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

Alexander Stein
2025-08-05T07:09:39Z

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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