Re: [PATCH v2 10/10] drm/hisilicon: Add support for external bridge

[Xinliang Liu <xinliang.liu@linaro.org>]

On 1 December 2015 at 17:04, Archit Taneja <architt@codeaurora.org> wrote:
>
>
> On 11/28/2015 04:09 PM, Xinliang Liu wrote:
>>
>> Add support for external HDMI bridge.
>>
>> Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
>> Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
>> Signed-off-by: Andy Green <andy.green@linaro.org>
>> ---
>>   drivers/gpu/drm/hisilicon/hisi_drm_dsi.c | 51
>> ++++++++++++++++++++++++++++++++
>>   1 file changed, 51 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/hisilicon/hisi_drm_dsi.c
>> b/drivers/gpu/drm/hisilicon/hisi_drm_dsi.c
>> index 066e08d..9e056db 100644
>> --- a/drivers/gpu/drm/hisilicon/hisi_drm_dsi.c
>> +++ b/drivers/gpu/drm/hisilicon/hisi_drm_dsi.c
>> @@ -78,6 +78,7 @@ struct dsi_hw_ctx {
>>
>>   struct hisi_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;
>> @@ -671,6 +672,25 @@ static int dsi_host_init(struct device *dev, struct
>> hisi_dsi *dsi)
>>         return 0;
>>   }
>>
>> +static int dsi_bridge_init(struct drm_device *dev, struct hisi_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 exteranl bridge\n");
>
>
> s/exteranl/external
>

will be fixed in v3.

>
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>   static int dsi_bind(struct device *dev, struct device *master, void
>> *data)
>>   {
>>         struct dsi_data *ddata = dev_get_drvdata(dev);
>> @@ -686,6 +706,10 @@ 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;
>>   }
>>
>> @@ -702,8 +726,35 @@ static const struct component_ops dsi_ops = {
>>   static int dsi_parse_dt(struct platform_device *pdev, struct hisi_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 port
>> +        * to which the external HDMI bridge is connected.
>> +        */
>> +       endpoint = of_graph_get_next_endpoint(np, NULL);
>> +       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;
>
>
> This could be left for later, but it would be better if the dsi driver
> registers even if the bridge driver module isn't inserted yet, or
> happens much later in boot.
>
> We could achieve this by trying to attach the bridge (done in
> dsi_bridge_init) in the dsi_host_attach callback instead of having it
> in dsi_bind.

Do you mean that it is the right time or place to attach the bridge in
dsi_host_attach callback.
Why? Because at this time bridge driver must be register?

Thanks,
-xinliang

>
> Thanks,
> Archit
>
>>
>>         ctx->dsi_cfg_clk = devm_clk_get(&pdev->dev, "pclk_dsi");
>>         if (IS_ERR(ctx->dsi_cfg_clk)) {
>>
>
> --
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