Re: [PATCH 23/27] drm: bridge: dw-hdmi: Attach to next bridge if available

[Jonas Karlman <jonas@kwiboo.se>]

On 2020-05-26 14:50, Neil Armstrong wrote:
> On 26/05/2020 03:15, Laurent Pinchart wrote:
>> On all platforms except i.MX and Rockchip, the dw-hdmi DT bindings
>> require a video output port connected to an HDMI sink (most likely an
>> HDMI connector, in rare cases another bridges converting HDMI to another
>> protocol). For those platforms, retrieve the next bridge and attach it
>> from the dw-hdmi bridge attach handler.
>>
>> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>> ---
>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 52 ++++++++++++++++++++++-
>>  include/drm/bridge/dw_hdmi.h              |  2 +
>>  2 files changed, 53 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index 6148a022569a..512e67bb1c32 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -143,6 +143,7 @@ struct dw_hdmi_phy_data {
>>  struct dw_hdmi {
>>  	struct drm_connector connector;
>>  	struct drm_bridge bridge;
>> +	struct drm_bridge *next_bridge;
>>  
>>  	unsigned int version;
>>  
>> @@ -2797,7 +2798,8 @@ static int dw_hdmi_bridge_attach(struct drm_bridge *bridge,
>>  	struct dw_hdmi *hdmi = bridge->driver_private;
>>  
>>  	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
>> -		return 0;
>> +		return drm_bridge_attach(bridge->encoder, hdmi->next_bridge,
>> +					 bridge, flags);
>>  
>>  	return dw_hdmi_connector_create(hdmi);
>>  }
>> @@ -3179,6 +3181,50 @@ static void dw_hdmi_init_hw(struct dw_hdmi *hdmi)
>>  		hdmi->phy.ops->setup_hpd(hdmi, hdmi->phy.data);
>>  }
>>  
>> +static int dw_hdmi_parse_dt(struct dw_hdmi *hdmi)
>> +{
>> +	struct device_node *endpoint;
>> +	struct device_node *remote;
>> +
>> +	if (!hdmi->plat_data->output_port)
>> +		return 0;
>> +
>> +	endpoint = of_graph_get_endpoint_by_regs(hdmi->dev->of_node,
>> +						 hdmi->plat_data->output_port,
>> +						 -1);
>> +	if (!endpoint) {
>> +		/*
>> +		 * Don't treat this as a fatal error as the Rockchip DW-HDMI
>> +		 * binding doesn't make the output port mandatory.
>> +		 */
>> +		dev_dbg(hdmi->dev, "Missing endpoint in port@%u\n",
>> +			hdmi->plat_data->output_port);
>> +		return 0;

After this series only rcar-du set output_port so this block should only
run for rcar-du, for platforms without output_port the if-statement
for !hdmi->plat_data->output_port already return success so you can
probably return fatal error here.

The comment is a little bit misleading because of the if-statement above
or am I missing something?

Regards,
Jonas

>> +	}
>> +
>> +	remote = of_graph_get_remote_port_parent(endpoint);
>> +	of_node_put(endpoint);
>> +	if (!remote) {
>> +		dev_err(hdmi->dev, "Endpoint in port@%u unconnected\n",
>> +			hdmi->plat_data->output_port);
>> +		return -ENODEV;
>> +	}
>> +
>> +	if (!of_device_is_available(remote)) {
>> +		dev_err(hdmi->dev, "port@%u remote device is disabled\n",
>> +			hdmi->plat_data->output_port);
>> +		of_node_put(remote);
>> +		return -ENODEV;
>> +	}
>> +
>> +	hdmi->next_bridge = of_drm_find_bridge(remote);
>> +	of_node_put(remote);
>> +	if (!hdmi->next_bridge)
>> +		return -EPROBE_DEFER;
> 
> I'll be safer to print a warn for now until all platforms has been tested.
> 
>> +
>> +	return 0;
>> +}
>> +
>>  static struct dw_hdmi *
>>  __dw_hdmi_probe(struct platform_device *pdev,
>>  		const struct dw_hdmi_plat_data *plat_data)
>> @@ -3216,6 +3262,10 @@ __dw_hdmi_probe(struct platform_device *pdev,
>>  	mutex_init(&hdmi->cec_notifier_mutex);
>>  	spin_lock_init(&hdmi->audio_lock);
>>  
>> +	ret = dw_hdmi_parse_dt(hdmi);
>> +	if (ret < 0)
>> +		return ERR_PTR(ret);
>> +
>>  	ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
>>  	if (ddc_node) {
>>  		hdmi->ddc = of_get_i2c_adapter_by_node(ddc_node);
>> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
>> index ea34ca146b82..8ebeb65d6371 100644
>> --- a/include/drm/bridge/dw_hdmi.h
>> +++ b/include/drm/bridge/dw_hdmi.h
>> @@ -126,6 +126,8 @@ struct dw_hdmi_phy_ops {
>>  struct dw_hdmi_plat_data {
>>  	struct regmap *regm;
>>  
>> +	unsigned int output_port;
>> +
>>  	unsigned long input_bus_encoding;
>>  	bool use_drm_infoframe;
>>  	bool ycbcr_420_allowed;
>>
> 
> I must check on meson, since I'm not sure for now if the connector probes.
> 
> Anyway, this looks fine.
> 
> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
>