[1/5] HID: wacom: generic: Scale battery capacity measurements to percentages

Commit Message

Gerecke, Jason April 28, 2017, 4:25 p.m. UTC

The power_supply subsystem expects us to provide it with capacity values
measured in percent. In particular, AES devices (HID_DG_BATTERYSTRENGTH)
use the range 0-255, which needs to be rescaled. The MobileStudio Pro
(WACOM_HID_WD_BATTERY_LEVEL) uses the range 0-100, but there's no guarantee
that future devices will share the same range.

Signed-off-by: Jason Gerecke <[e-mail]>
---
 drivers/hid/wacom_wac.c | 2 ++
 1 file changed, 2 insertions(+)

Patch

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 6b8f6b816195..1878da3321f8 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1811,6 +1811,7 @@  static void wacom_wac_pad_battery_event(struct hid_device *hdev, struct hid_fiel
 
 	switch (equivalent_usage) {
 	case WACOM_HID_WD_BATTERY_LEVEL:
+		value = value * 100 / (field->logical_maximum - field->logical_minimum);
 		wacom_wac->hid_data.battery_capacity = value;
 		wacom_wac->hid_data.bat_connected = 1;
 		break;
@@ -2033,6 +2034,7 @@  static void wacom_wac_pen_event(struct hid_device *hdev, struct hid_field *field
 			wacom_wac->hid_data.sense_state = value;
 		return;
 	case HID_DG_BATTERYSTRENGTH:
+		value = value * 100 / (field->logical_maximum - field->logical_minimum);
 		wacom_wac->hid_data.battery_capacity = value;
 		wacom_wac->hid_data.bat_connected = 1;
 		break;