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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7021DC4332F for ; Mon, 25 Oct 2021 05:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ECA160E0B for ; Mon, 25 Oct 2021 05:33:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229843AbhJYFfa (ORCPT ); Mon, 25 Oct 2021 01:35:30 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:40060 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S229499AbhJYFf3 (ORCPT ); Mon, 25 Oct 2021 01:35:29 -0400 X-UUID: 662247fad7024c07b84259580f507b19-20211025 X-UUID: 662247fad7024c07b84259580f507b19-20211025 Received: from mtkcas11.mediatek.inc [(172.21.101.40)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 252174150; Mon, 25 Oct 2021 13:33:03 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 25 Oct 2021 13:33:02 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 25 Oct 2021 13:33:02 +0800 Message-ID: Subject: Re: [PATCH v11 09/16] soc: mediatek: add mtk-mmsys support for mt8195 vdosys0 From: Jason-JH Lin To: Fei Shao CC: AngeloGioacchino Del Regno , Rob Herring , Matthias Brugger , Chun-Kuang Hu , "Philipp Zabel" , Enric Balletbo i Serra , Maxime Coquelin , David Airlie , Daniel Vetter , Alexandre Torgue , , , , Fabien Parent , Yongqiang Niu , , , , , , , , Date: Mon, 25 Oct 2021 13:33:01 +0800 In-Reply-To: References: <20210921155218.10387-1-jason-jh.lin@mediatek.com> <20210921155218.10387-10-jason-jh.lin@mediatek.com> <8b509551-7cfa-f55c-fc0f-db7d0a3886eb@collabora.com> <29992126d39a7f381a516fdb9cd6e39f1e51afdb.camel@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Fei, Thanks for the reviews. On Mon, 2021-10-25 at 13:05 +0800, Fei Shao wrote: > On Fri, Oct 22, 2021 at 6:13 PM Jason-JH Lin < > jason-jh.lin@mediatek.com> wrote: > > > > Hi Angelo, > > > > Thanks for the reviews. > > > > > > On Thu, 2021-10-14 at 16:05 +0200, AngeloGioacchino Del Regno > > wrote: > > > > Add mt8195 vdosys0 clock driver name and routing table to > > > > the driver data of mtk-mmsys. > > > > > > > > [snip] > > > > > > > > > > --- > > > > > > Hello Jason, > > > thanks for the patch! However, there are a few things to improve: > > > > > > > [snip] > > > > > > +#define > > > > MT8195_VDO0_SEL_IN 0xf34 > > > > +#define MT8195_SEL_IN_VPP_MERGE_FROM_DSC_WRAP0_OUT (0 > > > > << > > > > 0) > > > > > > Bitshifting 0 by 0 bits == 0, so this is simply 0. > > > > > > > +#define MT8195_SEL_IN_VPP_MERGE_FROM_DISP_DITHER1 (1 > > > > << > > > > 0) > > > > > > I would write 0x1 here > > > > > > > +#define MT8195_SEL_IN_VPP_MERGE_FROM_VDO1_VIRTUAL0 (2 > > > > << > > > > 0) > > > > > > ....and 0x2 here: bitshifting of 0 bits makes little sense. > > > > > > > +#define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_DISP_DITHER0 > > > > (0 << 4) > > > > > > Bitshifting 0 by 4 bits is still 0, so this is again 0. > > > This is repeated too many times, so I will not list it for all of > > > the > > > occurrences. > > > > > > > +#define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_VPP_MERGE (1 > > > > << > > > > 4) > > > > > > This is BIT(4). > > > > > > > +#define MT8195_SEL_IN_DSC_WRAP1_IN_FROM_DISP_DITHER1 > > > > (0 << 5) > +#define MT8195_SEL_IN_DSC_WRAP1_IN_FROM_VPP_MERGE > > > > (1 << 5) > > > > > > ...and this is BIT(5) > > > > > > > +#define MT8195_SEL_IN_SINA_VIRTUAL0_FROM_VPP_MERGE (0 > > > > << > > > > 8) > > > > +#define MT8195_SEL_IN_SINA_VIRTUAL0_FROM_DSC_WRAP1_OUT > > > > (1 << 8) > > > > > > BIT(8) > > > > > > > +#define MT8195_SEL_IN_SINB_VIRTUAL0_FROM_DSC_WRAP0_OUT > > > > (0 << 9) > > > > +#define MT8195_SEL_IN_DP_INTF0_FROM_DSC_WRAP1_OUT (0 > > > > << > > > > 12) > > > > +#define MT8195_SEL_IN_DP_INTF0_FROM_VPP_MERGE > > > > (1 << 12) > > > > > > BIT(12) > > > > > > > +#define MT8195_SEL_IN_DP_INTF0_FROM_VDO1_VIRTUAL0 (2 > > > > << > > > > 12) > > > > > > BIT(13) > > > > > > ... and please, use the BIT(nr) macro for all these bit > > > definitions, > > > it's way more > > > readable like that. > > > > > > Regards, > > > - Angelo > > > > Because the HW register design of MT8195_VDO0_SEL_IN 0xf34 is like > > this: > > > > bit[1:0] as MT8195_SEL_IN_VPP_MERGE and > > value: 0 as MT8195_SEL_IN_VPP_MERGE_FROM_DSC_WRAP0_OUT > > value: 1 as MT8195_SEL_IN_VPP_MERGE_FROM_DISP_DITHER1 > > value: 2 as MT8195_SEL_IN_VPP_MERGE_FROM_VDO1_VIRTUAL0 > > bit[4:4] as MT8195_SEL_IN_DSC_WRAP0_IN and > > value 0 as MT8195_SEL_IN_DSC_WRAP0_IN_FROM_DISP_DITHER0 > > value 1 as MT8195_SEL_IN_DSC_WRAP0_IN_FROM_VPP_MERGE > > bit[5:5] as MT8195_SEL_IN_DSC_WRAP1_IN and > > value 0 as > > MT8195_SEL_IN_DSC_WRAP1_IN_FROM_DISP_DITHER1 > > value 1 as > > MT8195_SEL_IN_DSC_WRAP1_IN_FROM_VPP_MERGE > > and so on... > > > > I think using BIT(nr) macro directly is not easy to debug. > > > > > > Is it better to define another MACRO like this? > > > > #define BIT_VAL(val, bit) ((val) << (bit)) > > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_DISP_DITHER0 BIT_VAL(0, 4) > > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_VPP_MERGE BIT_VAL(1, 4) > > ... > > > > or > > > > #define MT8195_SEL_IN_DSC_WRAP0_IN (4) > > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_DISP_DITHER0 (0 > > << MT8195_SEL_IN_DSC_WRAP0_IN) > > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_VPP_MERGE (1 << > > MT8195_SEL_IN_DSC_WRAP0_IN) > > ... > > > > What do you think? > > Hi Jason, > > If that's the case you can still use BIT(nr) for the definitions and > describe their usage in the comment, so both code readability and the > ease of maintenance are preserved, and people can easily tell if > there > are duplicated/missing definitions while reading through the code. > Adding informative comments is never a bad thing. > > I would do something like this (and further split the definitions > into > sections by their functionalities with blank lines for visual > comfort): > > /* > * MT8195_VDO0_SEL_IN[1:0]: VPP_MERGE > * 0x0 : DSC_WRAP0_OUT > * 0x1 : DISP_DITHER1 > * 0x10: VDO1_VIRTUAL0 > */ > #define MT8195_SEL_IN_VPP_MERGE_FROM_DSC_WRAP0_OUT 0 > #define MT8195_SEL_IN_VPP_MERGE_FROM_DISP_DITHER1 BIT(0) > #define MT8195_SEL_IN_VPP_MERGE_FROM_VDO1_VIRTUAL0 BIT(1) > > /* > * MT8195_VDO0_SEL_IN[4:4]: DSC_WRAP0_IN > * 0x0: DISP_DITHER0 > * 0x1: VPP_MERGE > */ > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_DISP_DITHER0 0 > #define MT8195_SEL_IN_DSC_WRAP0_IN_FROM_VPP_MERGE BIT(4) > ... and so on. > > Regards, > Fei > OK, I'll fix it. > > > > > > Regards, > > Jason-JH Lin > > -- Jason-JH Lin