drm/bridge: sii902x: Fix HDMI detection with DRM_BRIDGE_ATTACH_NO_CONNECTOR

The sii902x driver was caching HDMI detection state in a sink_is_hdmi field
and checking it in mode_set() to determine whether to set HDMI or DVI
output mode. This approach had two problems:

1. With DRM_BRIDGE_ATTACH_NO_CONNECTOR (used by modern display drivers like
TIDSS), the bridge's get_modes() is never called. Instead, the
drm_bridge_connector helper calls the bridge's edid_read() and updates the
connector itself. This meant sink_is_hdmi was never populated, causing the
driver to default to DVI mode and breaking HDMI audio.

2. The mode_set() callback doesn't receive atomic state or connector
pointer, making it impossible to check connector->display_info.is_hdmi
directly at that point.

Fix this by moving the HDMI vs DVI decision from mode_set() to
atomic_enable(), where we can access the connector via
drm_atomic_get_new_connector_for_encoder(). This works for both connector
models:

- With DRM_BRIDGE_ATTACH_NO_CONNECTOR: Returns the drm_bridge_connector
  created by the display driver, which has already been updated by the
helper's call to drm_edid_connector_update()

- Without DRM_BRIDGE_ATTACH_NO_CONNECTOR (legacy): Returns the connector
  embedded in sii902x struct, which gets updated by the bridge's own
get_modes()

Fixes: 3de47e1309c2 ("drm/bridge: sii902x: use display info is_hdmi")
Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251030151635.3019864-1-devarsht@ti.com

diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
index d537b1d036fb09ce55a690a0809dcc28fc0f41be..1f0aba28ad1e1b299cedc1681149441b2fa0590a 100644 (file)
--- a/drivers/gpu/drm/bridge/sii902x.c
+++ b/drivers/gpu/drm/bridge/sii902x.c
@@ -179,7 +179,6 @@ struct sii902x {
        struct drm_connector connector;
        struct gpio_desc *reset_gpio;
        struct i2c_mux_core *i2cmux;
-       bool sink_is_hdmi;
        u32 bus_width;
 
        /*
@@ -315,8 +314,6 @@ static int sii902x_get_modes(struct drm_connector *connector)
                drm_edid_free(drm_edid);
        }
 
-       sii902x->sink_is_hdmi = connector->display_info.is_hdmi;
-
        return num;
 }
 
@@ -342,9 +339,17 @@ static void sii902x_bridge_atomic_enable(struct drm_bridge *bridge,
                                         struct drm_atomic_state *state)
 {
        struct sii902x *sii902x = bridge_to_sii902x(bridge);
+       struct drm_connector *connector;
+       u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
+
+       connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
+       if (connector && connector->display_info.is_hdmi)
+               output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
 
        mutex_lock(&sii902x->mutex);
 
+       regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
+                          SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
        regmap_update_bits(sii902x->regmap, SII902X_PWR_STATE_CTRL,
                           SII902X_AVI_POWER_STATE_MSK,
                           SII902X_AVI_POWER_STATE_D(0));
@@ -359,16 +364,12 @@ static void sii902x_bridge_mode_set(struct drm_bridge *bridge,
                                    const struct drm_display_mode *adj)
 {
        struct sii902x *sii902x = bridge_to_sii902x(bridge);
-       u8 output_mode = SII902X_SYS_CTRL_OUTPUT_DVI;
        struct regmap *regmap = sii902x->regmap;
        u8 buf[HDMI_INFOFRAME_SIZE(AVI)];
        struct hdmi_avi_infoframe frame;
        u16 pixel_clock_10kHz = adj->clock / 10;
        int ret;
 
-       if (sii902x->sink_is_hdmi)
-               output_mode = SII902X_SYS_CTRL_OUTPUT_HDMI;
-
        buf[0] = pixel_clock_10kHz & 0xff;
        buf[1] = pixel_clock_10kHz >> 8;
        buf[2] = drm_mode_vrefresh(adj);
@@ -384,11 +385,6 @@ static void sii902x_bridge_mode_set(struct drm_bridge *bridge,
 
        mutex_lock(&sii902x->mutex);
 
-       ret = regmap_update_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA,
-                                SII902X_SYS_CTRL_OUTPUT_MODE, output_mode);
-       if (ret)
-               goto out;
-
        ret = regmap_bulk_write(regmap, SII902X_TPI_VIDEO_DATA, buf, 10);
        if (ret)
                goto out;