RE: [PATCH] usb: dwc3: imx8mp: detect dwc3 core node via compatible string

[Felipe Balbi <balbi@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 3114 bytes --]


Hi,

Jun Li <jun.li@nxp.com> writes:
>> -----Original Message-----
>> From: Felipe Balbi <balbi@kernel.org>
>> Sent: Friday, April 30, 2021 4:24 PM
>> To: Jun Li <jun.li@nxp.com>; gregkh@linuxfoundation.org
>> Cc: shawnguo@kernel.org; dl-linux-imx <linux-imx@nxp.com>;
>> thunder.leizhen@huawei.com; linux-usb@vger.kernel.org
>> Subject: Re: [PATCH] usb: dwc3: imx8mp: detect dwc3 core node via compatible
>> string
>> 
>> Li Jun <jun.li@nxp.com> writes:
>> 
>> > New schema of usb controller DT-node should be named with prefix
>> > "^usb(@.*)?", dt changed the node name, but missed counter part change
>> > in driver, fix it by switching to use compatible string as the dwc3
>> > core compatible string keeps "snps,dwc3" in all dt.
>> >
>> > Fixes: d1689cd3c0f4 ("arm64: dts: imx8mp: Use the correct name for
>> > child node "snps, dwc3"")
>> > Signed-off-by: Li Jun <jun.li@nxp.com>
>> 
>> 
>> Nice fix :-) It may break down if we have two dwc3 nodes as child of a single
>> parent, but I guess that's very unlikely anyway.
>> 
>> Acked-by: Felipe Balbi <balbi@kernel.org>
>> 
>> That being said, why do need to keep a pointer to the child? I had a quick
>> look at the driver and it doesn't seem like the pointer is necessary at all.
>
> I need keep the child pointer(dwc3 core platform device) to find the dwc3 core
> instance struct(struct dwc3), the wakeup setting need check the dwc3 core's
> current_dr_role and do runtime resume based on the child's dev. 

Right, you're talking about the code below. Some suggestions inline:

> static void dwc3_imx8mp_wakeup_enable(struct dwc3_imx8mp *dwc3_imx)
> {
> 	struct dwc3	*dwc3 = platform_get_drvdata(dwc3_imx->dwc3);
> 	u32		val;
>
> 	if (!dwc3)
> 		return;

I don't think you need to care if dwc3 has probed or not here.

> 	val = readl(dwc3_imx->glue_base + USB_WAKEUP_CTRL);
>
> 	if ((dwc3->current_dr_role == DWC3_GCTL_PRTCAP_HOST) && dwc3->xhci)
> 		val |= USB_WAKEUP_EN | USB_WAKEUP_SS_CONN |
> 		       USB_WAKEUP_U3_EN | USB_WAKEUP_DPDM_EN;
> 	else if (dwc3->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE)
> 		val |= USB_WAKEUP_EN | USB_WAKEUP_VBUS_EN |
> 		       USB_WAKEUP_VBUS_SRC_SESS_VAL;

for this, you could register a listener to the extcon notifier and
update these bits accordingly. With that, you would already *know* that
dwc3 is probed.

> static irqreturn_t dwc3_imx8mp_interrupt(int irq, void *_dwc3_imx)
> {
> 	struct dwc3_imx8mp	*dwc3_imx = _dwc3_imx;
> 	struct dwc3		*dwc = platform_get_drvdata(dwc3_imx->dwc3);
>
> 	if (!dwc3_imx->pm_suspended)
> 		return IRQ_HANDLED;
>
> 	disable_irq_nosync(dwc3_imx->irq);
> 	dwc3_imx->wakeup_pending = true;
>
> 	if ((dwc->current_dr_role == DWC3_GCTL_PRTCAP_HOST) && dwc->xhci)
> 		pm_runtime_resume(&dwc->xhci->dev);
> 	else if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE)
> 		pm_runtime_get(dwc->dev);
>
> 	return IRQ_HANDLED;
> }

for this, maybe you need to teach dwc3 core about wakeup irqs
instead. Have a look dev_pm_set_dedicated_wake_irq().

That would clean things up, I think ;)

-- 
balbi

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 511 bytes --]