On Fri, Sep 04, 2020 at 04:48:32PM +0300, Laurent Pinchart wrote: > On Fri, Sep 04, 2020 at 02:00:13PM +0300, Sakari Ailus wrote: > > On Fri, Sep 04, 2020 at 12:35:50PM +0200, Jacopo Mondi wrote: > > > On Fri, Sep 04, 2020 at 12:36:26PM +0300, Sakari Ailus wrote: > > > > On Fri, Sep 04, 2020 at 11:20:49AM +0200, Jacopo Mondi wrote: > > > > > 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: > > > > > > > > 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 > > > > > > > > > <[email protected]> > > > > > > > > > Reviewed-by: Biju Das <[email protected]> > > > > > > > > > --- > > > > > > > > > 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 <media/v4l2-ctrls.h> > > > > > > > > > #include <media/v4l2-device.h> > > > > > > > > > #include <media/v4l2-event.h> > > > > > > > > > +#include <media/v4l2-fwnode.h> > > > > > > > > > #include <media/v4l2-image-sizes.h> > > > > > > > > > #include <media/v4l2-subdev.h> > > > > > > > > > > > > > > > > > > @@ -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 = regmaup_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/[email protected]/ > > > > > > > > > > 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? > > > > > > I think going forward we want to make it mandatory, don't we ? The > > > older dts will fail at dt validation time against the new yaml bindings, > > > but > > > my understanding is that this is not a problem. > > > > For new devices, yes. I still wouldn't make DT binding changes that render > > the old DT source invalid, at least unless it's absolutely mandatory. And > > that is not the case here. > > > > I guess it may be a bit grey area. At least leave a comment in the driver > > on how the old bindings were so the code isn't accidentally "fixed". > > > > > Binary compatibility, with the introduction of BT.656 support becomes > > > more complex instead :/ > > > > > > Before this series parallel was the only supported bus type and no > > > endpoint properties were required. The driver picked the default > > > settings for signal polarities and that was it. > > > > > > With the introduction of BT.656 no signal polarity properties means > > > BT.656 when autoguess is in use. So going forward the bus-type shall > > > be explicitly set, but we might receive old DTBs with no bus-type and > > > no endpoint properties which assumes 'parallel' is in use. > > > > > > One possible way forward could be: > > > - verify if bus-type is present in the fwnode > > > - if it is, we have a new DTB and we can rely on autoguess > > It's not guessing if the bus type is specified :-) > > > > - if it's not assume we have an old DTB that assumed 'parallel'. Parse > > > the fwnode and if any relevant V4L2_MBUS_ flag is set use it, > > > otherwise use the defaults. > > > > > > If we make bus-type optional in new bindings, the old DTB with no > > > parallel endpoint properties would be identified as BT.656 breaking > > > capture operation, am I wrong ? > > > > There's no technical reason why it has to be so. > > > > You simply try endpoint parsing with parallel bus first, with the old > > defaults, and if that succeeds, then you don't attempt to parse it as > > Bt.656 anymore. > > If bus-type is optional with new bindings, > v4l2_fwnode_endpoint_parse(V4L2_MBUS_PARALLEL) will always succeed if > the bus-type DT property isn't set.
Correct. And that's the idea, isn't it? > > > > This might require a bit more work from Prabhakar I'm sorry. The old > > > bindings were clearly falling short once BT.656 becomes supported. > > -- > Regards, > > Laurent Pinchart -- Sakari Ailus
