Re: [PATCH] usb: typec: ucsi: Get the connector fwnode based on reg value

[Heikki Krogerus]

On Wed, Sep 16, 2026 at 09:58:08AM +0530, Prashanth K wrote:
> ucsi_find_fwnode() currently maps UCSI connectors to Device tree
> connector nodes based on the order in which connector child nodes
> are described in DT.
> 
> This can fail because the ordering of child nodes isn't guaranteed
> in Device-tree. For example, DTB may contain connector@1 before
> connector@0, causing connector numbers to be associated with the wrong
> fwnode. As a result, role switch and Type-C notifications can be
> delivered to the wrong remote endpoints.
> 
> Fix this by using the "reg" property of each connector to match
> its corresponding fwnode. While at it, if the reg property isn't
> present, then fall back to the old method.
> 
> Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")

That commit does not yet include any kind of support for DT.

Thanks,

> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Prashanth K <prashanth.k@xxxxxxxxxxxxxxxx>
> ---
>  drivers/usb/typec/ucsi/ucsi.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index bef3f9b71d71..c1450639c795 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1801,10 +1801,21 @@ static struct fwnode_handle *ucsi_find_fwnode(struct ucsi_connector *con)
>  {
>  	struct fwnode_handle *fwnode;
>  	int i = 1;
> +	int ret;
> +	u32 port;
>  
> -	device_for_each_child_node(con->ucsi->dev, fwnode)
> -		if (i++ == con->num)
> -			return fwnode;
> +	device_for_each_child_node(con->ucsi->dev, fwnode) {
> +		ret = fwnode_property_read_u32(fwnode, "reg", &port);
> +		if (ret < 0) {
> +			if (i == con->num)
> +				return fwnode;
> +		} else {
> +			if (port == con->num - 1)
> +				return fwnode;
> +		}
> +
> +		i++;
> +	}
>  	return NULL;
>  }
>  
> -- 
> 2.34.1

-- 
heikki