netdev - Re: [PATCH net] net: stmmac: dwmac-rk: Ensure clk

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Message-ID: <aLlyb6WvoBiBfUx3@shell.armlinux.org.uk>
Date: Thu, 4 Sep 2025 12:05:19 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Chaoyi Chen <chaoyi.chen@...k-chips.com>
Cc: Yao Zi <ziyao@...root.org>, Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Jonas Karlman <jonas@...boo.se>, David Wu <david.wu@...k-chips.com>,
	netdev@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH net] net: stmmac: dwmac-rk: Ensure clk_phy doesn't
 contain invalid address

On Thu, Sep 04, 2025 at 07:03:10PM +0800, Chaoyi Chen wrote:
> 
> On 9/4/2025 6:58 PM, Russell King (Oracle) wrote:
> > On Thu, Sep 04, 2025 at 03:12:24AM +0000, Yao Zi wrote:
> > >   	if (plat->phy_node) {
> > >   		bsp_priv->clk_phy = of_clk_get(plat->phy_node, 0);
> > >   		ret = PTR_ERR_OR_ZERO(bsp_priv->clk_phy);
> > > -		/* If it is not integrated_phy, clk_phy is optional */
> > > +		/*
> > > +		 * If it is not integrated_phy, clk_phy is optional. But we must
> > > +		 * set bsp_priv->clk_phy to NULL if clk_phy isn't proivded, or
> > > +		 * the error code could be wrongly taken as an invalid pointer.
> > > +		 */
> > I'm concerned by this. This code is getting the first clock from the DT
> > description of the PHY. We don't know what type of PHY it is, or what
> > the DT description of that PHY might suggest that the first clock would
> > be.
> > 
> > However, we're geting it and setting it to 50MHz. What if the clock is
> > not what we think it is?
> 
> We only set integrated_phy to 50M, which are all known targets. For external PHYs, we do not perform frequency settings.

Same question concerning enabling and disabling another device's clock
that the other device should be handling.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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