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=-11.5 required=3.0 tests=BAYES_00, 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 37437C43461 for ; Fri, 4 Sep 2020 09:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A895207EA for ; Fri, 4 Sep 2020 09:37:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730025AbgIDJhC (ORCPT ); Fri, 4 Sep 2020 05:37:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725812AbgIDJhA (ORCPT ); Fri, 4 Sep 2020 05:37:00 -0400 Received: from hillosipuli.retiisi.org.uk (hillosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::81:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76B63C061244; Fri, 4 Sep 2020 02:36:59 -0700 (PDT) Received: from valkosipuli.localdomain (valkosipuli.retiisi.org.uk [IPv6:2a01:4f9:c010:4572::80:2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by hillosipuli.retiisi.org.uk (Postfix) with ESMTPS id ABB79634C8C; Fri, 4 Sep 2020 12:36:26 +0300 (EEST) Received: from sailus by valkosipuli.localdomain with local (Exim 4.92) (envelope-from ) id 1kE88w-0001Zt-I0; Fri, 04 Sep 2020 12:36:26 +0300 Date: Fri, 4 Sep 2020 12:36:26 +0300 From: Sakari Ailus To: Jacopo Mondi Cc: Laurent Pinchart , Lad Prabhakar , Mauro Carvalho Chehab , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Biju Das , Prabhakar Subject: Re: [PATCH v3 1/2] media: i2c: ov772x: Add support for BT656 mode Message-ID: <20200904093626.GF4392@valkosipuli.retiisi.org.uk> References: <20200824190406.27478-1-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200824190406.27478-2-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200904012000.GA9369@pendragon.ideasonboard.com> <20200904075553.qjdyskcpext7fxcy@uno.localdomain> <20200904082104.GE4392@valkosipuli.retiisi.org.uk> <20200904092049.6lokfmln4vulswrn@uno.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200904092049.6lokfmln4vulswrn@uno.localdomain> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 04, 2020 at 11:20:49AM +0200, Jacopo Mondi wrote: > Hi Sakari, > > On Fri, Sep 04, 2020 at 11:21:04AM +0300, Sakari Ailus wrote: > > Hi Laurent, Jacopo, > > > > On Fri, Sep 04, 2020 at 09:55:53AM +0200, Jacopo Mondi wrote: > > > Hi Laurent, > > > > > > On Fri, Sep 04, 2020 at 04:20:00AM +0300, Laurent Pinchart wrote: > > > > Hi Prabhakar, > > > > > > > > Thank you for the patch. > > > > > > > > On Mon, Aug 24, 2020 at 08:04:05PM +0100, Lad Prabhakar wrote: > > > > > Add support to read the bus-type and enable BT656 mode if needed. > > > > > > > > > > Also fail probe if unsupported bus_type is detected. > > > > > > > > > > Signed-off-by: Lad Prabhakar > > > > > Reviewed-by: Biju Das > > > > > --- > > > > > drivers/media/i2c/ov772x.c | 32 ++++++++++++++++++++++++++++++++ > > > > > 1 file changed, 32 insertions(+) > > > > > > > > > > diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c > > > > > index 2cc6a678069a..67764d647526 100644 > > > > > --- a/drivers/media/i2c/ov772x.c > > > > > +++ b/drivers/media/i2c/ov772x.c > > > > > @@ -31,6 +31,7 @@ > > > > > #include > > > > > #include > > > > > #include > > > > > +#include > > > > > #include > > > > > #include > > > > > > > > > > @@ -434,6 +435,7 @@ struct ov772x_priv { > > > > > #ifdef CONFIG_MEDIA_CONTROLLER > > > > > struct media_pad pad; > > > > > #endif > > > > > + struct v4l2_fwnode_endpoint ep; > > > > > }; > > > > > > > > > > /* > > > > > @@ -581,6 +583,13 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable) > > > > > if (priv->streaming == enable) > > > > > goto done; > > > > > > > > > > + if (priv->ep.bus_type == V4L2_MBUS_BT656) { > > > > > + ret = regmap_update_bits(priv->regmap, COM7, ITU656_ON_OFF, > > > > > + enable ? ITU656_ON_OFF : ~ITU656_ON_OFF); > > > > > + if (ret) > > > > > + goto done; > > > > > + } > > > > > + > > > > > ret = regmap_update_bits(priv->regmap, COM2, SOFT_SLEEP_MODE, > > > > > enable ? 0 : SOFT_SLEEP_MODE); > > > > > if (ret) > > > > > @@ -1354,6 +1363,7 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = { > > > > > > > > > > static int ov772x_probe(struct i2c_client *client) > > > > > { > > > > > + struct fwnode_handle *endpoint; > > > > > struct ov772x_priv *priv; > > > > > int ret; > > > > > static const struct regmap_config ov772x_regmap_config = { > > > > > @@ -1415,6 +1425,28 @@ static int ov772x_probe(struct i2c_client *client) > > > > > goto error_clk_put; > > > > > } > > > > > > > > > > + endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev), > > > > > + NULL); > > > > > + if (!endpoint) { > > > > > + dev_err(&client->dev, "endpoint node not found\n"); > > > > > + ret = -EINVAL; > > > > > + goto error_clk_put; > > > > > + } > > > > > + > > > > > + ret = v4l2_fwnode_endpoint_parse(endpoint, &priv->ep); > > > > > > > > v4l2_fwnode_endpoint_parse() is deprecated for new drivers, > > > > v4l2_fwnode_endpoint_alloc_parse() is recommended instead. Please note > > > > that v4l2_fwnode_endpoint_free() then needs to be called in the error > > > > path and in remove(). > > > > > > Doesn't alloc_parse() differ from just _parse() as it reserve space > > > for the 'link-frequencies' array ? As this device does not support > > > CSI-2 and the 'link-frequencies' property is not allows in bindings, > > > isn't using endpoint_parse() better as it saves a call to _free() ? > > > > Yeah. I think the documentation needs to be updated. > > > > The thinking was there would be other variable size properties that drivers > > would need but that didn't happen. So feel free to continue use > > v4l2_fwnode_endpoint_parse() where it does the job. > > > > > > > > Or are we deprecating that function unconditionally ? The > > > documentation suggests "please use v4l2_fwnode_endpoint_alloc_parse() > > > in new drivers" but here it doesn't seem required.. > > > > > > > > > > > On the other hand, not setting .bus_type and letting the parse() > > > > function determine the but type automatically is also deprecated, and I > > > > don't think forcing drivers to call v4l2_fwnode_endpoint_alloc_parse() > > > > once for each bus type until one succeeds is a good API. As change will > > > > be needed in that API, you can ignore v4l2_fwnode_endpoint_alloc_parse() > > > > for the time being if you want. > > > > > > But indeed relying on auto-guessing of the bus type is deprecated since > > > some time now (and the API could be improved, yes). Sorry I missed > > > that yesterday. > > > > There's one case where the bus type does not need to be set: when bindings > > require it *and* at the same time you have no default configuration that > > requires something to be set in the bus specific struct. Bindings where > > bus-type is required were added later so I think the documentation should > > be changed there, too. > > > > I can send the patches. > > > > > > > > As we support parallel and bt.656 only I must be honest I don't mind > > > it here as otherwise the code would be more complex for no real gain, > > > but I defer this to Sakari which has been fighting the battle against > > > auto-guessing since a long time now :) > > > > I think you should require bus-type property in bindings in that case. > > > > But as it's an existing driver, bus-type will be optional. You'll need to > > default to what was supported earlier. This is actually an interesting case > > as bindings do not document it. > > For reference: > https://patchwork.linuxtv.org/project/linux-media/patch/20200903131029.18334-3-jacopo+renesas@jmondi.org/ > > But yes, we might have DTBs in the wild without bus-type specified :( Shouldn't that be then that the bus-type is optional and defaults to parallel? -- Sakari Ailus