From: Liu Ying <[email protected]>

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 <[email protected]>
[[email protected]: port to v6.18-rc1]
[[email protected]: add review feedback (Alexander)]
[[email protected]: fix to short Kconfig description (checkpath)]
[[email protected]: use "GPL" instead of "GPL v2" (checkpatch)]
[[email protected]: make use of reg property]
[[email protected]: add bus-width support]
Signed-off-by: Marco Felsch <[email protected]>
---
 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 <[email protected]>");
+MODULE_LICENSE("GPL");

-- 
2.47.3

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