[U-Boot] [PATCH v1 05/18] usb: dwc3: switch to peripheral mode when exiting

[Jean-Jacques Hiblot]

On 29/04/2019 11:56, Marek Vasut wrote:
> On 4/5/19 2:55 PM, Jean-Jacques Hiblot wrote:
>> This allow the phy to enter idle and then suspend.
>> the K2 platforms require the PHY to be suspended before the USB domain
>> clock can be turned off.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>
>> ---
>>
>>   drivers/usb/dwc3/core.c | 13 +++++++++++++
>>   1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 56e2a046bf..ae01490306 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -581,6 +581,12 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
>>   	return 0;
>>   }
>>   
>> +static void dwc3_gadget_run(struct dwc3 *dwc)
>> +{
>> +	dwc3_writel(dwc->regs, DWC3_DCTL, DWC3_DCTL_RUN_STOP);
>> +	mdelay(100);
> That's long, is this really needed ?

I took my queue from the old keystone code 
(keystone_xhci_phy_suspend(void) in v2018.11) and also from several 
places in this core.c.

I don't know what would be the exact value required: mdelay(10) is too 
short, mdelay(20) works for me. mdelay(100) seems quite safe.

I don't think that is a big problem here, IMHO USB init/exit are not 
time critical.


>
>> +}
>> +
>>   static void dwc3_core_exit_mode(struct dwc3 *dwc)
>>   {
>>   	switch (dwc->dr_mode) {
>> @@ -598,6 +604,13 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
>>   		/* do nothing */
>>   		break;
>>   	}
>> +
>> +	/*
>> +	 * switch back to peripheral mode
>> +	 * This enables the phy to enter idle and then, if enabled, suspend.
>> +	 */
>> +	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
>> +	dwc3_gadget_run(dwc);
>>   }
>>   
>>   #define DWC3_ALIGN_MASK		(16 - 1)
>>
>