On Tue, Oct 19, 2021 at 11:51 AM Dmitry Torokhov
[off-list ref] wrote:

Hi Ping,

On Mon, Oct 18, 2021 at 10:41:55AM -0700, Ping Cheng wrote:

quoted

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.

I am really confused about this distinction. Could you please elaborate
why wacom driver only supports 0x056a (and, curiously, some Lenovo)
devices.

Thanks.

quoted

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

Sorry about that,
Ping

Signed-off-by: Alistair Francis <redacted>

quoted

---
 .../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

Do these really need to be controlled separately from the main
touchcsreen orientation?

I don't think so actually.

quoted

quoted

+
+  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

We already have touchscreen-inverted-x/y defined in
Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml,
why are they not sufficient?

The touchscreen-* properties aren't applied to HID devices though, at
least not that I can tell.

Alistair

quoted

quoted

+
+  flip-distance:
+    type: boolean
+    description: Flip the distance values read from device

I am still confused of the notion of flipped distance.

quoted

quoted

+
 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]);

You are still parsing raw data. The point of HID is to provide common
framework for scaling raw values.

Thanks.

--
Dmitry