From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA990C352A4 for ; Fri, 7 Feb 2020 12:38:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81C2F21741 for ; Fri, 7 Feb 2020 12:38:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="kuLckCUB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727011AbgBGMiq (ORCPT ); Fri, 7 Feb 2020 07:38:46 -0500 Received: from mail26.static.mailgun.info ([104.130.122.26]:40563 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726798AbgBGMiq (ORCPT ); Fri, 7 Feb 2020 07:38:46 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1581079126; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=qzairh/+yw4wEAbV6wFRDDG7JyWfCMeJmBCkct0T2fc=; b=kuLckCUBy6u9CFWfKnjXHAqKTcyI4ARj9v6iT87gLfJOi87PyC/oy9hfehyvMhW4/upYnCSS rBlfIeMElaxIJolMVEoHAU0T6BYoe9gmJWEl9jNXrgsFaRXO2zXxDuDYwM9Hl49Dulwj83S1 cVcMOO7aL5CtdVX8s/t2MH8MLKs= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI1YmJiNiIsICJkZXZpY2V0cmVlQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e3d5a50.7f5eb23fa5e0-smtp-out-n01; Fri, 07 Feb 2020 12:38:40 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 61BBAC433A2; Fri, 7 Feb 2020 12:38:40 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: harigovi) by smtp.codeaurora.org (Postfix) with ESMTPSA id E5976C43383; Fri, 7 Feb 2020 12:38:39 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 07 Feb 2020 18:08:39 +0530 From: harigovi@codeaurora.org To: Jeffrey Hugo Cc: "open list:DRM PANEL DRIVERS" , MSM , freedreno , DTML , lkml , Rob Clark , nganji@codeaurora.org, Sean Paul , kalyan_t@codeaurora.org, "Kristian H. Kristensen" Subject: Re: [Freedreno] [v1] drm/msm/dsi/pll: call vco set rate explicitly In-Reply-To: References: <1580980321-19256-1-git-send-email-harigovi@codeaurora.org> Message-ID: <2f5abc857910f70faa119fea5bda81d7@codeaurora.org> X-Sender: harigovi@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 2020-02-06 20:29, Jeffrey Hugo wrote: > On Thu, Feb 6, 2020 at 2:13 AM Harigovindan P > wrote: >> >> For a given byte clock, if VCO recalc value is exactly same as >> vco set rate value, vco_set_rate does not get called assuming >> VCO is already set to required value. But Due to GDSC toggle, >> VCO values are erased in the HW. To make sure VCO is programmed >> correctly, we forcefully call set_rate from vco_prepare. > > Is this specific to certain SoCs? I don't think I've observed this. As far as Qualcomm SOCs are concerned, since pll is analog and the value is directly read from hardware if we get recalc value same as set rate value, the vco_set_rate will not be invoked. We checked in our idp device which has the same SOC but it works there since the rates are different.