From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05B945DF16; Thu, 15 Feb 2024 19:39:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708025972; cv=none; b=ffompPJnM8qLgDl5Z8ic8MHpgkaW5z2DTH8zMvaUH+Kbmzfy2wp1NTBbXu/aDjkPaq9aBqtyWlxPHgwjj0viNGBD2Wt6bzywlTF6/sMwqevtQosZ0W/lzHrfMduNYHL2gXrGgyVtO4/P0LNTV2VTrbVYFJPnFA8Zoxr/W1VBKzI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708025972; c=relaxed/simple; bh=lnJROVnckTmteDEbP/T2C4WoTvrQNTHlrX+h6G5UKQQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SoPOHCSvLKFkOy+H6KsDHtdiV+MtEcLayMJHOrkxM7Trbqm4uJiuRmqNsfssPYwK0RnW+xWYogfvfdxYKVdBy5CcB/11rzP4EkI4eoF/rb3TCsM8tsciSOM03SbwnTzDUq++PCPu4aTBap9cULZ1KeTa7c4NPUNGoPpGkk9DEjU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xj4aDh/w; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Xj4aDh/w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B7DDC433F1; Thu, 15 Feb 2024 19:39:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708025971; bh=lnJROVnckTmteDEbP/T2C4WoTvrQNTHlrX+h6G5UKQQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Xj4aDh/wvg83T77RgYb8/CZYmPb03V+3YOM0ahGjqlCiHI04YTLEmtszPZEpGv6aN 5ujsRcBXBAFC087z4SaWgVfocoJTbzAoKbnrjsTrkra+Ix2kbDOB4EK05BJtjlpAtD /AkijIN2sZiDLYEXlzwbTEqAcjGRAzVW1bYqpKa2QFm70K8YCOsR/W7yHMzsnVXLlL KgGeTq+ilB+srMbqxdAb1GU802bqB0vE5CPnauB3XYXe16U6ihnobhCf4huYqGYUq6 qSC408dCYejb5Nh388pL59LEFbaMaE/7NEmCG4kpBSSlP/gIjIVvnnZKqU+lVgTNwn uEirmsKEjH1Pg== Date: Thu, 15 Feb 2024 19:39:26 +0000 From: Conor Dooley To: Radhey Shyam Pandey Cc: gregkh@linuxfoundation.org, robh@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, balbi@kernel.org, Thinh.Nguyen@synopsys.com, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, git@amd.com, Piyush Mehta Subject: Re: [PATCH] dt-bindings: usb: dwc3: Add snps,enable_guctl1_ipd_quirk Message-ID: <20240215-crying-lunchtime-977afb05e45f@spud> References: <1708023665-1441674-1-git-send-email-radhey.shyam.pandey@amd.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="n9jI1ZoH10PjuklW" Content-Disposition: inline In-Reply-To: <1708023665-1441674-1-git-send-email-radhey.shyam.pandey@amd.com> --n9jI1ZoH10PjuklW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 16, 2024 at 12:31:05AM +0530, Radhey Shyam Pandey wrote: > From: Piyush Mehta >=20 > SNPS controller when configured in HOST mode maintains Inter Packet > Delay (IPD) of ~380ns which works with most of the super-speed hubs > except VIA-LAB hubs. When IPD is ~380ns HOST controller fails to > enumerate FS/LS devices when connected behind VIA-LAB hubs. >=20 > To address the above issue, add 'snps,enable_guctl1_ipd_quirk' quirk, > This quirk set the bit 9 of GUCTL1 that enables the workaround in HW to > reduce the ULPI clock latency by 1 cycle, thus reducing the IPD (~360ns). >=20 > Signed-off-by: Piyush Mehta > Signed-off-by: Radhey Shyam Pandey > --- > In the zynqmp public database GUCTL1 bit 9 is reserved but it is used to > enable a fix related to Inter Packet Delay in HW. The documentation team > is working to update GUCTL1 bit 9 description. Does this just affect the zynqmp? If it does, then you don't need a property - do this based on compatible.=20 If it does affect other devices, what prevents the workaround being performed for all dwc3 controllers? Cheers, Conor. > --- > Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 7 +++++++ > 1 file changed, 7 insertions(+) >=20 > diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Docum= entation/devicetree/bindings/usb/snps,dwc3.yaml > index 8f5d250070c7..b226457a6e50 100644 > --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml > +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml > @@ -280,6 +280,13 @@ properties: > xhci reset. And the vbus will back to 5V automatically when reset = done. > type: boolean > =20 > + snps,enable_guctl1_ipd_quirk: No underscores in properties please. > + description: > + When set, HW reduce the ULPI clock latency by 1 cycle, thus reduci= ng > + the IPD (~360ns) and making controller enumerate FS/LS devices > + connected behind via-hubs. > + type: boolean > + > snps,is-utmi-l1-suspend: > description: > True when DWC3 asserts output signal utmi_l1_suspend_n, false when > --=20 > 2.34.1 >=20 --n9jI1ZoH10PjuklW Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZc5obgAKCRB4tDGHoIJi 0l7TAQCNQRDS4vsEFSVQ8ov4nOn8FfznlW91DryqSTYqunOlVwD/f90BI+v2r4Xy xBG6YLClNWWmnSMN2ve5dAOyW5SDeAc= =aXB9 -----END PGP SIGNATURE----- --n9jI1ZoH10PjuklW--