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Subject[PATCH 1/9 v2] Input: synaptics - refactor y inversion
Date
From: Daniel Kurtz <djkurtz@chromium.org>

Synaptics touchpads report increasing y from bottom to top.
This is inverted from normal userspace "top of screen is 0" coordinates.
Thus, the kernel driver reports inverted y coordinates to userspace.

This patch refactors this inversion.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
---
drivers/input/mouse/synaptics.c | 15 ++++++++++++---
1 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 5538fc6..297e88f 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -44,6 +44,16 @@
#define YMIN_NOMINAL 1408
#define YMAX_NOMINAL 4448

+/*
+ * Synaptics touchpads report the y coordinate from bottom to top, which is
+ * opposite from what userspace expects.
+ * This function is used to invert y before reporting.
+ */
+static int invert_y(int y)
+{
+ return YMAX_NOMINAL + YMIN_NOMINAL - y;
+}
+

/*****************************************************************************
* Stuff we need even when we do not want native Synaptics support
@@ -502,8 +512,7 @@ static void synaptics_report_semi_mt_slot(struct input_dev *dev, int slot,
input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
if (active) {
input_report_abs(dev, ABS_MT_POSITION_X, x);
- input_report_abs(dev, ABS_MT_POSITION_Y,
- YMAX_NOMINAL + YMIN_NOMINAL - y);
+ input_report_abs(dev, ABS_MT_POSITION_Y, invert_y(y));
}
}

@@ -597,7 +606,7 @@ static void synaptics_process_packet(struct psmouse *psmouse)

if (num_fingers > 0) {
input_report_abs(dev, ABS_X, hw.x);
- input_report_abs(dev, ABS_Y, YMAX_NOMINAL + YMIN_NOMINAL - hw.y);
+ input_report_abs(dev, ABS_Y, invert_y(hw.y));
}
input_report_abs(dev, ABS_PRESSURE, hw.z);

--
1.7.3.1


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