Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937579AbdIZXKi (ORCPT ); Tue, 26 Sep 2017 19:10:38 -0400 Received: from gate2.alliedtelesis.co.nz ([202.36.163.20]:49420 "EHLO gate2.alliedtelesis.co.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937380AbdIZXKg (ORCPT ); Tue, 26 Sep 2017 19:10:36 -0400 From: Kalyan Kinthada To: Gregory CLEMENT CC: "devicetree@vger.kernel.org" , "wsa@the-dreams.de" , "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Chris Packham Subject: Re: [PATCH] dt-bindings: i2c: Add armada-38x i2c binding Thread-Topic: [PATCH] dt-bindings: i2c: Add armada-38x i2c binding Thread-Index: AQHTNr5ff+HOSDwxcUGJff8P6E1bWKLG8eGA Date: Tue, 26 Sep 2017 23:10:32 +0000 Message-ID: References: <20170922020429.20941-1-kalyan.kinthada@alliedtelesis.co.nz> <87377fmbpw.fsf@free-electrons.com> <1506289460890.34765@alliedtelesis.co.nz> <87lgl1ishv.fsf@free-electrons.com> In-Reply-To: <87lgl1ishv.fsf@free-electrons.com> Accept-Language: en-NZ, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.32.16.78] Content-Type: text/plain; charset="utf-8" Content-ID: <4882B9BC784E6E428382950FF3FFD48B@atlnz.lc> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v8QNBYLw025622 Content-Length: 3966 Lines: 100 On 27/09/17 00:55, Gregory CLEMENT wrote: > Hi Kalyan, > > Please try avoid top-posting. I am sorry. Fixed it now. > > On dim., sept. 24 2017, Kalyan Kinthada wrote: > >> Hi Gregory, >> >> I got this information from Armada-38x functional errata document. > OK but in any case just adding a new compatible was not enough you have > to update the driver in the same time, however for this case we won't > need it, see below. > >> I can add the "marvell,mv78230-i2c" compatible string to the appropriate device tree files >> but the i2c-mv64xxx driver enables an additional feature (offload i2c transactions) >> based on the compatible string "marvell,mv78230-i2c". >> >> I am not sure if this feature (offload i2c transactions) should be enabled for Armada-38x devices. >> That is the reason I felt for the need of a new compatible string >> specifically for Armada-38x SoCs. > Indeed the Armada-38x SoCs does not support hardware offloading (at > least according the datasheet). But it happens that in the earlier > version of the Armada XP the hardware offloading was buggy, so we > introduced a compatible for this case: marvell,mv78230-a0-i2c. This > compatible enable the errata fix but not the offloading feature. That > means that it is exactly the compatible you need for Armada 38x (and > Armada 39x and 375 I think). Ok. I will add "marvell,mv78230-a0-i2c" to the Armada-38x device tree file. I will send a new patch with these changes. Thanks for your time. Regards, Kalyan > > Gregory > >> Thanks, >> Kalyan >> ________________________________________ >> From: Gregory CLEMENT >> Sent: Friday, 22 September 2017 7:30 p.m. >> To: Kalyan Kinthada >> Cc: devicetree@vger.kernel.org; wsa@the-dreams.de; robh+dt@kernel.org; >> pawel.moll@arm.com; mark.rutland@arm.com; >> ijc+devicetree@hellion.org.uk; galak@codeaurora.org; >> linux-i2c@vger.kernel.org; linux-kernel@vger.kernel.org; Chris Packham >> Subject: Re: [PATCH] dt-bindings: i2c: Add armada-38x i2c binding >> >> Hi Kalyan, >> >> On ven., sept. 22 2017, Kalyan Kinthada wrote: >> >>> All armada-38x variants(380, 385, 388) SoCs have an issue >>> in i2c controller which violates the i2c repeated start timing. >> >> Did you had an issue with one of the SoC ? >> If yes what was your setting ? >> On my side I never managed to have this sort of issue on Armada 38x. >> >>> This errata is fixed in the i2c-mv64xxx driver but enabled >>> only for devices with compatible string "marvell,mv78230-i2c". >> In this case why not just adding the "marvell,mv78230-i2c" as compatible >> string in the appropriate device tree files ? >> >> Gregory >> >>> This patch introduces a new compatible string >>> "marvell,armada-38x-i2c" for the i2c controller on armada-38x SoCs >>> so that the workaound is enabled. >> >>> Signed-off-by: Kalyan Kinthada >>> --- >>> Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt >>> index 5c30026921..fc100b6bdb 100644 >>> --- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt >>> +++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt >>> @@ -14,6 +14,7 @@ Required properties : >>> very rare, initial version of the SoC which >>> had broken offload support. Linux >>> auto-detects this and sets it appropriately. >>> + - "marvell,armada-38x-i2c" >>> - interrupts : The interrupt number >>> >>> Optional properties : >>> -- >>> 2.14.1 >>> >> -- >> Gregory Clement, Free Electrons >> Kernel, drivers, real-time and embedded Linux >> development, consulting, training and support. >> http://free-electrons.com