On probe the dwc2 driver tries two path to get an usb phy, first calling
devm_phy_get() and secondly with devm_usb_get_phy().
However the current implementation of devm_phy_get() never return a valid
phy for usb-nop-xceiv. And the current implementation of devm_usb_get_phy
only check for phy that's has already been registered.
During boot, I see the dwc2 driver being probed before the usb-nop-xceiv
probe, this means that during the dwc2 probe the function devm_usb_get_phy
never finds the a phy (because it hasn't been registered yet) but never
cause the dwc2 probe to defer.
I tried to follow what is done by dwc3_core_get_phy(): if the current
device has an of_node then try to get the usb_phy by phandle instead of
using devm_usb_get_phy(). This way when the probe order is not good the
devm_usb_get_phy_by_phandle() function will return -EPROBE_DEFER.
Signed-off-by: Jules Maselbas <jmaselbas@xxxxxxxxx>
--- 8< ---
A snippet of the device-tree source I am using:
&usb0 {
phys = <&usb_phy0>;
phy-names = "usb2-phy";
};
&usb_phy0 {
#phy-cells = <0>;
compatible = "usb-nop-xceiv";
reset-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
};
---
drivers/usb/dwc2/platform.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index db9fd4bd1a38..b58ce996add7 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -251,7 +251,12 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
}
if (!hsotg->phy) {
- hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
+ if (hsotg->dev->of_node)
+ i = of_property_match_string(hsotg->dev->of_node, "phy-names", "usb2-phy");
+ if (hsotg->dev->of_node && i >= 0)
+ hsotg->uphy = devm_usb_get_phy_by_phandle(hsotg->dev, "phys", i);
+ else
+ hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
if (IS_ERR(hsotg->uphy)) {
ret = PTR_ERR(hsotg->uphy);
switch (ret) {
--
2.17.1
