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Message-ID: <20251215164754.5amfk7hasaol7tdt@pengutronix.de>
Date: Mon, 15 Dec 2025 17:47:54 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: Liu Ying <victor.liu@....com>
Cc: 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>,
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>,
devicetree@...r.kernel.org, imx@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v7 2/3] drm/bridge: imx: Add i.MX93 parallel display
format configuration support
Hi,
On 25-12-08, Liu Ying wrote:
> Hi Marco,
>
> On 12/02/2025, Marco Felsch wrote:
> > 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 | 227 ++++++++++++++++++++++++++++++++
> > 3 files changed, 239 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..624389def0ac3f24158edc64a8913375a4cc2f12
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
> > @@ -0,0 +1,227 @@
> > +// 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_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>
>
> Drop this header file if you won't use DRM_DEV_DEBUG_DRIVER() in v5.
Sure.
> > +#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,
>
> s/exist/exists/
Thanks
> > + * 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:
>
> The case MEDIA_BUS_FMT_FIXED is also valid.
Good point, I think we should drop this from the
imx93_pdfc_bus_output_fmts completely since we know that only prallel panels
with an actual format can be attached to this bridge.
> > + 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);
>
> Nit: DT binding just defines endpoint not endpoint0, so set the reg parameter
> to -1.
Good point, thanks.
> > + 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", },
>
> The cover letter and Kconfig say that both i.MX91 and i.MX93 are supported,
> so need an additional compatible string for i.MX91?
I don't think so, according the imx91_93_common.dtsi, there are a lot
IPs which are shared between the i.MX91 and the i.MX93, even the clock
defines.
Thanks for the review.
Regards,
Marco
>
> > + { /* 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");
> >
>
>
> --
> Regards,
> Liu Ying
>
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