[PATCH] clk: Fix return value of of_clk_get_by_name()

[Ahmad Fatoum]

Hi Alexander,

On 06.10.23 07:28, Alexander Shiyan wrote:
> of_clk_get_by_name() is used by clk_bulk_get_optional() => clk_get() function,
> so in case some clocks are missing we should return -ENOENT error code,
> as this is normal for optional clocks.
> The current implementation of of_clk_get_by_name() returns the -EINVAL error
> that comes from of_clk_get() with index <0 if the clock is not described
> in the device tree.

I stumbled upon the same problem and found that of_clk_get_by_name() returning
ERR_PTR(-EINVAL) in this case is documented Linux behavior (for of_parse_clkspec()).

The correct solution is thus to leave of_clk_get_by_name() alone and align
clk_get return values with Linux.

I did this in
https://lore.barebox.org/barebox/20230921080236.GX637806@pengutronix.de/T/#t

Can you test with that and see if it solves your issue?

Cheers,
Ahmad 

> 
> Signed-off-by: Alexander Shiyan <eagle.alexander923 at gmail.com>
> ---
>  drivers/clk/clkdev.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
> index dbe998b6af..f6c2fcdf10 100644
> --- a/drivers/clk/clkdev.c
> +++ b/drivers/clk/clkdev.c
> @@ -52,10 +52,9 @@ EXPORT_SYMBOL(of_clk_get);
>   */
>  struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
>  {
> -	struct clk *clk = ERR_PTR(-ENOENT);
> -
>  	/* Walk up the tree of devices looking for a clock that matches */
>  	while (np) {
> +		struct clk *clk;
>  		int index = 0;
>  
>  		/*
> @@ -68,11 +67,12 @@ struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
>  							 name);
>  		clk = of_clk_get(np, index);
>  		if (!IS_ERR(clk))
> -			break;
> -		else if (name && index >= 0) {
> +			return clk;
> +
> +		if (name && index >= 0) {
>  			pr_err("ERROR: could not get clock %pOF:%s(%i)\n",
>  				np, name ? name : "", index);
> -			return clk;
> +			return ERR_PTR(-ENOENT);
>  		}
>  
>  		/*
> @@ -85,7 +85,7 @@ struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
>  			break;
>  	}
>  
> -	return clk;
> +	return ERR_PTR(-ENOENT);
>  }
>  EXPORT_SYMBOL(of_clk_get_by_name);
>  #endif

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