Commit 65dc2e725286 ("usb: dwc2: Update Core Reset programming flow.") revealed that the phy isn't ready immediately after enabling it's clocks. The dwc2_check_core_version() fails and the dwc2 usb driver errors out.
Add a short delay to let the phy get up and running. There isn't any documentation how much time is required, the value was chosen based on tests.
Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Mathias Kresin dev@kresin.me --- drivers/phy/lantiq/phy-lantiq-rcu-usb2.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c index a7d126192cf1..29d246ea24b4 100644 --- a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c +++ b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c @@ -124,8 +124,16 @@ static int ltq_rcu_usb2_phy_power_on(struct phy *phy) reset_control_deassert(priv->phy_reset);
ret = clk_prepare_enable(priv->phy_gate_clk); - if (ret) + if (ret) { dev_err(dev, "failed to enable PHY gate\n"); + return ret; + } + + /* + * at least the xrx200 usb2 phy requires some extra time to be + * operational after enabling the clock + */ + usleep_range(100, 200);
return ret; }