Re: [RFC 2/2] clk: samsung: add exynos5250 composite clock for hdmi

[Saravana Kannan <skannan@codeaurora.org>]

On 05/20/2013 11:57 AM, Tomasz Figa wrote:
> Hi Rahul,
>
> On Monday 20 of May 2013 19:47:08 Rahul Sharma wrote:
>> HDMI driver needs to change the parent of sclk_hdmi clock to
>> sclk_pixel or to sclk_hdmiphy, depends on the status of hdmiphy.
>> sclk_hdmi which is gate clock doesn't support the set_parent
>> operation.
>
> Wouldn't it be better to simply allow calling clk_set_parent() on gate
> clocks and propagate parent change to nearest mux, just like it is done
> with clk_set_rate()?
>
> It wouldn't require any SoC-specific composite clocks and keep the nice
> property of the clock tree, which is built from basic, generic clock
> blocks that nicely correspond to blocks shown in the documentation.
>
> We had discussed this already at SRPOL and got to the conclusion that it's
> a step backwards, making the clock driver more complex, because each
> composite block would have to be described using a structure with many
> fields. In addition there are many special cases, for which the composite
> scheme wouldn't work anyway and they would end up with simple clocks
> attached after the composite block, defeating the purpose of your patch.
>

+1 to all these comments.

-Saravana

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation