Re: [PATCH 4/9] clk: sunxi-ng: mux: Add support for mux tables

From: Maxime Ripard
Date: Wed Jul 27 2016 - 03:40:40 EST


On Wed, Jul 27, 2016 at 09:18:27AM +0200, Jean-Francois Moine wrote:
> On Wed, 27 Jul 2016 08:59:34 +0200
> Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On Tue, Jul 26, 2016 at 07:43:06PM +0200, Jean-Francois Moine wrote:
> > > On Tue, 26 Jul 2016 15:04:26 +0800
> > > Chen-Yu Tsai <wens@xxxxxxxx> wrote:
> > >
> > > > Some clock muxes have holes, i.e. invalid or unconnected inputs,
> > > > between parent mux values.
> > > >
> > > > Add support for specifying a mux table to map clock parents to
> > > > mux values.
> > >
> > > Putting empty strings in the holes should work. No?
> > > Ex:
> > >
> > > static const char * const csi_mclk_parents[] =
> > > { "pll-video0", "pll-video1", "", "", "", "osc24M" };
> >
> > Not really. The clock would be declared as orphan, while it's really
> > not.
> >
> > Parenting functions would also not work as expected,
> > clk_hw_get_parent_by_index being the obvious example, in that case
> > returning the empty string for an invalid parent, while it should
> > really return NULL.
>
> I don't see why the clock should be orphan.
> Then, when a parent is "", clk_hw_get_parent_by_index() returns NULL.

Why? It should return NULL when there's no parent, while you
explicitly registered a parent.

Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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