Re: [net-next PATCH v5 9/9] net: phy: qca807x: add support for configurable LED

[Russell King (Oracle)]

On Fri, Feb 02, 2024 at 06:08:33PM +0100, Andrew Lunn wrote:
> On Fri, Feb 02, 2024 at 05:40:21PM +0100, Christian Marangi wrote:
> > On Fri, Feb 02, 2024 at 02:43:37AM +0100, Andrew Lunn wrote:
> > > > +
> > > > +			phydev->drv->led_brightness_set = NULL;
> > > > +			phydev->drv->led_blink_set = NULL;
> > > > +			phydev->drv->led_hw_is_supported = NULL;
> > > > +			phydev->drv->led_hw_control_set = NULL;
> > > > +			phydev->drv->led_hw_control_get = NULL;
> > > 
> > > I don't see how that works. You have multiple PHYs using this
> > > driver. Some might have LEDs, some might have GPOs. But if you modify
> > > the driver structure like this, you prevent all PHYs from having LEDs,
> > > and maybe cause a Opps if a PHY device has already registered its
> > > LEDs?
> > >
> > 
> > God you are right! Off-topic but given the effects this may cause, why
> > the thing is not const?
> 
> I would like it to be, but its not easy. There are fields in the
> driver structure that phylib needs to modify. e.g. mdiodrv.driver gets
> passed to the driver core when registering the driver, and it modifies
> it. mdiodrv.flags is also manipulated. So we cannot make the whole
> structure const.

We can make phy_device's drv pointer const though, which would have the
effect of catching code such as the above. That doesn't impact the
driver model nor the mdio layer.

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