Re: [PATCH v20 2/6] phy: core: Add phy_get_by_of_node()

[Bryan O'Donoghue]

On 18/09/2026 15:10, Neil Armstrong wrote:
> >   EXPORT_SYMBOL_GPL(devm_of_phy_get_by_index);
> > +/**
> > + * phy_get_by_of_node() - lookup and obtain a reference to a phy by 
> > device_node
> > + * @np: node containing the phy
> > + *
> > + * Returns: the phy associated with the device node or ERR_PTR.
> > + */
> > +struct phy *phy_get_by_of_node(struct device_node *np)
> > +{
> > +    struct of_phandle_args args = { .np = np, .args_count = 0 };
> > +    struct phy *phy;
> > +
> > +    mutex_lock(&phy_provider_mutex);
>
> I don't really understand the usage of lockdep_assert_held(), but why
> does _of_phy_get() uses lockdep_assert_held() and here you use mutex_lock()
> like before patch 1 ?
>
> Neil

assert_lockdep_held() is just an assertion that the lock is held, Loic 
suggested adding it BTW. It ensures that when another function calls 
this function it holds phy_provider_mutex.

i.e.

phy_get_by_of_node()
{
	mutex_lock(&phy_provider_mutex);
	_of_phy_get();
	mutex_unlock(&phy_provider_mutex);
}
EXPORT_SYMBOL(phy_get_by_of_node);

_of_phy_get()
{
	lockdep_assert_held(&phy_provider_mutex);
	/* happy days */
}

phy_broken_locking()
{
	_of_phy_get();
}
EXPORT_SYMBOL(phy_broken_locking);

_of_phy_get()
{
	lockdep_assert_held(&phy_provider_mutex);
	/* wails plaintively into the void */
}

---
bod