[PATCH V2] usb: host: xhci-plat: allow sysdev to inherit from ACPI

[Adam Wallis]

Currently, xhci_plat is not set up properly when the parent device is an
ACPI node. The conditions that xhci_plat_probe should satisfy are

1. xhci_plat comes from firmware
2. xhci_plat is child of a device from firmware (dwc3-plat)
3. xhci_plat is grandchild of a pci device (dwc3-pci)

Case 2 is covered when the child is an OF node (by checking
sysdev->parent->of_node), however, an ACPI parent will return NULL in
the of_node check and will thus not result in sysdev being set to
sysdev->parent

[   17.591549] xhci-hcd: probe of xhci-hcd.6.auto failed with error -5

This change adds a check for ACPI to completely allow for condition 2.
This is done by first checking if the parent node is of type ACPI (e.g.,
dwc3-plat) and set sysdev to sysdev->parent if either of the two
following conditions are met:

1: If fwnode is empty (in the case that platform_device_add_properties
was not called on the allocated platform device)
2: fwnode exists but is not of type ACPI (this would happen if
platform_device_add_properties was called on the allocated device.
Instead of type FWNODE_ACPI, you would end up with FWNODE_PDATA)

Cc: stable at vger.kernel.org #4.12.x
Cc: stable at vger.kernel.org #4.13.x

Signed-off-by: Adam Wallis <awallis at codeaurora.org>
---
Changes in v2: Incorporate the simplified fwnode check as suggested
by Mathias

 drivers/usb/host/xhci-plat.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index c04144b..2087407 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -186,14 +186,18 @@ static int xhci_plat_probe(struct platform_device *pdev)
 	 * 2. xhci_plat is child of a device from firmware (dwc3-plat)
 	 * 3. xhci_plat is grandchild of a pci device (dwc3-pci)
 	 */
-	sysdev = &pdev->dev;
-	if (sysdev->parent && !sysdev->of_node && sysdev->parent->of_node)
-		sysdev = sysdev->parent;
+	for (sysdev = &pdev->dev; sysdev; sysdev = sysdev->parent) {
+		if (is_of_node(sysdev->fwnode) ||
+			is_acpi_device_node(sysdev->fwnode))
+			break;
 #ifdef CONFIG_PCI
-	else if (sysdev->parent && sysdev->parent->parent &&
-		 sysdev->parent->parent->bus == &pci_bus_type)
-		sysdev = sysdev->parent->parent;
+		else if (sysdev->bus == &pci_bus_type)
+			break;
 #endif
+	}
+
+	if (!sysdev)
+		sysdev = &pdev->dev;
 
 	/* Try to set 64-bit DMA first */
 	if (WARN_ON(!sysdev->dma_mask))
-- 
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