[v4,08/13] drm/msm/dp: Implement hpd_notify()

  From: Bjorn Andersson <bjorn.andersson@linaro.org>

The DisplayPort controller's hot-plug mechanism is based on pinmuxing a
physical signal on a GPIO pin into the controller. This is not always
possible, either because there aren't dedicated GPIOs available or
because the hot-plug signal is a virtual notification, in cases such as
USB Type-C.

For these cases, by implementing the hpd_notify() callback for the
DisplayPort controller's drm_bridge, a downstream drm_bridge
(next_bridge) can be used to track and signal the connection status
changes.

This makes it possible to use downstream drm_bridges such as
display-connector or any virtual mechanism, as long as they are
implemented as a drm_bridge.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[bjorn: Drop connector->fwnode assignment and dev from struct msm_dp]
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---

Changes since v3:
- None

 drivers/gpu/drm/msm/dp/dp_display.c | 22 ++++++++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_drm.c     |  1 +
 drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
 3 files changed, 25 insertions(+)
  

On 5 December 2022 20:44:28 GMT+03:00, Bjorn Andersson <quic_bjorande@quicinc.com> wrote:
>From: Bjorn Andersson <bjorn.andersson@linaro.org>
>
>The DisplayPort controller's hot-plug mechanism is based on pinmuxing a
>physical signal on a GPIO pin into the controller. This is not always
>possible, either because there aren't dedicated GPIOs available or
>because the hot-plug signal is a virtual notification, in cases such as
>USB Type-C.
>
>For these cases, by implementing the hpd_notify() callback for the
>DisplayPort controller's drm_bridge, a downstream drm_bridge
>(next_bridge) can be used to track and signal the connection status
>changes.
>
>This makes it possible to use downstream drm_bridges such as
>display-connector or any virtual mechanism, as long as they are
>implemented as a drm_bridge.
>
>Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>[bjorn: Drop connector->fwnode assignment and dev from struct msm_dp]
>Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
>---
>
>Changes since v3:
>- None
>
> drivers/gpu/drm/msm/dp/dp_display.c | 22 ++++++++++++++++++++++
> drivers/gpu/drm/msm/dp/dp_drm.c     |  1 +
> drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
> 3 files changed, 25 insertions(+)
>
>diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>index 666b45c8ab80..17fcf8cd84cd 100644
>--- a/drivers/gpu/drm/msm/dp/dp_display.c
>+++ b/drivers/gpu/drm/msm/dp/dp_display.c
>@@ -1772,3 +1772,25 @@ 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_display = dp_bridge->dp_display;
>+	struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
>+
>+	/* Without next_bridge interrupts are handled by the DP core directly */
>+	if (!dp_display->next_bridge)
>+		return;

Can we use hpd_notify in all the cases by dropping the corresponding piece of code from the core driver? 


>+
>+	if (!dp->core_initialized) {
>+		drm_dbg_dp(dp->drm_dev, "not initialized\n");
>+		return;
>+	}
>+
>+	if (!dp_display->is_connected && status == connector_status_connected)
>+		dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
>+	else if (dp_display->is_connected && status == connector_status_disconnected)
>+		dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
>+}
>diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
>index 6db82f9b03af..3898366ebd5e 100644
>--- a/drivers/gpu/drm/msm/dp/dp_drm.c
>+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
>@@ -102,6 +102,7 @@ static const struct drm_bridge_funcs dp_bridge_ops = {
> 	.get_modes    = dp_bridge_get_modes,
> 	.detect       = dp_bridge_detect,
> 	.atomic_check = dp_bridge_atomic_check,
>+	.hpd_notify   = dp_bridge_hpd_notify,
> };
> 
> struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
>diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
>index 82035dbb0578..79e6b2cf2d25 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_ */
  

On 5 December 2022 20:44:28 GMT+03:00, Bjorn Andersson <quic_bjorande@quicinc.com> wrote:
>From: Bjorn Andersson <bjorn.andersson@linaro.org>
>
>The DisplayPort controller's hot-plug mechanism is based on pinmuxing a
>physical signal on a GPIO pin into the controller. This is not always
>possible, either because there aren't dedicated GPIOs available or
>because the hot-plug signal is a virtual notification, in cases such as
>USB Type-C.
>
>For these cases, by implementing the hpd_notify() callback for the
>DisplayPort controller's drm_bridge, a downstream drm_bridge
>(next_bridge) can be used to track and signal the connection status
>changes.
>
>This makes it possible to use downstream drm_bridges such as
>display-connector or any virtual mechanism, as long as they are
>implemented as a drm_bridge.
>
>Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>[bjorn: Drop connector->fwnode assignment and dev from struct msm_dp]
>Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Minor nit: if for the next revision you reorder the patches to have hpd_enable first, then missing conditions, then this patch, it will look more logical.

>---
>
>Changes since v3:
>- None
>
> drivers/gpu/drm/msm/dp/dp_display.c | 22 ++++++++++++++++++++++
> drivers/gpu/drm/msm/dp/dp_drm.c     |  1 +
> drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
> 3 files changed, 25 insertions(+)
>
>diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>index 666b45c8ab80..17fcf8cd84cd 100644
>--- a/drivers/gpu/drm/msm/dp/dp_display.c
>+++ b/drivers/gpu/drm/msm/dp/dp_display.c
>@@ -1772,3 +1772,25 @@ 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_display = dp_bridge->dp_display;
>+	struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
>+
>+	/* Without next_bridge interrupts are handled by the DP core directly */
>+	if (!dp_display->next_bridge)
>+		return;
>+
>+	if (!dp->core_initialized) {
>+		drm_dbg_dp(dp->drm_dev, "not initialized\n");
>+		return;
>+	}
>+
>+	if (!dp_display->is_connected && status == connector_status_connected)
>+		dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
>+	else if (dp_display->is_connected && status == connector_status_disconnected)
>+		dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
>+}
>diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
>index 6db82f9b03af..3898366ebd5e 100644
>--- a/drivers/gpu/drm/msm/dp/dp_drm.c
>+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
>@@ -102,6 +102,7 @@ static const struct drm_bridge_funcs dp_bridge_ops = {
> 	.get_modes    = dp_bridge_get_modes,
> 	.detect       = dp_bridge_detect,
> 	.atomic_check = dp_bridge_atomic_check,
>+	.hpd_notify   = dp_bridge_hpd_notify,
> };
> 
> struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
>diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
>index 82035dbb0578..79e6b2cf2d25 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_ */
  

On Tue, Dec 06, 2022 at 12:29:13AM +0300, Dmitry Baryshkov wrote:
> 
> 
> On 5 December 2022 20:44:28 GMT+03:00, Bjorn Andersson <quic_bjorande@quicinc.com> wrote:
> >From: Bjorn Andersson <bjorn.andersson@linaro.org>
> >
> >The DisplayPort controller's hot-plug mechanism is based on pinmuxing a
> >physical signal on a GPIO pin into the controller. This is not always
> >possible, either because there aren't dedicated GPIOs available or
> >because the hot-plug signal is a virtual notification, in cases such as
> >USB Type-C.
> >
> >For these cases, by implementing the hpd_notify() callback for the
> >DisplayPort controller's drm_bridge, a downstream drm_bridge
> >(next_bridge) can be used to track and signal the connection status
> >changes.
> >
> >This makes it possible to use downstream drm_bridges such as
> >display-connector or any virtual mechanism, as long as they are
> >implemented as a drm_bridge.
> >
> >Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> >[bjorn: Drop connector->fwnode assignment and dev from struct msm_dp]
> >Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 
> Minor nit: if for the next revision you reorder the patches to have
> hpd_enable first, then missing conditions, then this patch, it will
> look more logical.

You're right, that will look better. I'll do so.

Thanks,
Bjorn

> 
> >---
> >
> >Changes since v3:
> >- None
> >
> > drivers/gpu/drm/msm/dp/dp_display.c | 22 ++++++++++++++++++++++
> > drivers/gpu/drm/msm/dp/dp_drm.c     |  1 +
> > drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
> > 3 files changed, 25 insertions(+)
> >
> >diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> >index 666b45c8ab80..17fcf8cd84cd 100644
> >--- a/drivers/gpu/drm/msm/dp/dp_display.c
> >+++ b/drivers/gpu/drm/msm/dp/dp_display.c
> >@@ -1772,3 +1772,25 @@ 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_display = dp_bridge->dp_display;
> >+	struct dp_display_private *dp = container_of(dp_display, struct dp_display_private, dp_display);
> >+
> >+	/* Without next_bridge interrupts are handled by the DP core directly */
> >+	if (!dp_display->next_bridge)
> >+		return;
> >+
> >+	if (!dp->core_initialized) {
> >+		drm_dbg_dp(dp->drm_dev, "not initialized\n");
> >+		return;
> >+	}
> >+
> >+	if (!dp_display->is_connected && status == connector_status_connected)
> >+		dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
> >+	else if (dp_display->is_connected && status == connector_status_disconnected)
> >+		dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
> >+}
> >diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
> >index 6db82f9b03af..3898366ebd5e 100644
> >--- a/drivers/gpu/drm/msm/dp/dp_drm.c
> >+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
> >@@ -102,6 +102,7 @@ static const struct drm_bridge_funcs dp_bridge_ops = {
> > 	.get_modes    = dp_bridge_get_modes,
> > 	.detect       = dp_bridge_detect,
> > 	.atomic_check = dp_bridge_atomic_check,
> >+	.hpd_notify   = dp_bridge_hpd_notify,
> > };
> > 
> > struct drm_bridge *dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
> >diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
> >index 82035dbb0578..79e6b2cf2d25 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_ */
> 
> -- 
> With best wishes
> Dmitry