Re: [PATCH v11 1/4] HID: wacom_sys: Add support for flipping the data values

On Tue, Oct 19, 2021 at 3:42 AM Ping Cheng [off-list ref] wrote:

Hi Alistair,

On Sat, Oct 9, 2021, 4:44 AM Alistair Francis [off-list ref] wrote:

quoted

Add support to the Wacom HID device for flipping the values based on
device tree settings. This allows us to support devices where the panel
is installed in a different orientation, such as the reMarkable2.

This device was designed for hid-generic driver, if it's not driven by wacom_i2c.c or an out of tree driver.

wacom.ko doesn't support vid 0x2d1f devices.

Nacked-by: Ping Cheng [off-list ref]

Any ideas how to support the hardware then?

I can't use the wacom_i2c driver as the panel supports I2C HID. But I
can't use the I2C HID driver as I need the values flipped to support
the installed orientation.

Alistair

Sorry about that,
Ping

quoted

Signed-off-by: Alistair Francis <redacted>
---
 .../bindings/input/hid-over-i2c.txt           | 20 ++++++
 drivers/hid/wacom_sys.c                       | 25 ++++++++
 drivers/hid/wacom_wac.c                       | 61 +++++++++++++++++++
 drivers/hid/wacom_wac.h                       | 13 ++++
 4 files changed, 119 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
index c76bafaf98d2..16ebd7c46049 100644
--- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt
+++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt

@@ -33,6 +33,26 @@ device-specific compatible properties, which should be used in addition to the
 - post-power-on-delay-ms: time required by the device after enabling its regulators
   or powering it on, before it is ready for communication.

+  flip-tilt-x:
+    type: boolean
+    description: Flip the tilt X values read from device
+
+  flip-tilt-y:
+    type: boolean
+    description: Flip the tilt Y values read from device
+
+  flip-pos-x:
+    type: boolean
+    description: Flip the X position values read from device
+
+  flip-pos-y:
+    type: boolean
+    description: Flip the Y position values read from device
+
+  flip-distance:
+    type: boolean
+    description: Flip the distance values read from device
+
 Example:

        i2c-hid-dev@2c {

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
index 93f49b766376..47d9590b10bd 100644
--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c

@@ -10,6 +10,7 @@

 #include "wacom_wac.h"
 #include "wacom.h"
+#include <linux/of.h>
 #include <linux/input/mt.h>

 #define WAC_MSG_RETRIES                5

@@ -2730,6 +2731,28 @@ static void wacom_mode_change_work(struct work_struct *work)
        return;
 }

+static void wacom_of_read(struct hid_device *hdev, struct wacom_wac *wacom_wac)
+{
+       if (IS_ENABLED(CONFIG_OF)) {
+               wacom_wac->flip_tilt_x = of_property_read_bool(hdev->dev.parent->of_node,
+                                                       "flip-tilt-x");
+               wacom_wac->flip_tilt_y = of_property_read_bool(hdev->dev.parent->of_node,
+                                                       "flip-tilt-y");
+               wacom_wac->flip_pos_x = of_property_read_bool(hdev->dev.parent->of_node,
+                                                       "flip-pos-x");
+               wacom_wac->flip_pos_y = of_property_read_bool(hdev->dev.parent->of_node,
+                                                       "flip-pos-y");
+               wacom_wac->flip_distance = of_property_read_bool(hdev->dev.parent->of_node,
+                                                       "flip-distance");
+       } else {
+               wacom_wac->flip_tilt_x = false;
+               wacom_wac->flip_tilt_y = false;
+               wacom_wac->flip_pos_x = false;
+               wacom_wac->flip_pos_y = false;
+               wacom_wac->flip_distance = false;
+       }
+}
+
 static int wacom_probe(struct hid_device *hdev,
                const struct hid_device_id *id)
 {

@@ -2797,6 +2820,8 @@ static int wacom_probe(struct hid_device *hdev,
                                 error);
        }

+       wacom_of_read(hdev, wacom_wac);
+
        wacom_wac->probe_complete = true;
        return 0;
 }

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 33a6908995b1..c01f683e23fa 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c

@@ -3261,6 +3261,63 @@ static int wacom_status_irq(struct wacom_wac *wacom_wac, size_t len)
        return 0;
 }

+static int wacom_of_irq(struct wacom_wac *wacom_wac, size_t len)
+{
+       const struct wacom_features *features = &wacom_wac->features;
+       unsigned char *data = wacom_wac->data;
+       struct input_dev *input = wacom_wac->pen_input;
+       unsigned int x, y, pressure;
+       unsigned char tsw, f1, f2, ers;
+       short tilt_x, tilt_y, distance;
+
+       if (!IS_ENABLED(CONFIG_OF))
+               return 0;
+
+       tsw = data[1] & WACOM_TIP_SWITCH_bm;
+       ers = data[1] & WACOM_ERASER_bm;
+       f1 = data[1] & WACOM_BARREL_SWITCH_bm;
+       f2 = data[1] & WACOM_BARREL_SWITCH_2_bm;
+       x = le16_to_cpup((__le16 *)&data[2]);
+       y = le16_to_cpup((__le16 *)&data[4]);
+       pressure = le16_to_cpup((__le16 *)&data[6]);
+
+       /* Signed */
+       tilt_x = get_unaligned_le16(&data[9]);
+       tilt_y = get_unaligned_le16(&data[11]);
+
+       distance = get_unaligned_le16(&data[13]);
+
+       /* keep touch state for pen events */
+       if (!wacom_wac->shared->touch_down)
+               wacom_wac->tool[0] = (data[1] & 0x0c) ?
+                       BTN_TOOL_RUBBER : BTN_TOOL_PEN;
+
+       wacom_wac->shared->touch_down = data[1] & 0x20;
+
+       // Flip the values based on properties from the device tree
+
+       // Default to a negative value for distance as HID compliant Wacom
+       // devices generally specify the hovering distance as negative.
+       distance = wacom_wac->flip_distance ? distance : -distance;
+       x = wacom_wac->flip_pos_x ? (features->x_max - x) : x;
+       y = wacom_wac->flip_pos_y ? (features->y_max - y) : y;
+       tilt_x = wacom_wac->flip_tilt_x ? -tilt_x : tilt_x;
+       tilt_y = wacom_wac->flip_tilt_y ? -tilt_y : tilt_y;
+
+       input_report_key(input, BTN_TOUCH, tsw || ers);
+       input_report_key(input, wacom_wac->tool[0], wacom_wac->shared->touch_down);
+       input_report_key(input, BTN_STYLUS, f1);
+       input_report_key(input, BTN_STYLUS2, f2);
+       input_report_abs(input, ABS_X, x);
+       input_report_abs(input, ABS_Y, y);
+       input_report_abs(input, ABS_PRESSURE, pressure);
+       input_report_abs(input, ABS_DISTANCE, distance);
+       input_report_abs(input, ABS_TILT_X, tilt_x);
+       input_report_abs(input, ABS_TILT_Y, tilt_y);
+
+       return 1;
+}
+
 void wacom_wac_irq(struct wacom_wac *wacom_wac, size_t len)
 {
        bool sync;

@@ -3379,6 +3436,10 @@ void wacom_wac_irq(struct wacom_wac *wacom_wac, size_t len)
                        sync = wacom_remote_irq(wacom_wac, len);
                break;

+       case HID_GENERIC:
+               sync = wacom_of_irq(wacom_wac, len);
+               break;
+
        default:
                sync = false;
                break;

diff --git a/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
index 8b2d4e5b2303..4dd5a56bf347 100644
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h

@@ -157,6 +157,14 @@
 #define WACOM_HID_WT_Y                  (WACOM_HID_UP_WACOMTOUCH | 0x131)
 #define WACOM_HID_WT_REPORT_VALID       (WACOM_HID_UP_WACOMTOUCH | 0x1d0)

+// Bitmasks (for data[3])
+#define WACOM_TIP_SWITCH_bm         (1 << 0)
+#define WACOM_BARREL_SWITCH_bm      (1 << 1)
+#define WACOM_ERASER_bm             (1 << 2)
+#define WACOM_INVERT_bm             (1 << 3)
+#define WACOM_BARREL_SWITCH_2_bm    (1 << 4)
+#define WACOM_IN_RANGE_bm           (1 << 5)
+
 #define WACOM_BATTERY_USAGE(f) (((f)->hid == HID_DG_BATTERYSTRENGTH) || \
                                 ((f)->hid == WACOM_HID_WD_BATTERY_CHARGING) || \
                                 ((f)->hid == WACOM_HID_WD_BATTERY_LEVEL))

@@ -357,6 +365,11 @@ struct wacom_wac {
        bool has_mode_change;
        bool is_direct_mode;
        bool is_invalid_bt_frame;
+       bool flip_tilt_x;
+       bool flip_tilt_y;
+       bool flip_pos_x;
+       bool flip_pos_y;
+       bool flip_distance;
 };

 #endif
--

2.31.1