drm/bridge: make bridge registration independent of drm flow

Currently, third party bridge drivers(ptn3460) are dependent
on the corresponding encoder driver init, since bridge driver
needs a drm_device pointer to finish drm initializations.
The encoder driver passes the drm_device pointer to the
bridge driver. Because of this dependency, third party drivers
like ptn3460 doesn't adhere to the driver model.

In this patch, we reframe the bridge registration framework
so that bridge initialization is split into 2 steps, and
bridge registration happens independent of drm flow:
--Step 1: gather all the bridge settings independent of drm and
	  add the bridge onto a global list of bridges.
--Step 2: when the encoder driver is probed, call drm_bridge_attach
	  for the corresponding bridge so that the bridge receives
	  drm_device pointer and continues with connector and other
	  drm initializations.

The old set of bridge helpers are removed, and a set of new helpers
are added to accomplish the 2 step initialization.

The bridge devices register themselves onto global list of bridges
when they get probed by calling "drm_bridge_add".

The parent encoder driver waits till the bridge is available
in the lookup table(by calling "of_drm_find_bridge") and then
continues with its initialization.

The encoder driver should also call "drm_bridge_attach" to pass
on the drm_device to the bridge object.

drm_bridge_attach inturn calls "bridge->funcs->attach" so that
bridge can continue with drm related initializations.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Tested-by: Rahul Sharma <rahul.sharma@samsung.com>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Tested-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 13 insertions, 14 deletions

diff --git a/drivers/gpu/drm/bridge/ptn3460.c b/drivers/gpu/drm/bridge/ptn3460.c
index a2ddc8d73c6a..4a818c1b62e0 100644
--- a/drivers/gpu/drm/bridge/ptn3460.c
+++ b/drivers/gpu/drm/bridge/ptn3460.c
@@ -176,24 +176,11 @@ static void ptn3460_post_disable(struct drm_bridge *bridge)
 {
 }
 
-static void ptn3460_bridge_destroy(struct drm_bridge *bridge)
-{
-	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
-
-	drm_bridge_cleanup(bridge);
-	if (gpio_is_valid(ptn_bridge->gpio_pd_n))
-		gpio_free(ptn_bridge->gpio_pd_n);
-	if (gpio_is_valid(ptn_bridge->gpio_rst_n))
-		gpio_free(ptn_bridge->gpio_rst_n);
-	/* Nothing else to free, we've got devm allocated memory */
-}
-
 static struct drm_bridge_funcs ptn3460_bridge_funcs = {
 	.pre_enable = ptn3460_pre_enable,
 	.enable = ptn3460_enable,
 	.disable = ptn3460_disable,
 	.post_disable = ptn3460_post_disable,
-	.destroy = ptn3460_bridge_destroy,
 };
 
 static int ptn3460_get_modes(struct drm_connector *connector)
@@ -314,7 +301,7 @@ int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
 	}
 
 	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
-	ret = drm_bridge_init(dev, &ptn_bridge->bridge);
+	ret = drm_bridge_attach(dev, &ptn_bridge->bridge);
 	if (ret) {
 		DRM_ERROR("Failed to initialize bridge with drm\n");
 		goto err;
@@ -343,3 +330,15 @@ err:
 	return ret;
 }
 EXPORT_SYMBOL(ptn3460_init);
+
+void ptn3460_destroy(struct drm_bridge *bridge)
+{
+	struct ptn3460_bridge *ptn_bridge = bridge->driver_private;
+
+	if (gpio_is_valid(ptn_bridge->gpio_pd_n))
+		gpio_free(ptn_bridge->gpio_pd_n);
+	if (gpio_is_valid(ptn_bridge->gpio_rst_n))
+		gpio_free(ptn_bridge->gpio_rst_n);
+	/* Nothing else to free, we've got devm allocated memory */
+}
+EXPORT_SYMBOL(ptn3460_destroy);