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From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     Woojung Huh <woojung.huh@microchip.com>,
        UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH net-next v3 03/17] net: dsa: microchip: don't announce extended register support on non Gbit chips
Date:   Tue, 23 Aug 2022 10:02:17 +0200
Message-Id: <20220823080231.2466017-4-o.rempel@pengutronix.de>
In-Reply-To: <20220823080231.2466017-1-o.rempel@pengutronix.de>
References: <20220823080231.2466017-1-o.rempel@pengutronix.de>
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This issue was detected after adding support of regmap_ranges for KSZ8563R
chip. This chip is reporting extended registers support without having
actual extended registers. This made PHYlib request not existing
registers.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/dsa/microchip/ksz9477.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 0f7f44358d7b3..acd4be196b69c 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -264,6 +264,17 @@ void ksz9477_port_init_cnt(struct ksz_device *dev, int port)
 	mutex_unlock(&mib->cnt_mutex);
 }
 
+
+static void ksz9477_r_phy_quirks(struct ksz_device *dev, u16 addr, u16 reg,
+				 u16 *data)
+{
+	/* KSZ8563R do not have extended registers but BMSR_ESTATEN and
+	 * BMSR_ERCAP bits are set.
+	 */
+	if (dev->chip_id == KSZ8563_CHIP_ID && reg == MII_BMSR)
+		*data &= ~(BMSR_ESTATEN | BMSR_ERCAP);
+}
+
 void ksz9477_r_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 *data)
 {
 	u16 val = 0xffff;
@@ -308,6 +319,7 @@ void ksz9477_r_phy(struct ksz_device *dev, u16 addr, u16 reg, u16 *data)
 		}
 	} else {
 		ksz_pread16(dev, addr, 0x100 + (reg << 1), &val);
+		ksz9477_r_phy_quirks(dev, addr, reg, &val);
 	}
 
 	*data = val;
-- 
2.30.2