Message-Id: <20251201-v6-18-topic-imx93-parallel-display-v6-2-7b056e1e5b1e@pengutronix.de>
Date: Mon, 01 Dec 2025 18:15:21 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Peng Fan <peng.fan@....com>, 
 Liu Ying <victor.liu@....com>, Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: devicetree@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 dri-devel@...ts.freedesktop.org, Marco Felsch <m.felsch@...gutronix.de>
Subject: [PATCH v6 2/3] drm/bridge: imx: Add i.MX93 parallel display format
 configuration support

From: Liu Ying <victor.liu@....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.

Signed-off-by: Liu Ying <victor.liu@....com>
[m.felsch@...gutronix.de: port to v6.18-rc1]
[m.felsch@...gutronix.de: add review feedback (Alexander)]
[m.felsch@...gutronix.de: fix to short Kconfig description (checkpath)]
[m.felsch@...gutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
[m.felsch@...gutronix.de: make use of reg property]
[m.felsch@...gutronix.de: add bus-width support]
Signed-off-by: Marco Felsch <m.felsch@...gutronix.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 9a480c6abb856276df9b71d23b39a43b3a9c542d..28fd7a00473a0ec50bf0ffb5d50972abc209ceec 100644
--- a/drivers/gpu/drm/bridge/imx/Kconfig
+++ b/drivers/gpu/drm/bridge/imx/Kconfig
@@ -88,4 +88,15 @@ config DRM_IMX93_MIPI_DSI
 	  Choose this to enable MIPI DSI controller found in Freescale i.MX93
 	  processor.
 
+config DRM_IMX93_PARALLEL_DISP_FMT_CONFIG
+	tristate "NXP i.MX91/i.MX93 parallel display format configuration"
+	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 dd5d4858480663bade98bd58039d1cb6f8aa18da..f4ccc5cbef72a576443d5fecf666b76dfba8aa94 100644
--- a/drivers/gpu/drm/bridge/imx/Makefile
+++ b/drivers/gpu/drm/bridge/imx/Makefile
@@ -8,3 +8,4 @@ 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_CONFIG) += 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..8923012108ab9794c74813c1c58c1b4ab36cb5ae
--- /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/media-bus-format.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.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>
+#include <drm/drm_print.h>
+
+#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 drm_bridge *next_bridge;
+	struct device *dev;
+	struct regmap *regmap;
+	u64 disp_mux_reg_off;
+	u32 phy_bus_width;
+};
+
+static int
+imx93_pdfc_bridge_attach(struct drm_bridge *bridge, struct drm_encoder *encoder,
+			 enum drm_bridge_attach_flags flags)
+{
+	struct imx93_pdfc *pdfc = bridge->driver_private;
+
+	return drm_bridge_attach(bridge->encoder, pdfc->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->driver_private;
+	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:
+		val = FORMAT_RGB888_TO_RGB888;
+		if (pdfc->phy_bus_width == 18) {
+			/*
+			 * Can be valid if physical bus limitation exist,
+			 * 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, pdfc->disp_mux_reg_off, mask, val);
+}
+
+static const u32 imx93_pdfc_bus_output_fmts[] = {
+	MEDIA_BUS_FMT_RGB888_1X24,
+	MEDIA_BUS_FMT_RGB666_1X18,
+	MEDIA_BUS_FMT_RGB565_1X16,
+	MEDIA_BUS_FMT_FIXED
+};
+
+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)
+{
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	if (!imx93_pdfc_bus_output_fmt_supported(output_fmt))
+		return NULL;
+
+	input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	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;
+	}
+
+	*num_input_fmts = 1;
+
+	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->driver_private;
+
+	switch (bridge_state->output_bus_cfg.format) {
+	case MEDIA_BUS_FMT_RGB888_1X24:
+	case MEDIA_BUS_FMT_RGB666_1X18:
+	case MEDIA_BUS_FMT_RGB565_1X16:
+		return 0;
+	default:
+		dev_warn(pdfc->dev, "Unsupported output bus format: 0x%x\n",
+			 bridge_state->output_bus_cfg.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 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");
+
+	err = of_property_read_reg(dev->of_node, 0, &pdfc->disp_mux_reg_off, NULL);
+	if (err)
+		return dev_err_probe(dev, err,
+				     "failed to get display-mux reg\n");
+
+	/* No limits per default */
+	pdfc->phy_bus_width = 24;
+
+	/* Get output ep (port1/endpoint0) */
+	ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, 0);
+	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");
+	}
+
+	pdfc->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+	if (IS_ERR(pdfc->next_bridge))
+		return dev_err_probe(dev, PTR_ERR(pdfc->next_bridge),
+				     "failed to get next bridge\n");
+
+	pdfc->dev = dev;
+	pdfc->bridge.driver_private = pdfc;
+	pdfc->bridge.of_node = dev->of_node;
+	pdfc->bridge.type = DRM_MODE_CONNECTOR_DPI;
+
+	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@....com>");
+MODULE_LICENSE("GPL");

-- 
2.47.3

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