Re: [PATCH v6 1/9] drivers: phy: add generic PHY framework

[Kishon Vijay Abraham I]

Hi,

On Tuesday 04 June 2013 07:13 PM, Sylwester Nawrocki wrote:
> Hi,
>
> On 06/04/2013 02:26 PM, Kishon Vijay Abraham I wrote:
> > > > +static inline int phy_init(struct phy *phy)
> > > > +{
> > > > +	pm_runtime_get_sync(&phy->dev);
> > >
> > > Hmm, no need to check return value here ? Also it looks a bit unexpected to
> >
> > I purposely dint check the return values in order to support platforms
> > that don’t enable pm_runtime.
>
> Then I guess this should be called conditionally and any errors returned
> if runtime PM is enabled ? Not sure if pm_runtime_enabled() would be
> helpful such situation.
Indeed. I think it can be used.
> > > possibly have runtime_resume callback of a PHY device called before ops->init()
> > > call ? It seems a bit unclear what the purpose of init() callback is.
> >
> > Not really. Anything that is used to initialize the PHY (internal
> > configuration) can go in phy_init. Usually in runtime_resume callback,
> > optional functional clocks are enabled and also in some cases context
> > restore is done. So it really makes sense to enable clocks/module
> > (pm_runtime_get_sync) before doing a PHY configuration (phy_init).
>
> OK, that makes sense. All PHY device resources must be prepared anyway
> before a PHY object is registered with the PHY core.
>
> > > > +	if (phy->ops->init)
> > > > +		return phy->ops->init(phy);
> > > > +
> > > > +	return -EINVAL;
> > > > +}
> > > > +
> > > > +static inline int phy_exit(struct phy *phy)
> > > > +{
> > > > +	int ret = -EINVAL;
> > > > +
> > > > +	if (phy->ops->exit)
> > > > +		ret = phy->ops->exit(phy);
> > > > +
> > > > +	pm_runtime_put_sync(&phy->dev);
> > > > +
> > > > +	return ret;
> > > > +}
> > >
> > > Do phy_init/phy_exit need to be mandatory ? What if there is really
> >
> > No. phy_init/phy_exit is not mandatory at all.
> > > nothing to do in those callbacks ? Perhaps -ENOIOCTLCMD should be
> > > returned if a callback is not implemented, so PHY users can recognize
> > > such situation and proceed ?
> >
> > So currently these APIs return -EINVAL if these callbacks are not
> > populated which is good enough IMHO.
>
> But -EINVAL could be well returned from the callback function. Perhaps
> ENOTSUPP could be used instead ?

hmm.. could be..

Thanks
Kishon
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