[PATCH v6 11/11] iio: cros_ec: flush as hwfifo attribute

[Gwendal Grignou <gwendal@chromium.org>]

Add buffer/hwfifo_flush. It is not part of the ABI, but it follows ST
and HID lead: Tells the sensor hub to send to the host all pending
sensor events.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
---
New in v6.

 .../cros_ec_sensors/cros_ec_sensors_core.c    | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index c831915ca7e56..aaf124a82e0e4 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -113,6 +113,33 @@ static int cros_ec_sensor_set_ec_rate(struct cros_ec_sensors_core_state *st,
 	return ret;
 }
 
+static ssize_t cros_ec_sensors_flush(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int ret = 0;
+	bool flush;
+
+	ret = strtobool(buf, &flush);
+	if (ret < 0)
+		return ret;
+	if (!flush)
+		return -EINVAL;
+
+	mutex_lock(&st->cmd_lock);
+	st->param.cmd = MOTIONSENSE_CMD_FIFO_FLUSH;
+	ret = cros_ec_motion_send_host_cmd(st, 0);
+	if (ret != 0)
+		dev_warn(&indio_dev->dev, "Unable to flush sensor\n");
+	mutex_unlock(&st->cmd_lock);
+	return ret ? ret : len;
+}
+
+static IIO_DEVICE_ATTR(hwfifo_flush, 0644, NULL,
+		       cros_ec_sensors_flush, 0);
+
 static ssize_t cros_ec_sensor_set_report_latency(struct device *dev,
 						 struct device_attribute *attr,
 						 const char *buf, size_t len)
@@ -175,6 +202,7 @@ static ssize_t hwfifo_watermark_max_show(struct device *dev,
 static IIO_DEVICE_ATTR_RO(hwfifo_watermark_max, 0);
 
 const struct attribute *cros_ec_sensor_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_flush.dev_attr.attr,
 	&iio_dev_attr_hwfifo_timeout.dev_attr.attr,
 	&iio_dev_attr_hwfifo_watermark_max.dev_attr.attr,
 	NULL,
-- 
2.25.1.696.g5e7596f4ac-goog