From: Marco Felsch <m.felsch@pengutronix.de>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: mchehab@kernel.org, hans.verkuil@cisco.com,
jacopo+renesas@jmondi.org, robh+dt@kernel.org,
laurent.pinchart@ideasonboard.com, devicetree@vger.kernel.org,
kernel@pengutronix.de, linux-media@vger.kernel.org
Subject: Re: [PATCH v11 04/15] media: v4l2-fwnode: add initial connector parsing support
Date: Tue, 19 Nov 2019 12:37:12 +0100 [thread overview]
Message-ID: <20191119113712.epb32sstnhfwwdzy@pengutronix.de> (raw)
In-Reply-To: <20191115233439.GB2696@mara.localdomain>
Hi Sakari,
On 19-11-16 01:34, Sakari Ailus wrote:
> Hi Marco,
>
> On Mon, Sep 30, 2019 at 11:38:49AM +0200, Marco Felsch wrote:
> > The patch adds the initial connector parsing code, so we can move from a
> > driver specific parsing code to a generic one. Currently only the
> > generic fields and the analog-connector specific fields are parsed. Parsing
> > the other connector specific fields can be added by a simple callbacks.
> >
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> > [1] https://patchwork.kernel.org/cover/10794703/
> >
> > v10:
> > - drop V4L2_CONN_HDMI support
> > - adapt pr_err msg to reflect new state (-> connector is unkown)
> >
> > v9:
> > - Fix leading semicolon found by kbuild semicolon.cocci
> >
> > v8:
> > - V4L2_CON_* -> V4L2_CONN_*
> > - tvnorms -> sdtv-standards
> > - adapt to new v4l2_fwnode_connector_analog member
> > - return error in case of V4L2_CONN_HDMI
> >
> > v7:
> > @Jacopo: I dropped your r b tag becuase of the amount of changes I
> > made..
> >
> > - drop unnecessary comments
> > - fix commet style
> > - s/v4l2_fwnode_connector_conv.name/v4l2_fwnode_connector_conv.compatible/
> > - make label size variable and drop V4L2_CONNECTOR_MAX_LABEL usage
> > - do not assign a default label in case of no label was specified
> > - remove useless /* fall through */ comments
> > - add support for N connector links
> > - rename local variables to be more meaningful
> > - adjust kernedoc
> > - add v4l2_fwnode_connector_free()
> > - improve error handling (use different error values)
> > - make use of pr_warn_once()
> >
> > v6:
> > - use unsigned count var
> > - fix comment and style issues
> > - place '/* fall through */' to correct places
> > - fix error handling and cleanup by releasing fwnode
> > - drop vga and dvi parsing support as those connectors are rarely used
> > these days
> >
> > v5:
> > - s/strlcpy/strscpy/
> >
> > v2-v4:
> > - nothing since the patch was squashed from series [1] into this
> > series.
> > ---
> > drivers/media/v4l2-core/v4l2-fwnode.c | 129 ++++++++++++++++++++++++++
> > include/media/v4l2-fwnode.h | 38 ++++++++
> > 2 files changed, 167 insertions(+)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > index 3bd1888787eb..0bfa7cbf78df 100644
> > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -595,6 +595,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> > }
> > EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
> >
> > +static const struct v4l2_fwnode_connector_conv {
> > + enum v4l2_connector_type type;
> > + const char *compatible;
> > +} connectors[] = {
> > + {
> > + .type = V4L2_CONN_COMPOSITE,
> > + .compatible = "composite-video-connector",
> > + }, {
> > + .type = V4L2_CONN_SVIDEO,
> > + .compatible = "svideo-connector",
> > + },
> > +};
> > +
> > +static enum v4l2_connector_type
> > +v4l2_fwnode_string_to_connector_type(const char *con_str)
> > +{
> > + unsigned int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(connectors); i++)
> > + if (!strcmp(con_str, connectors[i].compatible))
> > + return connectors[i].type;
> > +
> > + return V4L2_CONN_UNKNOWN;
> > +}
> > +
> > +static int
> > +v4l2_fwnode_connector_parse_analog(struct fwnode_handle *fwnode,
> > + struct v4l2_fwnode_connector *vc)
> > +{
> > + u32 stds;
> > + int ret;
> > +
> > + ret = fwnode_property_read_u32(fwnode, "sdtv-standards", &stds);
> > +
> > + /* The property is optional. */
> > + vc->connector.analog.sdtv_stds = ret ? V4L2_STD_ALL : stds;
> > +
> > + return 0;
> > +}
> > +
> > +void v4l2_fwnode_connector_free(struct v4l2_fwnode_connector *connector)
> > +{
> > + unsigned int i;
> > +
> > + if (IS_ERR_OR_NULL(connector))
> > + return;
> > +
> > + for (i = 0; i < connector->nr_of_links; i++)
> > + v4l2_fwnode_put_link(&connector->links[i]);
> > + kfree(connector->links);
>
> Please do set connector->links NULL here. That avoids accidentally double
> kfree on the pointer.
Okay, I will do that.
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_fwnode_connector_free);
> > +
> > +int v4l2_fwnode_connector_alloc_parse(struct fwnode_handle *fwnode,
> > + struct v4l2_fwnode_connector *connector)
> > +{
> > + struct fwnode_handle *remote_pp, *remote_ep;
> > + const char *type_name;
> > + unsigned int i = 0, ep_num = 0;
> > + int err;
> > +
> > + memset(connector, 0, sizeof(*connector));
> > +
> > + remote_pp = fwnode_graph_get_remote_port_parent(fwnode);
> > + if (!remote_pp)
> > + return -ENOLINK;
Should I drop this logic here and force the caller to pass the connector
endpoint?
> > +
> > + /* Parse all common properties first. */
> > + fwnode_graph_for_each_endpoint(remote_pp, remote_ep)
> > + ep_num++;
>
> If there are no endpoints, ep_num will be zero and kmalloc_array() will
> return NULL? There should be a way there are no endpoints, rather than
> returning -ENOMEM.
Hm.. using the current implementation (please see my above comment)
ensures that there is always one link but if I change that I need to
check this, good point.
> > +
> > + connector->nr_of_links = ep_num;
> > + connector->links = kmalloc_array(ep_num, sizeof(*connector->links),
> > + GFP_KERNEL);
> > + if (!connector->links) {
> > + err = -ENOMEM;
> > + goto err_put_fwnode;
> > + }
> > +
> > + fwnode_graph_for_each_endpoint(remote_pp, remote_ep) {
> > + err = v4l2_fwnode_parse_link(remote_ep, &connector->links[i]);
>
> If you start parsing a connector starting from another device connected to
> it, nothing seems to prevent parsing the same links twice, in case the
> connector is connected to more than one sub-device.
>
> Or do I miss something crucial here?
That is true because currently each sub-device implements their own
connector parsing/handling stuff.. What i wanted to address with this
code is that one sub-device can have multiple links to one connector
e.g. s-video connectors (1xluma 1xchroma). I don't know how to handle
this without a simple connector device.
Regards,
Marco
> > + if (err) {
> > + fwnode_handle_put(remote_ep);
> > + goto err_free_links;
> > + }
> > + i++;
> > + }
> > +
> > + /*
> > + * Links reference counting guarantees access -> no duplication needed
> > + */
> > + fwnode_property_read_string(remote_pp, "label", &connector->label);
> > +
> > + /* The connector-type is stored within the compatible string. */
> > + err = fwnode_property_read_string(remote_pp, "compatible", &type_name);
> > + if (err) {
> > + err = -EINVAL;
> > + goto err_free_links;
> > + }
> > + connector->type = v4l2_fwnode_string_to_connector_type(type_name);
> > +
> > + /* Now parse the connector specific properties. */
> > + switch (connector->type) {
> > + case V4L2_CONN_COMPOSITE:
> > + case V4L2_CONN_SVIDEO:
> > + err = v4l2_fwnode_connector_parse_analog(remote_pp, connector);
> > + break;
> > + case V4L2_CONN_UNKNOWN:
> > + default:
> > + pr_err("Unknown connector type\n");
> > + err = -EINVAL;
> > + goto err_free_links;
> > + }
> > +
> > + fwnode_handle_put(remote_pp);
> > +
> > + return err;
> > +
> > +err_free_links:
> > + for (i = 0; i < ep_num; i++)
> > + v4l2_fwnode_put_link(&connector->links[i]);
> > + kfree(connector->links);
> > +err_put_fwnode:
> > + fwnode_handle_put(remote_pp);
> > +
> > + return err;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_fwnode_connector_alloc_parse);
> > +
> > static int
> > v4l2_async_notifier_fwnode_parse_endpoint(struct device *dev,
> > struct v4l2_async_notifier *notifier,
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index 65da646b579e..800302aa84d8 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -276,6 +276,44 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> > */
> > void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> >
> > +/**
> > + * v4l2_fwnode_connector_free() - free the V4L2 connector acquired by
> > + * v4l2_fwnode_parse_connector()
>
> This would be nicer aligned with the text after the dash.
>
> > + * @connector: the V4L2 connector the resources of which are to be released
> > + *
> > + * Drop references to the connection link partners and free the memory allocated
> > + * by v4l2_fwnode_parse_connector() call.
> > + *
> > + * It is safe to call this function with NULL argument or on a V4L2 connector
> > + * the parsing of which failed.
> > + */
> > +void v4l2_fwnode_connector_free(struct v4l2_fwnode_connector *connector);
> > +
> > +/**
> > + * v4l2_fwnode_parse_connector() - parse the connector on endpoint
>
> The name is different from the actual function.
>
> > + * @fwnode: pointer to the endpoint's fwnode handle where the connector is
> > + * connected to
> > + * @connector: pointer to the V4L2 fwnode connector data structure
> > + *
> > + * Fill the connector data structure with the connector type, label, all found
> > + * links between the host and the connector as well as connector specific data.
> > + * Since the label is optional it can be %NULL if no one was found.
> > + *
> > + * A reference is taken to both the connector and the connector destination
> > + * where the connector belongs to. This must be dropped when no longer needed.
> > + * Also the memory it has allocated to store the variable size data must be
> > + * freed. Both dropping the references and freeing the memory is done by
> > + * v4l2_fwnode_connector_free().
> > + *
> > + * Return:
> > + * * %0 on success or a negative error code on failure:
> > + * * %-ENOMEM if memory allocation failed
> > + * * %-ENOLINK if the connector can't be found
> > + * * %-EINVAL on parsing failure
>
> Could this error code tell the endpoint is not connected to a connector?
>
> I think the perfectly suitable error code for this would be -ENOTCONN. :-D
>
> > + */
> > +int v4l2_fwnode_connector_alloc_parse(struct fwnode_handle *fwnode,
> > + struct v4l2_fwnode_connector *connector);
> > +
> > /**
> > * typedef parse_endpoint_func - Driver's callback function to be called on
> > * each V4L2 fwnode endpoint.
> >
>
> --
> Regards,
>
> Sakari Ailus
> sakari.ailus@linux.intel.com
>
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next prev parent reply other threads:[~2019-11-19 11:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190930093900.16524-1-m.felsch@pengutronix.de>
[not found] ` <20190930093900.16524-12-m.felsch@pengutronix.de>
2019-10-24 11:59 ` [PATCH v11 11/15] media: tvp5150: add s_power callback Sakari Ailus
2019-11-08 10:25 ` Marco Felsch
2019-11-08 10:38 ` Sakari Ailus
[not found] ` <20190930093900.16524-5-m.felsch@pengutronix.de>
2019-11-15 23:34 ` [PATCH v11 04/15] media: v4l2-fwnode: add initial connector parsing support Sakari Ailus
2019-11-19 11:37 ` Marco Felsch [this message]
2019-11-27 8:17 ` Marco Felsch
2020-01-08 15:36 ` Marco Felsch
2020-01-09 7:07 ` Marco Felsch
2020-01-15 17:06 ` Marco Felsch
2020-02-18 12:18 ` Sakari Ailus
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