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Date:   Tue, 24 Mar 2020 02:50:41 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Marek Vasut <marex@denx.de>
Cc:     netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
        Lukas Wunner <lukas@wunner.de>, Petr Stetiar <ynezz@true.cz>,
        YueHaibing <yuehaibing@huawei.com>
Subject: Re: [PATCH 08/14] net: ks8851: Use 16-bit read of RXFC register
Message-ID: <20200324015041.GO3819@lunn.ch>
References: <20200323234303.526748-1-marex@denx.de>
 <20200323234303.526748-9-marex@denx.de>
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> @@ -470,7 +455,7 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
>  	unsigned rxstat;
>  	u8 *rxpkt;
>  
> -	rxfc = ks8851_rdreg8(ks, KS_RXFC);
> +	rxfc = (ks8851_rdreg16(ks, KS_RXFCTR) >> 8) & 0xff;

The datasheet says:

2. When software driver reads back Receive Frame Count (RXFCTR)
Register; the KSZ8851 will update both Receive Frame Header Status and
Byte Count Registers (RXFHSR/RXFHBCR)

Are you sure there is no side affect here?

    Andrew