HID: multitouch: Add quirks for flipped axes

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>

drivers/hid/hid-multitouch.c

@@ -71,6 +71,7 @@ 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_ORIENTATION_INVERT	BIT(22)
 
 #define MT_INPUTMODE_TOUCHSCREEN	0x02
 #define MT_INPUTMODE_TOUCHPAD		0x03
@@ -1009,6 +1010,7 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
 			    struct mt_usages *slot)
 {
 	struct input_mt *mt = input->mt;
+	struct hid_device *hdev = td->hdev;
 	__s32 quirks = app->quirks;
 	bool valid = true;
 	bool confidence_state = true;
@@ -1086,6 +1088,10 @@ 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 +1110,9 @@ static int mt_process_slot(struct mt_device *td, struct input_dev *input,
 			if (azimuth > max_azimuth * 2)
 				azimuth -= max_azimuth * 4;
 			orientation = -azimuth;
+			if (quirks & MT_QUIRK_ORIENTATION_INVERT)
+				orientation = -orientation;
+
 		}
 
 		if (quirks & MT_QUIRK_TOUCH_SIZE_SCALING) {
@@ -1115,10 +1124,23 @@ 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 = hdev->quirks & HID_QUIRK_X_INVERT ?
+			input_abs_get_max(input, ABS_MT_POSITION_X) - *slot->x :
+			*slot->x;
+		y = hdev->quirks & HID_QUIRK_Y_INVERT ?
+			input_abs_get_max(input, ABS_MT_POSITION_Y) - *slot->y :
+			*slot->y;
+		cx = hdev->quirks & HID_QUIRK_X_INVERT ?
+			input_abs_get_max(input, ABS_MT_POSITION_X) - *slot->cx :
+			*slot->cx;
+		cy = hdev->quirks & HID_QUIRK_Y_INVERT ?
+			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);
@@ -1735,6 +1757,15 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
 		td->serial_maybe = true;
 
+
+	/* Orientation is inverted if the X or Y axes are
+	 * flipped, but normalized if both are inverted.
+	 */
+	if (hdev->quirks & (HID_QUIRK_X_INVERT | HID_QUIRK_Y_INVERT) &&
+	    !((hdev->quirks & HID_QUIRK_X_INVERT)
+	      && (hdev->quirks & HID_QUIRK_Y_INVERT)))
+		td->mtclass.quirks = MT_QUIRK_ORIENTATION_INVERT;
+
 	/* This allows the driver to correctly support devices
 	 * that emit events over several HID messages.
 	 */

drivers/hid/hid-quirks.c

@@ -19,6 +19,7 @@
 #include <linux/input/elan-i2c-ids.h>
 
 #include "hid-ids.h"
+#include "i2c-hid/i2c-hid.h"
 
 /*
  * Alphabetically sorted by vendor then product.
@@ -1298,6 +1299,10 @@ unsigned long hid_lookup_quirk(const struct hid_device *hdev)
 		quirks = hid_gets_squirk(hdev);
 	mutex_unlock(&dquirks_lock);
 
+	/* Get quirks specific to I2C devices */
+	if (IS_ENABLED(CONFIG_DMI) && hdev->bus == BUS_I2C)
+		quirks |= i2c_hid_get_dmi_quirks(hdev->vendor, hdev->product);
+
 	return quirks;
 }
 EXPORT_SYMBOL_GPL(hid_lookup_quirk);

drivers/hid/i2c-hid/i2c-hid-dmi-quirks.c

@@ -10,8 +10,10 @@
 #include <linux/types.h>
 #include <linux/dmi.h>
 #include <linux/mod_devicetable.h>
+#include <linux/hid.h>
 
 #include "i2c-hid.h"
+#include "../hid-ids.h"
 
 
 struct i2c_hid_desc_override {
@@ -416,6 +418,28 @@ static const struct dmi_system_id i2c_hid_dmi_desc_override_table[] = {
 	{ }	/* Terminate list */
 };
 
+static const struct hid_device_id i2c_hid_elan_flipped_quirks = {
+	HID_DEVICE(BUS_I2C, HID_GROUP_MULTITOUCH_WIN_8, USB_VENDOR_ID_ELAN, 0x2dcd),
+		HID_QUIRK_X_INVERT | HID_QUIRK_Y_INVERT
+};
+
+/*
+ * This list contains devices which have specific issues based on the system
+ * they're on and not just the device itself. The driver_data will have a
+ * specific hid device to match against.
+ */
+static const struct dmi_system_id i2c_hid_dmi_quirk_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 *)&i2c_hid_elan_flipped_quirks,
+	},
+	{ }	/* Terminate list */
+};
+
 
 struct i2c_hid_desc *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name)
 {
@@ -450,3 +474,22 @@ char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
 	*size = override->hid_report_desc_size;
 	return override->hid_report_desc;
 }
+
+u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product)
+{
+	u32 quirks = 0;
+	const struct dmi_system_id *system_id =
+			dmi_first_match(i2c_hid_dmi_quirk_table);
+
+	if (system_id) {
+		const struct hid_device_id *device_id =
+				(struct hid_device_id *)(system_id->driver_data);
+
+		if (device_id && device_id->vendor == vendor &&
+		    device_id->product == product)
+			quirks = device_id->driver_data;
+	}
+
+	return quirks;
+}
+EXPORT_SYMBOL_GPL(i2c_hid_get_dmi_quirks);

drivers/hid/i2c-hid/i2c-hid.h

@@ -9,13 +9,16 @@
 struct i2c_hid_desc *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name);
 char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
 					       unsigned int *size);
+u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product);
 #else
 static inline struct i2c_hid_desc
 		   *i2c_hid_get_dmi_i2c_hid_desc_override(uint8_t *i2c_name)
 { return NULL; }
 static inline char *i2c_hid_get_dmi_hid_report_desc_override(uint8_t *i2c_name,
 							     unsigned int *size)
 { return NULL; }
+static inline u32 i2c_hid_get_dmi_quirks(const u16 vendor, const u16 product)
+{ return 0; }
 #endif
 
 /**