Thread (10 messages) 10 messages, 3 authors, 2016-02-08

Re: [RFC 2/9] clk: bcm2835: add support for parent selection in DT

From: Martin Sperl <hidden>
Date: 2016-02-08 13:30:39
Also in: linux-arm-kernel, linux-clk


On 21.01.2016 09:26, Sascha Hauer wrote:
Martin,

On Tue, Jan 19, 2016 at 02:51:33PM +0000, kernel@martin.sperl.org wrote:
quoted
From: Martin Sperl <redacted>

Allow for a per clock custom selection of clocks in the device tree.

Basic setup in dt looks like this:
   clock@BCM2835_CLOCK_PCM {
     reg = <BCM2835_CLOCK_PCM>;
     parent-clock-names = "xosc", "plld_per", "plla_per", "pll_aux_per";
   };
Isn't this the same as the already existing assigned-clock-parents property?
If yes, that should be used.
It is not 100% identical, as the parent-clock-names do provide ordering
of clocks to be selected, which - under some circumstances may be
beneficial - e.g: when having a parent clock with 500MHz and 1000MHz,
then the higher clock could get given preference by switching ordering...

Also when using:
assigned-clock-parents = <&clk_osc 0>, <&clocks BCM2835_PLLD_PER>;

I get strange indexes passed when calling set_parent - so this would
need to get rewritten to support assigned-clock-parents correctly -
calculating the index on the fly...

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