[PATCH] usb: dwc3: fix backwards compat with rockchip devices

[Peter Geis <pgwipeout@gmail.com>]

Commit 33fb697ec7e5 ("usb: dwc3: Get clocks individually") moved from
the clk_bulk api to individual clocks, following the snps,dwc3.yaml
dt-binding for clock names.
Unfortunately the rk3328 (and upcoming rk356x support) use the
rockchip,dwc3.yaml which has different clock names, which are common on
devices using the glue layer.
The rk3328 does not use a glue layer, but attaches directly to the dwc3
core driver.
The offending patch series failed to account for this, thus dwc3 was
broken on rk3328.

To retain backwards compatibility with rk3328 device trees we must also
check for the alternate clock names.

Fixes: 33fb697ec7e5 ("usb: dwc3: Get clocks individually")

Reported-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
---

This patch is standalone to fix the backwards compatibility, and is
necessary no matter if we decide to retain the clock names in
rockchip,dwc3.yaml as is or align with snps,dwc3.yaml.

 drivers/usb/dwc3/core.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 1170b800acdc..5bfd3e88af35 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1690,21 +1690,44 @@ static int dwc3_probe(struct platform_device *pdev)
 		/*
 		 * Clocks are optional, but new DT platforms should support all
 		 * clocks as required by the DT-binding.
+		 * Some devices have different clock names in legacy device trees,
+		 * check for them to retain backwards compatibility.
 		 */
 		dwc->bus_clk = devm_clk_get_optional(dev, "bus_early");
 		if (IS_ERR(dwc->bus_clk))
 			return dev_err_probe(dev, PTR_ERR(dwc->bus_clk),
 					     "could not get bus clock\n");
 
+		if (dwc->bus_clk == NULL) {
+			dwc->bus_clk = devm_clk_get_optional(dev, "bus_clk");
+			if (IS_ERR(dwc->bus_clk))
+				return dev_err_probe(dev, PTR_ERR(dwc->bus_clk),
+						     "could not get bus clock\n");
+		}
+
 		dwc->ref_clk = devm_clk_get_optional(dev, "ref");
 		if (IS_ERR(dwc->ref_clk))
 			return dev_err_probe(dev, PTR_ERR(dwc->ref_clk),
 					     "could not get ref clock\n");
 
+		if (dwc->ref_clk == NULL) {
+			dwc->ref_clk = devm_clk_get_optional(dev, "ref_clk");
+			if (IS_ERR(dwc->ref_clk))
+				return dev_err_probe(dev, PTR_ERR(dwc->ref_clk),
+						     "could not get ref clock\n");
+		}
+
 		dwc->susp_clk = devm_clk_get_optional(dev, "suspend");
 		if (IS_ERR(dwc->susp_clk))
 			return dev_err_probe(dev, PTR_ERR(dwc->susp_clk),
 					     "could not get suspend clock\n");
+
+		if (dwc->susp_clk == NULL) {
+			dwc->susp_clk = devm_clk_get_optional(dev, "suspend_clk");
+			if (IS_ERR(dwc->susp_clk))
+				return dev_err_probe(dev, PTR_ERR(dwc->susp_clk),
+						     "could not get suspend clock\n");
+		}
 	}
 
 	ret = reset_control_deassert(dwc->reset);
-- 
2.25.1