[PATCH] usb: typec: retimer: Add missing id check in match callback

[PATCH] usb: typec: retimer: Add missing id check in match callback

[Nícolas F. R. A. Prado]

The fwnode_connection_find_match() function handles two cases: named
references and graph endpoints. In the second case, the match function
passed in is called with the id to check for the match. However, the
match function for the recently added type-c retimer class assumes the
connection has already been matched (which is only true for the first
case).

The result is that with that change, all type-c nodes with graph
endpoints defer probe indefinitely, independently of having a retimer
connection or not.

Add the missing check, like is done by the type-c mux and usb role
switch code, to fix the issue.

Fixes: ddaf8d96f93b ("usb: typec: Add support for retimers")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

---

 drivers/usb/typec/retimer.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c
index 051eaa7d2899..2003731f1bee 100644
--- a/drivers/usb/typec/retimer.c
+++ b/drivers/usb/typec/retimer.c
@@ -36,8 +36,13 @@ static int retimer_fwnode_match(struct device *dev, const void *fwnode)
 
 static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
 {
-	struct device *dev  = class_find_device(&retimer_class, NULL, fwnode,
-						retimer_fwnode_match);
+	struct device *dev;
+
+	if (id && !fwnode_property_present(fwnode, id))
+		return NULL;
+
+	dev = class_find_device(&retimer_class, NULL, fwnode,
+				retimer_fwnode_match);
 
 	return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
 }
-- 
2.37.0

Re: [PATCH] usb: typec: retimer: Add missing id check in match callback

[Prashant Malani]

HI Nícolas,

On Mon, Jul 25, 2022 at 1:31 PM Nícolas F. R. A. Prado
<nfraprado@collabora.com> wrote:
>
> The fwnode_connection_find_match() function handles two cases: named
> references and graph endpoints. In the second case, the match function
> passed in is called with the id to check for the match. However, the
> match function for the recently added type-c retimer class assumes the
> connection has already been matched (which is only true for the first
> case).
>
> The result is that with that change, all type-c nodes with graph
> endpoints defer probe indefinitely, independently of having a retimer
> connection or not.
>
> Add the missing check, like is done by the type-c mux and usb role
> switch code, to fix the issue.
>
> Fixes: ddaf8d96f93b ("usb: typec: Add support for retimers")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
FWIW,
Reviewed-by: Prashant Malani <pmalani@chromium.org>

Re: [PATCH] usb: typec: retimer: Add missing id check in match callback

[Heikki Krogerus]

On Mon, Jul 25, 2022 at 04:31:29PM -0400, Nícolas F. R. A. Prado wrote:
> The fwnode_connection_find_match() function handles two cases: named
> references and graph endpoints. In the second case, the match function
> passed in is called with the id to check for the match. However, the
> match function for the recently added type-c retimer class assumes the
> connection has already been matched (which is only true for the first
> case).
> 
> The result is that with that change, all type-c nodes with graph
> endpoints defer probe indefinitely, independently of having a retimer
> connection or not.
> 
> Add the missing check, like is done by the type-c mux and usb role
> switch code, to fix the issue.
> 
> Fixes: ddaf8d96f93b ("usb: typec: Add support for retimers")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> 
>  drivers/usb/typec/retimer.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c
> index 051eaa7d2899..2003731f1bee 100644
> --- a/drivers/usb/typec/retimer.c
> +++ b/drivers/usb/typec/retimer.c
> @@ -36,8 +36,13 @@ static int retimer_fwnode_match(struct device *dev, const void *fwnode)
>  
>  static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
>  {
> -	struct device *dev  = class_find_device(&retimer_class, NULL, fwnode,
> -						retimer_fwnode_match);
> +	struct device *dev;
> +
> +	if (id && !fwnode_property_present(fwnode, id))
> +		return NULL;
> +
> +	dev = class_find_device(&retimer_class, NULL, fwnode,
> +				retimer_fwnode_match);
>  
>  	return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
>  }

thanks,

-- 
heikki