[PATCH v11 2/3] drm/bridge: imx: Add i.MX93 parallel display format configuration support

Marco Felsch
2026-03-03T10:34:38Z

From: Liu Ying <victor.liu@nxp.com>

NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
configures parallel display format by using the "PARALLEL_DISP_FORMAT"
field. Add a DRM bridge driver to support the display format configuration.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
[m.felsch@pengutronix.de: port to v7.0-rc1]
[m.felsch@pengutronix.de: add review feedback (Alexander)]
[m.felsch@pengutronix.de: fix to short Kconfig description (checkpath)]
[m.felsch@pengutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
[m.felsch@pengutronix.de: add bus-width support]
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
drivers/gpu/drm/bridge/imx/Kconfig | 11 ++
drivers/gpu/drm/bridge/imx/Makefile | 1 +
drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 225 ++++++++++++++++++++++++++++++++
3 files changed, 237 insertions(+)

diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
index b9028a5e5a065c3237b404111d8df57e8e017f9d..47829300a4486a090514ebe914b7667a703039a9 100644
--- a/drivers/gpu/drm/bridge/imx/Kconfig
+++ b/drivers/gpu/drm/bridge/imx/Kconfig
@@ -99,4 +99,15 @@ config DRM_IMX93_MIPI_DSI
Choose this to enable MIPI DSI controller found in Freescale i.MX93
processor.

+config DRM_IMX93_PARALLEL_DISP_FMT_CONVERTER
+ tristate "NXP i.MX91/i.MX93 parallel display format converter"
+ depends on OF
+ select DRM_KMS_HELPER
+ help
+ On i.MX93 and i.MX91 SoCs the parallel display format output is
+ controlled via the MEDIAMIX BLK-CTRL DISPLAY_MUX.
+
+ Say 'Y' or 'M' if you use the parallel display output path on a
+ i.MX93 or i.MX91 SoC.
+
endif # ARCH_MXC || COMPILE_TEST
diff --git a/drivers/gpu/drm/bridge/imx/Makefile b/drivers/gpu/drm/bridge/imx/Makefile
index 8d01fda25451aaa1bf51a068da18948094327116..da57fde2d813b88cdde89115ca801b4cfc69afbd 100644
--- a/drivers/gpu/drm/bridge/imx/Makefile
+++ b/drivers/gpu/drm/bridge/imx/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-combiner.o
obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK_TO_DPI) += imx8qxp-pxl2dpi.o
obj-$(CONFIG_DRM_IMX93_MIPI_DSI) += imx93-mipi-dsi.o
+obj-$(CONFIG_DRM_IMX93_PARALLEL_DISP_FMT_CONVERTER) += imx93-pdfc.o
diff --git a/drivers/gpu/drm/bridge/imx/imx93-pdfc.c b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
new file mode 100644
index 0000000000000000000000000000000000000000..27a54424319838517b206ab7d7447538aa1489eb
--- /dev/null
+++ b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Copyright 2022-2025 NXP
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/media-bus-format.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_bridge.h>
+
+#define IMX93_DISPLAY_MUX_REG 0x60
+#define PARALLEL_DISP_FORMAT GENMASK(10, 8)
+#define FORMAT_RGB888_TO_RGB888 FIELD_PREP(PARALLEL_DISP_FORMAT, 0)
+#define FORMAT_RGB888_TO_RGB666 FIELD_PREP(PARALLEL_DISP_FORMAT, 1)
+#define FORMAT_RGB565_TO_RGB565 FIELD_PREP(PARALLEL_DISP_FORMAT, 2)
+
+struct imx93_pdfc {
+ struct drm_bridge bridge;
+ struct device *dev;
+ struct regmap *regmap;
+ u32 phy_bus_width;
+};
+
+static struct imx93_pdfc *bridge_to_imx93_pdfc(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct imx93_pdfc, bridge);
+}
+
+static int
+imx93_pdfc_bridge_attach(struct drm_bridge *bridge, struct drm_encoder *encoder,
+ enum drm_bridge_attach_flags flags)
+{
+ return drm_bridge_attach(bridge->encoder, bridge->next_bridge, bridge, flags);
+}
+
+static void imx93_pdfc_bridge_atomic_enable(struct drm_bridge *bridge,
+ struct drm_atomic_state *state)
+{
+ struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
+ const struct drm_bridge_state *bridge_state;
+ unsigned int mask = PARALLEL_DISP_FORMAT;
+ unsigned int val;
+
+ bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+
+ switch (bridge_state->output_bus_cfg.format) {
+ case MEDIA_BUS_FMT_RGB888_1X24:
+ case MEDIA_BUS_FMT_FIXED:
+ val = FORMAT_RGB888_TO_RGB888;
+ if (pdfc->phy_bus_width == 18) {
+ /*
+ * Can be valid if physical bus limitation exists,
+ * therefore use dev_dbg().
+ */
+ dev_dbg(pdfc->dev, "Truncate two LSBs from each color\n");
+ val = FORMAT_RGB888_TO_RGB666;
+ }
+ break;
+ case MEDIA_BUS_FMT_RGB666_1X18:
+ val = FORMAT_RGB888_TO_RGB666;
+ break;
+ case MEDIA_BUS_FMT_RGB565_1X16:
+ val = FORMAT_RGB565_TO_RGB565;
+ break;
+ }
+
+ regmap_update_bits(pdfc->regmap, IMX93_DISPLAY_MUX_REG, mask, val);
+}
+
+/* TODO: Add YUV formats */
+static const u32 imx93_pdfc_bus_output_fmts[] = {
+ MEDIA_BUS_FMT_FIXED,
+ MEDIA_BUS_FMT_RGB888_1X24,
+ MEDIA_BUS_FMT_RGB666_1X18,
+ MEDIA_BUS_FMT_RGB565_1X16,
+};
+
+static bool imx93_pdfc_bus_output_fmt_supported(u32 fmt)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(imx93_pdfc_bus_output_fmts); i++) {
+ if (imx93_pdfc_bus_output_fmts[i] == fmt)
+ return true;
+ }
+
+ return false;
+}
+
+static u32 *
+imx93_pdfc_bridge_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)
+{
+ struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
+ u32 *input_fmts;
+
+ *num_input_fmts = 0;
+
+ input_fmts = kmalloc_obj(*input_fmts);
+ if (!input_fmts)
+ return NULL;
+
+ *num_input_fmts = 1;
+
+ if (!imx93_pdfc_bus_output_fmt_supported(output_fmt)) {
+ dev_dbg(pdfc->dev, "No valid output bus-fmt detected, fallback to MEDIA_BUS_FMT_RGB888_1X24\n");
+ input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+ return input_fmts;
+ }
+
+ switch (output_fmt) {
+ case MEDIA_BUS_FMT_RGB888_1X24:
+ case MEDIA_BUS_FMT_RGB565_1X16:
+ input_fmts[0] = output_fmt;
+ break;
+ case MEDIA_BUS_FMT_RGB666_1X18:
+ case MEDIA_BUS_FMT_FIXED:
+ input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+ break;
+ }
+
+ return input_fmts;
+}
+
+static int imx93_pdfc_bridge_atomic_check(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state)
+{
+ struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
+ u32 format = bridge_state->output_bus_cfg.format;
+
+ if (imx93_pdfc_bus_output_fmt_supported(format))
+ return 0;
+
+ dev_warn(pdfc->dev, "Unsupported output bus format: 0x%x\n", format);
+
+ return -EINVAL;
+}
+
+static const struct drm_bridge_funcs funcs = {
+ .attach = imx93_pdfc_bridge_attach,
+ .atomic_enable = imx93_pdfc_bridge_atomic_enable,
+ .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+ .atomic_get_input_bus_fmts = imx93_pdfc_bridge_atomic_get_input_bus_fmts,
+ .atomic_check = imx93_pdfc_bridge_atomic_check,
+ .atomic_reset = drm_atomic_helper_bridge_reset,
+};
+
+static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct drm_bridge *next_bridge;
+ struct imx93_pdfc *pdfc;
+ struct device_node *ep;
+ int err;
+
+ pdfc = devm_drm_bridge_alloc(dev, struct imx93_pdfc, bridge, &funcs);
+ if (IS_ERR(pdfc))
+ return PTR_ERR(pdfc);
+
+ pdfc->regmap = syscon_node_to_regmap(dev->of_node->parent);
+ if (IS_ERR(pdfc->regmap))
+ return dev_err_probe(dev, PTR_ERR(pdfc->regmap),
+ "failed to get regmap\n");
+
+ /* No limits per default */
+ pdfc->phy_bus_width = 24;
+
+ /* Get output ep (port1/endpoint) */
+ ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
+ if (ep) {
+ err = of_property_read_u32(ep, "bus-width", &pdfc->phy_bus_width);
+ of_node_put(ep);
+
+ /* bus-width is optional but it must have valid data if present */
+ if (err && err != -EINVAL)
+ return dev_err_probe(dev, err,
+ "failed to query bus-width\n");
+ }
+
+ next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+ if (IS_ERR(next_bridge))
+ return dev_err_probe(dev, PTR_ERR(next_bridge),
+ "failed to get next bridge\n");
+ pdfc->dev = dev;
+ pdfc->bridge.of_node = dev->of_node;
+ pdfc->bridge.type = DRM_MODE_CONNECTOR_DPI;
+ pdfc->bridge.next_bridge = next_bridge;
+
+ return devm_drm_bridge_add(dev, &pdfc->bridge);
+}
+
+static const struct of_device_id imx93_pdfc_dt_ids[] = {
+ { .compatible = "nxp,imx93-pdfc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx93_pdfc_dt_ids);
+
+static struct platform_driver imx93_pdfc_bridge_driver = {
+ .probe = imx93_pdfc_bridge_probe,
+ .driver = {
+ .of_match_table = imx93_pdfc_dt_ids,
+ .name = "imx93_pdfc",
+ },
+};
+module_platform_driver(imx93_pdfc_bridge_driver);
+
+MODULE_DESCRIPTION("NXP i.MX93 parallel display format configuration driver");
+MODULE_AUTHOR("Liu Ying <victor.liu@nxp.com>");
+MODULE_LICENSE("GPL");

--
2.47.3