netdev - Re: [PATCH RFC net-next 5/5] net: dsa: mt7530: Add mediatek,ephy-handle to isolate external phy

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Message-ID: <2a421ed9-94ed-a454-29c2-f52f6a070a70@pobox.com>
Date:   Mon, 24 Jun 2019 19:22:41 -0500
From:   Daniel Santos <daniel.santos@...ox.com>
To:     Andrew Lunn <andrew@...n.ch>,
        René van Dorst <opensource@...rst.com>
Cc:     sean.wang@...iatek.com, f.fainelli@...il.com,
        linux@...linux.org.uk, davem@...emloft.net, matthias.bgg@...il.com,
        vivien.didelot@...il.com, frank-w@...lic-files.de,
        netdev@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-mips@...r.kernel.org
Subject: Re: [PATCH RFC net-next 5/5] net: dsa: mt7530: Add
 mediatek,ephy-handle to isolate external phy

On 6/24/19 4:52 PM, Andrew Lunn wrote:
>> +static int mt7530_isolate_ephy(struct dsa_switch *ds,
>> +			       struct device_node *ephy_node)
>> +{
>> +	struct phy_device *phydev = of_phy_find_device(ephy_node);
>> +	int ret;
>> +
>> +	if (!phydev)
>> +		return 0;
>> +
>> +	ret = phy_modify(phydev, MII_BMCR, 0, (BMCR_ISOLATE | BMCR_PDOWN));
> genphy_suspend() does what you want.
>
>> +	if (ret)
>> +		dev_err(ds->dev, "Failed to put phy %s in isolation mode!\n",
>> +			ephy_node->full_name);
>> +	else
>> +		dev_info(ds->dev, "Phy %s in isolation mode!\n",
>> +			 ephy_node->full_name);
> No need to clog up the system with yet more kernel messages.
>
>    Andrew
>
Yes, keep in mind that many mt7530-based devices have a 56k serial
console that gets ring buffer spew.  This created a real problem on the
mt7620 wifi drivers when they spewed every time a packet needed to be
dropped.  So at the very least, for any message that can be spammed,
rate limit it please.

Daniel