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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 C7329C43215 for ; Tue, 3 Dec 2019 06:25:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D434206DF for ; Tue, 3 Dec 2019 06:25:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="h6qBeI/W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfLCGZK (ORCPT ); Tue, 3 Dec 2019 01:25:10 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:56278 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727044AbfLCGZK (ORCPT ); Tue, 3 Dec 2019 01:25:10 -0500 Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id ED8F8309; Tue, 3 Dec 2019 07:25:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1575354306; bh=xMhIy5HaiSKkNSrpN5V89DDzQfYcJU5ugOWimrHaPOs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=h6qBeI/WhmgWblAgjLQFXmZpvICtdJ7ang5ZAu5QF/RWsHFhxgfKLrUQgLiN0ZySP te8cQY0l0xw5SKujiIaFAPliBjJuQRSuy8VjWqLPVlmREWdKpCygHfjb38yR1iYlaQ x2aoQRv36caeBrjXBdi/fF336MdBMzwTFlpaN1nk= Date: Tue, 3 Dec 2019 08:24:59 +0200 From: Laurent Pinchart To: Sam Ravnborg Cc: dri-devel@lists.freedesktop.org, Thierry Reding , Abhinav Kumar , Andrzej Hajda , Benjamin Gaignard , Boris Brezillon , Daniel Vetter , David Airlie , Jagan Teki , Jitao Shi , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-tegra@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Neil Armstrong , NXP Linux Team , Pengutronix Kernel Team , Purism Kernel Team , Sean Paul , Stefan Agner , Tomi Valkeinen Subject: Re: [PATCH v1 01/26] drm/drm_panel: no error when no callback Message-ID: <20191203062459.GA4730@pendragon.ideasonboard.com> References: <20191202193230.21310-1-sam@ravnborg.org> <20191202193230.21310-2-sam@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191202193230.21310-2-sam@ravnborg.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org Hi Sam, Thank you for the patch. On Mon, Dec 02, 2019 at 08:32:05PM +0100, Sam Ravnborg wrote: > The callbacks in drm_panel_funcs are optional, so do not > return an error just because no callback is assigned. Unless I'm mistaken the callbacks are not documented as optional. Should this be fixed too ? > Signed-off-by: Sam Ravnborg > Cc: Maarten Lankhorst > Cc: Maxime Ripard > Cc: Thierry Reding > Cc: Sam Ravnborg > Cc: David Airlie > Cc: Daniel Vetter > --- > drivers/gpu/drm/drm_panel.c | 35 +++++++++++++++++++++++++---------- > 1 file changed, 25 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c > index ed7985c0535a..2d59cdd05e50 100644 > --- a/drivers/gpu/drm/drm_panel.c > +++ b/drivers/gpu/drm/drm_panel.c > @@ -151,10 +151,13 @@ EXPORT_SYMBOL(drm_panel_detach); > */ > int drm_panel_prepare(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->prepare) > + if (!panel) > + return -EINVAL; > + > + if (panel->funcs && panel->funcs->prepare) > return panel->funcs->prepare(panel); > > - return panel ? -ENOSYS : -EINVAL; > + return 0; > } > EXPORT_SYMBOL(drm_panel_prepare); > > @@ -171,10 +174,13 @@ EXPORT_SYMBOL(drm_panel_prepare); > */ > int drm_panel_unprepare(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->unprepare) > + if (!panel) > + return -EINVAL; > + > + if (panel->funcs && panel->funcs->unprepare) > return panel->funcs->unprepare(panel); > > - return panel ? -ENOSYS : -EINVAL; > + return 0; > } > EXPORT_SYMBOL(drm_panel_unprepare); > > @@ -190,10 +196,13 @@ EXPORT_SYMBOL(drm_panel_unprepare); > */ > int drm_panel_enable(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->enable) > + if (!panel) > + return -EINVAL; > + > + if (panel->funcs && panel->funcs->enable) > return panel->funcs->enable(panel); > > - return panel ? -ENOSYS : -EINVAL; > + return 0; > } > EXPORT_SYMBOL(drm_panel_enable); > > @@ -209,10 +218,13 @@ EXPORT_SYMBOL(drm_panel_enable); > */ > int drm_panel_disable(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->disable) > + if (!panel) > + return -EINVAL; > + > + if (panel->funcs && panel->funcs->disable) > return panel->funcs->disable(panel); > > - return panel ? -ENOSYS : -EINVAL; > + return 0; > } > EXPORT_SYMBOL(drm_panel_disable); > > @@ -228,10 +240,13 @@ EXPORT_SYMBOL(drm_panel_disable); > */ > int drm_panel_get_modes(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->get_modes) > + if (!panel) > + return -EINVAL; > + > + if (panel->funcs && panel->funcs->get_modes) > return panel->funcs->get_modes(panel); Should get_modes() be optional ? As far as I can tell all the panel drivers in drivers/gpu/drm/panel/ implement it, and I'm not sure to see how a panel could be usable if it can't return its mode. On the other hand you return 0 if the callback isn't implemented, which doesn't mean success here, so I suppose that's fine, but I don't think we should document .get_modes() as being optional. With these issues addressed (if they need to be), Reviewed-by: Laurent Pinchart > > - return panel ? -ENOSYS : -EINVAL; > + return 0; > } > EXPORT_SYMBOL(drm_panel_get_modes); > -- Regards, Laurent Pinchart