[v7,15/36] drm/connector: hdmi: Calculate TMDS character rate

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 8730137baa86..26f9e525c0a0 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1148,6 +1148,7 @@  static void drm_atomic_connector_print_state(struct drm_printer *p,
 		drm_printf(p, "\toutput_bpc=%u\n", state->hdmi.output_bpc);
 		drm_printf(p, "\toutput_format=%s\n",
 			   drm_hdmi_connector_get_output_format_name(state->hdmi.output_format));
+		drm_printf(p, "\ttmds_char_rate=%llu\n", state->hdmi.tmds_char_rate);
 	}
 
 	if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index ae99765c45de..63a96c691460 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -640,6 +640,63 @@  int drm_atomic_helper_connector_tv_check(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_atomic_helper_connector_tv_check);
 
+static const struct drm_display_mode *
+connector_state_get_mode(const struct drm_connector_state *conn_state)
+{
+	struct drm_atomic_state *state;
+	struct drm_crtc_state *crtc_state;
+	struct drm_crtc *crtc;
+
+	state = conn_state->state;
+	if (!state)
+		return NULL;
+
+	crtc = conn_state->crtc;
+	if (!crtc)
+		return NULL;
+
+	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+	if (!crtc_state)
+		return NULL;
+
+	return &crtc_state->mode;
+}
+
+static enum drm_mode_status
+hdmi_clock_valid(const struct drm_connector *connector,
+		 const struct drm_display_mode *mode,
+		 unsigned long long clock)
+{
+	const struct drm_display_info *info = &connector->display_info;
+
+	if (info->max_tmds_clock && clock > info->max_tmds_clock * 1000)
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
+static int
+hdmi_compute_clock(const struct drm_connector *connector,
+		   struct drm_connector_state *state,
+		   const struct drm_display_mode *mode,
+		   unsigned int bpc, enum hdmi_colorspace fmt)
+{
+	enum drm_mode_status status;
+	unsigned long long clock;
+
+	clock = drm_connector_hdmi_compute_mode_clock(mode, bpc, fmt);
+	if (!clock)
+		return -EINVAL;
+
+	status = hdmi_clock_valid(connector, mode, clock);
+	if (status != MODE_OK)
+		return -EINVAL;
+
+	state->hdmi.tmds_char_rate = clock;
+
+	return 0;
+}
+
 /**
  * drm_atomic_helper_connector_hdmi_check() - Helper to check HDMI connector atomic state
  * @connector: DRM Connector
@@ -659,6 +716,15 @@  int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector,
 		drm_atomic_get_old_connector_state(state, connector);
 	struct drm_connector_state *new_state =
 		drm_atomic_get_new_connector_state(state, connector);
+	const struct drm_display_mode *mode =
+		connector_state_get_mode(new_state);
+	int ret;
+
+	ret = hdmi_compute_clock(connector, new_state, mode,
+				 new_state->hdmi.output_bpc,
+				 new_state->hdmi.output_format);
+	if (ret)
+		return ret;
 
 	if (old_state->hdmi.output_bpc != new_state->hdmi.output_bpc ||
 	    old_state->hdmi.output_format != new_state->hdmi.output_format) {
diff --git a/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c b/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
index 1c3dd8a98fb0..f2acbd4c216c 100644
--- a/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
@@ -70,6 +70,9 @@  static int light_up_connector(struct kunit *test,
 	conn_state = drm_atomic_get_connector_state(state, connector);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, conn_state);
 
+	conn_state->hdmi.output_bpc = connector->max_bpc;
+	conn_state->hdmi.output_format = HDMI_COLORSPACE_RGB;
+
 	ret = drm_atomic_set_crtc_for_connector(conn_state, crtc);
 	KUNIT_EXPECT_EQ(test, ret, 0);
 
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index a859ad7ee04b..e3917ea93986 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1050,6 +1050,11 @@  struct drm_connector_state {
 		 * @output_format: Pixel format to output in.
 		 */
 		enum hdmi_colorspace output_format;
+
+		/**
+		 * @tmds_char_rate: TMDS Character Rate, in Hz.
+		 */
+		unsigned long long tmds_char_rate;
 	} hdmi;
 };