From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [PATCH] touchscreen: sun4i-ts: Really fix A10 temperature reporting Date: Tue, 23 Jun 2015 21:46:20 +0200 Message-ID: <5589B78C.4080600@redhat.com> References: <1425893870-28715-1-git-send-email-hdegoede@redhat.com> <41a7a857-96fd-48ab-9778-127cfc091ef0@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <41a7a857-96fd-48ab-9778-127cfc091ef0@googlegroups.com> Sender: linux-input-owner@vger.kernel.org To: m.silentcreek@gmail.com, linux-sunxi@googlegroups.com Cc: linux-input@vger.kernel.org, dmitry.torokhov@gmail.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, wens@csie.org, maxime.ripard@free-electrons.com List-Id: devicetree@vger.kernel.org Hi, On 06/23/2015 05:06 PM, m.silentcreek@gmail.com wrote: > Hi Hans, > > is it possible that this patch (and the parent commit "Input: sun4i-t= s - allow controlling filter and sensitivity via DT") has quite an adve= rsial effect on other boards than the ones tested? > > On my Lemaker Bananapi the temperature is now being reported as somwh= ere between -15=C2=B0C to -10=C2=B0C with the latest Kernel 4.1.0. Thes= e negative values are obviously way off. On Kernel 4.0.5 the temperatur= e reading was usually around 40=C2=B0C. While that might not have been = accurate either, it was at least plausible. The temperature curve for the A20 SoC was not changed, if it did change= then you're using an old dtb file with a new kernel, you must always update = your dtb file together with the kernel. > > Given that there is no Documentation and things seem quite board-spec= ific, I really don't know how this could be improved, so I can merely r= eport 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 curv= e" >> contains a math error, the offset it uses is in degrees, but the act= ual code >> applies the offset before multiplying by stepsize :| >> >> Given that this is rather backwards (every math course ever thought = applies >> the multiplication before the offset for linear functions), this com= mit >> fixes things by changing the code applying the offset to do the logi= cal >> thing, adjusting the offset for the other models accordingly. >> >> This has been tested on an A10, A13, A20 and A31 to make sure everyt= hing 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 curv= e" >> 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/to= uchscreen/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_= data *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_devi= ce *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_devi= ce *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 > Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-input" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: hdegoede@redhat.com (Hans de Goede) Date: Tue, 23 Jun 2015 21:46:20 +0200 Subject: [PATCH] touchscreen: sun4i-ts: Really fix A10 temperature reporting In-Reply-To: <41a7a857-96fd-48ab-9778-127cfc091ef0@googlegroups.com> References: <1425893870-28715-1-git-send-email-hdegoede@redhat.com> <41a7a857-96fd-48ab-9778-127cfc091ef0@googlegroups.com> Message-ID: <5589B78C.4080600@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 06/23/2015 05:06 PM, m.silentcreek at gmail.com 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 somwhere between -15?C to -10?C with the latest Kernel 4.1.0. These negative values are obviously way off. On Kernel 4.0.5 the temperature reading was usually around 40?C. While that might not have been accurate either, it was at least plausible. The temperature curve for the A20 SoC was not changed, if it did change then you're using an old dtb file with a new kernel, you must always update your dtb file together with the kernel. > > Given that there is no Documentation and things seem quite board-specific, I really don't know how this could be improved, so I can merely report my observation. > > Kind regards, > > Timo > > > Am Montag, 9. M?rz 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 actual code >> applies the offset before multiplying by stepsize :| >> >> Given that this is rather backwards (every math course ever thought applies >> the multiplication before the offset for linear functions), this commit >> fixes things by changing the code applying the offset to do the logical >> thing, adjusting the offset for the other models accordingly. >> >> This has been tested on an A10, A13, A20 and A31 to make sure everything 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/touchscreen/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_data *ts, long *temp) >> if (ts->temp_data == -1) >> return -EAGAIN; >> >> - *temp = (ts->temp_data - ts->temp_offset) * ts->temp_step; >> + *temp = 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 = true; >> ts->temp_data = -1; >> if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) { >> - /* Allwinner SDK has temperature = -271 + (value / 6) (C) */ >> - ts->temp_offset = 1626; >> + /* Allwinner SDK has temperature (C) = (value / 6) - 271 */ >> + ts->temp_offset = 271000; >> ts->temp_step = 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 = 2570; >> + ts->temp_offset = 257000; >> ts->temp_step = 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 = -144.7 + (value * 0.1) >> + * temperature (C) = (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 = 1447; >> + ts->temp_offset = 144700; >> ts->temp_step = 100; >> } >> >> -- >> 2.3.1 > Regards, Hans