[PATCH 1/2] HID: wacom: Properly handle AES serial number and tool type

[Jason Gerecke <killertofu@gmail.com>]

Current AES sensors relay tool type and serial number information with
a different set of usages than those prescribed by the modern (i.e.
MobileStudio Pro and newer) EMR tablet standard. To ensure the driver
properly understands these usages, we modify them to be compatible.
The identifying information is split across three consecutive fields:
a 16-bit WACOM_HID_WT_SERIALNUMBER (which is more accurately described
as WACOM_HID_WD_TOOLTYPE), a 32-bit HID_DG_TOOLSERIALNUMBER, and an
8-bit 0xFF000000 (which should be WACOM_HID_WD_SERIALHI). While we're
at it, we also define proper min/max values since may may be undefined
on some devices.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
---
 drivers/hid/wacom_wac.c | 42 +++++++++++++++++++++++++++++++++---------
 drivers/hid/wacom_wac.h |  3 +++
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 16af6886e828..ff679ee3b358 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -2086,6 +2086,27 @@ static void wacom_wac_pen_usage_mapping(struct hid_device *hdev,
 		break;
 	case HID_DG_TOOLSERIALNUMBER:
 		wacom_map_usage(input, usage, field, EV_MSC, MSC_SERIAL, 0);
+
+		/* Adjust AES usages to match modern convention */
+		if (usage->hid == WACOM_HID_WT_SERIALNUMBER && field->report_size == 16) {
+			if (field->index + 2 < field->report->maxfield) {
+				struct hid_field *a = field->report->field[field->index + 1];
+				struct hid_field *b = field->report->field[field->index + 2];
+
+				if (a->maxusage > 0 && a->usage[0].hid == HID_DG_TOOLSERIALNUMBER && a->report_size == 32 &&
+				    b->maxusage > 0 && b->usage[0].hid == 0xFF000000 && b->report_size == 8) {
+					features->quirks |= WACOM_QUIRK_AESPEN;
+					usage->hid = WACOM_HID_WD_TOOLTYPE;
+					field->logical_minimum = S16_MIN;
+					field->logical_maximum = S16_MAX;
+					a->logical_minimum = S32_MIN;
+					a->logical_maximum = S32_MAX;
+					b->usage[0].hid = WACOM_HID_WD_SERIALHI;
+					b->logical_minimum = 0;
+					b->logical_maximum = U8_MAX;
+				}
+			}
+		}
 		break;
 	case WACOM_HID_WD_SENSE:
 		features->quirks |= WACOM_QUIRK_SENSE;
@@ -2093,15 +2114,18 @@ static void wacom_wac_pen_usage_mapping(struct hid_device *hdev,
 		break;
 	case WACOM_HID_WD_SERIALHI:
 		wacom_map_usage(input, usage, field, EV_ABS, ABS_MISC, 0);
-		set_bit(EV_KEY, input->evbit);
-		input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
-		input_set_capability(input, EV_KEY, BTN_TOOL_RUBBER);
-		input_set_capability(input, EV_KEY, BTN_TOOL_BRUSH);
-		input_set_capability(input, EV_KEY, BTN_TOOL_PENCIL);
-		input_set_capability(input, EV_KEY, BTN_TOOL_AIRBRUSH);
-		if (!(features->device_type & WACOM_DEVICETYPE_DIRECT)) {
-			input_set_capability(input, EV_KEY, BTN_TOOL_MOUSE);
-			input_set_capability(input, EV_KEY, BTN_TOOL_LENS);
+
+		if (!(features->quirks & WACOM_QUIRK_AESPEN)) {
+			set_bit(EV_KEY, input->evbit);
+			input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
+			input_set_capability(input, EV_KEY, BTN_TOOL_RUBBER);
+			input_set_capability(input, EV_KEY, BTN_TOOL_BRUSH);
+			input_set_capability(input, EV_KEY, BTN_TOOL_PENCIL);
+			input_set_capability(input, EV_KEY, BTN_TOOL_AIRBRUSH);
+			if (!(features->device_type & WACOM_DEVICETYPE_DIRECT)) {
+				input_set_capability(input, EV_KEY, BTN_TOOL_MOUSE);
+				input_set_capability(input, EV_KEY, BTN_TOOL_LENS);
+			}
 		}
 		break;
 	case WACOM_HID_WD_FINGERWHEEL:
diff --git a/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
index 69dda27e8dde..00bcc8ad5945 100644
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -86,6 +86,7 @@
 /* device quirks */
 #define WACOM_QUIRK_BBTOUCH_LOWRES	0x0001
 #define WACOM_QUIRK_SENSE		0x0002
+#define WACOM_QUIRK_AESPEN		0x0004
 #define WACOM_QUIRK_BATTERY		0x0008
 
 /* device types */
@@ -107,6 +108,7 @@
 #define WACOM_HID_WD_PEN                (WACOM_HID_UP_WACOMDIGITIZER | 0x02)
 #define WACOM_HID_WD_SENSE              (WACOM_HID_UP_WACOMDIGITIZER | 0x36)
 #define WACOM_HID_WD_DIGITIZERFNKEYS    (WACOM_HID_UP_WACOMDIGITIZER | 0x39)
+#define WACOM_HID_WD_SERIALNUMBER       (WACOM_HID_UP_WACOMDIGITIZER | 0x5b)
 #define WACOM_HID_WD_SERIALHI           (WACOM_HID_UP_WACOMDIGITIZER | 0x5c)
 #define WACOM_HID_WD_TOOLTYPE           (WACOM_HID_UP_WACOMDIGITIZER | 0x77)
 #define WACOM_HID_WD_DISTANCE           (WACOM_HID_UP_WACOMDIGITIZER | 0x0132)
@@ -150,6 +152,7 @@
 #define WACOM_HID_WT_TOUCHSCREEN        (WACOM_HID_UP_WACOMTOUCH | 0x04)
 #define WACOM_HID_WT_TOUCHPAD           (WACOM_HID_UP_WACOMTOUCH | 0x05)
 #define WACOM_HID_WT_CONTACTMAX         (WACOM_HID_UP_WACOMTOUCH | 0x55)
+#define WACOM_HID_WT_SERIALNUMBER       (WACOM_HID_UP_WACOMTOUCH | 0x5b)
 #define WACOM_HID_WT_X                  (WACOM_HID_UP_WACOMTOUCH | 0x130)
 #define WACOM_HID_WT_Y                  (WACOM_HID_UP_WACOMTOUCH | 0x131)
 
-- 
2.15.0