Commit 36acd5e2 authored by Mathias Kresin's avatar Mathias Kresin Committed by Vinod Koul
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phy: lantiq: rcu-usb2: wait after clock enable 



Commit 65dc2e72 ("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.

Signed-off-by: default avatarMathias Kresin <dev@kresin.me>
Acked-by: default avatarHauke Mehrtens <hauke@hauke-m.de>
Acked-by: default avatarMartin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: <stable@vger.kernel.org> # v5.7+
Link: https://lore.kernel.org/r/20210107224901.2102479-1-dev@kresin.me


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent c1883654

drivers/phy/lantiq/phy-lantiq-rcu-usb2.c

+9 −1
Original line number Diff line number Diff line
@@ -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;

}