Re: clk_set_parent() by name ?

[Jared McNeill <jmcneill%invisible.ca@localhost>]

On Mon, 19 Mar 2018, Manuel Bouyer wrote:

> Looking at what we have now, I see 2 ways for doing this:
> - clk_set_parent(). But this one takes a "struct clk*" as parent,
>  and I don't have this handy in the driver. There is clk_get(), but it
>  need the ckock domain, which I also don't have it in the driver.
>  There is no clk_get_domain()
> - clk->set_parent(), which takes a clock name. But for this I need to
>  use a struct sunxi_ccu_clk * instead of struct clk *.
>
> So what should I do to solve this ? Introduce clk_get_domain() or
> clk_set_parent_byname() in sys/dev/clk/, or use struct sunxi_ccu_clk in
> the sunxi drivers ?

The dt should have references to the parent clocks - the hdmi node has:

   clocks = <&ccu CLK_AHB_HDMI0>, <&ccu CLK_HDMI>,
            <&ccu 9>,
            <&ccu 18>;
   clock-names = "ahb", "mod", "pll-0", "pll-1";

So you can do something like:

   struct clk *clk_hdmi = fdtbus_clock_get(phandle, "mod");
   struct clk *clk_video0 = fdtbus_clock_get(phandle, "pll-0");
   struct clk *clk_video1 = fdtbus_clock_get(phandle, "pll-1");

   ...

   clk_set_parent(clk_hdmi, use_video0 ? clk_video0 : clk_video1);


Cheers,
Jared