[RFC PATCH 3/9] of: mtd: add NAND timings retrieval support

[boris brezillon]

Hello Jason,

On 09/01/2014 18:35, Jason Gunthorpe wrote:
> On Thu, Jan 09, 2014 at 09:36:18AM +0100, boris brezillon wrote:
>
>>> You might want to check if you can boil down the DT timings from the
>>> huge list to just an ONFI mode number..
>> Sure, but the sunxi driver needs at least 19 of them...
> So does mvebu's NAND driver..
>
> What I ment was you could have a
>
>    onfi,nand-timing-mode = 0
>
> in the DT. Each of the modes defines all ~19 parameters, higher modes
> are faster.
>
> Pick a mode value that fits all the parameters of the connected
> non-ONFI flash.
>
> This would be instead of defining each parameter
> individually.. Provide some helpers to convert from a onfi mode number
> to all the onfi defined timing parameters so that drivers can
> configure the HW..

Are you suggesting we should provide a function that converts these
modes into a nand_timings struct, or just use the timing modes and
let the NAND controller drivers configure its IP accordingly ?

I found the ONFI timing tables in this document:

www.*onfi*.org/~/media/*ONFI*/specs/*onfi*_3_1_spec.pdf‎ (chapter 4.16).

I suppose my nand_timings struct should use the names described
page 110-111 (at least if we decide to use nand_timings and not
nand_timing_modes), right ?

Best Regards,

Boris

>
> Jason