[PATCH 4.9 02/47] iio: hid-sensor-prox: Fix scale not correct issue

[Greg Kroah-Hartman]

From: Ye Xiang <xiang.ye@xxxxxxxxx>

commit d68c592e02f6f49a88e705f13dfc1883432cf300 upstream

Currently, the proxy sensor scale is zero because it just return the
exponent directly. To fix this issue, this patch use
hid_sensor_format_scale to process the scale first then return the
output.

Fixes: 39a3a0138f61 ("iio: hid-sensors: Added Proximity Sensor Driver")
Signed-off-by: Ye Xiang <xiang.ye@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210130102530.31064-1-xiang.ye@xxxxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/iio/light/hid-sensor-prox.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/iio/light/hid-sensor-prox.c
+++ b/drivers/iio/light/hid-sensor-prox.c
@@ -37,6 +37,9 @@ struct prox_state {
 	struct hid_sensor_common common_attributes;
 	struct hid_sensor_hub_attribute_info prox_attr;
 	u32 human_presence;
+	int scale_pre_decml;
+	int scale_post_decml;
+	int scale_precision;
 };
 
 /* Channel definitions */
@@ -105,8 +108,9 @@ static int prox_read_raw(struct iio_dev
 		ret_type = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_SCALE:
-		*val = prox_state->prox_attr.units;
-		ret_type = IIO_VAL_INT;
+		*val = prox_state->scale_pre_decml;
+		*val2 = prox_state->scale_post_decml;
+		ret_type = prox_state->scale_precision;
 		break;
 	case IIO_CHAN_INFO_OFFSET:
 		*val = hid_sensor_convert_exponent(
@@ -240,6 +244,12 @@ static int prox_parse_report(struct plat
 			st->common_attributes.sensitivity.index,
 			st->common_attributes.sensitivity.report_id);
 	}
+
+	st->scale_precision = hid_sensor_format_scale(
+				hsdev->usage,
+				&st->prox_attr,
+				&st->scale_pre_decml, &st->scale_post_decml);
+
 	return ret;
 }