[PATCH v4 5/5] drm/msm/dp: Implement hpd_notify()

[Kuogee Hsieh]

On 5/2/2022 9:53 AM, Bjorn Andersson wrote:
> The Qualcomm DisplayPort driver contains traces of the necessary
> plumbing to hook up USB HPD, in the form of the dp_hpd module and the
> dp_usbpd_cb struct. Use this as basis for implementing the
> hpd_notify() callback, by amending the dp_hpd module with the
> missing logic.
>
> Overall the solution is similar to what's done downstream, but upstream
> all the code to disect the HPD notification lives on the calling side of
> drm_connector_oob_hotplug_event().
>
> drm_connector_oob_hotplug_event() performs the lookup of the
> drm_connector based on fwnode, hence the need to assign the fwnode in
> dp_drm_connector_init().
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson at linaro.org>
> ---
>
> Changes since v3:
> - Implements hpd_notify instead of oob_hotplug_event
> - Rebased on new cleanup patch from Dmitry
> - Set hpd_state to ST_MAINLINK_READY when dp_display_usbpd_configure() succeeds
>
>   drivers/gpu/drm/msm/dp/dp_display.c | 26 ++++++++++++++++++++++++++
>   drivers/gpu/drm/msm/dp/dp_display.h |  1 +
>   drivers/gpu/drm/msm/dp/dp_drm.c     |  3 +++
>   drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
>   4 files changed, 32 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index b447446d75e9..080294ac6144 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -83,6 +83,8 @@ struct dp_display_private {
>   	bool hpd_irq_on;
>   	bool audio_supported;
>   
> +	bool connected;
> +
>   	struct drm_device *drm_dev;
>   	struct platform_device *pdev;
>   	struct dentry *root;
> @@ -1271,6 +1273,7 @@ static int dp_display_probe(struct platform_device *pdev)
>   	if (!desc)
>   		return -EINVAL;
>   
> +	dp->dp_display.dev = &pdev->dev;
>   	dp->pdev = pdev;
>   	dp->name = "drm_dp";
>   	dp->dp_display.connector_type = desc->connector_type;
> @@ -1760,3 +1763,26 @@ void dp_bridge_mode_set(struct drm_bridge *drm_bridge,
>   	dp_display->dp_mode.h_active_low =
>   		!!(dp_display->dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
>   }
> +
> +void dp_bridge_hpd_notify(struct drm_bridge *bridge,
> +			  enum drm_connector_status status)
> +{
> +	struct msm_dp_bridge *dp_bridge = to_dp_bridge(bridge);
> +	struct msm_dp *dp = dp_bridge->dp_display;
> +	struct dp_display_private *dp_display = container_of(dp, struct dp_display_private, dp_display);
> +	int ret;
> +
> +	drm_dbg_dp(dp_display->drm_dev, "status: %d connected: %d\n", status, dp_display->connected);
> +
> +	if (!dp_display->connected && status == connector_status_connected) {
> +		dp_display->connected = true;
> +		ret = dp_display_usbpd_configure(dp_display);
> +		if (!ret)
> +			dp_display->hpd_state = ST_MAINLINK_READY;
> +	} else if (status != connector_status_connected) {
> +		dp_display->connected = false;
> +		dp_display_notify_disconnect(dp_display);
> +	} else {
> +		dp_display_usbpd_attention(dp_display);
> +	}
> +}

I would assume dp_bridge_hpd_notify() will server same purpose as 
dp_display_irq_handler() if hpd_notification is enabled.

In that case, should dp_bridge_hpd_notify() add 
EV_HPD_PLUG_INT/EV_IRQ_HPD_INT/EV_HPD_UNPLUG_INT

into event q to kick off corresponding 
dp_hpd_plug_handle()/dp_irq_hpd_handle()/dp_hpd_unplug_handle()?

By the way, I am going to test this patch out.

Any patches I have to pull in before apply this serial patches?

> diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
> index 4f9fe4d7610b..2d2614bc5a14 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.h
> +++ b/drivers/gpu/drm/msm/dp/dp_display.h
> @@ -11,6 +11,7 @@
>   #include "disp/msm_disp_snapshot.h"
>   
>   struct msm_dp {
> +	struct device *dev;
>   	struct drm_device *drm_dev;
>   	struct device *codec_dev;
>   	struct drm_bridge *bridge;
> diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
> index 62d58b9c4647..821cfd37b1fb 100644
> --- a/drivers/gpu/drm/msm/dp/dp_drm.c
> +++ b/drivers/gpu/drm/msm/dp/dp_drm.c
> @@ -68,6 +68,7 @@ static const struct drm_bridge_funcs dp_bridge_ops = {
>   	.mode_valid   = dp_bridge_mode_valid,
>   	.get_modes    = dp_bridge_get_modes,
>   	.detect       = dp_bridge_detect,
> +	.hpd_notify   = dp_bridge_hpd_notify,
>   };
>   
>   struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
> @@ -138,6 +139,8 @@ struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display)
>   	if (IS_ERR(connector))
>   		return connector;
>   
> +	connector->fwnode = fwnode_handle_get(dev_fwnode(dp_display->dev));
> +
>   	drm_connector_attach_encoder(connector, dp_display->encoder);
>   
>   	return connector;
> diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
> index f4b1ed1e24f7..3b7480a86844 100644
> --- a/drivers/gpu/drm/msm/dp/dp_drm.h
> +++ b/drivers/gpu/drm/msm/dp/dp_drm.h
> @@ -32,5 +32,7 @@ enum drm_mode_status dp_bridge_mode_valid(struct drm_bridge *bridge,
>   void dp_bridge_mode_set(struct drm_bridge *drm_bridge,
>   			const struct drm_display_mode *mode,
>   			const struct drm_display_mode *adjusted_mode);
> +void dp_bridge_hpd_notify(struct drm_bridge *bridge,
> +			  enum drm_connector_status status);
>   
>   #endif /* _DP_DRM_H_ */