[PATCH v6 03/13] media: v4l2-fwnode: add initial connector parsing support

[Marco Felsch <m.felsch@pengutronix.de>]

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>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
---
[1] https://patchwork.kernel.org/cover/10794703/

v6:
- use 'unsigned int' 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 | 111 ++++++++++++++++++++++++++
 include/media/v4l2-fwnode.h           |  16 ++++
 2 files changed, 127 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 20571846e636..f1cca95c8fef 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -592,6 +592,117 @@ 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 *name;
+} connectors[] = {
+	{
+		.type = V4L2_CON_COMPOSITE,
+		.name = "composite-video-connector",
+	}, {
+		.type = V4L2_CON_SVIDEO,
+		.name = "svideo-connector",
+	}, {
+		.type = V4L2_CON_HDMI,
+		.name = "hdmi-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].name))
+			return connectors[i].type;
+
+	/* no valid connector found */
+	return V4L2_CON_UNKNOWN;
+}
+
+static int
+v4l2_fwnode_connector_parse_analog(struct fwnode_handle *fwnode,
+				   struct v4l2_fwnode_connector *vc)
+{
+	u32 tvnorms;
+	int ret;
+
+	ret = fwnode_property_read_u32(fwnode, "tvnorms", &tvnorms);
+
+	/* tvnorms is optional */
+	vc->connector.analog.supported_tvnorms = ret ? V4L2_STD_ALL : tvnorms;
+
+	return 0;
+}
+
+int v4l2_fwnode_parse_connector(struct fwnode_handle *__fwnode,
+				struct v4l2_fwnode_connector *connector)
+{
+	struct fwnode_handle *fwnode;
+	struct fwnode_endpoint __ep;
+	const char *c_type_str, *label;
+	int ret;
+
+	memset(connector, 0, sizeof(*connector));
+
+	fwnode = fwnode_graph_get_remote_port_parent(__fwnode);
+	if (!fwnode)
+		return -EINVAL;
+
+	/* parse all common properties first */
+	/* connector-type is stored within the compatible string */
+	ret = fwnode_property_read_string(fwnode, "compatible", &c_type_str);
+	if (ret) {
+		fwnode_handle_put(fwnode);
+		return -EINVAL;
+	}
+
+	connector->type = v4l2_fwnode_string_to_connector_type(c_type_str);
+
+	fwnode_graph_parse_endpoint(__fwnode, &__ep);
+	connector->remote_port = __ep.port;
+	connector->remote_id = __ep.id;
+
+	ret = fwnode_property_read_string(fwnode, "label", &label);
+	if (!ret) {
+		/* ensure label doesn't exceed V4L2_CONNECTOR_MAX_LABEL size */
+		strscpy(connector->label, label, V4L2_CONNECTOR_MAX_LABEL);
+	} else {
+		/*
+		 * labels are optional, if none is given create one:
+		 * <connector-type-string>@port<endpoint_port>/ep<endpoint_id>
+		 */
+		snprintf(connector->label, V4L2_CONNECTOR_MAX_LABEL,
+			 "%s@port%u/ep%u", c_type_str, connector->remote_port,
+			 connector->remote_id);
+	}
+
+	/* now parse the connector specific properties */
+	switch (connector->type) {
+	case V4L2_CON_COMPOSITE:
+		/* fall through */
+	case V4L2_CON_SVIDEO:
+		ret = v4l2_fwnode_connector_parse_analog(fwnode, connector);
+		break;
+	case V4L2_CON_HDMI:
+		pr_warn("Connector specific parsing is currently not supported for %s\n",
+			c_type_str);
+		ret = 0;
+		break;
+	case V4L2_CON_UNKNOWN:
+		/* fall through */
+	default:
+		pr_err("Unknown connector type\n");
+		ret = -EINVAL;
+	};
+
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_connector);
+
 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 f4df1b95c5ef..e072f2915ddb 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -269,6 +269,22 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
  */
 void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
 
+/**
+ * v4l2_fwnode_parse_connector() - parse the connector on endpoint
+ * @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 and the
+ * endpoint id and port where the connector belongs to. If no label is present
+ * a unique one will be created. Labels with more than 40 characters are cut.
+ *
+ * Return: %0 on success or a negative error code on failure:
+ *	   %-EINVAL on parsing failure
+ */
+int v4l2_fwnode_parse_connector(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.
-- 
2.20.1