[RFC PATCH] usb: host: Default CONFIG_USB_XHCI_RCAR to module

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

On R-Car Gen3 and RZ/G2HMNE SoCs, when CONFIG_USB_XHCI_RCAR is built-in
and the system boots with an NFS root filesystem, the xHCI controller
probes before firmware becomes available. As a result, the firmware
request fails:

  xhci-renesas-hcd ee000000.usb: Direct firmware load for
  r8a779x_usb3_v3.dlmem failed with error -2

Default CONFIG_USB_XHCI_RCAR to module on ARCH_RENESAS so that probing
is deferred until after the root filesystem is mounted, ensuring that
the firmware is accessible.

Configurations explicitly selecting CONFIG_USB_XHCI_RCAR=y are
unaffected.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
---
 drivers/usb/host/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 0a277a07cf70..b70e019cc3ac 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -90,7 +90,7 @@ config USB_XHCI_RCAR
 	tristate "xHCI support for Renesas R-Car SoCs"
 	depends on USB_XHCI_PLATFORM
 	depends on ARCH_RENESAS || COMPILE_TEST
-	default ARCH_RENESAS
+	default m if ARCH_RENESAS
 	help
 	  Say 'Y' to enable the support for the xHCI host controller
 	  found in Renesas R-Car and RZ/G3E alike ARM SoCs.
-- 
2.54.0