[PATCH v2 1/2] drm/bridge: sii902x: Fix mode_valid hook

[Jayesh Choudhary]

Currently, mode_valid hook returns all mode as valid and it is
defined only in drm_connector_helper_funcs. With the introduction of
'DRM_BRIDGE_ATTACH_NO_CONNECTOR', connector is not initialized in
bridge_attach call for cases when the encoder has this flag enabled.
So add the mode_valid hook in drm_bridge_funcs as well with proper
clock checks for maximum and minimum pixel clock supported by the
bridge.

Signed-off-by: Jayesh Choudhary <j-choudhary at ti.com>
---
 drivers/gpu/drm/bridge/sii902x.c | 38 ++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
index 2fbeda9025bf..ef7c3ab3386c 100644
--- a/drivers/gpu/drm/bridge/sii902x.c
+++ b/drivers/gpu/drm/bridge/sii902x.c
@@ -163,6 +163,14 @@
 
 #define SII902X_AUDIO_PORT_INDEX		3
 
+/*
+ * The maximum resolution supported by the HDMI bridge is 1080p at 60Hz
+ * and 1920x1200 requiring a pixel clock of 165MHz and the minimum
+ * resolution supported is 480p at 60Hz requiring a pixel clock of 25MHz
+ */
+#define SII902X_MIN_PIXEL_CLOCK_KHZ		25000
+#define SII902X_MAX_PIXEL_CLOCK_KHZ		165000
+
 struct sii902x {
 	struct i2c_client *i2c;
 	struct regmap *regmap;
@@ -310,12 +318,26 @@ static int sii902x_get_modes(struct drm_connector *connector)
 	return num;
 }
 
+static enum
+drm_mode_status sii902x_validate(struct sii902x *sii902x,
+				 const struct drm_display_mode *mode)
+{
+	if (mode->clock < SII902X_MIN_PIXEL_CLOCK_KHZ)
+		return MODE_CLOCK_LOW;
+
+	if (mode->clock > SII902X_MAX_PIXEL_CLOCK_KHZ)
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
 static enum drm_mode_status sii902x_mode_valid(struct drm_connector *connector,
 					       struct drm_display_mode *mode)
 {
-	/* TODO: check mode */
+	struct sii902x *sii902x = connector_to_sii902x(connector);
+	const struct drm_display_mode *mod = mode;
 
-	return MODE_OK;
+	return sii902x_validate(sii902x, mod);
 }
 
 static const struct drm_connector_helper_funcs sii902x_connector_helper_funcs = {
@@ -499,11 +521,22 @@ static int sii902x_bridge_atomic_check(struct drm_bridge *bridge,
 	 * There might be flags negotiation supported in future but
 	 * set the bus flags in atomic_check statically for now.
 	 */
+
 	bridge_state->input_bus_cfg.flags = bridge->timings->input_bus_flags;
 
 	return 0;
 }
 
+static enum drm_mode_status
+sii902x_bridge_mode_valid(struct drm_bridge *bridge,
+			  const struct drm_display_info *info,
+			  const struct drm_display_mode *mode)
+{
+	struct sii902x *sii902x = bridge_to_sii902x(bridge);
+
+	return sii902x_validate(sii902x, mode);
+}
+
 static const struct drm_bridge_funcs sii902x_bridge_funcs = {
 	.attach = sii902x_bridge_attach,
 	.mode_set = sii902x_bridge_mode_set,
@@ -516,6 +549,7 @@ static const struct drm_bridge_funcs sii902x_bridge_funcs = {
 	.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,
+	.mode_valid = sii902x_bridge_mode_valid,
 };
 
 static int sii902x_mute(struct sii902x *sii902x, bool mute)
-- 
2.25.1