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From:   Nathan Chancellor <natechancellor@gmail.com>
To:     Vladimir Oltean <olteanv@gmail.com>, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, clang-built-linux@googlegroups.com,
        Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] net: dsa: sja1105: Do not use address of compatible member in sja1105_check_device_id
Date:   Fri, 21 Aug 2020 15:25:16 -0700
Message-Id: <20200821222515.414167-1-natechancellor@gmail.com>
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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@gmail.com>
---
 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