On 1/7/21 11:49 PM, Mathias Kresin wrote:

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

Acked-by: Hauke Mehrtens hauke@hauke-m.de

I do not know how long you have to wait here, but this looks ok, when it works.

Hauke

---

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; }