linux-kernel - Re: [PATCH] net/phy: micrel: Add clock support for KSZ8021/KSZ8031

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Message-ID: <20141010074454.GO4992@pengutronix.de>
Date:	Fri, 10 Oct 2014 09:44:54 +0200
From:	Sascha Hauer <s.hauer@...gutronix.de>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel@...gutronix.de
Subject: Re: [PATCH] net/phy: micrel: Add clock support for KSZ8021/KSZ8031

On Thu, Oct 09, 2014 at 10:01:15AM -0700, Florian Fainelli wrote:
> On 10/09/2014 05:32 AM, Sascha Hauer wrote:
> >  static int ksz8021_config_init(struct phy_device *phydev)
> >  {
> > +	struct clk *clk;
> >  	const u16 val = KSZPHY_OMSO_B_CAST_OFF | KSZPHY_OMSO_RMII_OVERRIDE;
> >  	int rc;
> >  
> > +	clk = devm_clk_get(&phydev->dev, "rmii-ref");
> > +	if (!IS_ERR(clk)) {
> > +		unsigned long rate = clk_get_rate(clk);
> > +
> > +		if (rate > 24500000 && rate < 25500000)
> > +			phydev->dev_flags |= MICREL_PHY_25MHZ_CLK;
> > +		else if (rate > 49500000 && rate < 50500000)
> > +			phydev->dev_flags |= MICREL_PHY_50MHZ_CLK;
> > +	}
> 
> I suppose that you could move this to the PHY driver probe() callback,
> and perform the rate checking from here, rejecting a clock whose rate is
> out of the acceptable range, and return an error to prevent the PHY
> driver registration? It is really up to you though.

Oh, it seems doing this in config_init is really wrong as it can be
called multiple times, even as a response to the SIOCSMIIREG ioctl.
We would request the clock each time then without ever releasing it.
I'll send an updated version with clock handling in probe().

Sascha

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