[PATCH 4/4] Input: goodix - Support interchanging x and y coordinates in hardware

[Franklin S Cooper Jr]

On systems with a fixed display/touchscreen orientation it is important to
pass in the "correct" x and y coordinates based on the orientation.
Currently, to support landscape and portrait touchscreen-swapped-x-y
simply does the following:

Assuming touchscreen is as follows:
X: 1280 Y:800 programmed in touchscreen controller and also interchange
bit cleared. Assuming ts mounted in portrait mode.

1280 (X)
------
|    |
|    | 800 (Y)
|    |
|    |
------

800 (Y)
------
|    |
|    | 1280 (X)
|    |
|    |
------

However, the above isn't really what we want especially in distros that
assumes a fixed orientation. In this case what we really want is to
interchange the x and y coordinates so the Y coordinate can return a max
value of 1280 and X can return a max value of 800.

800 (X)
------
|    |
|    | 1280 (Y)
|    |
|    |
------

Since the driver is limited to the value reported by the touchscreen
controller this issue can't be fixed purely in the driver. Therefore,
add a new DT property that supports interchanging X and Y coordinates
internally within the hardware.

Signed-off-by: Franklin S Cooper Jr <fcoo...@ti.com>
---
 .../devicetree/bindings/input/touchscreen/goodix.txt        |  2 ++
 drivers/input/touchscreen/goodix.c                          | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt 
b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
index ebc7cb7..b8be2ab 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
@@ -25,6 +25,8 @@ Optional properties:
  - touchscreen-inverted-y  : Y axis is inverted (boolean)
  - touchscreen-swapped-x-y : X and Y axis are swapped (boolean)
                              (swapping is done after inverting the axis)
+ - touchscreen-inter-x-y   : X and Y maximum values programmed in the device
+                             are interchanged internally in hardware. (boolean)
 
 Example:
 
diff --git a/drivers/input/touchscreen/goodix.c 
b/drivers/input/touchscreen/goodix.c
index c2428e1..3f93375 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -39,6 +39,7 @@ struct goodix_ts_data {
        bool swapped_x_y;
        bool inverted_x;
        bool inverted_y;
+       bool interchange_x_y;
        unsigned int max_touch_num;
        unsigned int int_trigger_type;
        int cfg_len;
@@ -76,6 +77,9 @@ struct goodix_ts_data {
 #define MAX_CONTACTS_LOC       5
 #define TRIGGER_LOC            6
 
+/* Register Bits */
+#define XY_COORD_INTER         3
+
 static const unsigned long goodix_irq_flags[] = {
        IRQ_TYPE_EDGE_RISING,
        IRQ_TYPE_EDGE_FALLING,
@@ -500,6 +504,10 @@ static void goodix_tweak_config(struct goodix_ts_data *ts)
        put_unaligned_le16(ts->abs_x_max, &config[RESOLUTION_LOC]);
        put_unaligned_le16(ts->abs_y_max, &config[RESOLUTION_LOC + 2]);
 
+       if (ts->interchange_x_y)
+               config[TRIGGER_LOC] = config[TRIGGER_LOC] |
+                                     (1 << XY_COORD_INTER);
+
        check_sum = goodix_calculate_checksum(ts->cfg_len, config);
 
        config[raw_cfg_len] = check_sum;
@@ -700,6 +708,11 @@ static int goodix_configure_dev(struct goodix_ts_data *ts)
                }
        }
 
+       ts->interchange_x_y = device_property_read_bool(&ts->client->dev,
+                                                   "touchscreen-inter-x-y");
+       if (ts->interchange_x_y)
+               alter_config = true;
+
        if (alter_config)
                goodix_tweak_config(ts);
 
-- 
2.10.0