On Wed, Feb 14, 2024 at 11:28:37AM +0100, Lukas Wunner wrote:
> On Wed, Feb 14, 2024 at 02:18:31PM +0530, Manivannan Sadhasivam wrote:
> > +/**
> > + * of_pci_bridge_d3 - Check if the bridge is supporting D3 states or not
> > + *
> > + * @node: device tree node of the bridge
> > + *
> > + * Return: True if the bridge is supporting D3 states, False otherwise.
>
> A lot of kernel-doc uses %true and %false.
>
Ack.
>
> > +bool of_pci_bridge_d3(struct device_node *node)
> > +{
> > + return of_property_read_bool(node, "supports-d3");
> > +}
>
> What's the difference between of_property_read_bool() and
> of_property_present()? When should one use which?
> The former has 691 occurrences in the tree, the latter 120.
> The latter would seem more "literary" / readable here,
> but maybe that's just me.
>
of_property_present() just calls of_property_read_bool() and it is fairly new.
But yeah, the API name itself indicates that it is better suited for the
purpose. Will change it.
>
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1142,6 +1142,9 @@ static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
> > if (pci_use_mid_pm())
> > return false;
> >
> > + if (dev->dev.of_node)
> > + return of_pci_bridge_d3(dev->dev.of_node);
> > +
> > return acpi_pci_bridge_d3(dev);
> > }
>
> This will result in an unnecessary test on non-DT platforms (e.g. ACPI)
> whether dev->dev.of_node is set.
>
> Please use dev_of_node() instead of "dev->dev.of_node" so that the
> code added here can be optimized away by the compiler on non-DT
> platforms (due to the IS_ENABLED(CONFIG_OF)).
>
Sounds good.
- Mani
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