[U-Boot] [RESEND PATCH 3/5] usb: host: dwc2: force reset assert

From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RESEND PATCH 3/5] usb: host: dwc2: force reset assert
Date: Wed, 6 Nov 2019 23:00:25 +0100	[thread overview]
Message-ID: <5e90369b-c273-028e-ee27-bfd7249ae64e@denx.de> (raw)
In-Reply-To: <3e13407a0c24443fb5325318de75e357@SFHDAG6NODE3.st.com>

On 11/6/19 7:27 PM, Patrick DELAUNAY wrote:
> Hi,

Hi,

[...]

>>> diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c index
>>> 51023b0c2c..3086411fc4 100644
>>> --- a/drivers/usb/host/dwc2.c
>>> +++ b/drivers/usb/host/dwc2.c
>>> @@ -1149,6 +1149,8 @@ static int dwc2_reset(struct udevice *dev)
>>>  			return ret;
>>>  	}
>>>
>>> +	reset_assert_bulk(&priv->resets);
>>> +	udelay(2);
>>
>> Why is there a 2 uS delay ?
> 
> I think: no real reason to have 2 us....
> 
> It was jus a reasonable time to be sure that the device reset is correctly
> performed, the reset signal is propagated....
> 
> but perhaps that no delay is working...
> I can test without delay if you prefer...
> 
> PS: I use the same value than DWC2 gadget driver:
>        Added by my commit c2c74f97afff

Isn't there a way to poll the IP to determine whether the reset completed ?

[...]

-- 
Best regards,
Marek Vasut