[v3 3/5] drm/bridge: add psr support during panel bridge enable & disable sequence

[Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>]

This change avoids panel prepare/unprepare based on self-refresh
state.

Signed-off-by: Sankeerth Billakanti <quic_sbillaka@xxxxxxxxxxx>
Signed-off-by: Kalyan Thota <quic_kalyant@xxxxxxxxxxx>
Signed-off-by: Vinod Polimera <quic_vpolimer@xxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/panel.c | 102 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 98 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 59a3496..6b09ae0 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -41,6 +41,40 @@ static int panel_bridge_connector_get_modes(struct drm_connector *connector)
 	return drm_panel_get_modes(panel_bridge->panel, connector);
 }
 
+static struct drm_crtc *bridge_drm_get_old_connector_crtc(struct drm_encoder *encoder,
+							struct drm_atomic_state *state)
+{
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+
+	connector = drm_atomic_get_old_connector_for_encoder(state, encoder);
+	if (!connector)
+		return NULL;
+
+	conn_state = drm_atomic_get_old_connector_state(state, connector);
+	if (!conn_state)
+		return NULL;
+
+	return conn_state->crtc;
+}
+
+static struct drm_crtc *bridge_drm_get_new_connector_crtc(struct drm_encoder *encoder,
+							struct drm_atomic_state *state)
+{
+	struct drm_connector *connector;
+	struct drm_connector_state *conn_state;
+
+	connector = drm_atomic_get_new_connector_for_encoder(state, encoder);
+	if (!connector)
+		return NULL;
+
+	conn_state = drm_atomic_get_new_connector_state(state, connector);
+	if (!conn_state)
+		return NULL;
+
+	return conn_state->crtc;
+}
+
 static const struct drm_connector_helper_funcs
 panel_bridge_connector_helper_funcs = {
 	.get_modes = panel_bridge_connector_get_modes,
@@ -108,30 +142,90 @@ static void panel_bridge_detach(struct drm_bridge *bridge)
 		drm_connector_cleanup(connector);
 }
 
-static void panel_bridge_atomic_pre_enable(struct drm_bridge *bridge)
+static void panel_bridge_atomic_pre_enable(struct drm_bridge *bridge,
+					struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+	struct drm_atomic_state *old_state = old_bridge_state->base.state;
+	struct drm_encoder *encoder = bridge->encoder;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *old_crtc_state;
+
+	crtc = bridge_drm_get_new_connector_crtc(encoder, old_state);
+	if (!crtc)
+		return;
+
+	old_crtc_state = drm_atomic_get_old_crtc_state(old_state, crtc);
+
+	/* Don't touch the panel if we're coming back from self refresh state */
+	if (old_crtc_state && old_crtc_state->self_refresh_active)
+		return;
 
 	drm_panel_prepare(panel_bridge->panel);
 }
 
-static void panel_bridge_atomic_enable(struct drm_bridge *bridge)
+static void panel_bridge_atomic_enable(struct drm_bridge *bridge,
+					struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+	struct drm_atomic_state *old_state = old_bridge_state->base.state;
+	struct drm_encoder *encoder = bridge->encoder;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *old_crtc_state;
+
+	crtc = bridge_drm_get_new_connector_crtc(encoder, old_state);
+	if (!crtc)
+		return;
+
+	old_crtc_state = drm_atomic_get_old_crtc_state(old_state, crtc);
+
+	/* Don't touch the panel if we're coming back from self refresh state */
+	if (old_crtc_state && old_crtc_state->self_refresh_active)
+		return;
 
 	drm_panel_enable(panel_bridge->panel);
 }
 
-static void panel_bridge_atomic_disable(struct drm_bridge *bridge)
+static void panel_bridge_atomic_disable(struct drm_bridge *bridge,
+					struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+	struct drm_atomic_state *old_state = old_bridge_state->base.state;
+	struct drm_encoder *encoder = bridge->encoder;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *new_crtc_state;
+
+	crtc = bridge_drm_get_old_connector_crtc(encoder, old_state);
+	if (!crtc)
+		return;
+
+	new_crtc_state = drm_atomic_get_new_crtc_state(old_state, crtc);
+
+	/* Don't do a full disable on PSR transitions if new state is self refresh state */
+	if (new_crtc_state && new_crtc_state->self_refresh_active)
+		return;
 
 	drm_panel_disable(panel_bridge->panel);
 }
 
-static void panel_bridge_atomic_post_disable(struct drm_bridge *bridge)
+static void panel_bridge_atomic_post_disable(struct drm_bridge *bridge,
+					struct drm_bridge_state *old_bridge_state)
 {
 	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+	struct drm_atomic_state *old_state = old_bridge_state->base.state;
+	struct drm_encoder *encoder = bridge->encoder;
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *new_crtc_state;
+
+	crtc = bridge_drm_get_old_connector_crtc(encoder, old_state);
+	if (!crtc)
+		return;
+
+	new_crtc_state = drm_atomic_get_new_crtc_state(old_state, crtc);
+
+	/* Don't do unprepare on PSR transitions if new state is self refresh state */
+	if (new_crtc_state && new_crtc_state->self_refresh_active)
+		return;
 
 	drm_panel_unprepare(panel_bridge->panel);
 }
-- 
2.7.4