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SubjectRe: [PATCH] clk: fix clock global name usage.
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Quoting Alexandre Mergnat (2019-05-24 00:27:45)
> A recent patch allows the clock framework to specify the parent
> relationship with either the clk_hw pointer, the global name or through
> Device Tree name.

You could point to the commit instead of saying "a recent patch". Would
provide more clarity.

>
> But the global name isn't handled by the clk framework because the DT name
> is considered valid even if it's NULL, so of_clk_get_hw() returns an
> unexpected clock (the first clock specified in DT).

Yes, the DT name can be NULL and then we would use the index.

>
> This can be fixed by calling of_clk_get_hw() only when DT name is not NULL.
>
> Fixes: fc0c209c147f ("clk: Allow parents to be specified without string names")
> Cc: Jerome Brunet <jbrunet@baylibre.com>
> Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
> ---
> drivers/clk/clk.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index bdb077ba59b9..9624a75e5a8d 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -368,7 +368,7 @@ static struct clk_core *clk_core_get(struct clk_core *core, u8 p_index)
> const char *dev_id = dev ? dev_name(dev) : NULL;
> struct device_node *np = core->of_node;
>
> - if (np && index >= 0)
> + if (name && np && index >= 0)

Do you set the index to 0 in this clk's parent_data? We purposefully set
the index to -1 in clk_core_populate_parent_map() so that the fw_name
can be NULL but the index can be something >= 0 and then we'll use that
to lookup the clk from DT. We need to support that combination.

fw_name | index | DT lookup?
----------+---------+------------
NULL | >= 0 | Y
NULL | -1 | N
non-NULL | -1 | ?
non-NULL | >= 0 | Y

Maybe we should support the ? case, because right now it will fail to do
the DT lookup when the index is -1.

So this patch instead?

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b34e84bb8167..a554cb9316a5 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -368,7 +368,7 @@ static struct clk_core *clk_core_get(struct clk_core *core, u8 p_index)
const char *dev_id = dev ? dev_name(dev) : NULL;
struct device_node *np = core->of_node;

- if (np && index >= 0)
+ if (np && (index >= 0 || name))
hw = of_clk_get_hw(np, index, name);

/*
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