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Message-ID: <87e4f794-669f-8d43-793c-b8c1878cbd15@broadcom.com>
Date:   Fri, 11 Aug 2023 16:40:01 -0700
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Subject: Re: [PATCH] net: phy: broadcom: stub c45 read/write for 54810
To:     Justin Chen <justin.chen@broadcom.com>, netdev@vger.kernel.org
Cc:     Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@broadcom.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        open list <linux-kernel@vger.kernel.org>
References: <1691796578-846-1-git-send-email-justin.chen@broadcom.com>
From:   Florian Fainelli <florian.fainelli@broadcom.com>
In-Reply-To: <1691796578-846-1-git-send-email-justin.chen@broadcom.com>
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On 8/11/2023 4:29 PM, Justin Chen wrote:
> The 54810 does not support c45. The mmd_phy_indirect accesses return
> arbirtary values leading to odd behavior like saying it supports EEE
> when it doesn't. We also see that reading/writing these non-existent
> MMD registers leads to phy instability in some cases.
> 
> Signed-off-by: Justin Chen <justin.chen@broadcom.com>

Thanks for submitting this fix, I would be tempted to slap a:

Fixes: b14995ac2527 ("net: phy: broadcom: Add BCM54810 PHY entry")

so we get it back ported to stable trees where appropriate. It is not 
clear whether we should return -EINVAL vs. -EOPNOTSUPP which may more 
clearly indicate the inability to support MMD registers?
-- 
Florian

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