drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pai.c

// 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 <linux/pm_runtime.h>
#include <linux/regmap.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   NUM_CH(n)			FIELD_PREP(NUM_CH_MASK, (n) - 1)

#define HTX_PAI_FIELD_CTRL		0x08
#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)

struct imx8mp_hdmi_pai {
	struct regmap	*regmap;
	struct device	*dev;
};

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 = pdata->priv_audio;
	int val;

	if (pm_runtime_resume_and_get(hdmi_pai->dev) < 0)
		return;

	/* PAI set control extended */
	val =  WTMK_HIGH(3) | WTMK_LOW(3);
	val |= NUM_CH(channel);
	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 {
		/*
		 * The allowed PCM widths are 24bit and 32bit, as they are supported
		 * by aud2htx module.
		 * for 24bit, D_SEL = 0, select all the bits.
		 * for 32bit, D_SEL = 8, select 24bit in MSB.
		 */
		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 = pdata->priv_audio;

	/* Stop PAI */
	regmap_write(hdmi_pai->regmap, HTX_PAI_CTRL, 0);

	pm_runtime_put_sync(hdmi_pai->dev);
}

static const struct regmap_config imx8mp_hdmi_pai_regmap_config = {
	.reg_bits = 32,
	.reg_stride = 4,
	.val_bits = 32,
	.max_register = HTX_PAI_FIELD_CTRL,
};

static int imx8mp_hdmi_pai_bind(struct device *dev, struct device *master, void *data)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct dw_hdmi_plat_data *plat_data = data;
	struct imx8mp_hdmi_pai *hdmi_pai;
	struct resource *res;
	void __iomem *base;
	int ret;

	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->regmap = devm_regmap_init_mmio_clk(dev, "apb", 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);
	}

	plat_data->enable_audio = imx8mp_hdmi_pai_enable;
	plat_data->disable_audio = imx8mp_hdmi_pai_disable;
	plat_data->priv_audio = hdmi_pai;

	hdmi_pai->dev = dev;
	ret = devm_pm_runtime_enable(dev);
	if (ret < 0) {
		dev_err(dev, "failed to enable PM runtime: %d\n", ret);
		return ret;
	}

	return 0;
}

static const struct component_ops imx8mp_hdmi_pai_ops = {
	.bind   = imx8mp_hdmi_pai_bind,
};

static int imx8mp_hdmi_pai_probe(struct platform_device *pdev)
{
	return component_add(&pdev->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");