {
+ dev_warn(sensorhub->dev,
+ "Too many samples: %d (%zd data) to %d entries for expected %d entries",
+ i, out - sensorhub->ring, i + number_data,
+ fifo_info->count);
+ break;
+ }
+
+ for (in = sensorhub->resp->fifo_read.data, j = 0;
+ j < number_data; j++, in++) {
+ if (cros_ec_sensor_ring_process_event(
+ sensorhub, fifo_info,
+ fifo_timestamp,
+ &current_timestamp,
+ in, out))
+ out++;
+ }
+ }
+ mutex_unlock(&sensorhub->cmd_lock);
+ last_out = out;
+
+ if (out == sensorhub->ring)
+ /* Unexpected empty FIFO. */
+ goto ring_handler_end;
+
+ /*
+ * Check if current_timestamp is ahead of the last sample.
+ * Normally, the EC appends a timestamp after the last sample, but if
+ * the AP is slow to respond to the IRQ, the EC may have added new
+ * samples. Use the FIFO info timestamp as last timestamp then.
+ */
+ if ((last_out - 1)->timestamp == current_timestamp)
+ current_timestamp = fifo_timestamp;
+
+ /* Warn on lost samples. */
+ if (fifo_info->total_lost)
+ for (i = 0; i < sensorhub->sensor_num; i++) {
+ if (fifo_info->lost[i])
+ dev_warn_ratelimited(sensorhub->dev,
+ "Sensor %d: lost: %d out of %d\n",
+ i, fifo_info->lost[i],
+ fifo_info->total_lost);
+ }
+
+ /* Push the event into the FIFO. */
+ for (out = sensorhub->ring; out < last_out; out++)
+ cros_sensorhub_send_sample(sensorhub, out);
+
+ring_handler_end:
+ sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] = current_timestamp;
+ return;
+
+error:
+ mutex_unlock(&sensorhub->cmd_lock);
+}
+
+static int cros_ec_sensorhub_event(struct notifier_block *nb,
+ unsigned long queued_during_suspend,
+ void *_notify)
+{
+ struct cros_ec_sensorhub *sensorhub;
+ struct cros_ec_device *ec_dev;
+
+ sensorhub = container_of(nb, struct cros_ec_sensorhub, notifier);
+ ec_dev = sensorhub->ec->ec_dev;
+
+ if (ec_dev->event_data.event_type != EC_MKBP_EVENT_SENSOR_FIFO)
+ return NOTIFY_DONE;
+
+ if (ec_dev->event_size != sizeof(ec_dev->event_data.data.sensor_fifo)) {
+ dev_warn(ec_dev->dev, "Invalid fifo info size\n");
+ return NOTIFY_DONE;
+ }
+
+ if (queued_during_suspend)
+ return NOTIFY_OK;
+
+ memcpy(sensorhub->fifo_info, &ec_dev->event_data.data.sensor_fifo.info,
+ sizeof(*sensorhub->fifo_info));
+ sensorhub->fifo_timestamp[CROS_EC_SENSOR_NEW_TS] =
+ ec_dev->last_event_time;
+ cros_ec_sensorhub_ring_handler(sensorhub);
+
+ return NOTIFY_OK;
+}
+
+/**
+ * cros_ec_sensorhub_ring_add() - Add the FIFO functionality if the EC
+ * supports it.
+ *
+ * @sensorhub : Sensor Hub object.
+ *
+ * Return: 0 on success.
+ */
+int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub)
+{
+ struct cros_ec_dev *ec = sensorhub->ec;
+ int ret;
+ int fifo_info_length =
+ sizeof(struct ec_response_motion_sense_fifo_info) +
+ sizeof(u16) * sensorhub->sensor_num;
+
+ /* Allocate the array for lost events. */
+ sensorhub->fifo_info = devm_kzalloc(sensorhub->dev, fifo_info_length,
+ GFP_KERNEL);
+ if (!sensorhub->fifo_info)
+ return -ENOMEM;
+
+ /* Retrieve FIFO information */
+ sensorhub->msg->version = 2;
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
+ sensorhub->msg->outsize = 1;
+ sensorhub->msg->insize = fifo_info_length;
+
+ ret = cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Allocate the full fifo. We need to copy the whole FIFO to set
+ * timestamps properly.
+ */
+ sensorhub->fifo_size = sensorhub->resp->fifo_info.size;
+ sensorhub->ring = devm_kcalloc(sensorhub->dev, sensorhub->fifo_size,
+ sizeof(*sensorhub->ring), GFP_KERNEL);
+ if (!sensorhub->ring)
+ return -ENOMEM;
+
+ /*
+ * Allocate the callback area based on the number of sensors.
+ */
+ sensorhub->push_data = devm_kcalloc(
+ sensorhub->dev, sensorhub->sensor_num,
+ sizeof(*sensorhub->push_data),
+ GFP_KERNEL);
+ if (!sensorhub->push_data)
+ return -ENOMEM;
+
+ sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] =
+ cros_ec_get_time_ns();
+
+ /* Register the notifier that will act as a top half interrupt. */
+ sensorhub->notifier.notifier_call = cros_ec_sensorhub_event;
+ ret = blocking_notifier_chain_register(&ec->ec_dev->event_notifier,
+ &sensorhub->notifier);
+ if (ret < 0)
+ return ret;
+
+ /* Start collection samples. */
+ return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
+}
+
+void cros_ec_sensorhub_ring_remove(void *arg)
+{
+ struct cros_ec_sensorhub *sensorhub = arg;
+ struct cros_ec_device *ec_dev = sensorhub->ec->ec_dev;
+
+ /* Disable the ring, prevent EC interrupt to the AP for nothing. */
+ cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
+ blocking_notifier_chain_unregister(&ec_dev->event_notifier,
+ &sensorhub->notifier);
+}
diff --git a/include/linux/platform_data/cros_ec_sensorhub.h b/include/linux/platform_data/cros_ec_sensorhub.h
index 7e46a47fd642b..b0950814f820e 100644
--- a/include/linux/platform_data/cros_ec_sensorhub.h
+++ b/include/linux/platform_data/cros_ec_sensorhub.h
@@ -8,8 +8,13 @@
#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H

+#include <linux/ktime.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
#include <linux/platform_data/cros_ec_commands.h>

+struct iio_dev;
+
/**
* struct cros_ec_sensor_platform - ChromeOS EC sensor platform information.
* @sensor_num: Id of the sensor, as reported by the EC.
@@ -18,15 +23,86 @@ struct cros_ec_sensor_platform {
u8 sensor_num;
};

+/**
+ * typedef cros_ec_sensorhub_push_data_cb_t - Callback function to send datum
+ * to specific sensors.
+ *
+ * @indio_dev: The IIO device that will process the sample.
+ * @data: Vector array of the ring sample.
+ * @timestamp: Timestamp in host timespace when the sample was acquired by
+ * the EC.
+ */
+typedef int (*cros_ec_sensorhub_push_data_cb_t)(struct iio_dev *indio_dev,
+ s16 *data,
+ s64 timestamp);
+
+struct cros_ec_sensorhub_sensor_push_data {
+ struct iio_dev *indio_dev;
+ cros_ec_sensorhub_push_data_cb_t push_data_cb;
+};
+
+enum {
+ CROS_EC_SENSOR_LAST_TS,
+ CROS_EC_SENSOR_NEW_TS,
+ CROS_EC_SENSOR_ALL_TS
+};
+
+struct cros_ec_sensors_ring_sample {
+ u8 sensor_id;
+ u8 flag;
+ s16 vector[3];
+ s64 timestamp;
+} __packed;
+
/**
* struct cros_ec_sensorhub - Sensor Hub device data.
*
+ * @dev: Device object, mostly used for logging.
* @ec: Embedded Controller where the hub is located.
* @sensor_num: Number of MEMS sensors present in the EC.
+ * @msg: Structure to send FIFO requests.
+ * @params: Pointer to parameters in msg.
+ * @resp: Pointer to responses in msg.
+ * @cmd_lock : Lock for sending msg.
+ * @notifier: Notifier to kick the FIFO interrupt.
+ * @ring: Preprocessed ring to store events.
+ * @fifo_timestamp: array for event timestamp and spreading.
+ * @fifo_info: copy of FIFO information coming from the EC.
+ * @fifo_size: size of the ring.
+ * @push_data: array of callback to send datums to iio sensor object.
*/
struct cros_ec_sensorhub {
+ struct device *dev;
struct cros_ec_dev *ec;
int sensor_num;
+
+ struct cros_ec_command *msg;
+ struct ec_params_motion_sense *params;
+ struct ec_response_motion_sense *resp;
+ struct mutex cmd_lock; /* Lock for protecting msg structure. */
+
+ struct notifier_block notifier;
+
+ struct cros_ec_sensors_ring_sample *ring;
+
+ ktime_t fifo_timestamp[CROS_EC_SENSOR_ALL_TS];
+ struct ec_response_motion_sense_fifo_info *fifo_info;
+ int fifo_size;
+
+ struct cros_ec_sensorhub_sensor_push_data *push_data;
};

+int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
+ u8 sensor_num,
+ struct iio_dev *indio_dev,
+ cros_ec_sensorhub_push_data_cb_t cb);
+
+void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
+ u8 sensor_num);
+
+int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub);
+void cros_ec_sensorhub_ring_remove(void *arg);
+int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
+ bool on);
+
#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
--
2.26.0.rc2.310.g2932bb562d-goog