Re: [alsa-devel] [PATCH v2] clkdev: add devm_of_clk_get()

From: Stephen Boyd
Date: Wed Nov 23 2016 - 14:10:45 EST


On 11/16, Kuninori Morimoto wrote:
>
> Hi Rob, Michael, Russell
>
>
> What is the conclusion of this patch ?
> We shouldn't add devm_of_clk_get() ? or can I continue ?
>
> The problem of current [devm_]clk_get() handles *dev only,
> but I need to get clocks from DT node, not dev
>
> sound_soc {
> ...
> cpu {
> ...
> => clocks = <&xxx>;
> };
> codec {
> ...
> => clocks = <&xxx>;
> };
> };
>

I've seen bindings that have the 'clocks' property at the top
level and the appropriate 'clock-names' property to relate the
clocks to a subnode.

sound_soc {
clocks = <&xxx>, <&xxx>;
clock-names = "cpu", "codec";
...
cpu {
...
};
codec {
...
};
};

Then the subnodes call clk_get() with the top level device and
the name of their node and things match up. I suppose this
binding is finalized though, so we can't really do that?

I see that the gpio framework has a similar design called
devm_get_gpiod_from_child(), so how about we add a
devm_get_clk_from_child() API? That would more closely match the
intent here, which is to restrict the clk_get() operation to
child nodes of the device passed as the first argument.

struct clk *devm_get_clk_from_child(struct device *dev,
const char *con_id,
struct device_node *child);

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