[U-Boot] [PATCH 3/4] mtd: nand: add Freescale NFC driver

Bill Pringlemeir
2014-08-14T14:26:12Z

On 13 Aug 2014, scottwood at freescale.com wrote:

> On Wed, 2014-08-13 at 17:44 -0400, Bill Pringlemeir wrote:
>> Regarding "can't know in advance", I think that some of the register
>> values maybe set by the boot rom. This might make more sense for
>> Linux than U-Boot. However, after the initial configuration, many do
>> need the 'read/modify/write' as there are many bit fields with
>> different functionality.

> If the register is only modified by software, and not asynchronously
> by hardware, then you could read the value once when the driver
> starts, and cache its value to avoid a reportedly expensive I/O access
> every time you need to modify it.

Yes, that is a good point. The regmap interface could be used in the
Linux kernel. I don't see any infrastructure like that in U-Boot? It
is fairly simple to re-invent as this driver only needs the flat
structure.

Regards,
Bill Pringlemeir.