usb: dwc3: Fix core validation in probe, move after clocks are enabled

The required clocks needs to be enabled before the first register
access. After commit fe8abf332b8f ("usb: dwc3: support clocks and resets
for DWC3 core"), this happens when the dwc3_core_is_valid function is
called, but the mentioned commit adds that call in the wrong place,
before the clocks are enabled. So, move that call after the
clk_bulk_enable() to ensure the clocks are enabled and the reset
deasserted.

I detected this while, as experiment, I tried to move the clocks and resets
from the glue layer to the DWC3 core on a Samsung Chromebook Plus.

That was not detected before because, in most cases, the glue layer
initializes SoC-specific things and then populates the child "snps,dwc3"
with those clocks already enabled.

Fixes: b873e2d0ea1ef ("usb: dwc3: Do core validation early on probe")
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 4aff1d8..6e9e172 100644 (file)
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1423,11 +1423,6 @@ static int dwc3_probe(struct platform_device *pdev)
        dwc->regs       = regs;
        dwc->regs_size  = resource_size(&dwc_res);
 
-       if (!dwc3_core_is_valid(dwc)) {
-               dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
-               return -ENODEV;
-       }
-
        dwc3_get_properties(dwc);
 
        dwc->reset = devm_reset_control_get_optional_shared(dev, NULL);
@@ -1460,6 +1455,12 @@ static int dwc3_probe(struct platform_device *pdev)
        if (ret)
                goto unprepare_clks;
 
+       if (!dwc3_core_is_valid(dwc)) {
+               dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
+               ret = -ENODEV;
+               goto disable_clks;
+       }
+
        platform_set_drvdata(pdev, dwc);
        dwc3_cache_hwparams(dwc);
 
@@ -1525,6 +1526,7 @@ err1:
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
 
+disable_clks:
        clk_bulk_disable(dwc->num_clks, dwc->clks);
 unprepare_clks:
        clk_bulk_unprepare(dwc->num_clks, dwc->clks);