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=-10.1 required=3.0 tests=BAYES_00,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 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 4D836C433E2 for ; Fri, 4 Sep 2020 13:41:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AC4B20C56 for ; Fri, 4 Sep 2020 13:41:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="t/3vUViV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730478AbgIDNkw (ORCPT ); Fri, 4 Sep 2020 09:40:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730447AbgIDNaV (ORCPT ); Fri, 4 Sep 2020 09:30:21 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E091C061245; Fri, 4 Sep 2020 06:29:33 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 2D53C540; Fri, 4 Sep 2020 15:29:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1599226164; bh=gaKQogjFkemHMpyyZ83iJjezV+gtGiFSIdmO7pGnQ3I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t/3vUViVhSO2SDIgevxig29k+/zBCmBsi0EwtNN/drZPC+MQc5uwwNrDJ+W+MKSW/ Bq6aNmoE905kePmpwCDjj7xi1raIBP8gRZZBZeo2SzWUeEvrCRuY9O62H8a+XLF19F di6kYDU18fAuIDrx5jbE+ClIDsuyQrWCN1KvV6OM= Date: Fri, 4 Sep 2020 16:29:00 +0300 From: Laurent Pinchart To: Sakari Ailus Cc: Jacopo Mondi , 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: <20200904132900.GA7518@pendragon.ideasonboard.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200904082104.GE4392@valkosipuli.retiisi.org.uk> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Sep 04, 2020 at 11:21:04AM +0300, Sakari Ailus wrote: > On Fri, Sep 04, 2020 at 09:55:53AM +0200, Jacopo Mondi wrote: > > On Fri, Sep 04, 2020 at 04:20:00AM +0300, Laurent Pinchart wrote: > > > 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. I thought the goal was to remove v4l2_fwnode_endpoint_parse() in the future. If Sakari is happy to keep it and see it used for parallel buses, I have no objection. > > 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. This patch shows a common use case, with a source supporting both parallel and BT.656. Having to call v4l2_fwnode_endpoint_parse() twice, once for each bus type, isn't a very good API in my opinion. I'd like v4l2_fwnode_endpoint_parse() to be able to determine the bus type (using the bus-type property) *and* support defaults with a single call. Speaking of defaults, I wonder if it's a good idea to let that up to drivers, or if we should standardize on one set of defaults that would be shared by all DT bindings. > > 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. > > > > Reviewed-by: Laurent Pinchart > > > > > > > + fwnode_handle_put(endpoint); > > > > + if (ret) { > > > > + dev_err(&client->dev, "Could not parse endpoint\n"); > > > > + goto error_clk_put; > > > > + } > > > > + > > > > + if (priv->ep.bus_type != V4L2_MBUS_PARALLEL && > > > > + priv->ep.bus_type != V4L2_MBUS_BT656) { > > > > + dev_err(&client->dev, "Unsupported bus type %d\n", > > > > + priv->ep.bus_type); > > > > + goto error_clk_put; > > > > + } > > > > + > > > > ret = ov772x_video_probe(priv); > > > > if (ret < 0) > > > > goto error_gpio_put; -- Regards, Laurent Pinchart