Re: [PATCH v3 5/6] drm/bridge: imx: add driver for HDMI TX Parallel Audio Interface

Shengjiu Wang
2025-08-06T03:49:36Z

On Tue, Aug 5, 2025 at 3:09 PM Alexander Stein
<alexander.stein@ew.tq-group.com> wrote:
>
> Hi,
>
> Am Montag, 4. August 2025, 12:47:21 CEST schrieb Shengjiu Wang:
> > The HDMI TX Parallel Audio Interface (HTX_PAI) is a digital module that
> > acts as the bridge between the Audio Subsystem to the HDMI TX Controller.
> > This IP block is found in the HDMI subsystem of the i.MX8MP SoC.
> >
> > Data received from the audio subsystem can have an arbitrary component
> > ordering. The HTX_PAI block has integrated muxing options to select which
> > sections of the 32-bit input data word will be mapped to each IEC60958
> > field. The HTX_PAI_FIELD_CTRL register contains mux selects to
> > individually select P,C,U,V,Data, and Preamble.
> >
> > Use component helper that imx8mp-hdmi-tx will be aggregate driver,
> > imx8mp-hdmi-pai will be component driver, then imx8mp-hdmi-pai can use
> > bind() ops to get the plat_data from imx8mp-hdmi-tx device.
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> > ---
> > drivers/gpu/drm/bridge/imx/Kconfig | 8 +
> > drivers/gpu/drm/bridge/imx/Makefile | 1 +
> > drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c | 205 +++++++++++++++++++
> > drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c | 55 +++++
> > include/drm/bridge/dw_hdmi.h | 6 +
> > 5 files changed, 275 insertions(+)
> > create mode 100644 drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c
> >
> > diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> > index 9a480c6abb85..6c1a8bc5d4a0 100644
> > --- a/drivers/gpu/drm/bridge/imx/Kconfig
> > +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> > @@ -18,12 +18,20 @@ config DRM_IMX8MP_DW_HDMI_BRIDGE
> > depends on OF
> > depends on COMMON_CLK
> > select DRM_DW_HDMI
> > + imply DRM_IMX8MP_HDMI_PAI
> > imply DRM_IMX8MP_HDMI_PVI
> > imply PHY_FSL_SAMSUNG_HDMI_PHY
> > help
> > Choose this to enable support for the internal HDMI encoder found
> > on the i.MX8MP SoC.
> >
> > +config DRM_IMX8MP_HDMI_PAI
> > + tristate "Freescale i.MX8MP HDMI PAI bridge support"
> > + depends on OF
> > + help
> > + Choose this to enable support for the internal HDMI TX Parallel
> > + Audio Interface found on the Freescale i.MX8MP SoC.
> > +
> > config DRM_IMX8MP_HDMI_PVI
> > tristate "Freescale i.MX8MP HDMI PVI bridge support"
> > depends on OF
> > diff --git a/drivers/gpu/drm/bridge/imx/Makefile b/drivers/gpu/drm/bridge/imx/Makefile
> > index dd5d48584806..8d01fda25451 100644
> > --- a/drivers/gpu/drm/bridge/imx/Makefile
> > +++ b/drivers/gpu/drm/bridge/imx/Makefile
> > @@ -1,6 +1,7 @@
> > obj-$(CONFIG_DRM_IMX_LDB_HELPER) += imx-ldb-helper.o
> > obj-$(CONFIG_DRM_IMX_LEGACY_BRIDGE) += imx-legacy-bridge.o
> > obj-$(CONFIG_DRM_IMX8MP_DW_HDMI_BRIDGE) += imx8mp-hdmi-tx.o
> > +obj-$(CONFIG_DRM_IMX8MP_HDMI_PAI) += imx8mp-hdmi-pai.o
> > obj-$(CONFIG_DRM_IMX8MP_HDMI_PVI) += imx8mp-hdmi-pvi.o
> > obj-$(CONFIG_DRM_IMX8QM_LDB) += imx8qm-ldb.o
> > obj-$(CONFIG_DRM_IMX8QXP_LDB) += imx8qxp-ldb.o
> > diff --git a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c
> > new file mode 100644
> > index 000000000000..9002974073ca
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c
> > @@ -0,0 +1,205 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2025 NXP
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/component.h>
> > +#include <linux/module.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <drm/bridge/dw_hdmi.h>
> > +#include <sound/asoundef.h>
> > +
> > +#define HTX_PAI_CTRL 0x00
> > +#define ENABLE BIT(0)
> > +
> > +#define HTX_PAI_CTRL_EXT 0x04
> > +#define WTMK_HIGH_MASK GENMASK(31, 24)
> > +#define WTMK_LOW_MASK GENMASK(23, 16)
> > +#define NUM_CH_MASK GENMASK(10, 8)
> > +#define WTMK_HIGH(n) FIELD_PREP(WTMK_HIGH_MASK, (n))
> > +#define WTMK_LOW(n) FIELD_PREP(WTMK_LOW_MASK, (n))
> > +
> > +#define HTX_PAI_FIELD_CTRL 0x08
> > +#define B_FILT BIT(31)
> > +#define PARITY_EN BIT(30)
> > +#define END_SEL BIT(29)
> > +#define PRE_SEL GENMASK(28, 24)
> > +#define D_SEL GENMASK(23, 20)
> > +#define V_SEL GENMASK(19, 15)
> > +#define U_SEL GENMASK(14, 10)
> > +#define C_SEL GENMASK(9, 5)
> > +#define P_SEL GENMASK(4, 0)
> > +
> > +#define HTX_PAI_STAT 0x0c
> > +#define HTX_PAI_IRQ_NOMASK 0x10
> > +#define HTX_PAI_IRQ_MASKED 0x14
> > +#define HTX_PAI_IRQ_MASK 0x18
> > +
> > +struct imx8mp_hdmi_pai {
> > + struct device *dev;
> > + struct regmap *regmap;
> > +};
> > +
> > +static void imx8mp_hdmi_pai_enable(struct dw_hdmi *dw_hdmi, int channel,
> > + int width, int rate, int non_pcm,
> > + int iec958)
> > +{
> > + const struct dw_hdmi_plat_data *pdata = dw_hdmi_to_plat_data(dw_hdmi);
> > + struct imx8mp_hdmi_pai *hdmi_pai = (struct imx8mp_hdmi_pai *)pdata->priv_audio;
> > + int val;
> > +
> > + /* PAI set control extended */
> > + val = WTMK_HIGH(3) | WTMK_LOW(3);
> > + val |= FIELD_PREP(NUM_CH_MASK, channel - 1);
> > + regmap_write(hdmi_pai->regmap, HTX_PAI_CTRL_EXT, val);
> > +
> > + /* IEC60958 format */
> > + if (iec958) {
> > + val = FIELD_PREP_CONST(P_SEL,
> > + __bf_shf(IEC958_SUBFRAME_PARITY));
> > + val |= FIELD_PREP_CONST(C_SEL,
> > + __bf_shf(IEC958_SUBFRAME_CHANNEL_STATUS));
> > + val |= FIELD_PREP_CONST(U_SEL,
> > + __bf_shf(IEC958_SUBFRAME_USER_DATA));
> > + val |= FIELD_PREP_CONST(V_SEL,
> > + __bf_shf(IEC958_SUBFRAME_VALIDITY));
> > + val |= FIELD_PREP_CONST(D_SEL,
> > + __bf_shf(IEC958_SUBFRAME_SAMPLE_24_MASK));
> > + val |= FIELD_PREP_CONST(PRE_SEL,
> > + __bf_shf(IEC958_SUBFRAME_PREAMBLE_MASK));
> > + } else {
> > + /* PCM choose 24bit*/
> > + val = FIELD_PREP(D_SEL, width - 24);
> > + }
> > +
> > + regmap_write(hdmi_pai->regmap, HTX_PAI_FIELD_CTRL, val);
> > +
> > + /* PAI start running */
> > + regmap_write(hdmi_pai->regmap, HTX_PAI_CTRL, ENABLE);
> > +}
> > +
> > +static void imx8mp_hdmi_pai_disable(struct dw_hdmi *dw_hdmi)
> > +{
> > + const struct dw_hdmi_plat_data *pdata = dw_hdmi_to_plat_data(dw_hdmi);
> > + struct imx8mp_hdmi_pai *hdmi_pai = (struct imx8mp_hdmi_pai *)pdata->priv_audio;
> > +
> > + /* Stop PAI */
> > + regmap_write(hdmi_pai->regmap, HTX_PAI_CTRL, 0);
> > +}
> > +
> > +static int imx8mp_hdmi_pai_bind(struct device *dev, struct device *master, void *data)
> > +{
> > + struct dw_hdmi_plat_data *plat_data = (struct dw_hdmi_plat_data *)data;
> > + struct imx8mp_hdmi_pai *hdmi_pai;
> > +
> > + hdmi_pai = dev_get_drvdata(dev);
> > +
> > + plat_data->enable_audio = imx8mp_hdmi_pai_enable;
> > + plat_data->disable_audio = imx8mp_hdmi_pai_disable;
> > + plat_data->priv_audio = hdmi_pai;
> > +
> > + return 0;
> > +}
> > +
> > +static void imx8mp_hdmi_pai_unbind(struct device *dev, struct device *master, void *data)
> > +{
> > + struct dw_hdmi_plat_data *plat_data = (struct dw_hdmi_plat_data *)data;
> > +
> > + plat_data->enable_audio = NULL;
> > + plat_data->disable_audio = NULL;
> > + plat_data->priv_audio = NULL;
> > +}
> > +
> > +static const struct component_ops imx8mp_hdmi_pai_ops = {
> > + .bind = imx8mp_hdmi_pai_bind,
> > + .unbind = imx8mp_hdmi_pai_unbind,
> > +};
> > +
> > +static bool imx8mp_hdmi_pai_volatile_reg(struct device *dev, unsigned int reg)
> > +{
> > + switch (reg) {
> > + case HTX_PAI_IRQ_NOMASK:
> > + case HTX_PAI_IRQ_MASKED:
> > + return true;
> > + default:
> > + return false;
> > + }
> > +}
> > +
> > +static bool imx8mp_hdmi_pai_writeable_reg(struct device *dev, unsigned int reg)
> > +{
> > + switch (reg) {
> > + case HTX_PAI_CTRL:
> > + case HTX_PAI_CTRL_EXT:
> > + case HTX_PAI_FIELD_CTRL:
> > + case HTX_PAI_IRQ_NOMASK:
> > + case HTX_PAI_IRQ_MASKED:
> > + case HTX_PAI_IRQ_MASK:
> > + return true;
> > + default:
> > + return false;
> > + }
> > +}
> > +
> > +static const struct regmap_config imx8mp_hdmi_pai_regmap_config = {
> > + .reg_bits = 32,
> > + .reg_stride = 4,
> > + .val_bits = 32,
> > + .max_register = HTX_PAI_IRQ_MASK,
> > + .volatile_reg = imx8mp_hdmi_pai_volatile_reg,
> > + .writeable_reg = imx8mp_hdmi_pai_writeable_reg,
> > +};
> > +
> > +static int imx8mp_hdmi_pai_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct imx8mp_hdmi_pai *hdmi_pai;
> > + struct resource *res;
> > + void __iomem *base;
> > +
> > + hdmi_pai = devm_kzalloc(dev, sizeof(*hdmi_pai), GFP_KERNEL);
> > + if (!hdmi_pai)
> > + return -ENOMEM;
> > +
> > + base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> > + if (IS_ERR(base))
> > + return PTR_ERR(base);
> > +
> > + hdmi_pai->dev = dev;
> > +
> > + hdmi_pai->regmap = devm_regmap_init_mmio(dev, base, &imx8mp_hdmi_pai_regmap_config);
> > + if (IS_ERR(hdmi_pai->regmap)) {
> > + dev_err(dev, "regmap init failed\n");
> > + return PTR_ERR(hdmi_pai->regmap);
> > + }
> > +
> > + dev_set_drvdata(dev, hdmi_pai);
> > +
> > + return component_add(dev, &imx8mp_hdmi_pai_ops);
> > +}
> > +
> > +static void imx8mp_hdmi_pai_remove(struct platform_device *pdev)
> > +{
> > + component_del(&pdev->dev, &imx8mp_hdmi_pai_ops);
> > +}
> > +
> > +static const struct of_device_id imx8mp_hdmi_pai_of_table[] = {
> > + { .compatible = "fsl,imx8mp-hdmi-pai" },
> > + { /* Sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, imx8mp_hdmi_pai_of_table);
> > +
> > +static struct platform_driver imx8mp_hdmi_pai_platform_driver = {
> > + .probe = imx8mp_hdmi_pai_probe,
> > + .remove = imx8mp_hdmi_pai_remove,
> > + .driver = {
> > + .name = "imx8mp-hdmi-pai",
> > + .of_match_table = imx8mp_hdmi_pai_of_table,
> > + },
> > +};
> > +module_platform_driver(imx8mp_hdmi_pai_platform_driver);
> > +
> > +MODULE_DESCRIPTION("i.MX8MP HDMI PAI driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> > index 1e7a789ec289..ee08084d2394 100644
> > --- a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> > +++ b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx.c
> > @@ -5,11 +5,13 @@
> > */
> >
> > #include <linux/clk.h>
> > +#include <linux/component.h>
> > #include <linux/mod_devicetable.h>
> > #include <linux/module.h>
> > #include <linux/platform_device.h>
> > #include <drm/bridge/dw_hdmi.h>
> > #include <drm/drm_modes.h>
> > +#include <drm/drm_of.h>
> >
> > struct imx8mp_hdmi {
> > struct dw_hdmi_plat_data plat_data;
> > @@ -79,11 +81,46 @@ static const struct dw_hdmi_phy_ops imx8mp_hdmi_phy_ops = {
> > .update_hpd = dw_hdmi_phy_update_hpd,
> > };
> >
> > +static int imx8mp_dw_hdmi_bind(struct device *dev)
> > +{
> > + struct dw_hdmi_plat_data *plat_data;
> > + struct imx8mp_hdmi *hdmi;
> > + int ret;
> > +
> > + hdmi = dev_get_drvdata(dev);
> > + plat_data = &hdmi->plat_data;
> > +
> > + ret = component_bind_all(dev, plat_data);
>
> Do you really need plat_data variable?

yes, it is used in imx8mp_hdmi_pai_bind()

>
> > + if (ret)
> > + return dev_err_probe(dev, ret, "component_bind_all failed!\n");
> > +
> > + return 0;
> > +}
> > +
> > +static void imx8mp_dw_hdmi_unbind(struct device *dev)
> > +{
> > + struct dw_hdmi_plat_data *plat_data;
> > + struct imx8mp_hdmi *hdmi;
> > +
> > + hdmi = dev_get_drvdata(dev);
> > + plat_data = &hdmi->plat_data;
> > +
> > + component_unbind_all(dev, plat_data);
>
> Do you really need plat_data variable?

yes, it is used by imx8mp_hdmi_pai_unbind()

>
> > +}
> > +
> > +static const struct component_master_ops imx8mp_dw_hdmi_ops = {
> > + .bind = imx8mp_dw_hdmi_bind,
> > + .unbind = imx8mp_dw_hdmi_unbind,
> > +};
> > +
> > static int imx8mp_dw_hdmi_probe(struct platform_device *pdev)
> > {
> > struct device *dev = &pdev->dev;
> > struct dw_hdmi_plat_data *plat_data;
> > + struct component_match *match;
>
> Set match = NULL for drm_of_component_match_add (and subcalls) to allocate memory.

Ok.

best regards
Shengjiu wang.
>
> Best regards
> Alexander
>
> > + struct device_node *remote;
> > struct imx8mp_hdmi *hdmi;
> > + int ret;
> >
> > hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
> > if (!hdmi)
> > @@ -108,6 +145,22 @@ static int imx8mp_dw_hdmi_probe(struct platform_device *pdev)
> >
> > platform_set_drvdata(pdev, hdmi);
> >
> > + /* port@2 is for hdmi_pai device */
> > + remote = of_graph_get_remote_node(pdev->dev.of_node, 2, 0);
> > + if (remote && of_device_is_available(remote)) {
> > + drm_of_component_match_add(dev, &match, component_compare_of, remote);
> > +
> > + of_node_put(remote);
> > +
> > + ret = component_master_add_with_match(dev, &imx8mp_dw_hdmi_ops, match);
> > + if (ret)
> > + dev_warn(dev, "Unable to register aggregate driver\n");
> > + /*
> > + * This audio function is optional for avoid blocking display.
> > + * So just print warning message and no error is returned.
> > + */
> > + }
> > +
> > return 0;
> > }
> >
> > @@ -115,6 +168,8 @@ static void imx8mp_dw_hdmi_remove(struct platform_device *pdev)
> > {
> > struct imx8mp_hdmi *hdmi = platform_get_drvdata(pdev);
> >
> > + component_master_del(&pdev->dev, &imx8mp_dw_hdmi_ops);
> > +
> > dw_hdmi_remove(hdmi->dw_hdmi);
> > }
> >
> > diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
> > index 095cdd9b7424..336f062e1f9d 100644
> > --- a/include/drm/bridge/dw_hdmi.h
> > +++ b/include/drm/bridge/dw_hdmi.h
> > @@ -143,6 +143,12 @@ struct dw_hdmi_plat_data {
> > const struct drm_display_info *info,
> > const struct drm_display_mode *mode);
> >
> > + /*
> > + * priv_audio is specially used for additional audio device to get
> > + * driver data through this dw_hdmi_plat_data.
> > + */
> > + void *priv_audio;
> > +
> > /* Platform-specific audio enable/disable (optional) */
> > void (*enable_audio)(struct dw_hdmi *hdmi, int channel,
> > int width, int rate, int non_pcm, int iec958);
> >
>
>
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