Hi

On Oct 10, 2013, at 11:16 AM, David Herrmann wrote:

Hi

On Sun, Oct 6, 2013 at 8:44 PM, Rafael Brune [off-list ref] wrote:

quoted

With these changes the Wii U Pro Controller fully complies
to the gamepad-API and with the calibration is fully usable
out-of-the-box without any user-space tools. This potentially
breaks compatibility with software that relies on the two
inverted Y-Axis but since current bluez 4.x and 5.x versions
don't even support pairing with the controller yet the amount
of people affected should be rather small.

Did anyone try to read the calibration values from the EEPROM? Doing
calibration in the kernel is fine, but I'd rather have the
hardware-calibration values instead. Even if we cannot figure it out
now, we should try to stay as compatible to the real values as we can.

So how about keeping the min/max and neutral point as we have it know
and instead adjusting the reported values by scaling/moving them?

After googling a little bit it seems like their might actually be no
calibration data for the Classic Controller and Wii U Pro Controller. The
midpoint is supposedly just detected when the device connects.
http://wiibrew.org/wiki/Classic_Controller

My code did not change what we output as the min/max/mid values it's
still -0x800,0x000,0x800. As you suggest it scales/moves the raw values
so that the reported values fall into that range.

quoted

Signed-off-by: Rafael Brune <redacted>
---
drivers/hid/hid-wiimote-modules.c | 45 +++++++++++++++++++++++++++++++++++----
1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-wiimote-modules.c b/drivers/hid/hid-wiimote-modules.c
index 2e7d644..1422b0b 100644
--- a/drivers/hid/hid-wiimote-modules.c
+++ b/drivers/hid/hid-wiimote-modules.c

@@ -1640,10 +1640,41 @@ static void wiimod_pro_in_ext(struct wiimote_data *wdata, const __u8 *ext)
       ly = (ext[4] & 0xff) | ((ext[5] & 0x0f) << 8);
       ry = (ext[6] & 0xff) | ((ext[7] & 0x0f) << 8);

-       input_report_abs(wdata->extension.input, ABS_X, lx - 0x800);
-       input_report_abs(wdata->extension.input, ABS_Y, ly - 0x800);
-       input_report_abs(wdata->extension.input, ABS_RX, rx - 0x800);
-       input_report_abs(wdata->extension.input, ABS_RY, ry - 0x800);
+       /* Calibrating the sticks by saving the global min/max per axis */
+       if (lx < wdata->state.calib_bboard[0][0])
+               wdata->state.calib_bboard[0][0] = lx;
+       if (lx > wdata->state.calib_bboard[0][1])
+               wdata->state.calib_bboard[0][1] = lx;
+
+       if (ly < wdata->state.calib_bboard[1][0])
+               wdata->state.calib_bboard[1][0] = ly;
+       if (ly > wdata->state.calib_bboard[1][1])
+               wdata->state.calib_bboard[1][1] = ly;
+
+       if (rx < wdata->state.calib_bboard[2][0])
+               wdata->state.calib_bboard[2][0] = rx;
+       if (rx > wdata->state.calib_bboard[2][1])
+               wdata->state.calib_bboard[2][1] = rx;
+
+       if (ry < wdata->state.calib_bboard[3][0])
+               wdata->state.calib_bboard[3][0] = ry;
+       if (ry > wdata->state.calib_bboard[3][1])
+               wdata->state.calib_bboard[3][1] = ry;
+
+       /* Normalize using int math to prevent conversion to/from float */
+       lx = -2048 + (((__s32)(lx - wdata->state.calib_bboard[0][0]) * 4096)/
+          (wdata->state.calib_bboard[0][1]-wdata->state.calib_bboard[0][0]));
+       ly = -2048 + (((__s32)(ly - wdata->state.calib_bboard[1][0]) * 4096)/
+          (wdata->state.calib_bboard[1][1]-wdata->state.calib_bboard[1][0]));
+       rx = -2048 + (((__s32)(rx - wdata->state.calib_bboard[2][0]) * 4096)/
+          (wdata->state.calib_bboard[2][1]-wdata->state.calib_bboard[2][0]));
+       ry = -2048 + (((__s32)(ry - wdata->state.calib_bboard[3][0]) * 4096)/
+          (wdata->state.calib_bboard[3][1]-wdata->state.calib_bboard[3][0]));

Don't use calib_bboard. Add a new array (or use a union). This is confusing.

I agree, will do that.

quoted

+
+       input_report_abs(wdata->extension.input, ABS_X,  lx);
+       input_report_abs(wdata->extension.input, ABS_Y, -ly);
+       input_report_abs(wdata->extension.input, ABS_RX,  rx);
+       input_report_abs(wdata->extension.input, ABS_RY, -ry);

       input_report_key(wdata->extension.input,
                        wiimod_pro_map[WIIMOD_PRO_KEY_RIGHT],

@@ -1760,6 +1791,12 @@ static int wiimod_pro_probe(const struct wiimod_ops *ops,
       if (!wdata->extension.input)
               return -ENOMEM;

+       /* Initialize min/max values for all Axis with reasonable values */
+       for (i = 0; i < 4; ++i) {
+               wdata->state.calib_bboard[i][0] = 0x780;
+               wdata->state.calib_bboard[i][1] = 0x880;

Ugh, these values look weird. We have a reported range of -0x400 to
+0x400 but you limit it to a virtual range of 0x100. That's a loss of
precision of 80%. Where are these values from?

I picked these values arbitrarily as starting points since they will update
during use of the gamepad as soon as lower/higher values are observed.
As soon as the sticks have been moved to their extreme positions once
everything is perfect.

We could also set those values in a similar fashion as to what Nintendo
seems to be doing. Wait for a first report of raw values, use them as the
mid point and set these min/max values as midpoint +/- ~0x800.

quoted

+       }
+
       set_bit(FF_RUMBLE, wdata->extension.input->ffbit);
       input_set_drvdata(wdata->extension.input, wdata);

Thanks for hacking this up. Could you give me some values from your
device so I can see how big the deviation is? My device reports:

Range: 0-4095 (0x0fff)
Neutral-Point: 2048 (0x800)

I haven't seen any big deviations from these values. I can try to take
this over if you want, just let me know.

Thanks
David

When I write out the observed raw min/max values of all Axis I get these:
LX: 1033 - 3326 (center~=2179 (0x883))
LY:  857 - 3211 (center~=2034 (0x7F2))
RX: 944 - 3176 (center~=2060 (0x80C))
RY: 853 - 3159 (center~=2006 (0x7D6))

So not really the whole range of 0x0FFF is actually used and offsets due
to manufacturing differences are present.


Regards,
 Rafael