[PATCH] net: dsa: sja1105: Do not use address of compatible member in sja1105_check_device_id

[Nathan Chancellor]

Clang warns:

drivers/net/dsa/sja1105/sja1105_main.c:3418:38: warning: address of
array 'match->compatible' will always evaluate to 'true'
[-Wpointer-bool-conversion]
        for (match = sja1105_dt_ids; match->compatible; match++) {
        ~~~                          ~~~~~~~^~~~~~~~~~
1 warning generated.

We should check the value of the first character in compatible to see if
it is empty or not. This matches how the rest of the tree iterates over
IDs.

Fixes: 0b0e299720bb ("net: dsa: sja1105: use detected device id instead of DT one on mismatch")
Link: https://github.com/ClangBuiltLinux/linux/issues/1139
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
---
 drivers/net/dsa/sja1105/sja1105_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index c3f6f124e5f0..5a28dfb36ec3 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -3415,7 +3415,7 @@ static int sja1105_check_device_id(struct sja1105_private *priv)
 
 	sja1105_unpack(prod_id, &part_no, 19, 4, SJA1105_SIZE_DEVICE_ID);
 
-	for (match = sja1105_dt_ids; match->compatible; match++) {
+	for (match = sja1105_dt_ids; match->compatible[0]; match++) {
 		const struct sja1105_info *info = match->data;
 
 		/* Is what's been probed in our match table at all? */

base-commit: 4af7b32f84aa4cd60e39b355bc8a1eab6cd8d8a4
-- 
2.28.0