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Some PCI devices must be powered-on before they can be detected on the bus. Introduce a simple framework reusing the existing PCI OF infrastructure. The way this works is: a DT node representing a PCI device connected to the port can be matched against its power control platform driver. If the match succeeds, the driver is responsible for powering-up the device and calling pci_pwrctl_device_set_ready() which will trigger a PCI bus rescan as well as subscribe to PCI bus notifications. When the device is detected and created, we'll make it consume the same DT node that the platform device did. When the device is bound, we'll create a device link between it and the parent power control device. Tested-by: Amit Pundir <amit.pundir@linaro.org> Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20240612082019.19161-5-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2024 Linaro Ltd.
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*/
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#ifndef __PCI_PWRCTL_H__
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#define __PCI_PWRCTL_H__
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#include <linux/notifier.h>
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struct device;
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struct device_link;
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/*
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* This is a simple framework for solving the issue of PCI devices that require
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* certain resources (regulators, GPIOs, clocks) to be enabled before the
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* device can actually be detected on the PCI bus.
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*
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* The idea is to reuse the platform bus to populate OF nodes describing the
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* PCI device and its resources, let these platform devices probe and enable
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* relevant resources and then trigger a rescan of the PCI bus allowing for the
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* same device (with a second associated struct device) to be registered with
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* the PCI subsystem.
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*
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* To preserve a correct hierarchy for PCI power management and device reset,
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* we create a device link between the power control platform device (parent)
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* and the supplied PCI device (child).
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*/
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/**
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* struct pci_pwrctl - PCI device power control context.
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* @dev: Address of the power controlling device.
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*
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* An object of this type must be allocated by the PCI power control device and
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* passed to the pwrctl subsystem to trigger a bus rescan and setup a device
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* link with the device once it's up.
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*/
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struct pci_pwrctl {
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struct device *dev;
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/* Private: don't use. */
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struct notifier_block nb;
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struct device_link *link;
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};
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int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl);
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void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl);
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int devm_pci_pwrctl_device_set_ready(struct device *dev,
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struct pci_pwrctl *pwrctl);
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#endif /* __PCI_PWRCTL_H__ */
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