Re: [PATCH v1 1/8] usb: phy: tegra: Add delay after power up

Sergei Shtylyov
2020-12-16T08:52:22Z

Hello!

On 15.12.2020 23:21, Dmitry Osipenko wrote:

> 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 <mattmerhar@protonmail.com>
> Tested-by: Nicolas Chauvet <kwizart@gmail.com>
> Tested-by: Peter Geis <pgwipeout@gmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> 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 03a333797382..cee9c9dbb775 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 to settle down */

Let the PHY settle down.

> + usleep_range(2000, 2500);
> +
> return 0;
> }
>

MBR, Sergei