[PATCH v11 08/14] drm/bridge: cdns-dsi: Add input format negotiation

From: Aradhya Bhatia
Date: Sat Mar 29 2025 - 07:41:16 EST


From: Aradhya Bhatia <a-bhatia1@xxxxxx>

Add support for the input format negotiation hook, that uses the helper
drm_mipi_dsi_get_input_bus_fmt() for dsi hosts, to figure out the
required input format.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Tested-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@xxxxxxxxx>
---
.../gpu/drm/bridge/cadence/cdns-dsi-core.c | 28 +++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
index 89a3f3efc522..c333b5c025d9 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
@@ -936,6 +936,33 @@ static void cdns_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
cdns_dsi_hs_init(dsi);
}

+static u32 *cdns_dsi_bridge_get_input_bus_fmts(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)
+{
+ struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
+ struct cdns_dsi *dsi = input_to_dsi(input);
+ struct cdns_dsi_output *output = &dsi->output;
+ u32 *input_fmts;
+
+ *num_input_fmts = 0;
+
+ input_fmts = kzalloc(sizeof(*input_fmts), GFP_KERNEL);
+ if (!input_fmts)
+ return NULL;
+
+ input_fmts[0] = drm_mipi_dsi_get_input_bus_fmt(output->dev->format);
+ if (!input_fmts[0])
+ return NULL;
+
+ *num_input_fmts = 1;
+
+ return input_fmts;
+}
+
static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
.attach = cdns_dsi_bridge_attach,
.mode_valid = cdns_dsi_bridge_mode_valid,
@@ -946,6 +973,7 @@ static const struct drm_bridge_funcs cdns_dsi_bridge_funcs = {
.atomic_reset = drm_atomic_helper_bridge_reset,
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+ .atomic_get_input_bus_fmts = cdns_dsi_bridge_get_input_bus_fmts,
};

static int cdns_dsi_attach(struct mipi_dsi_host *host,
--
2.34.1