[PATCH 1/2 v2] usb: dwc2: Make having a phy optional

[Daniel Brát]

Despite using 'phy_optional_get' to get a 'usb2-phy' inside its probe,
the driver would fail if it didnt find it. Also, there is no Kconfig
dependency on 'CONFIG_GENERIC_PHY', so without it defined the phy
functions are unimplemented and always return -ENOSYS making dwc2 probe
always fail too.
The header stub of 'phy_optional_get' was changed to return NULL and
the dwc2 driver was modified accordingly.

Signed-off-by: Daniel Brát <danek.brat at gmail.com>
---
 drivers/usb/dwc2/dwc2.c | 27 +++++++++++++++------------
 include/linux/phy/phy.h |  2 +-
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/dwc2/dwc2.c b/drivers/usb/dwc2/dwc2.c
index 9893977b8..472a0b7d9 100644
--- a/drivers/usb/dwc2/dwc2.c
+++ b/drivers/usb/dwc2/dwc2.c
@@ -73,19 +73,22 @@ static int dwc2_probe(struct device_d *dev)
 		goto clk_disable;
 
 	dwc2->phy = phy_optional_get(dev, "usb2-phy");
-	if (IS_ERR(dwc2->phy)) {
-		ret = PTR_ERR(dwc2->phy);
-		goto clk_disable;
+	if (dwc2->phy) {
+		if (IS_ERR(dwc2->phy)) {
+			dev_warn(dev, "Couldnt get 'usb2-phy': %s\n",
+					strerror(PTR_ERR(dwc2->phy)));
+			goto phy_bypass;
+		}
+
+		ret = phy_power_on(dwc2->phy);
+		if (ret)
+			goto clk_disable;
+
+		ret = phy_init(dwc2->phy);
+		if (ret)
+			goto phy_power_off;
 	}
-
-	ret = phy_power_on(dwc2->phy);
-	if (ret)
-		goto clk_disable;
-
-	ret = phy_init(dwc2->phy);
-	if (ret)
-		goto phy_power_off;
-
+phy_bypass:
 	ret = dwc2_check_core_version(dwc2);
 	if (ret)
 		goto error;
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 679ce6e42..321e546f9 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -195,7 +195,7 @@ static inline struct phy *phy_get(struct device_d *dev, const char *string)
 static inline struct phy *phy_optional_get(struct device_d *dev,
 					   const char *string)
 {
-	return ERR_PTR(-ENOSYS);
+	return NULL;
 }
 
 static inline struct phy *of_phy_get_by_phandle(struct device_d *dev,
-- 
2.17.1