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@samsung.com Signed-off-by: Archit Taneja architt@codeaurora.org --- 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 */