Re: [PATCH] net: phy: smsc: disable energy detect mode

[Heiko Schocher]

Hello Florian,

Am 13.10.2015 um 21:26 schrieb Florian Fainelli:
> On 12/10/15 22:13, Heiko Schocher wrote:
> > On some boards the energy enable detect mode leads in
> > trouble with some switches, so make the enabling of
> > this mode configurable through DT.
> >
> > Signed-off-by: Heiko Schocher <hs@xxxxxxx>
> > ---
> >
> >   .../devicetree/bindings/net/smsc-lan87xx.txt       | 19 +++++++++++++++++
> >   drivers/net/phy/smsc.c                             | 24 +++++++++++++++++-----
> >   2 files changed, 38 insertions(+), 5 deletions(-)
> >   create mode 100644 Documentation/devicetree/bindings/net/smsc-lan87xx.txt
> >
> > diff --git a/Documentation/devicetree/bindings/net/smsc-lan87xx.txt b/Documentation/devicetree/bindings/net/smsc-lan87xx.txt
> > new file mode 100644
> > index 0000000..39aa1dc
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/smsc-lan87xx.txt
> > @@ -0,0 +1,19 @@
> > +SMSC LAN87xx Ethernet PHY
> > +
> > +Some boards require special tuning values. Configure them
> > +through an Ethernet OF device node.
> > +
> > +Optional properties:
> > +
> > +- disable-energy-detect:
> > +  If set, do not enable energy detect mode for the SMSC phy.
> > +  default: enable energy detect mode
>
> Although energy detection is something that is implemented by many PHYs,
> I am not sure a generic property is suitable here, I would prefix that
> with the SMSC vendor prefix here to make it clear this only applies to
> this PHY.

Hmm... but all PHYs should be able to enable, disable it in some way, or?

> Would not you want to make it a reverse property here though, something
> like this:
>
> smsc,energy-detect: boolean, when present indicates the PHY reliably
> supports energy detection

Yes, that was also my first thought, but currently, on this PHYs
energy detect mode is on ... and if I introduce such a property,
it will disable it for all existing boards, because property is
missing ... so, maybe I break boards ...

> > +
> > +Examples:
> > +
> > +	/* Attach to an Ethernet device with autodetected PHY */
> > +	&cpsw_emac0 {
> > +		phy_id = <&davinci_mdio>, <0>;
> > +		phy-mode = "mii";
> > +		disable-energy-detect;
> > +	};
> > diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
> > index 70b0895..f90fbf3 100644
> > --- a/drivers/net/phy/smsc.c
> > +++ b/drivers/net/phy/smsc.c
> > @@ -43,16 +43,30 @@ static int smsc_phy_ack_interrupt(struct phy_device *phydev)
> >
> >   static int smsc_phy_config_init(struct phy_device *phydev)
> >   {
> > +#ifdef CONFIG_OF
> > +	int len;
> > +	struct device *dev = &phydev->dev;
> > +	struct device_node *of_node = dev->of_node;
>
> That does not need to be ifdefd out, at best annontate with __maybe_unused?

Yes, I try it.

> > +#endif
> >   	int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS);
> > +	int enable_energy = 1;
> >
> >   	if (rc < 0)
> >   		return rc;
> >
> > -	/* Enable energy detect mode for this SMSC Transceivers */
> > -	rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,
> > -		       rc | MII_LAN83C185_EDPWRDOWN);
> > -	if (rc < 0)
> > -		return rc;
> > +#ifdef CONFIG_OF
> > +	if (!of_node && dev->parent->of_node)
> > +		of_node = dev->parent->of_node;
>
> That looks strange, why would the property be placed at the parent level
> when this is a PHY device tree node property?

Hmm.. I recheck this.

> > +	if (of_find_property(of_node, "disable-energy-detect", &len))
> > +		enable_energy = 0;
> > +#endif
> > +	if (enable_energy) {
> > +		/* Enable energy detect mode for this SMSC Transceivers */
> > +		rc = phy_write(phydev, MII_LAN83C185_CTRL_STATUS,
> > +			       rc | MII_LAN83C185_EDPWRDOWN);
> > +		if (rc < 0)
> > +			return rc;
> > +	}
> >
> >   	return smsc_phy_ack_interrupt(phydev);
> >   }

Thanks for your review.

bye,
Heiko

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