iio: hid-sensor: Store restore poll and hysteresis on S3

This change undo the change done by 'commit 3bec24747446
("iio: hid-sensor-trigger: Change get poll value function order to avoid
sensor properties losing after resume from S3")' as this breaks some
USB/i2c sensor hubs.

Instead of relying on HW for restoring poll and hysteresis, driver stores
and restores on resume (S3). In this way user space modified settings are
not lost for any kind of sensor hub behavior.

In this change, whenever user space modifies sampling frequency or
hysteresis driver will get the feature value from the hub and store in the
per device hid_sensor_common data structure. On resume callback from S3,
system will set the feature to sensor hub, if user space ever modified the
feature value.

Fixes: 3bec24747446 ("iio: hid-sensor-trigger: Change get poll value function order to avoid sensor properties losing after resume from S3")
Reported-by: Ritesh Raj Sarraf <[e-mail]>
Tested-by: Ritesh Raj Sarraf <[e-mail]>
Tested-by: Song, Hongyan <[e-mail]>
Cc: [e-mail]
Signed-off-by: Srinivas Pandruvada <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/common/hid-sensors/hid-sensor-attributes.c

···
 	if (ret < 0 || value < 0)
 		ret = -EINVAL;
 
-	return ret;
+	ret = sensor_hub_get_feature(st->hsdev,
+				     st->poll.report_id,
+				     st->poll.index, sizeof(value), &value);
+	if (ret < 0 || value < 0)
+		return -EINVAL;
+
+	st->poll_interval = value;
+
+	return 0;
 }
 EXPORT_SYMBOL(hid_sensor_write_samp_freq_value);
 
···
 	if (ret < 0 || value < 0)
 		ret = -EINVAL;
 
-	return ret;
+	ret = sensor_hub_get_feature(st->hsdev,
+				     st->sensitivity.report_id,
+				     st->sensitivity.index, sizeof(value),
+				     &value);
+	if (ret < 0 || value < 0)
+		return -EINVAL;
+
+	st->raw_hystersis = value;
+
+	return 0;
 }
 EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);
 
···
 	/* Default unit of measure is milliseconds */
 	if (st->poll.units == 0)
 		st->poll.units = HID_USAGE_SENSOR_UNITS_MILLISECOND;
+
+	st->poll_interval = -1;
+
 	return 0;
 
 }
···
 			HID_FEATURE_REPORT, usage_id,
 			HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS,
 			 &st->sensitivity);
+
+	st->raw_hystersis = -1;
 
 	sensor_hub_input_get_attribute_info(hsdev,
 					    HID_INPUT_REPORT, usage_id,

drivers/iio/common/hid-sensors/hid-sensor-trigger.c

···
 			st->report_state.report_id,
 			st->report_state.index,
 			HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM);
+
+		poll_value = hid_sensor_read_poll_value(st);
 	} else {
 		int val;
 
···
 	sensor_hub_get_feature(st->hsdev, st->power_state.report_id,
 			       st->power_state.index,
 			       sizeof(state_val), &state_val);
-	if (state)
-		poll_value = hid_sensor_read_poll_value(st);
-	if (poll_value > 0)
+	if (state && poll_value)
 		msleep_interruptible(poll_value * 2);
 
 	return 0;
···
 	struct hid_sensor_common *attrb = container_of(work,
 						       struct hid_sensor_common,
 						       work);
+
+	if (attrb->poll_interval >= 0)
+		sensor_hub_set_feature(attrb->hsdev, attrb->poll.report_id,
+				       attrb->poll.index,
+				       sizeof(attrb->poll_interval),
+				       &attrb->poll_interval);
+
+	if (attrb->raw_hystersis >= 0)
+		sensor_hub_set_feature(attrb->hsdev,
+				       attrb->sensitivity.report_id,
+				       attrb->sensitivity.index,
+				       sizeof(attrb->raw_hystersis),
+				       &attrb->raw_hystersis);
+
 	_hid_sensor_power_state(attrb, true);
 }
 

include/linux/hid-sensor-hub.h

···
 	unsigned usage_id;
 	atomic_t data_ready;
 	atomic_t user_requested_state;
+	int poll_interval;
+	int raw_hystersis;
 	struct iio_trigger *trigger;
 	int timestamp_ns_scale;
 	struct hid_sensor_hub_attribute_info poll;