[PATCH v1 3/9] drm: add drm_atomic_helper_bridge_dsi_input_bus_fmt

[Sam Ravnborg <sam@ravnborg.org>]

There is a number of bridge drivers that supports a single media bus
format for DSI. Add a helper to avoid duplicating the code.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
---
 drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
 include/drm/drm_atomic_helper.h     |  7 +++++
 2 files changed, 48 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index a7a05e1e26bb..94f313dc196f 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3549,3 +3549,44 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
 	return input_fmts;
 }
 EXPORT_SYMBOL(drm_atomic_helper_bridge_propagate_bus_fmt);
+
+/**
+ * drm_atomic_helper_bridge_dsi_input_bus_fmt - Define one DSI output format
+ *
+ * @bridge: bridge control structure
+ * @bridge_state: new bridge state
+ * @crtc_state: new CRTC state
+ * @conn_state: new connector state
+ * @output_fmt: tested output bus format
+ * @num_input_fmts: will contain the size of the returned array
+ *
+ * This helper is an implementation of the
+ * &drm_bridge_funcs.atomic_get_input_bus_fmts operation for bridges that supports
+ * a single DSI media bus format MEDIA_BUS_FMT_RGB888_1X24.
+ *
+ * RETURNS
+ * A format array with one entry containing MEDIA_BUS_FMT_RGB888_1X24,
+ * or NULL if the allocation failed
+ */
+u32 *
+drm_atomic_helper_bridge_dsi_input_bus_fmt(struct drm_bridge *bridge,
+					   struct drm_bridge_state *bridge_state,
+					   struct drm_crtc_state *crtc_state,
+					   struct drm_connector_state *conn_state,
+					   u32 output_fmt,
+					   unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts), GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	/* This is the DSI-end bus format */
+	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+	*num_input_fmts = 1;
+
+	return input_fmts;
+}
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 4045e2507e11..0e81b6f637d6 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -231,4 +231,11 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
 					u32 output_fmt,
 					unsigned int *num_input_fmts);
 
+u32 *
+drm_atomic_helper_bridge_dsi_input_bus_fmt(struct drm_bridge *bridge,
+					   struct drm_bridge_state *bridge_state,
+					   struct drm_crtc_state *crtc_state,
+					   struct drm_connector_state *conn_state,
+					   u32 output_fmt,
+					   unsigned int *num_input_fmts);
 #endif /* DRM_ATOMIC_HELPER_H_ */
-- 
2.32.0