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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Marek Vasut <marex@denx.de>,
        "David S. Miller" <davem@davemloft.net>,
        Lukas Wunner <lukas@wunner.de>, Petr Stetiar <ynezz@true.cz>,
        YueHaibing <yuehaibing@huawei.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 22/86] net: ks8851-ml: Fix 16-bit IO operation
Date:   Tue, 10 Mar 2020 13:44:46 +0100
Message-Id: <20200310124531.980660280@linuxfoundation.org>
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References: <20200310124530.808338541@linuxfoundation.org>
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From: Marek Vasut <marex@denx.de>

[ Upstream commit 58292104832fef6cb4a89f736012c0e0724c3442 ]

The Micrel KSZ8851-16MLLI datasheet DS00002357B page 12 states that
BE[3:0] signals are active high. This contradicts the measurements
of the behavior of the actual chip, where these signals behave as
active low. For example, to read the CIDER register, the bus must
expose 0xc0c0 during the address phase, which means BE[3:0]=4'b1100.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Petr Stetiar <ynezz@true.cz>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/micrel/ks8851_mll.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/micrel/ks8851_mll.c b/drivers/net/ethernet/micrel/ks8851_mll.c
index aff1619fb0e0e..9de59facec218 100644
--- a/drivers/net/ethernet/micrel/ks8851_mll.c
+++ b/drivers/net/ethernet/micrel/ks8851_mll.c
@@ -485,7 +485,7 @@ static int msg_enable;
 
 static u16 ks_rdreg16(struct ks_net *ks, int offset)
 {
-	ks->cmd_reg_cache = (u16)offset | ((BE1 | BE0) << (offset & 0x02));
+	ks->cmd_reg_cache = (u16)offset | ((BE3 | BE2) >> (offset & 0x02));
 	iowrite16(ks->cmd_reg_cache, ks->hw_addr_cmd);
 	return ioread16(ks->hw_addr);
 }
@@ -500,7 +500,7 @@ static u16 ks_rdreg16(struct ks_net *ks, int offset)
 
 static void ks_wrreg16(struct ks_net *ks, int offset, u16 value)
 {
-	ks->cmd_reg_cache = (u16)offset | ((BE1 | BE0) << (offset & 0x02));
+	ks->cmd_reg_cache = (u16)offset | ((BE3 | BE2) >> (offset & 0x02));
 	iowrite16(ks->cmd_reg_cache, ks->hw_addr_cmd);
 	iowrite16(value, ks->hw_addr);
 }
-- 
2.20.1