usb: typec: mux: Fix matching with typec_altmode_desc

BugLink: https://bugs.launchpad.net/bugs/1931896
commit acf5631c239dfc53489f739c4ad47f490c5181ff upstream.

In typec_mux_match() "nval" is assigned the number of elements in the
"svid" fwnode property, then the variable is used to store the success
of the read and finally attempts to loop between 0 and "success" - i.e.
not at all - and the code returns indicating that no match was found.

Fix this by using a separate variable to track the success of the read,
to allow the loop to get a change to find a match.

Fixes: 96a6d031ca99 ("usb: typec: mux: Find the muxes by also matching against the device node")
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210516034730.621461-1-bjorn.andersson@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c
index cf720e944aaaa44eba12eb87d06d2e96c4ab9afa..42acdc8b684fe2694bc7a39a7c4bc5924fdae435 100644 (file)
--- a/drivers/usb/typec/mux.c
+++ b/drivers/usb/typec/mux.c
@@ -191,6 +191,7 @@ static void *typec_mux_match(struct fwnode_handle *fwnode, const char *id,
        bool match;
        int nval;
        u16 *val;
+       int ret;
        int i;
 
        /*
@@ -218,10 +219,10 @@ static void *typec_mux_match(struct fwnode_handle *fwnode, const char *id,
        if (!val)
                return ERR_PTR(-ENOMEM);
 
-       nval = fwnode_property_read_u16_array(fwnode, "svid", val, nval);
-       if (nval < 0) {
+       ret = fwnode_property_read_u16_array(fwnode, "svid", val, nval);
+       if (ret < 0) {
                kfree(val);
-               return ERR_PTR(nval);
+               return ERR_PTR(ret);
        }
 
        for (i = 0; i < nval; i++) {