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[24.155.109.49]) by smtp.gmail.com with ESMTPSA id l6sm936359otf.63.2019.02.22.12.35.00 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 22 Feb 2019 12:35:00 -0800 (PST) Date: Fri, 22 Feb 2019 14:34:59 -0600 From: Rob Herring To: Ran Wang Cc: Greg Kroah-Hartman , "linux-usb@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Ran Wang Subject: Re: [PATCH v2 1/2] usb: dwc3: Add avoiding vbus glitch happen during xhci reset Message-ID: <20190222203459.GA16999@bogus> References: <20190219072358.43493-1-ran.wang_1@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190219072358.43493-1-ran.wang_1@nxp.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Feb 2019 07:23:14 +0000, Ran Wang wrote: > When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS > (or its control signal) will turn on immediately on related Root Hub > ports. Then the VBUS will be de-asserted for a little while during xhci > reset (conducted by xhci driver) for a little while and back to normal. > > This VBUS glitch might cause some USB devices emuration fail if kernel > boot with them connected. One SW workaround which can fix this is to > program all PORTSC[PP] to 0 to turn off VBUS immediately after setting > host mode in DWC3 driver(per signal measurement result, it will be too > late to do it in xhci-plat.c or xhci.c). > > Signed-off-by: Ran Wang > --- > Changes in v2: > - Correct typos > - Shorten the name to snps,host-vbus-glitches > > Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > Reviewed-by: Rob Herring From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 1/2] usb: dwc3: Add avoiding vbus glitch happen during xhci reset Date: Fri, 22 Feb 2019 14:34:59 -0600 Message-ID: <20190222203459.GA16999@bogus> References: <20190219072358.43493-1-ran.wang_1@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190219072358.43493-1-ran.wang_1@nxp.com> Sender: linux-kernel-owner@vger.kernel.org Cc: Greg Kroah-Hartman , "linux-usb@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Ran Wang List-Id: devicetree@vger.kernel.org On Tue, 19 Feb 2019 07:23:14 +0000, Ran Wang wrote: > When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS > (or its control signal) will turn on immediately on related Root Hub > ports. Then the VBUS will be de-asserted for a little while during xhci > reset (conducted by xhci driver) for a little while and back to normal. > > This VBUS glitch might cause some USB devices emuration fail if kernel > boot with them connected. One SW workaround which can fix this is to > program all PORTSC[PP] to 0 to turn off VBUS immediately after setting > host mode in DWC3 driver(per signal measurement result, it will be too > late to do it in xhci-plat.c or xhci.c). > > Signed-off-by: Ran Wang > --- > Changes in v2: > - Correct typos > - Shorten the name to snps,host-vbus-glitches > > Documentation/devicetree/bindings/usb/dwc3.txt | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > Reviewed-by: Rob Herring From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v2,1/2] usb: dwc3: Add avoiding vbus glitch happen during xhci reset From: Rob Herring Message-Id: <20190222203459.GA16999@bogus> Date: Fri, 22 Feb 2019 14:34:59 -0600 To: Ran Wang Cc: Greg Kroah-Hartman , "linux-usb@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-ID: T24gVHVlLCAxOSBGZWIgMjAxOSAwNzoyMzoxNCArMDAwMCwgUmFuIFdhbmcgd3JvdGU6Cj4gV2hl biBEV0MzIGlzIHNldCB0byBob3N0IG1vZGUgYnkgcHJvZ3JhbW1pbmcgcmVnaXN0ZXIgRFdDM19H Q1RMLCBWQlVTCj4gKG9yIGl0cyBjb250cm9sIHNpZ25hbCkgd2lsbCB0dXJuIG9uIGltbWVkaWF0 ZWx5IG9uIHJlbGF0ZWQgUm9vdCBIdWIKPiBwb3J0cy4gVGhlbiB0aGUgVkJVUyB3aWxsIGJlIGRl LWFzc2VydGVkIGZvciBhIGxpdHRsZSB3aGlsZSBkdXJpbmcgeGhjaQo+IHJlc2V0IChjb25kdWN0 ZWQgYnkgeGhjaSBkcml2ZXIpIGZvciBhIGxpdHRsZSB3aGlsZSBhbmQgYmFjayB0byBub3JtYWwu Cj4gCj4gVGhpcyBWQlVTIGdsaXRjaCBtaWdodCBjYXVzZSBzb21lIFVTQiBkZXZpY2VzIGVtdXJh dGlvbiBmYWlsIGlmIGtlcm5lbAo+IGJvb3Qgd2l0aCB0aGVtIGNvbm5lY3RlZC4gT25lIFNXIHdv cmthcm91bmQgd2hpY2ggY2FuIGZpeCB0aGlzIGlzIHRvCj4gcHJvZ3JhbSBhbGwgUE9SVFNDW1BQ XSB0byAwIHRvIHR1cm4gb2ZmIFZCVVMgaW1tZWRpYXRlbHkgYWZ0ZXIgc2V0dGluZwo+IGhvc3Qg bW9kZSBpbiBEV0MzIGRyaXZlcihwZXIgc2lnbmFsIG1lYXN1cmVtZW50IHJlc3VsdCwgaXQgd2ls bCBiZSB0b28KPiBsYXRlIHRvIGRvIGl0IGluIHhoY2ktcGxhdC5jIG9yIHhoY2kuYykuCj4gCj4g U2lnbmVkLW9mZi1ieTogUmFuIFdhbmcgPHJhbi53YW5nXzFAbnhwLmNvbT4KPiAtLS0KPiBDaGFu Z2VzIGluIHYyOgo+ICAgLSBDb3JyZWN0IHR5cG9zCj4gICAtIFNob3J0ZW4gdGhlIG5hbWUgdG8g c25wcyxob3N0LXZidXMtZ2xpdGNoZXMKPiAKPiAgRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2Jp bmRpbmdzL3VzYi9kd2MzLnR4dCB8ICAgIDMgKysrCj4gIDEgZmlsZXMgY2hhbmdlZCwgMyBpbnNl cnRpb25zKCspLCAwIGRlbGV0aW9ucygtKQo+IAoKUmV2aWV3ZWQtYnk6IFJvYiBIZXJyaW5nIDxy b2JoQGtlcm5lbC5vcmc+Cg==