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,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 3EDA2C432C3 for ; Tue, 19 Nov 2019 00:16:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 101EC22303 for ; Tue, 19 Nov 2019 00:16:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="I5JiWhYw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726937AbfKSAQh (ORCPT ); Mon, 18 Nov 2019 19:16:37 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:60922 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726809AbfKSAQh (ORCPT ); Mon, 18 Nov 2019 19:16:37 -0500 Received: from pendragon.ideasonboard.com (unknown [38.98.37.142]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id AA4A9563; Tue, 19 Nov 2019 01:16:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1574122594; bh=8DSMhIt1red9wOEJPGSQTtqxJri+IPOlQSZhcYRsBJY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=I5JiWhYw3hHwBr6G3BJc16LkawhbHXpGMS+xZJTLk9uApp5X+yD0UhF2qi59OWZyA dDymuEHfNRLSwJWE2W0wVVTcM+OH80TGKTqwElh3G0fx7nWYXVAHuga65OhRy+AIqP NpWODRRsf22OR6GAgxVdHCokeOVln9iC6AHNgdkY= Date: Tue, 19 Nov 2019 02:16:16 +0200 From: Laurent Pinchart To: Fabrizio Castro Cc: Neil Armstrong , David Airlie , Daniel Vetter , Rob Herring , Mark Rutland , Andrzej Hajda , Simon Horman , Geert Uytterhoeven , Magnus Damm , Peter Rosin , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Chris Paterson , Biju Das , Kieran Bingham , Jacopo Mondi Subject: Re: [PATCH v4 12/13] [HACK] drm/bridge: lvds-codec: Enforce device specific compatible strings Message-ID: <20191119001616.GL5171@pendragon.ideasonboard.com> References: <1573660292-10629-1-git-send-email-fabrizio.castro@bp.renesas.com> <1573660292-10629-13-git-send-email-fabrizio.castro@bp.renesas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1573660292-10629-13-git-send-email-fabrizio.castro@bp.renesas.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Fabrizio, Thank you for the patch. On Wed, Nov 13, 2019 at 03:51:31PM +0000, Fabrizio Castro wrote: > The lvds-codec driver is a generic stub for transparent LVDS > encoders and decoders. > It's good practice to list a device specific compatible string s/good practice/mandatory/ > before the generic fallback (if any) in the DT node for the relevant > LVDS encoder/decoder, and it's also required by the dt-bindings. > A notable exception to the generic fallback mechanism is the case > of "thine,thc63lvdm83d", as documented in: > Documentation/devicetree/bindings/display/bridge/thine,thc63lvdm83d.txt > This patch enforces the adoption of a device specific compatible > string (as fist string in the list), by using markers for the s/fist/first/ > compatible string we match against and the index of the matching > compatible string in the list. > > Signed-off-by: Fabrizio Castro > > --- > Hi Laurent, > > I don't think we need to do anything in the driver to address your > comment, as we can "enforce" this with the bindings (please see the > next patch, as it would help with the "enforcing" of the compatible > string for the thine device). > I am sending this patch only so that you can see what a possible > solution in the driver could look like. > > v3->v4: > * New patch addressing the below comment from Laurent: > "I think the lvds-decoder driver should error out at probe time if only > one compatible string is listed." > --- > drivers/gpu/drm/bridge/lvds-codec.c | 55 +++++++++++++++++++++++++++++++++---- > 1 file changed, 49 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/lvds-codec.c b/drivers/gpu/drm/bridge/lvds-codec.c > index 784bbd3..145c25d 100644 > --- a/drivers/gpu/drm/bridge/lvds-codec.c > +++ b/drivers/gpu/drm/bridge/lvds-codec.c > @@ -14,11 +14,16 @@ > #include > #include > > +struct lvds_codec_data { > + u32 connector_type; > + bool device_specific; > +}; > + > struct lvds_codec { > struct drm_bridge bridge; > struct drm_bridge *panel_bridge; > struct gpio_desc *powerdown_gpio; > - u32 connector_type; > + const struct lvds_codec_data *data; > }; > > static int lvds_codec_attach(struct drm_bridge *bridge) > @@ -65,7 +70,30 @@ static int lvds_codec_probe(struct platform_device *pdev) > if (!lvds_codec) > return -ENOMEM; > > - lvds_codec->connector_type = (u32)of_device_get_match_data(&pdev->dev); > + lvds_codec->data = of_device_get_match_data(&pdev->dev); > + if (!lvds_codec->data) > + return -EINVAL; > + > + /* > + * If we haven't matched a device specific compatible string, we need > + * to work out if the generic compatible string we matched against was > + * listed first in the compatible property. > + */ Can't we do this unconditionally, and thus drop the lvds_codec_data structure ? > + if (!lvds_codec->data->device_specific) { > + const struct of_device_id *match; > + int compatible_index; > + > + match = of_match_node(dev->driver->of_match_table, > + dev->of_node); > + compatible_index = of_property_match_string(dev->of_node, > + "compatible", > + match->compatible); > + if (compatible_index == 0) { > + dev_err(dev, "Device specific compatible needed\n"); > + return -EINVAL; > + } > + } > + > lvds_codec->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown", > GPIOD_OUT_HIGH); > if (IS_ERR(lvds_codec->powerdown_gpio)) { > @@ -92,7 +120,7 @@ static int lvds_codec_probe(struct platform_device *pdev) > > lvds_codec->panel_bridge = > devm_drm_panel_bridge_add_typed(dev, panel, > - lvds_codec->connector_type); > + lvds_codec->data->connector_type); > if (IS_ERR(lvds_codec->panel_bridge)) > return PTR_ERR(lvds_codec->panel_bridge); > > @@ -119,18 +147,33 @@ static int lvds_codec_remove(struct platform_device *pdev) > return 0; > } > > +static const struct lvds_codec_data lvds_codec_decoder_data = { > + .connector_type = DRM_MODE_CONNECTOR_DPI, > + .device_specific = false, > +}; > + > +static const struct lvds_codec_data lvds_codec_encoder_data = { > + .connector_type = DRM_MODE_CONNECTOR_LVDS, > + .device_specific = false, > +}; > + > +static const struct lvds_codec_data lvds_codec_thc63lvdm83d_data = { > + .connector_type = DRM_MODE_CONNECTOR_LVDS, > + .device_specific = true, > +}; > + > static const struct of_device_id lvds_codec_match[] = { > { > .compatible = "lvds-decoder", > - .data = (void *)DRM_MODE_CONNECTOR_DPI, > + .data = &lvds_codec_decoder_data, > }, > { > .compatible = "lvds-encoder", > - .data = (void *)DRM_MODE_CONNECTOR_LVDS, > + .data = &lvds_codec_encoder_data, > }, > { > .compatible = "thine,thc63lvdm83d", > - .data = (void *)DRM_MODE_CONNECTOR_LVDS, > + .data = &lvds_codec_thc63lvdm83d_data, > }, > {}, > }; -- Regards, Laurent Pinchart