[PATCH 1/4] drm/panel: use fwnode based lookups for panel followers

[Jani Nikula]

Use firmware node based lookups for panel followers, to make the code
independent of OF and device tree, and make it work also for ACPI with
an appropriate _DSD.

ASL example:

        Package (0x02)
        {
                "panel", \_SB.PCI0.GFX0.LCD0
        }

Suggested-by: Heikki Krogerus <heikki.kroge...@linux.intel.com>
Cc: Neil Armstrong <neil.armstr...@linaro.org>
Cc: Jessica Zhang <jessica.zh...@oss.qualcomm.com>
Cc: Maxime Ripard <mrip...@kernel.org>
Cc: Doug Anderson <diand...@chromium.org>
Cc: Lee Shawn C <shawn.c....@intel.com>
Signed-off-by: Jani Nikula <jani.nik...@intel.com>
---
 drivers/gpu/drm/drm_panel.c | 39 +++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index fee65dc65979..3eb0a615f7a9 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -473,17 +473,40 @@ int of_drm_get_panel_orientation(const struct device_node 
*np,
 EXPORT_SYMBOL(of_drm_get_panel_orientation);
 #endif
 
-static struct drm_panel *of_find_panel(struct device *follower_dev)
+/* Find panel by fwnode */
+static struct drm_panel *find_panel_by_fwnode(const struct fwnode_handle 
*fwnode)
 {
-       struct device_node *panel_np;
        struct drm_panel *panel;
 
-       panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);
-       if (!panel_np)
+       if (!fwnode_device_is_available(fwnode))
                return ERR_PTR(-ENODEV);
 
-       panel = of_drm_find_panel(panel_np);
-       of_node_put(panel_np);
+       mutex_lock(&panel_lock);
+
+       list_for_each_entry(panel, &panel_list, list) {
+               if (dev_fwnode(panel->dev) == fwnode) {
+                       mutex_unlock(&panel_lock);
+                       return panel;
+               }
+       }
+
+       mutex_unlock(&panel_lock);
+
+       return ERR_PTR(-EPROBE_DEFER);
+}
+
+/* Find panel by follower device */
+static struct drm_panel *find_panel_by_dev(struct device *follower_dev)
+{
+       struct fwnode_handle *fwnode;
+       struct drm_panel *panel;
+
+       fwnode = fwnode_find_reference(dev_fwnode(follower_dev), "panel", 0);
+       if (IS_ERR_OR_NULL(fwnode))
+               return ERR_PTR(-ENODEV);
+
+       panel = find_panel_by_fwnode(fwnode);
+       fwnode_handle_put(fwnode);
 
        return panel;
 }
@@ -506,7 +529,7 @@ bool drm_is_panel_follower(struct device *dev)
         * don't bother trying to parse it here. We just need to know if the
         * property is there.
         */
-       return of_property_present(dev->of_node, "panel");
+       return device_property_present(dev, "panel");
 }
 EXPORT_SYMBOL(drm_is_panel_follower);
 
@@ -536,7 +559,7 @@ int drm_panel_add_follower(struct device *follower_dev,
        struct drm_panel *panel;
        int ret;
 
-       panel = of_find_panel(follower_dev);
+       panel = find_panel_by_dev(follower_dev);
        if (IS_ERR(panel))
                return PTR_ERR(panel);
 
-- 
2.39.5