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 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.
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Signed-off-by: Archit Taneja <architt@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_mipi_dsi.c | 39 +++++++++++++++++++++++++++++++++++++++
include/drm/drm_mipi_dsi.h | 3 +++
2 files changed, 42 insertions(+)
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 @@ void mipi_dsi_device_unregister(struct mipi_dsi_device *dsi)
}
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 @@ 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);
@@ -262,6 +297,10 @@ 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 06e0a93..7a9840f 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -96,14 +96,17 @@ struct mipi_dsi_host_ops {
* struct mipi_dsi_host - DSI host device
* @dev: driver model device node for this DSI host
* @ops: DSI host operations
+ * @list: list management
*/
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 */
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
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