From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.silentcreek-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Subject: Re: [PATCH] touchscreen: sun4i-ts: Really fix A10 temperature reporting Date: Tue, 23 Jun 2015 14:06:34 -0700 (PDT) Message-ID: <2b011bd9-f8a8-4fa9-adc8-2ee91b0e6527@googlegroups.com> References: <1425893870-28715-1-git-send-email-hdegoede@redhat.com> <41a7a857-96fd-48ab-9778-127cfc091ef0@googlegroups.com> <5589B78C.4080600@redhat.com> Reply-To: m.silentcreek-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_4830_678480457.1435093594477" Return-path: In-Reply-To: <5589B78C.4080600-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Cc: wens-jdAy2FN1RRM@public.gmane.org, hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-input-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org ------=_Part_4830_678480457.1435093594477 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi again, Am Dienstag, 23. Juni 2015 21:46:25 UTC+2 schrieb Hans de Goede: > Hi, >=20 > On 06/23/2015 05:06 PM, m.silentcreek-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote: > > Hi Hans, > > > > is it possible that this patch (and the parent commit "Input: sun4i-ts = - allow controlling filter and sensitivity via DT") has quite an adversial = effect on other boards than the ones tested? > > > > On my Lemaker Bananapi the temperature is now being reported as somwher= e between -15=C2=B0C to -10=C2=B0C with the latest Kernel 4.1.0. These nega= tive values are obviously way off. On Kernel 4.0.5 the temperature reading = was usually around 40=C2=B0C. While that might not have been accurate eithe= r, it was at least plausible. >=20 > The temperature curve for the A20 SoC was not changed, if it did change t= hen > you're using an old dtb file with a new kernel, you must always update yo= ur > dtb file together with the kernel. I just checked the diff for Linux 4.0 and 4.1 and noticed that sun7i-a20.dt= si in fact has not changed. Is it possible that something that should have = been merged got delayed? I looked in Maxime's tree "dt-for-4.2" and found this patch that looks like= it could be related: https://git.kernel.org/cgit/linux/kernel/git/mripard/= linux.git/commit/?h=3Dsunxi/dt-for-4.2&id=3D8bf1b9b3d90194a174493febc731f77= 83f2adf1a >=20 >=20 >=20 > > > > Given that there is no Documentation and things seem quite board-specif= ic, I really don't know how this could be improved, so I can merely report = my observation. > > > > Kind regards, > > > > Timo > > > > > > Am Montag, 9. M=C3=A4rz 2015 10:38:02 UTC+1 schrieb Hans de Goede: > >> The commit titled: > >> "touchscreen: sun4i-ts: A10 (sun4i) has a different temperature curve" > >> contains a math error, the offset it uses is in degrees, but the actua= l code > >> applies the offset before multiplying by stepsize :| > >> > >> Given that this is rather backwards (every math course ever thought ap= plies > >> the multiplication before the offset for linear functions), this commi= t > >> fixes things by changing the code applying the offset to do the logica= l > >> thing, adjusting the offset for the other models accordingly. > >> > >> This has been tested on an A10, A13, A20 and A31 to make sure everythi= ng really > >> is correct now. > >> > >> Signed-off-by: Hans de Goede > >> --- > >> Note if possible this commit should be squashed into the original > >> "touchscreen: sun4i-ts: A10 (sun4i) has a different temperature curve" > >> commit as a fixup. > >> --- > >> drivers/input/touchscreen/sun4i-ts.c | 14 +++++++------- > >> 1 file changed, 7 insertions(+), 7 deletions(-) > >> > >> diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touc= hscreen/sun4i-ts.c > >> index 66ccd5a..178d2ef 100644 > >> --- a/drivers/input/touchscreen/sun4i-ts.c > >> +++ b/drivers/input/touchscreen/sun4i-ts.c > >> @@ -193,7 +193,7 @@ static int sun4i_get_temp(const struct sun4i_ts_da= ta *ts, long *temp) > >> if (ts->temp_data =3D=3D -1) > >> return -EAGAIN; > >> > >> - *temp =3D (ts->temp_data - ts->temp_offset) * ts->temp_step; > >> + *temp =3D ts->temp_data * ts->temp_step - ts->temp_offset; > >> > >> return 0; > >> } > >> @@ -255,17 +255,17 @@ static int sun4i_ts_probe(struct platform_device= *pdev) > >> ts->ignore_fifo_data =3D true; > >> ts->temp_data =3D -1; > >> if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) { > >> - /* Allwinner SDK has temperature =3D -271 + (value / 6) (C) */ > >> - ts->temp_offset =3D 1626; > >> + /* Allwinner SDK has temperature (C) =3D (value / 6) - 271 */ > >> + ts->temp_offset =3D 271000; > >> ts->temp_step =3D 167; > >> } else if (of_device_is_compatible(np, "allwinner,sun4i-a10-ts")) { > >> /* > >> * The A10 temperature sensor has quite a wide spread, these > >> * parameters are based on the averaging of the calibration > >> * results of 4 completely different boards, with a spread of > >> - * temp_step from 96 - 170 and temp_offset from 1758 - 3310. > >> + * temp_step from 0.096 - 0.170 and temp_offset from 176 - 331. > >> */ > >> - ts->temp_offset =3D 2570; > >> + ts->temp_offset =3D 257000; > >> ts->temp_step =3D 133; > >> } else { > >> /* > >> @@ -273,13 +273,13 @@ static int sun4i_ts_probe(struct platform_device= *pdev) > >> * the temperature. The formula used here is from the AXP209, > >> * which is designed by X-Powers, an affiliate of Allwinner: > >> * > >> - * temperature =3D -144.7 + (value * 0.1) > >> + * temperature (C) =3D (value * 0.1) - 144.7 > >> * > >> * Allwinner does not have any documentation whatsoever for > >> * this hardware. Moreover, it is claimed that the sensor > >> * is inaccurate and cannot work properly. > >> */ > >> - ts->temp_offset =3D 1447; > >> + ts->temp_offset =3D 144700; > >> ts->temp_step =3D 100; > >> } > >> > >> -- > >> 2.3.1 > > >=20 > Regards, >=20 > Hans Regards, Timo --=20 You received this message because you are subscribed to the Google Groups "= linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to linux-sunxi+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit https://groups.google.com/d/optout. ------=_Part_4830_678480457.1435093594477--