2017-06-22 4:35 GMT+08:00 Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>: > On Tue, Jun 20, 2017 at 09:44:43PM +0800, Ziping Chen wrote: >> From: Ziping Chen <techping.chan@xxxxxxxxx> >> >> Allwinner A83T SoC has a low res adc like the one >> in Allwinner A10 SoC, however, the A10 SoC's vref >> of lradc internally is divided by 2/3 and the A83T >> SoC's isn't, thus add a hardware variant for it to >> be compatible with various devices. > > Where did you get that info from? > > Judging from the user manual, the threshold is actually set to 3/4, > and not 2/3, but there's still one. In the top of page 266 of the A10 User Manual V1.50, it said "2/3 ADC_REF (Level A)" which mean Level A is 2/3 of the vref. In the bottom of page 230 of the A83T User Manual V1.5.1, it said "1.35V (Level A)" meaning that Level A is 1.35V. Oh, it's my fault... It's 3/4 of the vref (A83T's ADC_REF is fixed at 1.8V). So... i will change r_lradc_variant_a83t.divisor_numerator to 3 and r_lradc_variant_a83t.divisor_denominator to 4... Is there any other problems? Thanks, Ziping > > Maxime > > -- > Maxime Ripard, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
