netdev - [PATCH net-next v2] net: pse-pd: tps23881: Fix the device ID check

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Message-ID: <20240731154152.4020668-1-kyle.swenson@est.tech>
Date: Wed, 31 Jul 2024 15:42:14 +0000
From: Kyle Swenson <kyle.swenson@....tech>
To: Kyle Swenson <kyle.swenson@....tech>, "o.rempel@...gutronix.de"
	<o.rempel@...gutronix.de>, "kory.maincent@...tlin.com"
	<kory.maincent@...tlin.com>, "kuba@...nel.org" <kuba@...nel.org>
CC: "davem@...emloft.net" <davem@...emloft.net>, "edumazet@...gle.com"
	<edumazet@...gle.com>, "pabeni@...hat.com" <pabeni@...hat.com>,
	"thomas.petazzoni@...tlin.com" <thomas.petazzoni@...tlin.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next v2] net: pse-pd: tps23881: Fix the device ID check

The DEVID register contains two pieces of information: the device ID in
the upper nibble, and the silicon revision number in the lower nibble.
The driver should work fine with any silicon revision, so let's mask
that out in the device ID check.

Fixes: 20e6d190ffe1 ("net: pse-pd: Add TI TPS23881 PSE controller driver")
Signed-off-by: Kyle Swenson <kyle.swenson@....tech>
---
v2:
 - Use FIELD_GET and defines instead of raw numbers

v1: https://lore.kernel.org/netdev/20240730161032.3616000-1-kyle.swenson@est.tech/

 drivers/net/pse-pd/tps23881.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/pse-pd/tps23881.c b/drivers/net/pse-pd/tps23881.c
index 61f6ad9c1934..f90db758554b 100644
--- a/drivers/net/pse-pd/tps23881.c
+++ b/drivers/net/pse-pd/tps23881.c
@@ -27,10 +27,12 @@
 #define TPS23881_REG_PORT_POWER	0x29
 #define TPS23881_REG_POEPLUS	0x40
 #define TPS23881_REG_TPON	BIT(0)
 #define TPS23881_REG_FWREV	0x41
 #define TPS23881_REG_DEVID	0x43
+#define TPS23881_REG_DEVID_MASK	0xF0
+#define TPS23881_DEVICE_ID	0x02
 #define TPS23881_REG_SRAM_CTRL	0x60
 #define TPS23881_REG_SRAM_DATA	0x61
 
 struct tps23881_port_desc {
 	u8 chan[2];
@@ -748,11 +750,11 @@ static int tps23881_i2c_probe(struct i2c_client *client)
 
 	ret = i2c_smbus_read_byte_data(client, TPS23881_REG_DEVID);
 	if (ret < 0)
 		return ret;
 
-	if (ret != 0x22) {
+	if (FIELD_GET(TPS23881_REG_DEVID_MASK, ret) != TPS23881_DEVICE_ID) {
 		dev_err(dev, "Wrong device ID\n");
 		return -ENXIO;
 	}
 
 	ret = tps23881_flash_sram_fw(client);
-- 
2.43.0