[PATCH 03/18] clk: imx: clk-imxrt1050: setup PLL5 for video in non-SPL

Giulio Benetti giulio.benetti at benettiengineering.com
Wed Feb 26 19:16:12 CET 2020

On 2/26/20 6:59 PM, Fabio Estevam wrote:
> Hi Giulio,
> On Wed, Feb 26, 2020 at 2:54 PM Giulio Benetti
> <giulio.benetti at benettiengineering.com> wrote:
>> Yes, it's a good idea. Doing this I've taken this[1] as example.
>> So I don't know where in u-boot PLLs are initialized according to a dts
>> file, can you please provide me an example? I will be happy to modify
>> this according to that!
> In the kernel device trees we use the 'assigned-clocks' and
> 'assigned-clock-parents' properties to establish a clock parent
> relationship.
> I suggest we follow the same approach in U-Boot.

Oh, I've seen now, need to study it before, but now in my mind it's 
getting more clear how that works. But will this work even if shrinked 
CCF in u-boot can't set parent clocks(at least this is what I've 
understood)? I mean, basically here for LCDIF I see that only last 
divider get set for achieving pixel-clock, while all parents are get 
only to recalcute the "last divider parent clock".

Also, I can't understand, is it ok setting PLL5 to 650Mhz and un-bypass 
it? The problem is only about clk_set_parent() for LCDIF?

Because if a peripheral would set a PLL5 frequency and another 
peripheral use it as parent, then it would set it again.

Best regards
Giulio Benetti
Benetti Engineering sas

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