Re: [PATCH 1/2] PCI: apple: Integrate pwrctrl API

[Yureka Lilian <yureka@cyberchaos.dev>]

On 7/9/26 14:29, Manivannan Sadhasivam wrote:
> On Tue, Jul 07, 2026 at 02:58:39PM +0100, Marc Zyngier wrote:
>> On Tue, 07 Jul 2026 13:04:21 +0100,
>> Yureka Lilian <yureka@cyberchaos.dev> wrote:
>>> On 7/7/26 11:25, Marc Zyngier wrote:
>>>> On Mon, 06 Jul 2026 23:38:27 +0100,
>>>> Yureka Lilian <yureka@cyberchaos.dev> wrote:
>>>>> Integrate the PCI pwrctrl framework into the Apple PCIe host driver to
>>>>> provide standardized power management for PCI devices.
>>>>>
>>>>> Notably, this allows enabling powering on the WiFi, SD card reader on
>>>>> various Macs by means of the pwrctrl framework before probing the ports.
>>>>>
>>>>> Previously, a custom solution for powering on the WiFi and SD card
>>>>> reader was proposed[1], but we can now use the new pci-pwrctrl-generic
>>>>> driver for this purpose.
>>>>>
>>>>> Link[1]: https://lore.kernel.org/lkml/20220502093832.32778-4-marcan@marcan.st/
>>>>>
>>>> nit: this paragraph and the accompanying link don't belong in the
>>>> commit message and should be moved below the --- mark or even better,
>>>> to the cover letter.
>>> ack, will leave it out of the commit message of the individual commit in v2
>>>>> Signed-off-by: Yureka Lilian <yureka@cyberchaos.dev>
>>>>> ---
>>>>>    drivers/pci/controller/Kconfig      |  1 +
>>>>>    drivers/pci/controller/pcie-apple.c | 16 ++++++++++++++++
>>>>>    2 files changed, 17 insertions(+)
>>>>>
>>>>> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
>>>>> index 2247709ef6d6..af64630d28fa 100644
>>>>> --- a/drivers/pci/controller/Kconfig
>>>>> +++ b/drivers/pci/controller/Kconfig
>>>>> @@ -46,6 +46,7 @@ config PCIE_APPLE
>>>>>    	depends on OF
>>>>>    	depends on PCI_MSI
>>>>>    	select PCI_HOST_COMMON
>>>>> +	select PCI_PWRCTRL_GENERIC
>>>>>    	select IRQ_MSI_LIB
>>>>>    	help
>>>>>    	  Say Y here if you want to enable PCIe controller support on Apple
>>>>> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
>>>>> index c2cffc0659f4..db038a9d4831 100644
>>>>> --- a/drivers/pci/controller/pcie-apple.c
>>>>> +++ b/drivers/pci/controller/pcie-apple.c
>>>>> @@ -30,6 +30,7 @@
>>>>>    #include <linux/msi.h>
>>>>>    #include <linux/of_irq.h>
>>>>>    #include <linux/pci-ecam.h>
>>>>> +#include <linux/pci-pwrctrl.h>
>>>>>      #include "pci-host-common.h"
>>>>>    @@ -825,6 +826,21 @@ static int apple_pcie_init(struct
>>>>> pci_config_window *cfg)
>>>>>    	if (WARN_ON(!pcie))
>>>>>    		return -ENOENT;
>>>>>    +	ret = pci_pwrctrl_create_devices(pcie->dev);
>>>>> +	if (ret) {
>>>>> +		dev_err(pcie->dev, "Failed to create pwrctrl devices: %pe\n", ret);
>>>>> +		return ret;
>>>>> +	}
>>>>> +
>>>>> +	ret = pci_pwrctrl_power_on_devices(pcie->dev);
>>>>> +	if (ret) {
>>>>> +		if (ret != -EPROBE_DEFER) {
>>>>> +			dev_err(pcie->dev, "Failed to power on devices: %pe\n", ret);
>>>>> +			pci_pwrctrl_destroy_devices(pcie->dev);
>>>>> +		}
>>>>> +		return ret;
>>>>> +	}
>>>>> +
>>>> Why is this done globally while the whole driver works on a per-port
>>>> basis, and that the proposed DT updates are also per port?
>>> pci_pwrctrl_power_on_devices takes a struct device as parameter, but
>>> pcie-apple does not allocate device structs for the individual ports.
>>> This could be changed of course. But since pci_pwrctrl_* operate on
>>> the subnodes recursively, it works just fine this way.
>> Works fine is one thing. Being consistent with the way the rest of the
>> driver works is another. pci_pwrctrl_create_device() and
>> pci_pwrctrl_power_on_device() appear to do exactly what would be
>> required for a single port. They just needs to be exported made
>> global/exported.
>>
> I'm fine with exporting pci_pwrctrl_create_device() and
> pci_pwrctrl_power_on_device() and calling them with per-port np.
>
> - Mani

In theory I do agree this would work to power on the slots, and I can 
send a v2 of the patch doing it that way, but I don't quite understand 
yet how this fits better with the existing driver code: If this is the 
case, what is the difference between pcie-apple and pcie-qcom and why 
should pcie-qcom use the recursive function but pcie-apple not?


Thanks,

— Yureka