[PATCH] drm/bridge: tc358767: Support input format negotiation hook

Aradhya Bhatia
2023-10-30T19:29:38Z

With new connector model, tc358767 will not create the connector, when
DRM_BRIDGE_ATTACH_NO_CONNECTOR is set and display-controller driver will
rely on format negotiation to setup the encoder format.

Add the missing input-format negotiation hook in the
drm_bridge_funcs to complete DRM_BRIDGE_ATTACH_NO_CONNECTOR support.

Input format is selected to MEDIA_BUS_FMT_RGB888_1X24 as default, as is
the case with older model.

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
---

Notes:

* Since I do not have hardware with me, this was just build tested. I would
appreciate it if someone could test and review it, especically somebody, who
uses the bridge for DPI/DSI to eDP format conversion.

* The Toshiba TC358767 bridge is not enabled in arm64 defconfig by default,
when it should be. Hence, I sent a quick patch[0] earlier.

[0]: https://lore.kernel.org/all/20231030152834.18450-1-a-bhatia1@ti.com/

drivers/gpu/drm/bridge/tc358767.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index ef2e373606ba..0affcefdeb1c 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1751,6 +1751,30 @@ tc_dpi_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
return input_fmts;
}

+static u32 *
+tc_edp_atomic_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)
+{
+ 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/DPI-end bus format */
+ input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+ *num_input_fmts = 1;
+
+ return input_fmts;
+}
+
static const struct drm_bridge_funcs tc_dpi_bridge_funcs = {
.attach = tc_dpi_bridge_attach,
.mode_valid = tc_dpi_mode_valid,
@@ -1777,6 +1801,7 @@ static const struct drm_bridge_funcs tc_edp_bridge_funcs = {
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
.atomic_reset = drm_atomic_helper_bridge_reset,
+ .atomic_get_input_bus_fmts = tc_edp_atomic_get_input_bus_fmts,
};

static bool tc_readable_reg(struct device *dev, unsigned int reg)

base-commit: c503e3eec382ac708ee7adf874add37b77c5d312
--
2.42.0