Re: [PATCH 2/2] mtd: rawnand: Add timings for Kioxia TH58NVG2S3HBAI4

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Wed, 20 May 2020 14:42:31 +0000
Rickard X Andersson <Rickard.Andersson@xxxxxxxx> wrote:

> > > If I understand you correctly you want me to use onfi_find_equivalent_sdr_mode in order to find the corresponding onfi mode. Then you want me to use onfi_fill_data_interface and loop towards mode 0 checking which mode the controller accepts? I just thought it was a "messy" to duplicate this code in all vendor drivers.
> > > Or do you mean that I should just use onfi_find_equivalent_sdr_mode to set ."timings.mode" and let nand_base to do the looping in case error is returned from th58nvg2s3hbai4_choose_data_interface (i.e specialized timings not accepted by the controller).  
> >
> > Sorry for the misunderstanding. What I think you should try is:
> > 1/ call onfi_find_equivalent_sdr_mode() to set the timings.mode field.
> > 2/ call nand_controller_supports_data_interface()
> > 3/ if the controller supports the timings, set
> > chip->default_timing_mode accordingly and return 0.

Why do we have to set the default_timing_mode field? Can't we just set
timings.mode directly?

> > 4/ if the controller does not support the timings, you may want to
> > propose other standard timings to test by setting
> > chip->default_timing_mode anyway but returning an error which means
> > "best interface has not been found yet" so the rest of the
> > choose_data_interface() helper will try the remaining ONFI modes
> > automatically (fallbacks to 0 anyway).

Again, I don't see why setting chip->default_timing_mode is needed here,
and I'm not sure trying remaining ONFI modes is useful, I guess we can
just fall back on mode 0 in that case.

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