On Tue, May 15, 2018 at 10:18:25AM -0700, Dmitry Torokhov wrote:
> Hi Hans,
>
> On Fri, May 11, 2018 at 03:30:40PM +0200, Hans de Goede wrote:
> > Some Silead bases touchscreens (depending on the firmware and/or the
> > regulator) report coordinates which never reach 0 along one or both
> > of their axis.
> >
> > This commit adds support for setting a "silead,min-x" and "min-y" property
> > which indicates the minimum x/y values reported.
> >
> > When enabled this fixes e.g. not being able to click things in the GNOME3
> > top-bar on same tablets.
> >
> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > ---
> > .../input/touchscreen/silead_gsl1680.txt | 3 +++
> > drivers/input/touchscreen/silead.c | 23 ++++++++++++++++---
> > 2 files changed, 23 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> > index 84752de12412..07e19ef46c56 100644
> > --- a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> > @@ -25,6 +25,9 @@ Optional properties:
> > - silead,max-fingers : maximum number of fingers the touchscreen can detect
> > - silead,home-button : Boolean, set to true on devices which have a
> > capacitive home-button build into the touchscreen
> > +- silead,min-x : minimum raw x value reported by the touchscreen, set
> > + this for firmwares/digitizers where this is not 0
> > +- silead,min-y : minimum raw y value reported by the touchscreen
>
> I'd rather this go into generic touchscreen bindings as
> "touchscreen-min-x" and "touchscreen-min-y". Rob?
>
> > - vddio-supply : regulator phandle for controller VDDIO
> > - avdd-supply : regulator phandle for controller AVDD
> >
> > diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
> > index ff7043f74a3d..024d15ba6d1b 100644
> > --- a/drivers/input/touchscreen/silead.c
> > +++ b/drivers/input/touchscreen/silead.c
> > @@ -77,6 +77,8 @@ struct silead_ts_data {
> > struct regulator_bulk_data regulators[2];
> > char fw_name[64];
> > struct touchscreen_properties prop;
> > + int min_x;
> > + int min_y;
> > u32 max_fingers;
> > u32 chip_id;
> > struct input_mt_pos pos[SILEAD_MAX_FINGERS];
> > @@ -144,6 +146,7 @@ static void silead_ts_read_data(struct i2c_client *client)
> > u8 *bufp, buf[SILEAD_TS_DATA_LEN];
> > int touch_nr, softbutton, error, i;
> > bool softbutton_pressed = false;
> > + int x, y;
> >
> > error = i2c_smbus_read_i2c_block_data(client, SILEAD_REG_DATA,
> > SILEAD_TS_DATA_LEN, buf);
> > @@ -182,9 +185,14 @@ static void silead_ts_read_data(struct i2c_client *client)
> > */
> > data->id[touch_nr] = (bufp[SILEAD_POINT_X_MSB_OFF] &
> > SILEAD_EXTRA_DATA_MASK) >> 4;
> > - touchscreen_set_mt_pos(&data->pos[touch_nr], &data->prop,
> > - get_unaligned_le16(&bufp[SILEAD_POINT_X_OFF]) & 0xfff,
> > - get_unaligned_le16(&bufp[SILEAD_POINT_Y_OFF]) & 0xfff);
> > +
> > + x = get_unaligned_le16(&bufp[SILEAD_POINT_X_OFF]) & 0xfff;
> > + x = max(x - data->min_x, 0);
> > +
> > + y = get_unaligned_le16(&bufp[SILEAD_POINT_Y_OFF]) & 0xfff;
> > + y = max(y - data->min_y, 0);
>
> "Normalizing" the coordinates is not what kernel normally does, but
> is better left for userpsace.
>
> Peter, will the userspace DTRT when presented with X/Y axis with
> non-zero minimum supplied?
yeah, we've been assuming non-zero minimums for axes for few years now. Only
exceptions are ABS_MT_SLOT and the axes where zero is a defined magic value
like ABS_MT_ORIENTATION.
There's also the LIBINPUT_CALIBRATION_MATRIX udev property which is intended
for devices that report correct-ish coordinates but are mounted wrong, e.g.
upside down.
Cheers,
Peter
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