Subject: Re: [PATCH RFC leds + net-next v4 1/2] net: phy: add API for LEDs controlled by PHY HW

From: Marek Behun <[email-masked]>
Date: Tue, 28 Jul 2020 19:27:13 +0200

On Tue, 28 Jul 2020 18:28:16 +0200
Andrew Lunn <[email-masked]> wrote:

> > > @@ -736,6 +777,16 @@ struct phy_driver {
> > >  	int (*set_loopback)(struct phy_device *dev, bool enable);
> > >  	int (*get_sqi)(struct phy_device *dev);
> > >  	int (*get_sqi_max)(struct phy_device *dev);
> > > +
> > > +	/* PHY LED support */
> > > +	int (*led_init)(struct phy_device *dev, struct
> > > phy_device_led *led);
> > > +	int (*led_brightness_set)(struct phy_device *dev, struct
> > > phy_device_led *led,
> > > +				  enum led_brightness brightness);
> > > +	const char *(*led_iter_hw_mode)(struct phy_device *dev,
> > > struct phy_device_led *led,
> > > +					void **	iter);
> > > +	int (*led_set_hw_mode)(struct phy_device *dev, struct
> > > phy_device_led *led,
> > > +			       const char *mode);
> > > +	const char *(*led_get_hw_mode)(struct phy_device *dev,
> > > struct phy_device_led *led); };
> > >  #define to_phy_driver(d)
> > > container_of(to_mdio_common_driver(d),		\ struct
> > > phy_driver, mdiodrv)  
> > 
> > The problem here is that the same code will have to be added to DSA
> > switch ops structure, which is not OK.  
> 
> Not necessarily. DSA drivers do have access to the phydev structure.
> 
> I think putting these members into a structure is a good idea. That
> structure can be part of phy_driver and initialised just like other
> members. But on probing the phy, it can be copied over to the
> phy_device structure. And we can provide an API which DSA drivers can
> use to register there own structure of ops to be placed into
> phy_device, which would call into the DSA driver.
> 
>       Andrew

On Marvell switches there are LEDs that do not necesarrily blink on
events on a specific port, but instead on the whole switch. Ie a LED
can be put into a mode "act on any port". Vendors may create devices
with this as intender mode for a LED, and such a LED may be on the
other side of the device from where the ports are, or something. Such a
LED should be described in the device tree not as a child of any PHY or
port, but instead as a child of the switch itself. And since all the
LEDs on Marvell switches are technically controlled by the switch, not
it's internal PHYs, I think all of them should be children of the
switch node (or a "leds" node which is a child of the switch node),
instead of being descended from the internal PHYs.

Marek