[PATCH] usb: host: ehci-generic: Make resets and clocks optional

[Andre Przywara]

The generic EHCI binding does not *require* resets and clocks
properties, and indeed for instance the Allwinner A20 SoCs does not
need or define any resets in its DT.

Don't easily give up if clk_get_bulk() or reset_get_bulk() return an
error, but check if that is due to the DT simply having no entries for
either of them.

This fixes USB operation on all boards with an Allwinner A10 or A20 SoC,
which were reporting an error after commit ba96176ab70e2999:
=======================
Bus usb at 1c14000: ehci_generic usb at 1c14000: Failed to get resets (err=-2)
probe failed, error -2
=======================

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 drivers/usb/host/ehci-generic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/ehci-generic.c b/drivers/usb/host/ehci-generic.c
index 4734af03962..15267e9a05a 100644
--- a/drivers/usb/host/ehci-generic.c
+++ b/drivers/usb/host/ehci-generic.c
@@ -69,7 +69,7 @@ static int ehci_usb_probe(struct udevice *dev)
 
 	err = 0;
 	ret = clk_get_bulk(dev, &priv->clocks);
-	if (ret) {
+	if (ret && ret != -ENOENT) {
 		dev_err(dev, "Failed to get clocks (ret=%d)\n", ret);
 		return ret;
 	}
@@ -81,7 +81,7 @@ static int ehci_usb_probe(struct udevice *dev)
 	}
 
 	err = reset_get_bulk(dev, &priv->resets);
-	if (err) {
+	if (ret && ret != -ENOENT) {
 		dev_err(dev, "Failed to get resets (err=%d)\n", err);
 		goto clk_err;
 	}
-- 
2.35.3