On 13 Aug 2014, scottw...@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. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
