[PATCH v4 12/17] drm/rockchip: analogix_dp: Add support to get panel from the DP AUX bus

[Damon Ding <damon.ding@rock-chips.com>]

Move drm_of_find_panel_or_bridge() a little later and combine it with
component_add() into a new function rockchip_dp_link_panel(). The function
will serve as done_probing() callback of devm_of_dp_aux_populate_bus(),
aiding to support for obtaining the eDP panel via the DP AUX bus.

If failed to get the panel from the DP AUX bus, it will then try the other
way to get panel information through the platform bus.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>

---

Changes in v4:
- Use done_probing() to call drm_of_find_panel_or_bridge() and
  component_add() when getting panel from the DP AUX bus
---
 .../gpu/drm/rockchip/analogix_dp-rockchip.c   | 48 +++++++++++++++----
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 256a0fd715e9..5381fb19e763 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -21,6 +21,7 @@
 #include <video/of_videomode.h>
 #include <video/videomode.h>
 
+#include <drm/display/drm_dp_aux_bus.h>
 #include <drm/display/drm_dp_helper.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -91,6 +92,11 @@ static struct rockchip_dp_device *pdata_encoder_to_dp(struct analogix_dp_plat_da
 	return container_of(plat_data, struct rockchip_dp_device, plat_data);
 }
 
+static struct analogix_dp_plat_data *aux_to_pdata(struct drm_dp_aux *aux)
+{
+	return container_of(aux, struct analogix_dp_plat_data, aux);
+}
+
 static int rockchip_grf_write(struct regmap *grf, u32 reg, u32 mask, u32 val)
 {
 	return regmap_write(grf, reg, (mask << 16) | (val & mask));
@@ -431,11 +437,28 @@ static const struct component_ops rockchip_dp_component_ops = {
 	.unbind = rockchip_dp_unbind,
 };
 
+static int rockchip_dp_link_panel(struct drm_dp_aux *aux)
+{
+	struct analogix_dp_plat_data *plat_data = aux_to_pdata(aux);
+	struct rockchip_dp_device *dp = pdata_encoder_to_dp(plat_data);
+	int ret;
+
+	ret = drm_of_find_panel_or_bridge(dp->dev->of_node, 1, 0, &plat_data->panel, NULL);
+	if (ret)
+		return ret;
+
+	ret = component_add(dp->dev, &rockchip_dp_component_ops);
+	if (ret)
+		return ret;
+
+	return ret;
+}
+
 static int rockchip_dp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct drm_dp_aux *aux;
 	const struct rockchip_dp_chip_data *dp_data;
-	struct drm_panel *panel = NULL;
 	struct rockchip_dp_device *dp;
 	struct resource *res;
 	int i;
@@ -445,10 +468,6 @@ static int rockchip_dp_probe(struct platform_device *pdev)
 	if (!dp_data)
 		return -ENODEV;
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);
-	if (ret < 0)
-		return ret;
-
 	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
 	if (!dp)
 		return -ENOMEM;
@@ -472,7 +491,6 @@ static int rockchip_dp_probe(struct platform_device *pdev)
 
 	dp->dev = dev;
 	dp->adp = ERR_PTR(-ENODEV);
-	dp->plat_data.panel = panel;
 	dp->plat_data.dev_type = dp->data->chip_type;
 	dp->plat_data.power_on = rockchip_dp_poweron;
 	dp->plat_data.power_off = rockchip_dp_powerdown;
@@ -488,9 +506,21 @@ static int rockchip_dp_probe(struct platform_device *pdev)
 	if (IS_ERR(dp->adp))
 		return PTR_ERR(dp->adp);
 
-	ret = component_add(dev, &rockchip_dp_component_ops);
-	if (ret)
-		return ret;
+	aux = &dp->plat_data.aux;
+	aux->dev = dp->dev;
+	drm_dp_aux_init(aux);
+
+	ret = devm_of_dp_aux_populate_bus(aux, rockchip_dp_link_panel);
+	if (ret) {
+		if (ret != -ENODEV) {
+			DRM_DEV_ERROR(dev, "failed to populate aux bus : %d\n", ret);
+			return ret;
+		}
+
+		ret = rockchip_dp_link_panel(aux);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
-- 
2.34.1