Re: [PATCH v11 1/4] HID: wacom_sys: Add support for flipping the data values
From: Dmitry Torokhov
Date: Mon Oct 18 2021 - 21:51:15 EST
Hi Ping,
On Mon, Oct 18, 2021 at 10:41:55AM -0700, Ping Cheng wrote:
> Hi Alistair,
>
> On Sat, Oct 9, 2021, 4:44 AM Alistair Francis <alistair@xxxxxxxxxxxxx>
> wrote:
>
> > 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.
>
> Nacked-by: Ping Cheng <Ping.Cheng@xxxxxxxxx>
>
> Sorry about that,
> Ping
>
> Signed-off-by: Alistair Francis <alistair@xxxxxxxxxxxxx>
> > ---
> > .../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?
> > +
> > + 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?
> > +
> > + flip-distance:
> > + type: boolean
> > + description: Flip the distance values read from device
I am still confused of the notion of flipped distance.
> > +
> > 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