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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98720C54EE9 for ; Thu, 22 Sep 2022 13:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231865AbiIVNwJ (ORCPT ); Thu, 22 Sep 2022 09:52:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231890AbiIVNv7 (ORCPT ); Thu, 22 Sep 2022 09:51:59 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A2A8EFA68; Thu, 22 Sep 2022 06:51:45 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id D0DE36BE; Thu, 22 Sep 2022 15:51:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1663854704; bh=uDPuHKFlxyNd6c23deR/oha4FWKGGQOVT5JIulE83wk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GO0rSUPLZvMRR7gbcy6/hstYDPuIWntiCMcw1GZSzRrkv9DB5gXfGfLDnjLFFqlWX VsRmUMNVY11ef9TxE4DkjVa4ZGRPT7hpwIkmQW6+hh5eK0lsuF/LtUNErzRUMVXad3 OOOJu/TafgOIH215k2TXIyqE/q8h9uVIBK1zAln4= Date: Thu, 22 Sep 2022 16:51:29 +0300 From: Laurent Pinchart To: "Lad, Prabhakar" Cc: Geert Uytterhoeven , Sakari Ailus , Lad Prabhakar , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Philipp Zabel , Jacopo Mondi , Niklas =?utf-8?Q?S=C3=B6derlund?= , Hans Verkuil , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Biju Das Subject: Re: [PATCH v2 3/4] media: platform: Add Renesas RZ/G2L MIPI CSI-2 receiver driver Message-ID: References: <20220905230406.30801-1-prabhakar.mahadev-lad.rj@bp.renesas.com> <20220905230406.30801-4-prabhakar.mahadev-lad.rj@bp.renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 22, 2022 at 02:27:15PM +0100, Lad, Prabhakar wrote: > On Thu, Sep 22, 2022 at 1:51 PM Geert Uytterhoeven wrote: > > On Thu, Sep 22, 2022 at 2:34 PM Sakari Ailus wrote: > > > On Thu, Sep 22, 2022 at 01:08:33PM +0100, Lad, Prabhakar wrote: > > > > > > * Switched to manually turn ON/OFF the clocks instead of pm_runtime so that > > > > > > the mipi/dhpy initialization happens as per the HW manual > > > > > > > > > > That doesn't look right. The driver doesn't use runtime PM anymore, so > > > > > power domains may not be handled properly. What was the problem with > > > > > clock handling using runtime PM ? > > > > > > > > > If we use the runtime PM all the clocks will be turned ON when we call > > > > pm_runtime_resume_and_get() which I dont want to. As per the "Starting > > > > reception for MIPI CSI-2 Input" section 35.3.1 for example we first > > > > need to turn ON all the clocks and later further down the line we need > > > > to just turn OFF VCLK -> Enable Link -> turn ON VCLK. Due to such > > > > cases I have switched to individual clock handling. > > > > > > If that is the case, then you should control just that clock directly, > > > outside runtime PM callbacks. > > > > > > Runtime PM may be needed e.g. for resuming a parent device. > > > > Exactly. > > So probably you should not consider R9A07G044_CRU_VCLK a PM clock, > > i.e. you need changes to rzg2l_cpg_is_pm_clk() to exclude it. > > Thanks for the pointer. In that case we will have to consider > R9A07G044_CRU_VCLK and R9A07G044_CRU_SYSCLK as not PM clocks. I like when patch review discussions continue on the list without my involvement, and the end result is exactly what I would have advised :-) > Does the below sound good? > - DEF_NO_PM() macro > - bool is_pm_clk in struct rzg2l_mod_clk. > > I still have to implement it, just wanted your opinion beforehand. Looks good to me, but I'm no expert in this area. I trust Geert's advice. -- Regards, Laurent Pinchart