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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS 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 DC0B0C10F06 for ; Thu, 14 Mar 2019 16:09:40 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC9892184E for ; Thu, 14 Mar 2019 16:09:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="aGwJwpDp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC9892184E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mansr.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-Reply-To: Date:References:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wQYHIF3xWLz+ZCeTPjzsVZ2pkI1TO7vp6EU5cp+F2bQ=; b=aGwJwpDp84GrJb O6S7NpP8Y6kd7n/XUW191fGK0yKIDbrwyO1ewZKiAPE1m+rhYyGa+TiUxgKi3mw41hBoR63DLAcqJ c0zKCM3fz86Yk7E+s3hufjPJ36BL9/VUHJHvbWwrOIOQEmR10fZtRnen59ISVqKRcz4KlbA8zoRpT EY3IaR6GPyQkvd/rN6reSkMeeRlunwF2cWb/GrpHT4UJobxv3fUCk/89qUqo/DF9LVJqTBj57DKdu g9+xXhWjMfyWepfx+k2kN8F5kXo8cd+1rah025UQ1ZhOGHq6WTmRIwrg4khf9NLEjRQNmQ1TlY0b3 4VjWt0nR1Wy8lI+7omog==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h4SvH-0007JX-0R; Thu, 14 Mar 2019 16:09:35 +0000 Received: from unicorn.mansr.com ([81.2.72.234]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h4SvE-0007Ib-Rd for linux-arm-kernel@lists.infradead.org; Thu, 14 Mar 2019 16:09:34 +0000 Received: by unicorn.mansr.com (Postfix, from userid 51770) id 0A69814CEA; Thu, 14 Mar 2019 16:09:13 +0000 (GMT) From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= To: Maxime Ripard Subject: Re: [PATCH] drm/sun4i: hdmi: add support for ddc-i2c-bus property References: <20190311134713.25876-1-mans@mansr.com> <20190311154702.eslw5ccol44vxcmy@flea> <20190314154105.o6r7hzeuiyajxh7v@flea> Date: Thu, 14 Mar 2019 16:09:13 +0000 In-Reply-To: <20190314154105.o6r7hzeuiyajxh7v@flea> (Maxime Ripard's message of "Thu, 14 Mar 2019 16:41:05 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190314_090933_225511_43148B3F X-CRM114-Status: GOOD ( 19.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , Chen-Yu Tsai , linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Maxime Ripard writes: > On Mon, Mar 11, 2019 at 04:11:06PM +0000, M=E5ns Rullg=E5rd wrote: >> Maxime Ripard writes: >> = >> > Hi! >> > >> > On Mon, Mar 11, 2019 at 01:47:13PM +0000, Mans Rullgard wrote: >> >> Sometimes it is desirabled to use a separate i2c controller for ddc >> >> access. This adds support for the ddc-i2c-bus property of the >> >> hdmi-connector node, using the specified controller if provided. >> >> = >> >> Signed-off-by: Mans Rullgard >> >> --- >> >> drivers/gpu/drm/sun4i/sun4i_hdmi.h | 1 + >> >> drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 37 +++++++++++++++++++++++-= -- >> >> 2 files changed, 35 insertions(+), 3 deletions(-) >> >> = >> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun= 4i/sun4i_hdmi.h >> >> index b685ee11623d..b08c4453d47c 100644 >> >> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h >> >> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h >> >> @@ -269,6 +269,7 @@ struct sun4i_hdmi { >> >> struct clk *tmds_clk; >> >> = >> >> struct i2c_adapter *i2c; >> >> + struct i2c_adapter *ddc_i2c; >> >> = >> >> /* Regmap fields for I2C adapter */ >> >> struct regmap_field *field_ddc_en; >> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm= /sun4i/sun4i_hdmi_enc.c >> >> index 061d2e0d9011..5b2fac79f5d6 100644 >> >> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c >> >> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c >> >> @@ -212,7 +212,7 @@ static int sun4i_hdmi_get_modes(struct drm_connec= tor *connector) >> >> struct edid *edid; >> >> int ret; >> >> = >> >> - edid =3D drm_get_edid(connector, hdmi->i2c); >> >> + edid =3D drm_get_edid(connector, hdmi->ddc_i2c ?: hdmi->i2c); >> > >> > You can't test whether ddc_i2c is NULL or not... >> > >> >> if (!edid) >> >> return 0; >> >> = >> >> @@ -228,6 +228,28 @@ static int sun4i_hdmi_get_modes(struct drm_conne= ctor *connector) >> >> return ret; >> >> } >> >> = >> >> +static struct i2c_adapter *sun4i_hdmi_get_ddc(struct device *dev) >> >> +{ >> >> + struct device_node *phandle, *remote; >> >> + struct i2c_adapter *ddc; >> >> + >> >> + remote =3D of_graph_get_remote_node(dev->of_node, 1, -1); >> >> + if (!remote) >> >> + return ERR_PTR(-EINVAL); >> >> + >> >> + phandle =3D of_parse_phandle(remote, "ddc-i2c-bus", 0); >> >> + of_node_put(remote); >> >> + if (!phandle) >> >> + return NULL; >> >> + >> >> + ddc =3D of_get_i2c_adapter_by_node(phandle); >> >> + of_node_put(phandle); >> >> + if (!ddc) >> >> + return ERR_PTR(-EPROBE_DEFER); >> >> + >> >> + return ddc; >> > >> > ... Since even in (most) error cases you're returning a !NULL pointer. >> > >> >> +} >> >> + >> >> static const struct drm_connector_helper_funcs sun4i_hdmi_connector_= helper_funcs =3D { >> >> .get_modes =3D sun4i_hdmi_get_modes, >> >> }; >> >> @@ -575,6 +597,12 @@ static int sun4i_hdmi_bind(struct device *dev, s= truct device *master, >> >> goto err_disable_mod_clk; >> >> } >> >> = >> >> + hdmi->ddc_i2c =3D sun4i_hdmi_get_ddc(dev); >> >> + if (IS_ERR(hdmi->ddc_i2c)) { >> = >> ... which is checked here. >> = >> The property is optional, so the idea was to return null in that case >> and use the built-in controller. If the property exists but some error >> occurs, we want to abort rather than proceed with the fallback which >> almost certainly won't work. >> = >> Maybe I got something wrong in that logic. > > Indeed, I just got confused. I guess returning ENODEV in such a case, > and testing for that, would make things more obvious. There's also a case I hadn't thought of: property exists but isn't a valid phandle. What do you think is the correct action in that case? -- = M=E5ns Rullg=E5rd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel