Re: [PATCH v2 0/3] increase TSCADC clock to 24MHz and fix ti,charge-delay to represent in nS

From: Mugunthan V N
Date: Thu Nov 24 2016 - 23:57:38 EST


Hi Dmitry Torokhov,

On Thursday 10 November 2016 10:05 PM, Mugunthan V N wrote:
> This patch series enables ADC to be clocked at 24MHz as the
> TI AM335x ADC driver has already adopted to use DMA to transfer
> ADC samples. Now ADC can generated upto 800K Samples per second
> with the patch [1] on AM335x BBB and AM437x GP EVM.
>
> when ADC ref clock is set at 24MHz, I am seeing some issue with
> touch screen pointer as the pointer jumps to random locations
> with free draw application. The issue is due to increase in ADC
> clock and charge delay for the touchscreen ADC line duration
> reduced.
>
> So the notation of ti,charge-delay in terms of ADC clock is
> wrong, it has to be represented in time and driver has to convert
> the charge delay time to ADC clocks based on what ADC clock
> frequency is set.
>
> Measured the performance with the iio_generic_buffer with the
> patch [2] applied
>
> Verified the touch screen on AM335x GP EVM and AM335x BBB LCD7
> cape with [3] dts for display and touch screen to work.
>

Since there are acks from DT and MFD maintainers, can you pull the patch
series if you do not have any more comments.

Regards
Mugunthan V N