linux-kernel - [PATCH 29/29] drm/bridge: sii902x: Implement hw state readout

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Message-Id: <20250902-drm-state-readout-v1-29-14ad5315da3f@kernel.org>
Date: Tue, 02 Sep 2025 10:32:57 +0200
From: Maxime Ripard <mripard@...nel.org>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
 Simona Vetter <simona@...ll.ch>, Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Jyri Sarha <jyri.sarha@....fi>, 
 Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: Devarsh Thakkar <devarsht@...com>, dri-devel@...ts.freedesktop.org, 
 linux-kernel@...r.kernel.org, Maxime Ripard <mripard@...nel.org>
Subject: [PATCH 29/29] drm/bridge: sii902x: Implement hw state readout

Let's implement the hardware state readout for the sii902x bridge now
that we have all the infrastructure in place.

Signed-off-by: Maxime Ripard <mripard@...nel.org>
---
 drivers/gpu/drm/bridge/sii902x.c | 51 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
index d537b1d036fb09ce55a690a0809dcc28fc0f41be..5ffceb9131540d2cb1b82a74b4f7cec9bc7fd8ca 100644
--- a/drivers/gpu/drm/bridge/sii902x.c
+++ b/drivers/gpu/drm/bridge/sii902x.c
@@ -540,17 +540,66 @@ sii902x_bridge_mode_valid(struct drm_bridge *bridge,
 		return MODE_CLOCK_HIGH;
 
 	return MODE_OK;
 }
 
+static int sii902x_bridge_connector_hw_readout(struct drm_bridge *bridge,
+					       struct drm_atomic_state *state,
+					       struct drm_connector_state *conn_state)
+{
+	struct sii902x *sii902x = bridge_to_sii902x(bridge);
+	struct drm_connector *connector = conn_state->connector;
+	struct drm_crtc_state *crtc_state;
+	struct drm_encoder *encoder;
+	struct drm_crtc *crtc;
+
+	if (regmap_test_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA, SII902X_SYS_CTRL_PWR_DWN))
+		return 0;
+
+	encoder = bridge->encoder;
+	crtc = encoder->funcs->get_current_crtc(encoder);
+	if (!crtc)
+		return -ENODEV;
+
+	crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
+	if (!crtc_state)
+		return -ENODEV;
+
+	crtc_state->encoder_mask |= drm_encoder_mask(encoder);
+	crtc_state->connector_mask |= drm_connector_mask(connector);
+
+	conn_state->crtc = crtc;
+	conn_state->best_encoder = encoder;
+
+	return 0;
+}
+
+static int sii902x_bridge_readout_state(struct drm_bridge *bridge,
+					struct drm_bridge_state *bridge_state,
+					struct drm_crtc_state *crtc_state,
+					struct drm_connector_state *conn_state)
+{
+	struct sii902x *sii902x = bridge_to_sii902x(bridge);
+
+	if (regmap_test_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA, SII902X_SYS_CTRL_PWR_DWN))
+		return 0;
+
+	/* bridge_state is pretty trivial, we don't have anything to do here */
+
+	return 0;
+}
+
 static const struct drm_bridge_funcs sii902x_bridge_funcs = {
 	.attach = sii902x_bridge_attach,
 	.mode_set = sii902x_bridge_mode_set,
 	.atomic_disable = sii902x_bridge_atomic_disable,
 	.atomic_enable = sii902x_bridge_atomic_enable,
+	.connector_hw_readout = sii902x_bridge_connector_hw_readout,
 	.detect = sii902x_bridge_detect,
 	.edid_read = sii902x_bridge_edid_read,
+	.atomic_compare_state = drm_atomic_helper_bridge_compare_state,
+	.atomic_readout_state = sii902x_bridge_readout_state,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 	.atomic_get_input_bus_fmts = sii902x_bridge_atomic_get_input_bus_fmts,
 	.atomic_check = sii902x_bridge_atomic_check,
@@ -1136,11 +1185,11 @@ static int sii902x_init(struct sii902x *sii902x)
 	if (ret)
 		goto err_unreg_audio;
 
 	sii902x->bridge.of_node = dev->of_node;
 	sii902x->bridge.timings = &default_sii902x_timings;
-	sii902x->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
+	sii902x->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_CONNECTOR_HW_READOUT;
 	sii902x->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
 
 	if (sii902x->i2c->irq > 0)
 		sii902x->bridge.ops |= DRM_BRIDGE_OP_HPD;
 

-- 
2.50.1