[alsa-devel] Question about devm_get_clk_from_child()

[Kuninori Morimoto]

Hi Stephen

> > index 14cbf23..96053a9 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -4213,7 +4213,7 @@ struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
> >         if (!np)
> >                 return ERR_PTR(-ENOENT);
> >  
> > -       return __of_clk_get(np, -1, np->full_name, name);
> > +       return __of_clk_get(np, 0, np->full_name, name);
> >  }
> 
> Yes this is correct. Thanks for debugging and fixing my thinko here. I
> was thinking that nobody would call of_clk_get_by_name() unless they
> wanted to find some clk that had a matching name, but it seems that we
> also allow NULL to be passed as the name to mean the typical "wildcard
> match" thing that clkdev has done for years. I'll throw this patch on
> top of the merge commit so the breakage window is small as I'd rather
> not rewrite the series just for this. Thanks.

Ahh, OK.
So, how about this ? it is including both opinion :)
I'm not sure which one should be applied, but both can solve my issue.

--------------------
From e75755351963c9b70ff3484f3088c4ed76d9d196 Mon Sep 17 00:00:00 2001
From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
Date: Thu, 7 Mar 2019 09:05:51 +0900
Subject: [PATCH] clk: fixup default index for of_clk_get_by_name()

of_clk_get_by_name() is using -1 for __of_clk_get() index.
It will goes to of_parse_clkspec(), and be used for
of_parse_phandle_with_args().
Here, if user doesn't specified clock name
(= of_clk_get_by_name(np, NULL)), this index is still -1,
and of_parse_phandle_with_args() will return -EINVAL
(This index will be updated if if it had clock name).

OTAH, nobody would call of_clk_get_by_name() unless they
wanted to find some clk that had a matching name.
But we also allow NULL to be passed as the name to mean the
typical "wildcard match" thing.

This means default index should be 0 instead of -1 if name was NULL.
This patch fixup it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
---
 drivers/clk/clk.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 14cbf23..66c71e9 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4210,10 +4210,12 @@ EXPORT_SYMBOL(of_clk_get);
  */
 struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
 {
+	int index = name ? -1 : 0;
+
 	if (!np)
 		return ERR_PTR(-ENOENT);
 
-	return __of_clk_get(np, -1, np->full_name, name);
+	return __of_clk_get(np, index, np->full_name, name);
 }
 EXPORT_SYMBOL(of_clk_get_by_name);
 
-- 
2.7.4