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

[Sergei Shtylyov]

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@xxxxxxxxxxxxxx>
> Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
> Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
>   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