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

[Alexander Stein <alexander.stein@ew.tq-group.com>]

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?

> +	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?

> +}
> +
> +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.

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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