drm: bridge: dw_hdmi: Audio: Add General Parallel Audio (GPA) driver

General Parallel Audio (GPA) interface is one of the supported
audio interface for synopsys HDMI module, which has verified for
i.MX8MPlus platform.
This is initial version for GPA.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/f21ba3e8c4d9d028ac74c6f3c588ddbffe739399.1649989179.git.Sandor.yu@nxp.com

drivers/gpu/drm/bridge/synopsys/Kconfig

@@ -25,6 +25,16 @@ config DRM_DW_HDMI_I2S_AUDIO
 	  Support the I2S Audio interface which is part of the Synopsys
 	  Designware HDMI block.
 
+config DRM_DW_HDMI_GP_AUDIO
+	tristate "Synopsys Designware GP Audio interface"
+	depends on DRM_DW_HDMI && SND
+	select SND_PCM
+	select SND_PCM_ELD
+	select SND_PCM_IEC958
+	help
+	  Support the GP Audio interface which is part of the Synopsys
+	  Designware HDMI block.
+
 config DRM_DW_HDMI_CEC
 	tristate "Synopsis Designware CEC interface"
 	depends on DRM_DW_HDMI

drivers/gpu/drm/bridge/synopsys/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
 obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
+obj-$(CONFIG_DRM_DW_HDMI_GP_AUDIO) += dw-hdmi-gp-audio.o
 obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
 obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
 

drivers/gpu/drm/bridge/synopsys/dw-hdmi-gp-audio.c

@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * dw-hdmi-gp-audio.c
+ *
+ * Copyright 2020-2022 NXP
+ */
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <drm/bridge/dw_hdmi.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_connector.h>
+
+#include <sound/hdmi-codec.h>
+#include <sound/asoundef.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_drm_eld.h>
+#include <sound/pcm_iec958.h>
+#include <sound/dmaengine_pcm.h>
+
+#include "dw-hdmi-audio.h"
+
+#define DRIVER_NAME "dw-hdmi-gp-audio"
+#define DRV_NAME    "hdmi-gp-audio"
+
+struct snd_dw_hdmi {
+	struct dw_hdmi_audio_data data;
+	struct platform_device  *audio_pdev;
+	unsigned int pos;
+};
+
+struct dw_hdmi_channel_conf {
+	u8 conf1;
+	u8 ca;
+};
+
+/*
+ * The default mapping of ALSA channels to HDMI channels and speaker
+ * allocation bits.  Note that we can't do channel remapping here -
+ * channels must be in the same order.
+ *
+ * Mappings for alsa-lib pcm/surround*.conf files:
+ *
+ *		Front	Sur4.0	Sur4.1	Sur5.0	Sur5.1	Sur7.1
+ * Channels	2	4	6	6	6	8
+ *
+ * Our mapping from ALSA channel to CEA686D speaker name and HDMI channel:
+ *
+ *				Number of ALSA channels
+ * ALSA Channel	2	3	4	5	6	7	8
+ * 0		FL:0	=	=	=	=	=	=
+ * 1		FR:1	=	=	=	=	=	=
+ * 2			FC:3	RL:4	LFE:2	=	=	=
+ * 3				RR:5	RL:4	FC:3	=	=
+ * 4					RR:5	RL:4	=	=
+ * 5						RR:5	=	=
+ * 6							RC:6	=
+ * 7							RLC/FRC	RLC/FRC
+ */
+static struct dw_hdmi_channel_conf default_hdmi_channel_config[7] = {
+	{ 0x03, 0x00 },	/* FL,FR */
+	{ 0x0b, 0x02 },	/* FL,FR,FC */
+	{ 0x33, 0x08 },	/* FL,FR,RL,RR */
+	{ 0x37, 0x09 },	/* FL,FR,LFE,RL,RR */
+	{ 0x3f, 0x0b },	/* FL,FR,LFE,FC,RL,RR */
+	{ 0x7f, 0x0f },	/* FL,FR,LFE,FC,RL,RR,RC */
+	{ 0xff, 0x13 },	/* FL,FR,LFE,FC,RL,RR,[FR]RC,[FR]LC */
+};
+
+static int audio_hw_params(struct device *dev,  void *data,
+			   struct hdmi_codec_daifmt *daifmt,
+			   struct hdmi_codec_params *params)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+	int ret = 0;
+	u8 ca;
+
+	dw_hdmi_set_sample_rate(dw->data.hdmi, params->sample_rate);
+
+	ca = default_hdmi_channel_config[params->channels - 2].ca;
+
+	dw_hdmi_set_channel_count(dw->data.hdmi, params->channels);
+	dw_hdmi_set_channel_allocation(dw->data.hdmi, ca);
+
+	dw_hdmi_set_sample_non_pcm(dw->data.hdmi,
+				   params->iec.status[0] & IEC958_AES0_NONAUDIO);
+	dw_hdmi_set_sample_width(dw->data.hdmi, params->sample_width);
+
+	return ret;
+}
+
+static void audio_shutdown(struct device *dev, void *data)
+{
+}
+
+static int audio_mute_stream(struct device *dev, void *data,
+			     bool enable, int direction)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (!enable)
+		dw_hdmi_audio_enable(dw->data.hdmi);
+	else
+		dw_hdmi_audio_disable(dw->data.hdmi);
+
+	return ret;
+}
+
+static int audio_get_eld(struct device *dev, void *data,
+			 u8 *buf, size_t len)
+{
+	struct dw_hdmi_audio_data *audio = data;
+	u8 *eld;
+
+	eld = audio->get_eld(audio->hdmi);
+	if (eld)
+		memcpy(buf, eld, min_t(size_t, MAX_ELD_BYTES, len));
+	else
+		/* Pass en empty ELD if connector not available */
+		memset(buf, 0, len);
+
+	return 0;
+}
+
+static int audio_hook_plugged_cb(struct device *dev, void *data,
+				 hdmi_codec_plugged_cb fn,
+				 struct device *codec_dev)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+
+	return dw_hdmi_set_plugged_cb(dw->data.hdmi, fn, codec_dev);
+}
+
+static const struct hdmi_codec_ops audio_codec_ops = {
+	.hw_params = audio_hw_params,
+	.audio_shutdown = audio_shutdown,
+	.mute_stream = audio_mute_stream,
+	.get_eld = audio_get_eld,
+	.hook_plugged_cb = audio_hook_plugged_cb,
+};
+
+static int snd_dw_hdmi_probe(struct platform_device *pdev)
+{
+	struct dw_hdmi_audio_data *data = pdev->dev.platform_data;
+	struct snd_dw_hdmi *dw;
+
+	const struct hdmi_codec_pdata codec_data = {
+		.i2s = 1,
+		.spdif = 0,
+		.ops = &audio_codec_ops,
+		.max_i2s_channels = 8,
+		.data = data,
+	};
+
+	dw = devm_kzalloc(&pdev->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	dw->data = *data;
+
+	platform_set_drvdata(pdev, dw);
+
+	dw->audio_pdev = platform_device_register_data(&pdev->dev,
+						       HDMI_CODEC_DRV_NAME, 1,
+						       &codec_data,
+						       sizeof(codec_data));
+
+	return PTR_ERR_OR_ZERO(dw->audio_pdev);
+}
+
+static int snd_dw_hdmi_remove(struct platform_device *pdev)
+{
+	struct snd_dw_hdmi *dw = platform_get_drvdata(pdev);
+
+	platform_device_unregister(dw->audio_pdev);
+
+	return 0;
+}
+
+static struct platform_driver snd_dw_hdmi_driver = {
+	.probe	= snd_dw_hdmi_probe,
+	.remove	= snd_dw_hdmi_remove,
+	.driver	= {
+		.name = DRIVER_NAME,
+	},
+};
+
+module_platform_driver(snd_dw_hdmi_driver);
+
+MODULE_AUTHOR("Shengjiu Wang <shengjiu.wang@nxp.com>");
+MODULE_DESCRIPTION("Synopsys Designware HDMI GPA ALSA interface");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);