[PATCH v11 3/7] usb: onboard-hub: add support for Microchip USB5744

[Marek Vasut]

On 11/12/24 7:42 AM, Abbarapu, Venkatesh wrote:
> Hi,
> 
>> -----Original Message-----
>> From: Marek Vasut <marex at denx.de>
>> Sent: Tuesday, November 12, 2024 11:28 AM
>> To: Abbarapu, Venkatesh <venkatesh.abbarapu at amd.com>; u-boot at lists.denx.de
>> Cc: Simek, Michal <michal.simek at amd.com>; fabrice.gasnier at foss.st.com; git
>> (AMD-Xilinx) <git at amd.com>
>> Subject: Re: [PATCH v11 3/7] usb: onboard-hub: add support for Microchip
>> USB5744
>>
>> On 11/12/24 6:07 AM, Venkatesh Yadav Abbarapu wrote:
>>> Add support for the Microchip USB5744 USB3.0 and USB2.0 Hub.
>>> The usb5744 driver trigger hub reset signal after soft reset.
>>> The usb5744 hub need to reset after the phy initialization, which
>>> toggles the gpio.
>>> Also update the usb2514 hub_data with the reset delay as 1us.
>>>
>>> Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
>>> Reviewed-by: Marek Vasut <marex at denx.de>
>>> ---
>>>    common/usb_onboard_hub.c | 20 ++++++++++++++++++--
>>>    1 file changed, 18 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/common/usb_onboard_hub.c b/common/usb_onboard_hub.c index
>>> 827ecf9b02..1d146eccee 100644
>>> --- a/common/usb_onboard_hub.c
>>> +++ b/common/usb_onboard_hub.c
>>> @@ -88,10 +88,26 @@ static int usb_onboard_hub_remove(struct udevice *dev)
>>>    	return ret;
>>>    }
>>>
>>> +static const struct onboard_hub_data usb2514_data = {
>>> +	.reset_us = 1,
>>> +};
>>> +
>>> +static const struct onboard_hub_data usb5744_data = {
>>> +	.power_on_delay_us = 10000,
>>> +	.reset_us = 10000,
>>> +};
>>> +
>>>    static const struct udevice_id usb_onboard_hub_ids[] = {
>>>    	/* Use generic usbVID,PID dt-bindings (usb-device.yaml) */
>>> -	{ .compatible = "usb424,2514" }, /* USB2514B USB 2.0 */
>>> -	{ }
>>> +	{	.compatible = "usb424,2514", /* USB2514B USB 2.0 */
>>> +		.data = (ulong)&usb2514_data,
>> This ^ hub has to be updated in 1/7 , otherwise if only 1/7 is applied (e.g. during
>> bisect), this hub reset will be operated out of specification.
>>
>> Also, looking at the USB2514 datasheet figure 5-3, it seems the hub needs t4=500us
>> recovery time in SMBus mode. Does that mean usb2514_data .power_on_delay_us
>> = 500 is missing too ?
>>
>> Also, it seems t_rstio is 5us in USB5477 datasheet figure 10-4 , where do these
>> 10000us figures above come from ?
> 
> We were seeing i2c failures when we update the reset delay and power on delay values mentioned from the datasheet so updated to 10000us, the linux reference is below
> https://github.com/torvalds/linux/commit/908f61bedb2c40c6d856bbfd7f870b967a4cb498
Is there a matching delay requirement specified in the USB hub datasheet 
or is this a workaround for some board-specific behavior ?