On Wed, Oct 23, 2024 at 12:23:57PM +0200, Bartosz Golaszewski wrote:
> On Tue, 22 Oct 2024 at 12:28, Manivannan Sadhasivam via B4 Relay
> <devnull+manivannan.sadhasivam.linaro.org@xxxxxxxxxx> wrote:
> >
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> >
> > This makes the pci_bus_add_device() API easier to maintain. Also add more
> > comments to the helper to describe how the devices are created.
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > ---
> > drivers/pci/bus.c | 59 ++++++++++++++++++++++++++++++++++++++-----------------
> > 1 file changed, 41 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> > index 351af581904f..c4cae1775c9e 100644
> > --- a/drivers/pci/bus.c
> > +++ b/drivers/pci/bus.c
> > @@ -321,6 +321,46 @@ void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
> >
> > void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
> >
> > +/*
> > + * Create pwrctl devices (if required) for the PCI devices to handle the power
> > + * state.
> > + */
> > +static void pci_pwrctl_create_devices(struct pci_dev *dev)
> > +{
> > + struct device_node *np = dev_of_node(&dev->dev);
> > + struct device *parent = &dev->dev;
> > + struct platform_device *pdev;
> > +
> > + /*
> > + * First ensure that we are starting from a PCI bridge and it has a
> > + * corresponding devicetree node.
> > + */
> > + if (np && pci_is_bridge(dev)) {
> > + /*
> > + * Now look for the child PCI device nodes and create pwrctl
> > + * devices for them. The pwrctl device drivers will manage the
> > + * power state of the devices.
> > + */
> > + for_each_child_of_node_scoped(np, child) {
> > + /*
> > + * First check whether the pwrctl device really needs to
> > + * be created or not. This is decided based on at least
> > + * one of the power supplies being defined in the
> > + * devicetree node of the device.
> > + */
> > + if (!of_pci_is_supply_present(child)) {
> > + pci_dbg(dev, "skipping OF node: %s\n", child->name);
> > + return;
> > + }
> > +
> > + /* Now create the pwrctl device */
> > + pdev = of_platform_device_create(child, NULL, parent);
> > + if (!pdev)
> > + pci_err(dev, "failed to create OF node: %s\n", child->name);
> > + }
> > + }
> > +}
> > +
> > /**
> > * pci_bus_add_device - start driver for a single device
> > * @dev: device to add
> > @@ -345,24 +385,7 @@ void pci_bus_add_device(struct pci_dev *dev)
> > pci_proc_attach_device(dev);
> > pci_bridge_d3_update(dev);
> >
> > - if (dev_of_node(&dev->dev) && pci_is_bridge(dev)) {
> > - for_each_child_of_node_scoped(dn, child) {
> > - /*
> > - * First check whether the pwrctl device needs to be
> > - * created or not. This is decided based on at least
> > - * one of the power supplies being defined in the
> > - * devicetree node of the device.
> > - */
> > - if (!of_pci_is_supply_present(child)) {
> > - pci_dbg(dev, "skipping OF node: %s\n", child->name);
> > - continue;
> > - }
> > -
> > - pdev = of_platform_device_create(child, NULL, &dev->dev);
> > - if (!pdev)
> > - pci_err(dev, "failed to create OF node: %s\n", child->name);
> > - }
> > - }
> > + pci_pwrctl_create_devices(dev);
> >
> > /*
> > * Create a device link between the PCI device and pwrctl device (if
> >
> > --
> > 2.25.1
> >
> >
>
> Would it be possible to move this into drivers/pwrctl/ and provide a
> header stub for when PCI_PWRCTL is disabled in Kconfig?
>
Unfortunately, no. Because the pwrctl drivers are modular and PCI core is
built-in. So if we use the pwrctl APIs in PCI core, then it will require pwrctl
to always be built-in, which we do not want.
- Mani
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