Hi again, Am Dienstag, 23. Juni 2015 21:46:25 UTC+2 schrieb Hans de Goede: > Hi, > > On 06/23/2015 05:06 PM, m.silentcreek@xxxxxxxxx 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. I just checked the diff for Linux 4.0 and 4.1 and noticed that sun7i-a20.dtsi 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=sunxi/dt-for-4.2&id=8bf1b9b3d90194a174493febc731f7783f2adf1a > > > > > > > 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. März 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 <hdegoede@xxxxxxxxxx> > >> --- > >> 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 Regards, Timo
