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[209.132.180.67]) by mx.google.com with ESMTP id d9-v6si6507745pli.382.2018.06.14.07.31.31; Thu, 14 Jun 2018 07:31:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=AOGuEGuY; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965974AbeFNO3u (ORCPT + 99 others); Thu, 14 Jun 2018 10:29:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:33316 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965867AbeFNO3m (ORCPT ); Thu, 14 Jun 2018 10:29:42 -0400 Received: from mail-io0-f171.google.com (mail-io0-f171.google.com [209.85.223.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0E0E4208DD; Thu, 14 Jun 2018 14:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528986582; bh=/gdIE/vnYAljSjYUn+hh1gc6Z58YSjbDPeLWd2UfQb0=; h=In-Reply-To:References:From:Date:Subject:To:Cc:From; b=AOGuEGuYWj64h7K+gYPJ6Xjx3Zi/ewevzD8reTZmVjVwfqtvJSKFaObJ925mDJJQP FeD0vAWCdbE9gJcs3r19RA5BsQ/CON8u34VHwoRRY/dVbzbmqlNTMzZX1YlSRu8pPN 5haFKHtk+NnQP6wV/03QZwIIGDKT5BEXW6swy8+c= Received: by mail-io0-f171.google.com with SMTP id f1-v6so7326879ioh.6; Thu, 14 Jun 2018 07:29:42 -0700 (PDT) X-Gm-Message-State: APt69E2Iyqy0enupnzMh1qpoagqSWp+H2dHu0pR+Ie6uZ4jZbjiGnA8O SRKOofx1F/ssfc3S1VPpldh4CMkARFbhwrUdzA== X-Received: by 2002:a6b:c689:: with SMTP id w131-v6mr2468142iof.79.1528986581472; Thu, 14 Jun 2018 07:29:41 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a4f:6403:0:0:0:0:0 with HTTP; Thu, 14 Jun 2018 07:29:20 -0700 (PDT) In-Reply-To: <000101d403d3$87210d20$95632760$@codeaurora.org> References: <1528455990-24572-1-git-send-email-sayalil@codeaurora.org> <1528455990-24572-2-git-send-email-sayalil@codeaurora.org> <20180612192636.GA31725@rob-hp-laptop> <000101d403d3$87210d20$95632760$@codeaurora.org> From: Rob Herring Date: Thu, 14 Jun 2018 08:29:20 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH V2 1/3] scsi: ufs: set the device reference clock setting To: sayali Cc: Subhash Jadavani , Can Guo , Vivek Gautam , Rajendra Nayak , Vinayak Holikatti , "James E.J. Bottomley" , "Martin K. Petersen" , asutoshd@codeaurora.org, Evan Green , linux-scsi@vger.kernel.org, Mark Rutland , Mathieu Malaterre , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 14, 2018 at 5:33 AM, sayali wrote: > Comment inline. > > Thanks, > Sayali > -----Original Message----- > From: Rob Herring [mailto:robh@kernel.org] > Sent: Wednesday, June 13, 2018 12:57 AM > To: Sayali Lokhande > Cc: subhashj@codeaurora.org; cang@codeaurora.org; > vivek.gautam@codeaurora.org; rnayak@codeaurora.org; vinholikatti@gmail.com; > jejb@linux.vnet.ibm.com; martin.petersen@oracle.com; > asutoshd@codeaurora.org; evgreen@chromium.org; linux-scsi@vger.kernel.org; > Mark Rutland ; Mathieu Malaterre ; > open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS > ; open list > Subject: Re: [PATCH V2 1/3] scsi: ufs: set the device reference clock > setting > > On Fri, Jun 08, 2018 at 04:36:28PM +0530, Sayali Lokhande wrote: >> From: Subhash Jadavani >> >> UFS host supplies the reference clock to UFS device and UFS device >> specification allows host to provide one of the 4 frequencies (19.2 >> MHz, >> 26 MHz, 38.4 MHz, 52 MHz) for reference clock. Host should set the >> device reference clock frequency setting in the device based on what >> frequency it is supplying to UFS device. >> >> Signed-off-by: Subhash Jadavani >> Signed-off-by: Can Guo >> Signed-off-by: Sayali Lokhande >> --- >> .../devicetree/bindings/ufs/ufshcd-pltfrm.txt | 7 +++ >> drivers/scsi/ufs/ufs.h | 9 ++++ >> drivers/scsi/ufs/ufshcd-pltfrm.c | 24 ++++++++++ >> drivers/scsi/ufs/ufshcd.c | 52 > ++++++++++++++++++++++ >> drivers/scsi/ufs/ufshcd.h | 1 + >> 5 files changed, 93 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt >> b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt >> index c39dfef..4522434 100644 >> --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt >> +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt >> @@ -41,6 +41,12 @@ Optional properties: >> -lanes-per-direction : number of lanes available per direction - either 1 > or 2. >> Note that it is assume same number of lanes is > used both >> directions at once. If not specified, default is 2 > lanes per direction. >> +- dev-ref-clk-freq : Specify the device reference clock frequency, must > be one of the following: >> + 0: 19.2 MHz >> + 1: 26 MHz >> + 2: 38.4 MHz >> + 3: 52 MHz >> + Defaults to 26 MHz if not specified. > > I must have misunderstood your last response. I thought you could handle > things without DT. If not, my question remains. > [Sayali]: Ref clk frequency setting could vary from > platfrom-to-platform(vendor specific). Hence we need to pass it via DT. > Currently in DT we do not set/mention any ref clk frequency > parameter. Hence I have added one new DT entry to configure > required ref clk freq. The clocks property contains "ref_clk". Is that not the same clock? Why can't you read what that frequency is? Or you need to be able to change it to a specific frequency? These all look like typical oscillator frequencies, so I wouldn't expect you could change them (other than divide by 2 maybe). Rob