[PATCH v2 10/18] platform: chrome: sensorhub: Add FIFO support

From: Gwendal Grignou
Date: Mon Oct 21 2019 - 01:55:04 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

Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
---
Changes sunce 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 | 3 +-
drivers/platform/chrome/cros_ec_sensorhub.c | 123 ++++--
.../platform/chrome/cros_ec_sensorhub_ring.c | 412 ++++++++++++++++++
.../linux/platform_data/cros_ec_sensorhub.h | 77 ++++
4 files changed, 583 insertions(+), 32 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 a164c40dc0996..cb709048c003e 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -17,7 +17,8 @@ obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_chardev.o
obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o
-obj-$(CONFIG_CROS_EC_SENSORHUB) += cros_ec_sensorhub.o
+cros_ec_sensorsupport-objs := cros_ec_sensorhub_ring.o cros_ec_sensorhub.o
+obj-$(CONFIG_CROS_EC_SENSORHUB) += cros_ec_sensorsupport.o
obj-$(CONFIG_CROS_EC_VBC) += cros_ec_vbc.o
obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o
obj-$(CONFIG_CROS_EC_SYSFS) += cros_ec_sysfs.o
diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
index 5fea4c28c5c95..87308dadc32c5 100644
--- a/drivers/platform/chrome/cros_ec_sensorhub.c
+++ b/drivers/platform/chrome/cros_ec_sensorhub.c
@@ -24,7 +24,6 @@

#define DRV_NAME "cros-ec-sensorhub"

-
static struct device_type cros_ec_sensorhub_dev_type = {
.name = "cros_ec_iio_sensor",
};
@@ -64,14 +63,13 @@ static int cros_ec_sensorhub_allocate_single_sensor(
}

static int cros_ec_sensorhub_register(struct device *dev,
- struct cros_ec_dev *ec)
+ struct cros_ec_sensorhub *sensorhub)
{
int ret, i, id, sensor_num;
int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
- struct ec_params_motion_sense *params;
- struct ec_response_motion_sense *resp;
- struct cros_ec_command *msg;
char *name;
+ struct cros_ec_command *msg = sensorhub->msg;
+ struct cros_ec_dev *ec = sensorhub->ec;

sensor_num = cros_ec_get_sensor_count(ec);
if (sensor_num < 0) {
@@ -86,32 +84,21 @@ static int cros_ec_sensorhub_register(struct device *dev,
return -EINVAL;
}

- /* Prepare a message to send INFO command to each sensor. */
- msg = kzalloc(sizeof(struct cros_ec_command) +
- max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
- if (!msg) {
- ret = -ENOMEM;
- goto error;
- }
-
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);

id = 0;
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) {
dev_warn(dev, "no info for EC sensor %d : %d/%d\n",
i, ret, msg->result);
continue;
}
- switch (resp->info.type) {
+ switch (sensorhub->resp->info.type) {
case MOTIONSENSE_TYPE_ACCEL:
name = "cros-ec-accel";
break;
@@ -134,14 +121,15 @@ 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_single_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)
@@ -152,9 +140,6 @@ static int cros_ec_sensorhub_register(struct device *dev,
ret = cros_ec_sensorhub_allocate_single_sensor(
dev, "cros-ec-lid-angle", 0);
}
-
-error:
- kfree(msg);
return ret;
}

@@ -163,34 +148,110 @@ 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);
int ret;
- struct cros_ec_sensorhub *data =
- kzalloc(sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
+ struct cros_ec_sensorhub *data;
+ struct cros_ec_command *msg;

+ 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->dev = dev;
data->ec = ec;
+
+ mutex_init(&data->cmd_lock);
+ 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. */
if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE)) {
- ret = cros_ec_sensorhub_register(dev, ec);
+ ret = cros_ec_sensorhub_register(dev, data);
} else {
ret = cros_ec_sensorhub_allocate_single_sensor(
dev, "cros-ec-accel-legacy", 0);
ret |= cros_ec_sensorhub_allocate_single_sensor(
dev, "cros-ec-accel-legacy", 1);
}
- if (ret)
+ if (ret) {
dev_err(dev, "failed to add EC sensors: error %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * 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);
+ /*
+ * The msg and its data is not under the control of the ring
+ * handler.
+ */
+ }
return ret;
}

+static int cros_ec_sensorhub_remove(struct platform_device *pdev)
+{
+ 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))
+ cros_ec_sensorhub_ring_remove(sensorhub);
+ return 0;
+}
+
+/*
+ * 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 __maybe_unused cros_ec_ring_prepare(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 void __maybe_unused cros_ec_ring_complete(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))
+ cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
+}
+
+#if CONFIG_PM_SLEEP
+static const struct dev_pm_ops cros_ec_sensorhub_ring_pm_ops = {
+ .prepare = cros_ec_ring_prepare,
+ .complete = cros_ec_ring_complete
+};
+#else
+static const struct dev_pm_ops cros_ec_sensorhub_ring_pm_ops = { };
+#endif
+
static struct platform_driver cros_ec_sensorhub_driver = {
.driver = {
.name = DRV_NAME,
+ .pm = &cros_ec_sensorhub_ring_pm_ops,
},
.probe = cros_ec_sensorhub_probe,
+ .remove = cros_ec_sensorhub_remove,
};

module_platform_driver(cros_ec_sensorhub_driver);
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..caf4b02d5e345
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * cros_ec_sensorhub_ring - Driver for Chrome OS EC Sensor hub FIFO.
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/cros_ec.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)
+{
+ int id = sample->sensor_id;
+ cros_ec_sensorhub_push_data_cb_t cb;
+ struct iio_dev *indio_dev;
+
+ if (id > CROS_EC_SENSOR_MAX)
+ 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);
+}
+
+/**
+ * Function to register the callback to the sensor hub.
+ * The callback cb will be used by cros_ec_sensorhub_ring to distribute events
+ * from the EC.
+ * @sensor_hub : 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.
+ */
+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 > CROS_EC_SENSOR_MAX)
+ return -EINVAL;
+ if (sensorhub->push_data[sensor_num].indio_dev != NULL)
+ 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);
+
+/**
+ * Enable or disable interrupt generation for FIFO events.
+ * To be called before sleeping or when noone is listening.
+ * @sensor_hub : Sensor Hub object
+ * @on : true when events are requested.
+ */
+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);
+ /* We expect to receive a payload of 4 bytes, ignore. */
+ if (ret > 0)
+ ret = 0;
+ mutex_unlock(&sensorhub->cmd_lock);
+
+ return ret;
+}
+
+/**
+ * cros_ec_ring_process_event: process one EC FIFO event
+ *
+ * Process one EC event, add it in the ring if necessary.
+ *
+ * @sensorhub: Sensorhub 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')
+ *
+ * Return true if out event has been populated.
+ */
+static bool cros_ec_ring_process_event(
+ struct cros_ec_sensorhub *sensorhub,
+ const struct cros_ec_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)
+{
+ int axis;
+ /* Do not populate the filter based on asynchronous events. */
+ const int async_flags = in->flags &
+ (MOTIONSENSE_SENSOR_FLAG_ODR | MOTIONSENSE_SENSOR_FLAG_FLUSH);
+ const s64 now = cros_ec_get_time_ns();
+
+ if (in->flags & MOTIONSENSE_SENSOR_FLAG_TIMESTAMP && !async_flags) {
+ s64 a = in->timestamp;
+ s64 b = fifo_info->info.timestamp;
+ s64 c = fifo_timestamp;
+ s64 new_timestamp;
+
+ /*
+ * disable filtering since we might add more jitter
+ * if b is in a random point in time
+ */
+ new_timestamp = c - b * 1000 + a * 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: device information.
+ *
+ * Called by the notifier, process the EC sensor FIFO queue.
+ */
+static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
+{
+ struct cros_ec_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;
+ unsigned long sensor_mask = 0;
+ 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->info.total_lost) {
+ /* Need to retrieve the number of lost vectors per sensor */
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
+ sensorhub->msg->outsize = 1;
+ sensorhub->msg->insize =
+ sizeof(struct ec_response_motion_sense_fifo_info) +
+ sizeof(u16) * CROS_EC_SENSOR_MAX;
+
+ if (cros_ec_cmd_xfer_status(ec->ec_dev, sensorhub->msg) < 0) {
+ mutex_unlock(&sensorhub->cmd_lock);
+ return;
+ }
+ memcpy(fifo_info, &sensorhub->resp->fifo_info,
+ sizeof(*fifo_info));
+
+ /*
+ * 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->info.count > sensorhub->fifo_size ||
+ fifo_info->info.size != sensorhub->fifo_size) {
+ dev_warn(sensorhub->dev,
+ "Mismatch EC data: count %d, size %d - expected %d",
+ fifo_info->info.count, fifo_info->info.size,
+ sensorhub->fifo_size);
+ mutex_unlock(&sensorhub->cmd_lock);
+ return;
+ }
+
+
+ /* 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->info.count; i += number_data) {
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_READ;
+ sensorhub->params->fifo_read.max_data_vector =
+ fifo_info->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->info.count - i) {
+ dev_warn(sensorhub->dev,
+ "Invalid EC data: too many entry received: %d, expected %d",
+ number_data, fifo_info->info.count - i);
+ break;
+ }
+ if (out + number_data >
+ sensorhub->ring + fifo_info->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->info.count);
+ break;
+ }
+
+ for (in = sensorhub->resp->fifo_read.data, j = 0;
+ j < number_data; j++, in++) {
+ if (cros_ec_ring_process_event(
+ sensorhub, fifo_info, fifo_timestamp,
+ &current_timestamp, in, out)) {
+ sensor_mask |= (1 << in->sensor_num);
+ 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. */
+ for_each_set_bit(i, &sensor_mask, BITS_PER_LONG) {
+ if (fifo_info->info.total_lost) {
+ int lost = fifo_info->lost[i];
+
+ if (lost) {
+ dev_warn_ratelimited(sensorhub->dev,
+ "Sensor %d: lost: %d out of %d\n", i,
+ lost, fifo_info->info.total_lost);
+ }
+ }
+ }
+
+ /* push the event into the kfifo */
+ 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;
+}
+
+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;
+
+ sensorhub->fifo_info.info = ec_dev->event_data.data.sensor_fifo.info;
+ sensorhub->fifo_timestamp[CROS_EC_SENSOR_NEW_TS] =
+ ec_dev->last_event_time;
+ cros_ec_sensorhub_ring_handler(sensorhub);
+
+ return NOTIFY_OK;
+}
+
+/**
+ * Add/Remove the fifo functionality if the EC supports it.
+ * @sensor_hub : Sensor Hub object
+ */
+int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub)
+{
+ struct cros_ec_dev *ec = sensorhub->ec;
+ int ret;
+
+ /* Retrieve FIFO information */
+ sensorhub->msg->version = 2;
+ sensorhub->params->cmd = MOTIONSENSE_CMD_FIFO_INFO;
+ sensorhub->msg->outsize = 1;
+ sensorhub->msg->insize =
+ sizeof(struct ec_response_motion_sense_fifo_info) +
+ sizeof(u16) * CROS_EC_SENSOR_MAX;
+
+ 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;
+
+ 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) {
+ dev_warn(sensorhub->dev, "failed to register notifier\n");
+ return ret;
+ }
+
+ /* Start collection samples. */
+ return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
+}
+
+int cros_ec_sensorhub_ring_remove(struct cros_ec_sensorhub *sensorhub)
+{
+ 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);
+
+ return 0;
+}
diff --git a/include/linux/platform_data/cros_ec_sensorhub.h b/include/linux/platform_data/cros_ec_sensorhub.h
index c18fba660bb62..595d010b58d95 100644
--- a/include/linux/platform_data/cros_ec_sensorhub.h
+++ b/include/linux/platform_data/cros_ec_sensorhub.h
@@ -8,6 +8,7 @@
#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H

+#include <linux/iio/iio.h>
#include <linux/platform_data/cros_ec_commands.h>

/**
@@ -18,12 +19,88 @@ struct cros_ec_sensor_platform {
u8 sensor_num;
};

+/**
+ * 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
+};
+
+#define CROS_EC_SENSOR_MAX 16
+
+struct __ec_todo_packed cros_ec_fifo_info {
+ struct ec_response_motion_sense_fifo_info info;
+ uint16_t lost[CROS_EC_SENSOR_MAX];
+};
+
+struct cros_ec_sensors_ring_sample {
+ uint8_t sensor_id;
+ uint8_t flag;
+ int16_t vector[3];
+ s64 timestamp;
+} __packed;
+
/*
* struct cros_ec_sensorhub - Sensor Hub device data.
*/
struct cros_ec_sensorhub {
+ /* Device object, mostly used for logging. */
+ struct device *dev;
+
/* Embedded Controller where the hub is located. */
struct cros_ec_dev *ec;
+
+ /* Structure to send FIFO requests. */
+ struct cros_ec_command *msg;
+ struct ec_params_motion_sense *params;
+ struct ec_response_motion_sense *resp;
+ struct mutex cmd_lock;
+
+ /* Notifier to kick the FIFO interrupt */
+ struct notifier_block notifier;
+
+ /* Preprocessed ring to send to kfifos */
+ struct cros_ec_sensors_ring_sample *ring;
+
+ ktime_t fifo_timestamp[CROS_EC_SENSOR_ALL_TS];
+ struct cros_ec_fifo_info fifo_info;
+ int fifo_size;
+
+ /*
+ * Dynamic array to be able to spread datum to iio sensor objects.
+ */
+ struct cros_ec_sensorhub_sensor_push_data push_data[CROS_EC_SENSOR_MAX];
};

+int cros_ec_sensorhub_register_push_data(
+ struct cros_ec_sensorhub *sensor_hub,
+ 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 *sensor_hub,
+ u8 sensor_num);
+
+int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensor_hub);
+int cros_ec_sensorhub_ring_remove(struct cros_ec_sensorhub *sensor_hub);
+int cros_ec_sensorhub_ring_fifo_enable(
+ struct cros_ec_sensorhub *sensorhub,
+ bool on);
+
#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
--
2.23.0.866.gb869b98d4c-goog