[PATCH 2/2] clk: mediatek: fix parent rate lookup for fixed PLL clocks

[David Lechner]

On 4/9/26 9:13 PM, Weijie Gao wrote:
> From: Sam Shih <sam.shih at mediatek.com>
> 
> The refactoring in commit 00d0ff7f81bf ("clk: mediatek: refactor parent
> rate lookup functions") introduced a regression where fixed PLL clocks
> using mtk_clk_fixed_pll_ops are not properly recognized as valid parents
> in the CLK_PARENT_APMIXED case.
> 
> Fixed PLL clocks are implemented using mtk_clk_fixed_pll_ops instead of
> mtk_clk_apmixedsys_ops, but they can also serve as parent clocks in the
> APMIXED domain. The parent lookup function needs to check for both
> driver ops to properly resolve the parent clock device.
> 
> Add mtk_clk_fixed_pll_ops checks alongside mtk_clk_apmixedsys_ops checks
> in mtk_find_parent_rate() to restore support for fixed PLL parent clocks.
> 


> Also refactor the grandparent lookup code to extract the repeated
> dev_get_parent(priv->parent) call into a local variable to keep lines
> under 100 characters and pass checkpatch validation.

This sounds like an unrelated change. Let's split that out into a
separate patch.

> 
> Fixes: 00d0ff7f81bf ("clk: mediatek: refactor parent rate lookup functions")
> Signed-off-by: Sam Shih <sam.shih at mediatek.com>
> Signed-off-by: Weijie Gao <weijie.gao at mediatek.com>
> ---
>  drivers/clk/mediatek/clk-mtk.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
> index 4adec4457b4..26db60dea7f 100644
> --- a/drivers/clk/mediatek/clk-mtk.c
> +++ b/drivers/clk/mediatek/clk-mtk.c
> @@ -207,20 +207,26 @@ static ulong mtk_clk_find_parent_rate(struct clk *clk, int id,
>  static ulong mtk_find_parent_rate(struct mtk_clk_priv *priv, struct clk *clk,
>  				  const int parent, u16 flags)
>  {
> +	struct udevice *grandparent_dev;

Putting this here is fine, but we could also declare it inside the
else scope instead since it is only used there.

>  	struct udevice *parent_dev;
>  
>  	switch (flags & CLK_PARENT_MASK) {
>  	case CLK_PARENT_APMIXED:
>  		/* APMIXEDSYS can be parent or grandparent. */
> -		if (dev_get_driver_ops(clk->dev) == &mtk_clk_apmixedsys_ops)
> +		if (dev_get_driver_ops(clk->dev) == &mtk_clk_apmixedsys_ops ||
> +		    dev_get_driver_ops(clk->dev) == &mtk_clk_fixed_pll_ops) {
>  			parent_dev = clk->dev;
> -		else if (dev_get_driver_ops(priv->parent) == &mtk_clk_apmixedsys_ops)
> +		} else if (dev_get_driver_ops(priv->parent) == &mtk_clk_apmixedsys_ops ||
> +			dev_get_driver_ops(priv->parent) == &mtk_clk_fixed_pll_ops) {
>  			parent_dev = priv->parent;
> -		else if (dev_get_driver_ops(dev_get_parent(priv->parent)) == &mtk_clk_apmixedsys_ops)
> -			parent_dev = dev_get_parent(priv->parent);
> -		else
> -			return -EINVAL;
> -
> +		} else {
> +			grandparent_dev = dev_get_parent(priv->parent);
> +			if (dev_get_driver_ops(grandparent_dev) == &mtk_clk_apmixedsys_ops ||
> +			    dev_get_driver_ops(grandparent_dev) == &mtk_clk_fixed_pll_ops)
> +				parent_dev = grandparent_dev;
> +			else
> +				return -EINVAL;
> +		}
>  		break;
>  	case CLK_PARENT_TOPCKGEN:
>  		if (dev_get_driver_ops(clk->dev) == &mtk_clk_topckgen_ops)