[PATCH 07/24] drm/msm: add the wide_bus_enabled callback to msm_display

From: Dmitry Baryshkov

Date: Wed Jul 22 2026 - 02:39:02 EST


dpu_encoder_is_widebus_enabled() switches on the interface type to call
either msm_dsi_wide_bus_enabled() or msm_dp_wide_bus_available(), two
differently named sub-block functions.

Replace them with a single mandatory wide_bus_enabled() callback on
struct msm_display_funcs. DSI and DP implement it (DP keeps its internal
msm_dp_wide_bus_available() helper, now declared privately in
dp_display.h); HDMI, which never drives a wide bus, returns false.

Add a dpu_encoder_get_display() helper that maps a struct msm_display_info
to its struct msm_display, so the DPU encoder can look up the sub-block
and call the callback without open-coding the interface-type switch. It is
reused by the following callback conversions.

No functional change intended.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 42 +++++++++++++++++++++--------
drivers/gpu/drm/msm/dp/dp_display.c | 8 ++++++
drivers/gpu/drm/msm/dp/dp_display.h | 1 +
drivers/gpu/drm/msm/dsi/dsi.c | 5 +++-
drivers/gpu/drm/msm/hdmi/hdmi.c | 6 +++++
drivers/gpu/drm/msm/msm_drv.h | 14 +++-------
6 files changed, 53 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 1f20695f81e3..ce358c1c9757 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -268,25 +268,45 @@ bool dpu_encoder_needs_periph_flush(struct dpu_encoder_phys *phys_enc)
msm_dp_needs_periph_flush(priv->kms->dp[disp_info->h_tile_instance[0]], mode);
}

+/**
+ * dpu_encoder_get_display - find the display sub-block driving an interface
+ * @dev: the DRM device
+ * @disp_info: the interface description
+ *
+ * Return: the &struct msm_display (DSI/DP/HDMI) driving the interface, or NULL
+ * for interfaces (e.g. writeback) that have no such sub-block.
+ */
+static struct msm_display *dpu_encoder_get_display(struct drm_device *dev,
+ const struct msm_display_info *disp_info)
+{
+ struct msm_drm_private *priv = dev->dev_private;
+ int index = disp_info->h_tile_instance[0];
+
+ switch (disp_info->intf_type) {
+ case INTF_DP:
+ return msm_dp_get_display(priv->kms->dp[index]);
+ case INTF_DSI:
+ return msm_dsi_get_display(priv->kms->dsi[index]);
+ case INTF_HDMI:
+ return msm_hdmi_get_display(priv->kms->hdmi);
+ default:
+ return NULL;
+ }
+}
+
/**
* dpu_encoder_is_widebus_enabled - return bool value if widebus is enabled
* @drm_enc: Pointer to previously created drm encoder structure
*/
bool dpu_encoder_is_widebus_enabled(const struct drm_encoder *drm_enc)
{
- const struct dpu_encoder_virt *dpu_enc;
- struct msm_drm_private *priv = drm_enc->dev->dev_private;
- const struct msm_display_info *disp_info;
- int index;
+ const struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
+ struct msm_display *display;

- dpu_enc = to_dpu_encoder_virt(drm_enc);
- disp_info = &dpu_enc->disp_info;
- index = disp_info->h_tile_instance[0];
+ display = dpu_encoder_get_display(drm_enc->dev, &dpu_enc->disp_info);

- if (disp_info->intf_type == INTF_DP)
- return msm_dp_wide_bus_available(priv->kms->dp[index]);
- else if (disp_info->intf_type == INTF_DSI)
- return msm_dsi_wide_bus_enabled(priv->kms->dsi[index]);
+ if (display)
+ return display->funcs->wide_bus_enabled(display);

return false;
}
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index f4fa86d1b9c7..04d291a93d20 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1354,9 +1354,17 @@ static int msm_dp_modeset_init(struct msm_display *display,
return 0;
}

+static bool msm_dp_display_wide_bus_enabled(struct msm_display *display)
+{
+ struct msm_dp *dp = container_of(display, struct msm_dp, display);
+
+ return msm_dp_wide_bus_available(dp);
+}
+
static const struct msm_display_funcs msm_dp_display_funcs = {
.modeset_init = msm_dp_modeset_init,
.snapshot = msm_dp_snapshot,
+ .wide_bus_enabled = msm_dp_display_wide_bus_enabled,
};

struct msm_display *msm_dp_get_display(struct msm_dp *msm_dp_display)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 20a71afb1f90..8c34a473c7db 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -34,6 +34,7 @@ int msm_dp_display_get_test_bpp(struct msm_dp *msm_dp_display);
void msm_dp_display_signal_audio_start(struct msm_dp *msm_dp_display);
void msm_dp_display_signal_audio_complete(struct msm_dp *msm_dp_display);
void msm_dp_display_set_psr(struct msm_dp *dp, bool enter);
+bool msm_dp_wide_bus_available(const struct msm_dp *dp_display);
void msm_dp_display_debugfs_init(struct msm_dp *msm_dp_display, struct dentry *dentry, bool is_edp);

#endif /* _DP_DISPLAY_H_ */
diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index c86142f66237..ce3b261123ea 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -17,8 +17,10 @@ struct drm_dsc_config *msm_dsi_get_dsc_config(struct msm_dsi *msm_dsi)
return msm_dsi_host_get_dsc_config(msm_dsi->host);
}

-bool msm_dsi_wide_bus_enabled(struct msm_dsi *msm_dsi)
+static bool msm_dsi_wide_bus_enabled(struct msm_display *display)
{
+ struct msm_dsi *msm_dsi = container_of(display, struct msm_dsi, display);
+
return msm_dsi_host_is_wide_bus_enabled(msm_dsi->host);
}

@@ -279,6 +281,7 @@ static void msm_dsi_snapshot(struct msm_display *display,
static const struct msm_display_funcs msm_dsi_display_funcs = {
.modeset_init = msm_dsi_modeset_init,
.snapshot = msm_dsi_snapshot,
+ .wide_bus_enabled = msm_dsi_wide_bus_enabled,
};

struct msm_display *msm_dsi_get_display(struct msm_dsi *msm_dsi)
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
index 72ab2e92964e..5f24f778c7ef 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
@@ -228,9 +228,15 @@ static void msm_hdmi_snapshot(struct msm_display *display,
hdmi->mmio, "hdmi");
}

+static bool msm_hdmi_wide_bus_enabled(struct msm_display *display)
+{
+ return false;
+}
+
static const struct msm_display_funcs msm_hdmi_display_funcs = {
.modeset_init = msm_hdmi_modeset_init,
.snapshot = msm_hdmi_snapshot,
+ .wide_bus_enabled = msm_hdmi_wide_bus_enabled,
};

struct msm_display *msm_hdmi_get_display(struct hdmi *hdmi)
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index d25d783b4f11..519571170207 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -283,12 +283,15 @@ struct msm_disp_state;
* to @encoder.
* @snapshot: capture the sub-block's state for a display snapshot;
* mandatory.
+ * @wide_bus_enabled: whether the sub-block drives a wide (2 pixel/clock) bus;
+ * mandatory.
*/
struct msm_display_funcs {
int (*modeset_init)(struct msm_display *display, struct drm_device *dev,
struct drm_encoder *encoder);
void (*snapshot)(struct msm_display *display,
struct msm_disp_state *disp_state);
+ bool (*wide_bus_enabled)(struct msm_display *display);
};

/**
@@ -327,7 +330,6 @@ struct msm_display *msm_dsi_get_display(struct msm_dsi *msm_dsi);
bool msm_dsi_is_cmd_mode(struct msm_dsi *msm_dsi);
bool msm_dsi_is_bonded_dsi(struct msm_dsi *msm_dsi);
bool msm_dsi_is_master_dsi(struct msm_dsi *msm_dsi);
-bool msm_dsi_wide_bus_enabled(struct msm_dsi *msm_dsi);
struct drm_dsc_config *msm_dsi_get_dsc_config(struct msm_dsi *msm_dsi);
const char *msm_dsi_get_te_source(struct msm_dsi *msm_dsi);
#else
@@ -353,10 +355,6 @@ static inline bool msm_dsi_is_master_dsi(struct msm_dsi *msm_dsi)
{
return false;
}
-static inline bool msm_dsi_wide_bus_enabled(struct msm_dsi *msm_dsi)
-{
- return false;
-}

static inline struct drm_dsc_config *msm_dsi_get_dsc_config(struct msm_dsi *msm_dsi)
{
@@ -376,7 +374,6 @@ void __exit msm_dp_unregister(void);
struct msm_display *msm_dp_get_display(struct msm_dp *dp_display);
bool msm_dp_needs_periph_flush(const struct msm_dp *dp_display,
const struct drm_display_mode *mode);
-bool msm_dp_wide_bus_available(const struct msm_dp *dp_display);

#else
static inline int __init msm_dp_register(void)
@@ -397,11 +394,6 @@ static inline bool msm_dp_needs_periph_flush(const struct msm_dp *dp_display,
return false;
}

-static inline bool msm_dp_wide_bus_available(const struct msm_dp *dp_display)
-{
- return false;
-}
-
#endif

#ifdef CONFIG_DRM_MSM_MDP4

--
2.47.3