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Date: Tue, 9 Jan 2024 22:04:20 +0100
From: Andrew Lunn <andrew@lunn.ch>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: linux-renesas-soc@vger.kernel.org, netdev@vger.kernel.org,
	Philippe Schenker <philippe.schenker@toradex.com>,
	Francesco Dolcini <francesco.dolcini@toradex.com>,
	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>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] net: phy: micrel: reset KSZ9x31 when resuming
Message-ID: <d9e86b0b-22cd-4055-90e1-44083ffbc05c@lunn.ch>
References: <20240109205223.40219-1-wsa+renesas@sang-engineering.com>
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> +static int ksz9x31_resume(struct phy_device *phydev)
> +{
> +	phy_device_reset(phydev, 1);
> +	phy_device_reset(phydev, 0);
> +
> +	return kszphy_resume(phydev);
> +}
> +
>  static int kszphy_probe(struct phy_device *phydev)
>  {
>  	const struct kszphy_type *type = phydev->drv->driver_data;
> @@ -4778,7 +4786,7 @@ static struct phy_driver ksphy_driver[] = {
>  	.get_strings	= kszphy_get_strings,
>  	.get_stats	= kszphy_get_stats,
>  	.suspend	= kszphy_suspend,
> -	.resume		= kszphy_resume,
> +	.resume		= ksz9x31_resume,

Humm, i'm not so sure about this.

phy_resume() is called by mdio_bus_phy_resume(). That first does a
call to phy_init_hw(), which will perform a soft reset on the PHY,
call the drivers config_init() callback, and the config_intr()
callback. Then it calls phy_resume().

Does phy_resume() hitting it with a reset clear out the configuration
done by config_init() and the interrupt configuration performed by
config_intr()?

	Andrew