[PATCH v7 09/11] drm/hisilicon: Add support for external bridge

[Xinliang Liu]

Add support for external HDMI bridge.

v7: None.
v6: None.
v5: None.
v4: None.
v3:
- Fix a typo: s/exteranl/external.
v2:
- Remove abtraction layer.

Signed-off-by: Xinliang Liu <xinliang.liu at linaro.org>
Signed-off-by: Xinwei Kong <kong.kongxinwei at hisilicon.com>
Reviewed-by: Archit Taneja <architt at codeaurora.org>
---
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c | 52 ++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c 
b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
index ea7711832959..bfbc2159250d 100644
--- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
+++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
@@ -80,6 +80,7 @@ struct dsi_hw_ctx {

 struct dw_dsi {
        struct drm_encoder encoder;
+       struct drm_bridge *bridge;
        struct mipi_dsi_host host;
        struct drm_display_mode cur_mode;
        struct dsi_hw_ctx *ctx;
@@ -700,6 +701,25 @@ static int dsi_host_init(struct device *dev, struct dw_dsi 
*dsi)
        return 0;
 }

+static int dsi_bridge_init(struct drm_device *dev, struct dw_dsi *dsi)
+{
+       struct drm_encoder *encoder = &dsi->encoder;
+       struct drm_bridge *bridge = dsi->bridge;
+       int ret;
+
+       /* associate the bridge to dsi encoder */
+       encoder->bridge = bridge;
+       bridge->encoder = encoder;
+
+       ret = drm_bridge_attach(dev, bridge);
+       if (ret) {
+               DRM_ERROR("failed to attach external bridge\n");
+               return ret;
+       }
+
+       return 0;
+}
+
 static int dsi_bind(struct device *dev, struct device *master, void *data)
 {
        struct dsi_data *ddata = dev_get_drvdata(dev);
@@ -715,6 +735,10 @@ static int dsi_bind(struct device *dev, struct device 
*master, void *data)
        if (ret)
                return ret;

+       ret = dsi_bridge_init(drm_dev, dsi);
+       if (ret)
+               return ret;
+
        return 0;
 }

@@ -731,8 +755,36 @@ static const struct component_ops dsi_ops = {
 static int dsi_parse_dt(struct platform_device *pdev, struct dw_dsi *dsi)
 {
        struct dsi_hw_ctx *ctx = dsi->ctx;
+       struct device_node *np = pdev->dev.of_node;
+       struct device_node *endpoint, *bridge_node;
+       struct drm_bridge *bridge;
        struct resource *res;

+       /*
+        * Get the endpoint node. In our case, dsi has one output port1
+        * to which the external HDMI bridge is connected.
+        */
+       endpoint = of_graph_get_endpoint_by_regs(np, 1, -1);
+       if (!endpoint) {
+               DRM_ERROR("no valid endpoint node\n");
+               return -ENODEV;
+       }
+       of_node_put(endpoint);
+
+       bridge_node = of_graph_get_remote_port_parent(endpoint);
+       if (!bridge_node) {
+               DRM_ERROR("no valid bridge node\n");
+               return -ENODEV;
+       }
+       of_node_put(bridge_node);
+
+       bridge = of_drm_find_bridge(bridge_node);
+       if (!bridge) {
+               DRM_INFO("wait for external HDMI bridge driver.\n");
+               return -EPROBE_DEFER;
+       }
+       dsi->bridge = bridge;
+
        ctx->pclk = devm_clk_get(&pdev->dev, "pclk");
        if (IS_ERR(ctx->pclk)) {
                DRM_ERROR("failed to get pclk clock\n");
-- 
2.7.1