drm/dsi: Get DSI host by DT device node
MIPI DSI devices are inherently aware of their host because they share a
parent-child hierarchy in the device tree.
Non-DSI drivers that create DSI device don't have this data. In order to
get this information, they require to a phandle to the DSI host in the
device tree.
Maintain a list of all the DSI hosts that are currently registered. This
list will be used to find the struct mipi_dsi_host corresponding to the
device tree node passed to of_find_mipi_dsi_host_by_node().
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index f2f5a6d..f5d8083 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -235,6 +235,37 @@
}
EXPORT_SYMBOL(mipi_dsi_device_unregister);
+static DEFINE_MUTEX(host_lock);
+static LIST_HEAD(host_list);
+
+/**
+ * of_find_mipi_dsi_host_by_node() - find the MIPI DSI host matching a
+ * device tree node
+ * @node: device tree node
+ *
+ * Returns:
+ * A pointer to the MIPI DSI host corresponding to @node or NULL if no
+ * such device exists (or has not been registered yet).
+ */
+struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node)
+{
+ struct mipi_dsi_host *host;
+
+ mutex_lock(&host_lock);
+
+ list_for_each_entry(host, &host_list, list) {
+ if (host->dev->of_node == node) {
+ mutex_unlock(&host_lock);
+ return host;
+ }
+ }
+
+ mutex_unlock(&host_lock);
+
+ return NULL;
+}
+EXPORT_SYMBOL(of_find_mipi_dsi_host_by_node);
+
int mipi_dsi_host_register(struct mipi_dsi_host *host)
{
struct device_node *node;
@@ -246,6 +277,10 @@
of_mipi_dsi_device_add(host, node);
}
+ mutex_lock(&host_lock);
+ list_add_tail(&host->list, &host_list);
+ mutex_unlock(&host_lock);
+
return 0;
}
EXPORT_SYMBOL(mipi_dsi_host_register);
@@ -262,6 +297,10 @@
void mipi_dsi_host_unregister(struct mipi_dsi_host *host)
{
device_for_each_child(host->dev, NULL, mipi_dsi_remove_device_fn);
+
+ mutex_lock(&host_lock);
+ list_del_init(&host->list);
+ mutex_unlock(&host_lock);
}
EXPORT_SYMBOL(mipi_dsi_host_unregister);