Re: [PATCH v2 2/4] usb: dwc2: Add binding for AHB burst

[Christian Lamparter <chunkeey-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>]

Hello John, hello Felipe

On Monday, November 28, 2016 7:32:20 PM CET John Youn wrote:
> On 11/22/2016 12:51 PM, Christian Lamparter wrote:
> > On Monday, November 21, 2016 7:32:30 PM CET John Youn wrote:
> >> On 11/21/2016 1:10 PM, Christian Lamparter wrote:
> >>> On Monday, November 21, 2016 12:16:31 PM CET John Youn wrote:
> >>>> On 11/18/2016 12:18 PM, Christian Lamparter wrote:
> >>>>> On Friday, November 18, 2016 8:16:08 AM CET Rob Herring wrote:
> >>>>>> Also, perhaps you should allow that the compatible string can define the 
> >>>>>> default.
> >>>>>>
> >>>>> I hoped you would say that :).
> >>>>>
> >>>>> I've attached a patch (on top of John Youn changes) [...]
> >>>>> ---
> >>>>> Subject: [PATCH] usb: dwc2: add a default ahb-burst setting for amcc,dwc-otg
> >>>>> [...]
> >>>>> @@ -1097,6 +1097,22 @@ static const char *const ahb_bursts[] = {
> >>>>> +/* [...] */
> >>>>> +static const struct of_device_id dwc2_compat_ahb_bursts[] = {
> >>>>> +	{
> >>>>> +		.compatible = "amcc,dwc-otg",
> >>>>> +		.data = (void *) GAHBCFG_HBSTLEN_INCR16,
> >>>>> +	},
> >>>>> +};
> >> [...]
> >>>>>> @@ -1107,6 +1123,12 @@ static int dwc2_get_property_ahb_burst(struct dwc2_hsotg *hsotg)
> >>>>>  	ret = device_property_read_string(hsotg->dev, "snps,ahb-burst", &str);
> >>>>>  	if (ret < 0) {
> >>>>> +		const struct of_device_id *match;
> >>>>> +
> >>>>> +		match = of_match_node(dwc2_compat_ahb_bursts, node);
> >>>>> +		if (match)
> >>>>> +			ret = (int)match->data;
> >>>>> +
> >> [...]
> >>>> I'd prefer if you use the binding which requires no extra code in
> >>>> dwc2.
> >>> I'm fine with either option. However it think that this would require
> >>> that either Mark or Rob would allow an exception to the "keep existing
> >>> dts the way they are) and ack the following change to the canyonlands.dts. 
> >> [...]
>
> Ok thanks for clearing that up. I understand.
> 
> For now we can just set the property to "INCR16" based on the
> compatible string. Perhaps in the future do this from a glue-layer
> driver which binds to all compatible strings other than "snps,dwc2".
> 
> I won't be able to do anything with this until next week though.
Ok, I think enough time has passed. I would like to see this
patch series (v3 [0]) being queued for 4.11+ together with
"usb: dwc2: add a default ahb-burst setting for amcc,dwc-otg" [1].

Felipe, if you want I can resend the series and add the
"amcc,dwc-otg" patch to it as well. Just let me know what you
prefer here.

Regards,
Christian

[0] <https://www.mail-archive.com/linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org/msg83401.html>
[1] <https://www.spinics.net/lists/linux-usb/msg149663.html>
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