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

Dmitry Osipenko
2020-12-16T09:10:25Z

16.12.2020 11:51, Sergei Shtylyov пишет:
> 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.

Hi,

I'll improve the comments in v2, thanks.