drm/mipi_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 a dummy 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 hosts DSI that are currently registered.

This list will be used to find the mipi_dsi_host corresponding to the
device_node passed in of_find_mipi_dsi_host_by_node.

Signed-off-by: Archit Taneja <architt@codeaurora.org>

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index 2d642752e1a5de34edf821b3187613623a7f80d3..e487f56ffc4c5367ca0d2b2ace642611f11578d5 100644 (file)
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -226,6 +226,28 @@ void mipi_dsi_unregister_device(struct mipi_dsi_device *dsi)
 }
 EXPORT_SYMBOL(mipi_dsi_unregister_device);
 
+static DEFINE_MUTEX(host_lock);
+static LIST_HEAD(host_list);
+
+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;
@@ -237,6 +259,10 @@ int mipi_dsi_host_register(struct mipi_dsi_host *host)
                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);
@@ -253,6 +279,10 @@ static int mipi_dsi_remove_device_fn(struct device *dev, void *priv)
 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);
 

diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index f95c8ef3003e7a92d3835692dbc0a5c3ba81c98b..fc1df05aeb855a7ffaa72398b2b8668e7dc13f86 100644 (file)
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -100,10 +100,12 @@ struct mipi_dsi_host_ops {
 struct mipi_dsi_host {
        struct device *dev;
        const struct mipi_dsi_host_ops *ops;
+       struct list_head list;
 };
 
 int mipi_dsi_host_register(struct mipi_dsi_host *host);
 void mipi_dsi_host_unregister(struct mipi_dsi_host *host);
+struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node);
 
 /* DSI mode flags */