usb: dwc3: fix backwards compat with rockchip devices

Commit 33fb697 ("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: 33fb697 ("usb: dwc3: Get clocks individually")
Reported-by: Frank Wunderlich <frank-w@public-files.de>
Tested-By: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Link: https://lore.kernel.org/r/20220409152116.3834354-1-pgwipeout@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: pgwipeout

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);