[RFC V2 3/3] drm/bridge: ptn3460: support bridge chaining

[Ajay Kumar <ajaykumar.rs@samsung.com>]

modify the driver to call the bridge->funcs of the next bridge
in the chain.
We assume that the bridge sitting next to ptn3460 is a bridge-panel.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
---
 drivers/gpu/drm/bridge/ptn3460.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ptn3460.c b/drivers/gpu/drm/bridge/ptn3460.c
index b171901..969869a 100644
--- a/drivers/gpu/drm/bridge/ptn3460.c
+++ b/drivers/gpu/drm/bridge/ptn3460.c
@@ -126,6 +126,8 @@ static void ptn3460_pre_enable(struct drm_bridge *bridge)
 		gpio_set_value(ptn_bridge->gpio_rst_n, 1);
 	}
 
+	if (bridge->next_bridge)
+		bridge->next_bridge->funcs->pre_enable(bridge->next_bridge);
 	/*
 	 * There's a bug in the PTN chip where it falsely asserts hotplug before
 	 * it is fully functional. We're forced to wait for the maximum start up
@@ -142,6 +144,8 @@ static void ptn3460_pre_enable(struct drm_bridge *bridge)
 
 static void ptn3460_enable(struct drm_bridge *bridge)
 {
+	if (bridge->next_bridge)
+		bridge->next_bridge->funcs->enable(bridge->next_bridge);
 }
 
 static void ptn3460_disable(struct drm_bridge *bridge)
@@ -153,6 +157,11 @@ static void ptn3460_disable(struct drm_bridge *bridge)
 
 	ptn_bridge->enabled = false;
 
+	if (bridge->next_bridge) {
+		bridge->next_bridge->funcs->disable(bridge->next_bridge);
+		bridge->next_bridge->funcs->post_disable(bridge->next_bridge);
+	}
+
 	if (gpio_is_valid(ptn_bridge->gpio_rst_n))
 		gpio_set_value(ptn_bridge->gpio_rst_n, 1);
 
@@ -197,7 +206,10 @@ int ptn3460_get_modes(struct drm_connector *connector)
 		return drm_add_edid_modes(connector, ptn_bridge->edid);
 
 	power_off = !ptn_bridge->enabled;
-	ptn3460_pre_enable(ptn_bridge->bridge);
+	if (power_off) {
+		ptn3460_pre_enable(ptn_bridge->bridge);
+		ptn3460_enable(ptn_bridge->bridge);
+	}
 
 	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
 	if (!edid) {
@@ -219,8 +231,10 @@ int ptn3460_get_modes(struct drm_connector *connector)
 	num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
 
 out:
-	if (power_off)
+	if (power_off) {
 		ptn3460_disable(ptn_bridge->bridge);
+		ptn3460_post_disable(ptn_bridge->bridge);
+	}
 
 	return num_modes;
 }
@@ -318,14 +332,13 @@ int ptn3460_init(struct drm_device *dev, struct drm_encoder *encoder,
 		goto err;
 	}
 
-	ret = drm_bridge_init(dev, bridge, &ptn3460_bridge_funcs);
+	ret = drm_bridge_init(dev, bridge, encoder, &ptn3460_bridge_funcs);
 	if (ret) {
 		DRM_ERROR("Failed to initialize bridge with drm\n");
 		goto err;
 	}
 
 	bridge->driver_private = ptn_bridge;
-	encoder->bridge = bridge;
 
 	ret = drm_connector_init(dev, &ptn_bridge->connector,
 			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
-- 
1.8.1.2