Input: goodix - fix touch coordinates on WinBook TW100 and TW700

The touchscreen on the WinBook TW100 and TW700 don't match the default
display, with 0,0 touches being reported when touching at the bottom
right of the screen.

  1280,800             0,800
         +-------------+
         |             |
         |             |
         |             |
         +-------------+
    1280,0             0,0

It's unfortunately impossible to detect this problem with data from the
DSDT, or other auxiliary metadata, so fallback to quirking this specific
model of tablet instead.

Signed-off-by: Bastien Nocera <hadess@hadess.net>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/goodix.c

@@ -15,6 +15,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/mt.h>
@@ -34,6 +35,7 @@ struct goodix_ts_data {
 	int abs_y_max;
 	unsigned int max_touch_num;
 	unsigned int int_trigger_type;
+	bool rotated_screen;
 };
 
 #define GOODIX_MAX_HEIGHT		4096
@@ -60,6 +62,30 @@ static const unsigned long goodix_irq_flags[] = {
 	IRQ_TYPE_LEVEL_HIGH,
 };
 
+/*
+ * Those tablets have their coordinates origin at the bottom right
+ * of the tablet, as if rotated 180 degrees
+ */
+static const struct dmi_system_id rotated_screen[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+	{
+		.ident = "WinBook TW100",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TW100")
+		}
+	},
+	{
+		.ident = "WinBook TW700",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "WinBook"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TW700")
+		},
+	},
+#endif
+	{}
+};
+
 /**
  * goodix_i2c_read - read data from a register of the i2c slave device.
  *
@@ -129,6 +155,11 @@ static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
 	int input_y = get_unaligned_le16(&coor_data[3]);
 	int input_w = get_unaligned_le16(&coor_data[5]);
 
+	if (ts->rotated_screen) {
+		input_x = ts->abs_x_max - input_x;
+		input_y = ts->abs_y_max - input_y;
+	}
+
 	input_mt_slot(ts->input_dev, id);
 	input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
 	input_report_abs(ts->input_dev, ABS_MT_POSITION_X, input_x);
@@ -223,6 +254,11 @@ static void goodix_read_config(struct goodix_ts_data *ts)
 		ts->abs_y_max = GOODIX_MAX_HEIGHT;
 		ts->max_touch_num = GOODIX_MAX_CONTACTS;
 	}
+
+	ts->rotated_screen = dmi_check_system(rotated_screen);
+	if (ts->rotated_screen)
+		dev_dbg(&ts->client->dev,
+			 "Applying '180 degrees rotated screen' quirk\n");
 }
 
 /**