[PATCH] mtd: mxc_nand: Set timing for v2 controllers

[s.hauer@pengutronix.de (Sascha Hauer)]

Hi Boris,

On Fri, Aug 26, 2016 at 09:46:53AM +0200, Boris Brezillon wrote:
> Hi Sascha,
> 
> On Tue, 23 Aug 2016 12:34:05 +0200
> Sascha Hauer <s.hauer@pengutronix.de> wrote:
> 
> AFAIR, you should apply the new mode on the NAND side
> (ONFI_FEATURE_ADDR_TIMING_MODE) before applying the new config to the
> controller.
> 
> See what's done here [1].
> 
> Note that on all the NANDs I tested, it seems to work even if you don't
> set ONFI_FEATURE_ADDR_TIMING_MODE, but the ONFI Spec describes the
> procedure as:

Indeed, works here without notifying the NAND chip aswell. I wasn't even
aware that there is a possibility to notify the NAND chip.

> 
> 1/ detect supported modes
> 2/ select one
> 3/ apply it to the NAND using set(ONFI_FEATURE_ADDR_TIMING_MODE)
> 4/ release the CS
> 5/ adjust the controller setting to match the new config
> 
> On a side note, I really think we should handle this timing selection in
> the core, and only ask the NAND controller drivers to adapt the
> controller settings.

I agree that the core should do this. Do you already have any thoughts
how the API could could look like? The Nand drivers probably have to
propagate somehow which modes they support, maybe we add a onfi_modes
field to struct nand_chip. Then if onfi_modes is nonzero we call a
nand_chip->set_onfi_mode() function?

Sascha

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