Re: [PATCH RFC 0/3] clk: CCF clock primitives + custom IO accessors

[Stephen Boyd]

On 03/03/14 11:13, SÃren Brinkmann wrote:
> On Mon, 2014-03-03 at 08:07PM +0100, Gerhard Sittig wrote:
>> On Mon, Mar 03, 2014 at 09:35 -0800, SÃren Brinkmann wrote:
>>> It would be nice if we could use the logic provided in the mux, div etc
>>> primitives independently of how the HW is accessed and what is
>>> necessary to shift and mask those register values around, right? I
>>> mean, at then end we want to model a clk-(div|mux) and not a
>>> clk-(div|mux) which has only a single, memory-mapped control register,
>>> that does not overlap with other things, ...
>> Did you lookup the ll_ops discussion in the thread that
>> originated from
>> http://article.gmane.org/gmane.linux.ports.arm.kernel/289895 and
>> did you see the outlined logic in
>> http://article.gmane.org/gmane.linux.ports.arm.omap/109233 and
>> http://article.gmane.org/gmane.linux.ports.arm.omap/109381 ?
>>
>> Support for regmap access instead of mere MMIO was one of the
>> things you could do with this approach.  You appear to be in the
>> situation where you need such an extension (or something similar,
>> but you really should look into the ll_ops thing).
> Thanks for those pointer, I have some reading to do. That seems to
> go into the right direction.  What is the status of those patches?
> Are they already merged or actively worked on?
>

Ugh. The ll_ops design is a simplified form of regmap. Why not just use
regmap? It seems like it would be possible to make a regmap per
clk_register_{basic_type}() call via regmap_init_mmio() while still
allowing those functions to take a void __iomem pointer. Then we could
remove clk_readl/clk_writel (after providing *_be variants of the
registration functions for PPC) and just use a regmap throughout the
basic clock type code. Finally we can introduce *_regmap() registration
functions that allow drivers to register basic clock types with regmaps.

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