Re: [PATCH v2] mux: convert to use fwnode interface

[Alvin Šipraga]

On Wed, Sep 16, 2026 at 07:26:34PM +0200, Fabio Forni wrote:
> As firmware node is a more common abstract, this will convert the whole
> thing to fwnode interface.
> 
> Co-developed-by: Xu Yang <xu.yang_2@xxxxxxx>
> Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
> Signed-off-by: Fabio Forni <development@xxxxxxxxxx>
> ---
> This patch migrates the multiplexer subsystem from using the of_*          
> family of functions and structs, to the more generic fwnode framework.     
>                                                                            
> It is a rebase of a single commit[1] contained in a old patch series[2]
> submitted by Xu Yang. The original commit plus follow-up comments were
> tested on kernel v6.12 on an arm64-based board, but this current rebase
> isn't tested yet.                                                  
>                                                                            
> Link: https://lore.kernel.org/all/20220823195429.1243516-3-xu.yang_2@xxxxxxx [1]
> Link: https://lore.kernel.org/all/20220823195429.1243516-1-xu.yang_2@xxxxxxx [2]
> ---
> Changes in v2:
> - Rename devm_mux_state_get_from_swnode into devm_mux_state_get_from_fwnode
> - Link to v1: https://lore.kernel.org/r/20260915-mux_fwnode-v1-1-ed5a6d8202d4@xxxxxxxxxx
> ---
>  drivers/mux/core.c                    | 96 ++++++++++++++++++-----------------
>  drivers/pinctrl/pinctrl-generic-mux.c |  4 +-
>  include/linux/mux/consumer.h          |  6 ++-
>  3 files changed, 57 insertions(+), 49 deletions(-)

[...]

>  static struct mux_control *mux_get(struct device *dev, const char *mux_name,
>  				   unsigned int *state, bool optional,
> -				   struct device_node *node)
> +				   struct fwnode_handle *node)
>  {
> -	struct device_node *np = node ? node : dev->of_node;
> -	struct of_phandle_args args;
> +	struct fwnode_handle *fwnode = node ? node : dev_fwnode(dev);
> +	struct fwnode_reference_args args;
>  	struct mux_chip *mux_chip;
>  	unsigned int controller;
>  	int index = 0;
> @@ -551,11 +552,13 @@ static struct mux_control *mux_get(struct device *dev, const char *mux_name,
>  
>  	if (mux_name) {
>  		if (state)
> -			index = of_property_match_string(np, "mux-state-names",
> -							 mux_name);
> +			index = fwnode_property_match_string(fwnode,
> +							     "mux-state-names",
> +							     mux_name);
>  		else
> -			index = of_property_match_string(np, "mux-control-names",
> -							 mux_name);
> +			index = fwnode_property_match_string(fwnode,
> +							     "mux-control-names",
> +							     mux_name);
>  		if (index < 0 && optional) {
>  			return NULL;
>  		} else if (index < 0) {
> @@ -566,39 +569,40 @@ static struct mux_control *mux_get(struct device *dev, const char *mux_name,
>  	}
>  
>  	if (state)
> -		ret = of_parse_phandle_with_args(np,
> -						 "mux-states", "#mux-state-cells",
> -						 index, &args);
> +		ret = fwnode_property_get_reference_args(fwnode, "mux-states",
> +							 "#mux-state-cells", 0,
> +							 index, &args);
>  	else
> -		ret = of_parse_phandle_with_args(np,
> -						 "mux-controls", "#mux-control-cells",
> -						 index, &args);
> +		ret = fwnode_property_get_reference_args(fwnode,
> +							 "mux-controls", "#mux-control-cells",
> +							 0, index, &args);
> +
>  	if (ret) {
>  		if (optional && ret == -ENOENT)
>  			return NULL;
>  
> -		dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n",
> -			np, state ? "state" : "control",
> -			mux_name ?: "", index);
> +		dev_err(dev, "%pfw: failed to get mux-%s %s(%i)\n",
> +			fwnode, state ? "state" : "control", mux_name ?: "",
> +			index);
>  		return ERR_PTR(ret);
>  	}
>  
> -	mux_chip = of_find_mux_chip_by_node(args.np);
> -	of_node_put(args.np);
> +	mux_chip = mux_chip_find_by_fwnode(args.fwnode);
> +	fwnode_handle_put(args.fwnode);

I'm actually not sure why there was an of_node_put() here in the first
place. It seems wrong to me. Any idea what it's for?

I want to give a Reviewed-by here for the rest of the code, but if the
above _put() erroneous, it might be better to add a patch before this
one to remove it (and cc the stable list with that patch).

>  	if (!mux_chip)
>  		return ERR_PTR(-EPROBE_DEFER);

Kind regards,
Alvin