[RFC v2 5/5] drm/dsi: Get DSI host by DT device node

From: Archit Taneja
Date: Tue Oct 06 2015 - 05:25:17 EST


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@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_mipi_dsi.c | 30 ++++++++++++++++++++++++++++++
include/drm/drm_mipi_dsi.h | 2 ++
2 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index cbb7373..c51d73e 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -216,6 +216,28 @@ of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
return mipi_dsi_device_new(host, &info);
}

+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;
@@ -227,6 +249,10 @@ 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);
@@ -243,6 +269,10 @@ 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 68f49f4..15d3068 100644
--- 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 */

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/