[PATCH v2] HID: multitouch: Add quirks for flipped axes

Allen Ballway
2022-12-08T16:59:13Z

Certain touchscreen devices, such as the ELAN9034, are oriented
incorrectly and report touches on opposite points on the X and Y axes.
For example, a 100x200 screen touched at (10,20) would report (90, 180)
and vice versa.

This is fixed by adding device quirks to transform the touch points
into the correct spaces, from X -> MAX(X) - X, and Y -> MAX(Y) - Y.

Signed-off-by: Allen Ballway <ballway@chromium.org>
---
V1 -> V2: Address review comments, change to use DMI match. Confirmed
MT_TOOL_X/Y require transformation and update orientation based on
flipped axes.

drivers/hid/hid-multitouch.c | 72 +++++++++++++++++++++++++++++++++---
1 file changed, 67 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 91a4d3fc30e08..8a4f77e534a75 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -39,6 +39,7 @@
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/timer.h>
+#include <linux/dmi.h>

MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
@@ -71,6 +72,8 @@ MODULE_LICENSE("GPL");
#define MT_QUIRK_SEPARATE_APP_REPORT BIT(19)
#define MT_QUIRK_FORCE_MULTI_INPUT BIT(20)
#define MT_QUIRK_DISABLE_WAKEUP BIT(21)
+#define MT_QUIRK_FLIP_X BIT(22)
+#define MT_QUIRK_FLIP_Y BIT(23)

#define MT_INPUTMODE_TOUCHSCREEN 0x02
#define MT_INPUTMODE_TOUCHPAD 0x03
@@ -212,6 +215,7 @@ static void mt_post_parse(struct mt_device *td, struct mt_application *app);
#define MT_CLS_GOOGLE 0x0111
#define MT_CLS_RAZER_BLADE_STEALTH 0x0112
#define MT_CLS_SMART_TECH 0x0113
+#define MT_CLS_ELAN_FLIPPED 0x0114

#define MT_DEFAULT_MAXCONTACT 10
#define MT_MAX_MAXCONTACT 250
@@ -396,9 +400,36 @@ static const struct mt_class mt_classes[] = {
MT_QUIRK_CONTACT_CNT_ACCURATE |
MT_QUIRK_SEPARATE_APP_REPORT,
},
+ { .name = MT_CLS_ELAN_FLIPPED,
+ .quirks = MT_QUIRK_ALWAYS_VALID |
+ MT_QUIRK_IGNORE_DUPLICATES |
+ MT_QUIRK_HOVERING |
+ MT_QUIRK_CONTACT_CNT_ACCURATE |
+ MT_QUIRK_STICKY_FINGERS |
+ MT_QUIRK_WIN8_PTP_BUTTONS |
+ MT_QUIRK_FLIP_X |
+ MT_QUIRK_FLIP_Y,
+ .export_all_inputs = true },
+
{ }
};

+/*
+ * This list contains devices which have specific issues based on the system
+ * they're on and not just the device itself.
+ */
+static const struct dmi_system_id mt_devices_dmi_override_table[] = {
+ {
+ .ident = "DynaBook K50/FR",
+ .matches = {
+ DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dynabook Inc."),
+ DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "dynabook K50/FR"),
+ },
+ .driver_data = (void *)MT_CLS_ELAN_FLIPPED,
+ },
+ { } /* Terminate list */
+};
+
static ssize_t mt_show_quirks(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -1086,6 +1117,10 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
int orientation = wide;
int max_azimuth;
int azimuth;
+ int x;
+ int y;
+ int cx;
+ int cy;

if (slot->a != DEFAULT_ZERO) {
/*
@@ -1104,6 +1139,16 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
if (azimuth > max_azimuth * 2)
azimuth -= max_azimuth * 4;
orientation = -azimuth;
+
+ /* Orientation is inverted if the X or Y axes are
+ * flipped, but normalized if both are inverted.
+ */
+ if (quirks & (MT_QUIRK_FLIP_X | MT_QUIRK_FLIP_Y) &&
+ !((quirks & MT_QUIRK_FLIP_X)
+ && (quirks & MT_QUIRK_FLIP_Y))) {
+ orientation = -orientation;
+ }
+
}

if (quirks & MT_QUIRK_TOUCH_SIZE_SCALING) {
@@ -1115,10 +1160,23 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
minor = minor >> 1;
}

- input_event(input, EV_ABS, ABS_MT_POSITION_X, *slot->x);
- input_event(input, EV_ABS, ABS_MT_POSITION_Y, *slot->y);
- input_event(input, EV_ABS, ABS_MT_TOOL_X, *slot->cx);
- input_event(input, EV_ABS, ABS_MT_TOOL_Y, *slot->cy);
+ x = quirks & MT_QUIRK_FLIP_X ?
+ input_abs_get_max(input, ABS_MT_POSITION_X) - *slot->x :
+ *slot->x;
+ y = quirks & MT_QUIRK_FLIP_Y ?
+ input_abs_get_max(input, ABS_MT_POSITION_Y) - *slot->y :
+ *slot->y;
+ cx = quirks & MT_QUIRK_FLIP_X ?
+ input_abs_get_max(input, ABS_MT_POSITION_X) - *slot->cx :
+ *slot->cx;
+ cy = quirks & MT_QUIRK_FLIP_Y ?
+ input_abs_get_max(input, ABS_MT_POSITION_Y) - *slot->cy :
+ *slot->cy;
+
+ input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
+ input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
+ input_event(input, EV_ABS, ABS_MT_TOOL_X, cx);
+ input_event(input, EV_ABS, ABS_MT_TOOL_Y, cy);
input_event(input, EV_ABS, ABS_MT_DISTANCE, !*slot->tip_state);
input_event(input, EV_ABS, ABS_MT_ORIENTATION, orientation);
input_event(input, EV_ABS, ABS_MT_PRESSURE, *slot->p);
@@ -1711,9 +1769,13 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
int ret, i;
struct mt_device *td;
const struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
+ const struct dmi_system_id *system_id
+ = dmi_first_match(mt_devices_dmi_override_table);
+ const long driver_data_name = system_id ?
+ (long)(system_id->driver_data) : id->driver_data;

for (i = 0; mt_classes[i].name ; i++) {
- if (id->driver_data == mt_classes[i].name) {
+ if (driver_data_name == mt_classes[i].name) {
mtclass = &(mt_classes[i]);
break;
}
--
2.39.0.rc1.256.g54fd8350bd-goog