linux-kernel - [PATCH v5] PCI: imx6: Enable the vpcie3v3aux regulator when fetch it

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Message-Id: <20250820022328.2143374-1-hongxing.zhu@nxp.com>
Date: Wed, 20 Aug 2025 10:23:28 +0800
From: Richard Zhu <hongxing.zhu@....com>
To: frank.li@....com,
	l.stach@...gutronix.de,
	lpieralisi@...nel.org,
	kwilczynski@...nel.org,
	mani@...nel.org,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	bhelgaas@...gle.com,
	shawnguo@...nel.org,
	s.hauer@...gutronix.de,
	kernel@...gutronix.de,
	festevam@...il.com
Cc: linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Richard Zhu <hongxing.zhu@....com>
Subject: [PATCH v5] PCI: imx6: Enable the vpcie3v3aux regulator when fetch it

Refer to PCIe CEM r6.0, sec 2.3 WAKE# Signal, WAKE# signal is only
asserted by the Add-in Card when all its functions are in D3Cold state
and at least one of its functions is enabled for wakeup generation. The
3.3V auxiliary power (+3.3Vaux) must be present and used for wakeup
process.

When the 3.3V auxiliary power is present, fetch this auxiliary regulator
at probe time and keep it enabled for the entire PCIe controller
lifecycle. This ensures support for outbound wake-up mechanism such as
WAKE# signaling.

Signed-off-by: Richard Zhu <hongxing.zhu@....com>
---
v5 changes:
- Use the vpcie3v3aux property instead of adding a duplicated one.
- Move the comments from the code changes into the description of
  commit.

v4 changes:
Move the dt-binding to snps,dw-pcie-common.yaml.

v3 changes:
Add a new vaux power supply used to specify the regulator powered up the
WAKE# circuit on the connector when WAKE# is supported.

v2 changes:
Update the commit message, and add reviewed-by from Frank.
https://patchwork.kernel.org/project/linux-pci/patch/20250619072438.125921-1-hongxing.zhu@nxp.com/
---
 drivers/pci/controller/dwc/pci-imx6.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 5a38cfaf989b1..5067da14bc053 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1739,6 +1739,10 @@ static int imx_pcie_probe(struct platform_device *pdev)
 	pci->max_link_speed = 1;
 	of_property_read_u32(node, "fsl,max-link-speed", &pci->max_link_speed);
 
+	ret = devm_regulator_get_enable_optional(&pdev->dev, "vpcie3v3aux");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to enable pcie3v3vaux");
+
 	imx_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
 	if (IS_ERR(imx_pcie->vpcie)) {
 		if (PTR_ERR(imx_pcie->vpcie) != -ENODEV)
-- 
2.37.1