[RFC 1/9] regmap: Add USB support

[Noralf Trønnes]

Den 17.02.2020 22.39, skrev Mark Brown:
> On Mon, Feb 17, 2020 at 10:33:58PM +0100, Noralf Trønnes wrote:
>> Den 17.02.2020 13.11, skrev Mark Brown:
> 
>>> This looks like you just don't support a straight write operation, if
>>> you need to do this emulation push it up the stack.
> 
>> After going through the stack I realise that I have a problem.
>> What I have failed to fully comprehend is this regmap requirement:
> 
>> 	if (val_len % map->format.val_bytes)
>> 		return -EINVAL;
> 
>> There will be a spi and i2c driver down the line which will transfer
>> buffers of any size, and having to use 8-bit register values will not be
>> great.
> 
> Out of interest why are 8 bit registers going to be a problem?
> 

I have written 3 drivers so far and they all have some registers that
need to deal with values larger than 255. If I would need to add a lot
of code because of dropping regmap, then I would have looked at ways to
work around this in order to keep regmap, hi/lo registers perhaps with
wrapping access functions. But it looks like the LOC won't change much,
I need a few lines to ensure values are little endian, but I can also
remove some lines that's not needed anymore.

Noralf.