From b100402e93dcae0a88fe59d88d8114ce06d01f1e Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Fri, 18 Dec 2020 15:02:38 +0300 Subject: [PATCH] usb: phy: tegra: Add delay after power up The PHY hardware needs the delay of 2ms after power up, otherwise initial interrupt may be lost if USB controller is accessed before PHY is settled down. Previously this issue was masked by implicit delays, but now it pops up after squashing the older ehci-tegra driver into the ChipIdea driver. Tested-by: Matt Merhar Tested-by: Nicolas Chauvet Tested-by: Peter Geis Tested-by: Ion Agorria Acked-by: Thierry Reding Acked-by: Peter Chen Signed-off-by: Dmitry Osipenko Link: https://lore.kernel.org/r/20201218120246.7759-2-digetx@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/phy/phy-tegra-usb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c index 03a3337..1296524 100644 --- a/drivers/usb/phy/phy-tegra-usb.c +++ b/drivers/usb/phy/phy-tegra-usb.c @@ -784,6 +784,9 @@ static int tegra_usb_phy_power_on(struct tegra_usb_phy *phy) phy->powered_on = true; + /* Let PHY settle down */ + usleep_range(2000, 2500); + return 0; } -- 2.7.4