[PATCH 4/7] clk: add clk-asm9260 driver

[Alexandre Belloni]

Hi,

On 18/09/2014 at 08:46:57 +0200, Oleksij Rempel wrote :
> Am 17.09.2014 um 15:54 schrieb Alexandre Belloni:
> > Hi,
> > 
> > Please have a look at https://lkml.org/lkml/2014/5/14/598 which describe
> > the preferred way of implementing clocks in the CCF where you only
> > declare the clock generator in the DT instead of each separate clocks.
> 
> hm... if i see it correctly. i will need to move almost everything from
> DT to clk-driver. And i will need to create separate driver for other
> SoC provided by AlphaScale. On other side with current (generic) driver
> i will need only to change DT and it will work.
> 
> May be instead of going qcom way, it will be better to have generic
> gate, div and mux bindings for DT? Sure it will make DT a bit fuzzy, but
> it will dramatically reduce kernel code and reduce the time of providing
> code to upstream.
> 
> I don't think drivers/clk/qcom/gcc-msm8974.c is less complicated solution.

IT is not less complicated but it is more flexible (for exemple when
setting flags on individual clocks, like CLK_SET_RATE_PARENT or
CLK_IGNORE_UNUSED). Describing all the individual clocks in DT is a
mistake we made in at91 and it will definitely bother you in the future,
for example when you realize that your clock controller is also taking
care of reset or power management.

Also, this is the kind of driver you write only once per SoC so it is
about the same doing it in DT or in C with the added advantage that
doing it in C takes less memory and is probably faster.

You can have a look at how it has been done for the berlin SoCs to see
how you can easily reuse code between drivers.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com