[PATCH v3 0/1] Add support for sun4i HDMI audio

[PATCH v3 0/1] Add support for sun4i HDMI audio

[Stefan Mavrodiev]

This patch series add support for HDMI audio for sun4i HDMI encored.
The code uses some parts from the Allwinners's BSP kernel.

In the previous patch series there was additional patch enabling the
cyclic DMA transfers. It was accepted, so it's omitted here.

The patch is tested on A20 chip. For the other chips, only the addresses
of the registers are checked.

Changes for v3:
 - Dropped the patch which enable the cyclic DMA transfers
 - In v2, a separate platform_driver was created. However this is not
   practical and the idea is dropped.
 - Since this module depends on SND_SOC, a new Kconfig entry is added. When
   SND_SOC is not enabled, the audio part is not initialized.
 - The "big" issue with v1 was that snd_soc_register_card() overwrites
   the driver_data pointer. To resolve this issue, the original pointer is
   stored as drvdata of the card. Then before card unregistering, the
   pointer is restored. This is done by calling additional destroy function.

Changes for v2:
 - Create a new platform driver instead of using the HDMI encoder
 - Expose a new kcontrol to the userspace holding the ELD data
 - Wrap all macro arguments in parentheses

Stefan Mavrodiev (1):
  drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

 drivers/gpu/drm/sun4i/Kconfig            |  11 +
 drivers/gpu/drm/sun4i/Makefile           |   3 +
 drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
 drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
 5 files changed, 515 insertions(+)
 create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c

-- 
2.17.1

[PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Stefan Mavrodiev]

Add HDMI audio support for the sun4i-hdmi encoder, used on
the older Allwinner chips - A10, A20, A31.

Most of the code is based on the BSP implementation. In it
dditional formats are supported (S20_3LE and S24_LE), however
there where some problems with them and only S16_LE is left.

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
---
Changes for v3:
 - Instead of platfrom_driver dynammicly register/unregister card
 - Add Kconfig dependencies
 - Restrore drvdata after card unregistering

Changes for v2:
 - Create a new platform driver instead of using the HDMI encoder
 - Expose a new kcontrol to the userspace holding the ELD data
 - Wrap all macro arguments in parentheses

 drivers/gpu/drm/sun4i/Kconfig            |  11 +
 drivers/gpu/drm/sun4i/Makefile           |   3 +
 drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
 drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
 5 files changed, 515 insertions(+)
 create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c

diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
index 37e90e42943f..ca2ab5d53dd4 100644
--- a/drivers/gpu/drm/sun4i/Kconfig
+++ b/drivers/gpu/drm/sun4i/Kconfig
@@ -23,6 +23,17 @@ config DRM_SUN4I_HDMI
 	  Choose this option if you have an Allwinner SoC with an HDMI
 	  controller.
 
+config DRM_SUN4I_HDMI_AUDIO
+	bool "Allwinner A10 HDMI Audio Support"
+	default y
+	depends on DRM_SUN4I_HDMI
+	depends on SND_SOC=y || SND_SOC=DRM_SUN4I_HDMI
+	select SND_PCM_ELD
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	help
+	  Choose this option if you have an Allwinner SoC with an HDMI
+	  controller and want to use audio.
+
 config DRM_SUN4I_HDMI_CEC
        bool "Allwinner A10 HDMI CEC Support"
        depends on DRM_SUN4I_HDMI
diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
index 0d04f2447b01..492bfd28ad2e 100644
--- a/drivers/gpu/drm/sun4i/Makefile
+++ b/drivers/gpu/drm/sun4i/Makefile
@@ -5,6 +5,9 @@ sun4i-frontend-y		+= sun4i_frontend.o
 sun4i-drm-y			+= sun4i_drv.o
 sun4i-drm-y			+= sun4i_framebuffer.o
 
+ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
+sun4i-drm-hdmi-y		+= sun4i_hdmi_audio.o
+endif
 sun4i-drm-hdmi-y		+= sun4i_hdmi_ddc_clk.o
 sun4i-drm-hdmi-y		+= sun4i_hdmi_enc.o
 sun4i-drm-hdmi-y		+= sun4i_hdmi_i2c.o
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
index 7ad3f06c127e..28621d289655 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
@@ -42,7 +42,32 @@
 #define SUN4I_HDMI_VID_TIMING_POL_VSYNC		BIT(1)
 #define SUN4I_HDMI_VID_TIMING_POL_HSYNC		BIT(0)
 
+#define SUN4I_HDMI_AUDIO_CTRL_REG	0x040
+#define SUN4I_HDMI_AUDIO_CTRL_ENABLE		BIT(31)
+#define SUN4I_HDMI_AUDIO_CTRL_RESET		BIT(30)
+
+#define SUN4I_HDMI_AUDIO_FMT_REG	0x048
+#define SUN4I_HDMI_AUDIO_FMT_SRC		BIT(31)
+#define SUN4I_HDMI_AUDIO_FMT_LAYOUT		BIT(3)
+#define SUN4I_HDMI_AUDIO_FMT_CH_CFG(n)		((n) - 1)
+#define SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK	GENMASK(2, 0)
+
+#define SUN4I_HDMI_AUDIO_PCM_REG	0x4c
+#define SUN4I_HDMI_AUDIO_PCM_CH_MAP(n, m)	(((m) - 1) << ((n) * 4))
+#define SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(n)	(GENMASK(2, 0) << ((n) * 4))
+
+#define SUN4I_HDMI_AUDIO_CTS_REG	0x050
+#define SUN4I_HDMI_AUDIO_CTS(n)			((n) & GENMASK(19, 0))
+
+#define SUN4I_HDMI_AUDIO_N_REG		0x054
+#define SUN4I_HDMI_AUDIO_N(n)			((n) & GENMASK(19, 0))
+
+#define SUN4I_HDMI_AUDIO_STAT0_REG	0x58
+#define SUN4I_HDMI_AUDIO_STAT0_FREQ(n)		((n) << 24)
+#define SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK	GENMASK(27, 24)
+
 #define SUN4I_HDMI_AVI_INFOFRAME_REG(n)	(0x080 + (n))
+#define SUN4I_HDMI_AUDIO_INFOFRAME_REG(n)	(0x0a0 + (n))
 
 #define SUN4I_HDMI_PAD_CTRL0_REG	0x200
 #define SUN4I_HDMI_PAD_CTRL0_BIASEN		BIT(31)
@@ -242,6 +267,11 @@ struct sun4i_hdmi_variant {
 	bool			ddc_fifo_has_dir;
 };
 
+struct sun4i_hdmi_audio {
+	struct snd_soc_card		*card;
+	u8				channels;
+};
+
 struct sun4i_hdmi {
 	struct drm_connector	connector;
 	struct drm_encoder	encoder;
@@ -283,9 +313,14 @@ struct sun4i_hdmi {
 	struct regmap_field	*field_ddc_sda_en;
 	struct regmap_field	*field_ddc_sck_en;
 
+
 	struct sun4i_drv	*drv;
 
 	bool			hdmi_monitor;
+	bool			hdmi_audio;
+
+	struct sun4i_hdmi_audio audio;
+
 	struct cec_adapter	*cec_adap;
 
 	const struct sun4i_hdmi_variant	*variant;
@@ -294,5 +329,7 @@ struct sun4i_hdmi {
 int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
 int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
 int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
+int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi);
+void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi);
 
 #endif /* _SUN4I_HDMI_H_ */
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
new file mode 100644
index 000000000000..f42f2cea4e9e
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 Olimex Ltd.
+ *   Author: Stefan Mavrodiev <stefan@olimex.com>
+ */
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_print.h>
+
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm_drm_eld.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#include "sun4i_hdmi.h"
+
+static int sun4i_hdmi_audio_ctl_eld_info(struct snd_kcontrol *kcontrol,
+					 struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
+	uinfo->count = MAX_ELD_BYTES;
+	return 0;
+}
+
+static int sun4i_hdmi_audio_ctl_eld_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_card *card = snd_soc_component_get_drvdata(component);
+	struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
+
+	memcpy(ucontrol->value.bytes.data,
+	       hdmi->connector.eld,
+	       MAX_ELD_BYTES);
+
+	return 0;
+}
+
+static const struct snd_kcontrol_new sun4i_hdmi_audio_controls[] = {
+	{
+		.access = SNDRV_CTL_ELEM_ACCESS_READ |
+			  SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+		.name = "ELD",
+		.info = sun4i_hdmi_audio_ctl_eld_info,
+		.get = sun4i_hdmi_audio_ctl_eld_get,
+	},
+};
+
+static const struct snd_soc_dapm_widget sun4i_hdmi_audio_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("TX"),
+};
+
+static const struct snd_soc_dapm_route sun4i_hdmi_audio_routes[] = {
+	{ "TX", NULL, "Playback" },
+};
+
+static const struct snd_soc_component_driver sun4i_hdmi_audio_component = {
+	.controls               = sun4i_hdmi_audio_controls,
+	.num_controls           = ARRAY_SIZE(sun4i_hdmi_audio_controls),
+	.dapm_widgets		= sun4i_hdmi_audio_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(sun4i_hdmi_audio_widgets),
+	.dapm_routes		= sun4i_hdmi_audio_routes,
+	.num_dapm_routes	= ARRAY_SIZE(sun4i_hdmi_audio_routes),
+};
+
+static int sun4i_hdmi_audio_startup(struct snd_pcm_substream *substream,
+				    struct snd_soc_dai *dai)
+{
+	struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
+	struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
+	u32 reg;
+	int ret;
+
+	regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
+	regmap_write(hdmi->regmap,
+		     SUN4I_HDMI_AUDIO_CTRL_REG,
+		     SUN4I_HDMI_AUDIO_CTRL_RESET);
+	ret = regmap_read_poll_timeout(hdmi->regmap,
+				       SUN4I_HDMI_AUDIO_CTRL_REG,
+				       reg, !reg, 100, 50000);
+	if (ret < 0) {
+		DRM_ERROR("Failed to reset HDMI Audio\n");
+		return ret;
+	}
+
+	regmap_write(hdmi->regmap,
+		     SUN4I_HDMI_AUDIO_CTRL_REG,
+		     SUN4I_HDMI_AUDIO_CTRL_ENABLE);
+
+	return snd_pcm_hw_constraint_eld(substream->runtime,
+					hdmi->connector.eld);
+}
+
+static void sun4i_hdmi_audio_shutdown(struct snd_pcm_substream *substream,
+				      struct snd_soc_dai *dai)
+{
+	struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
+	struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
+
+	regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
+}
+
+static int sun4i_hdmi_setup_audio_infoframes(struct sun4i_hdmi *hdmi)
+{
+	union hdmi_infoframe frame;
+	u8 buffer[14];
+	int i, ret;
+
+	ret = hdmi_audio_infoframe_init(&frame.audio);
+	if (ret < 0) {
+		DRM_ERROR("Failed to init HDMI audio infoframe\n");
+		return ret;
+	}
+
+	frame.audio.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
+	frame.audio.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
+	frame.audio.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
+	frame.audio.channels = hdmi->audio.channels;
+
+	ret = hdmi_infoframe_pack(&frame, buffer, sizeof(buffer));
+	if (ret < 0) {
+		DRM_ERROR("Failed to pack HDMI audio infoframe\n");
+		return ret;
+	}
+
+	for (i = 0; i < sizeof(buffer); i++)
+		writeb(buffer[i],
+		       hdmi->base + SUN4I_HDMI_AUDIO_INFOFRAME_REG(i));
+
+	return 0;
+}
+
+static void sun4i_hdmi_audio_set_cts_n(struct sun4i_hdmi *hdmi,
+				       struct snd_pcm_hw_params *params)
+{
+	struct drm_encoder *encoder = &hdmi->encoder;
+	struct drm_crtc *crtc = encoder->crtc;
+	const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
+	u32 rate = params_rate(params);
+	u32 n, cts;
+	u64 tmp;
+
+	/**
+	 * Calculate Cycle Time Stamp (CTS) and Numerator (N):
+	 *
+	 * N = 128 * Samplerate / 1000
+	 * CTS = (Ftdms * N) / (128 * Samplerate)
+	 */
+
+	n = 128 * rate / 1000;
+	tmp = (u64)(mode->clock * 1000) * n;
+	do_div(tmp, 128 * rate);
+	cts = tmp;
+
+	regmap_write(hdmi->regmap,
+		     SUN4I_HDMI_AUDIO_CTS_REG,
+		     SUN4I_HDMI_AUDIO_CTS(cts));
+
+	regmap_write(hdmi->regmap,
+		     SUN4I_HDMI_AUDIO_N_REG,
+		     SUN4I_HDMI_AUDIO_N(n));
+}
+
+static int sun4i_hdmi_audio_set_hw_rate(struct sun4i_hdmi *hdmi,
+					struct snd_pcm_hw_params *params)
+{
+	u32 rate = params_rate(params);
+	u32 val;
+
+	switch (rate) {
+	case 44100:
+		val = 0x0;
+		break;
+	case 48000:
+		val = 0x2;
+		break;
+	case 32000:
+		val = 0x3;
+		break;
+	case 88200:
+		val = 0x8;
+		break;
+	case 96000:
+		val = 0x9;
+		break;
+	case 176400:
+		val = 0xc;
+		break;
+	case 192000:
+		val = 0xe;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	regmap_update_bits(hdmi->regmap,
+			   SUN4I_HDMI_AUDIO_STAT0_REG,
+			   SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK,
+			   SUN4I_HDMI_AUDIO_STAT0_FREQ(val));
+
+	return 0;
+}
+
+static int sun4i_hdmi_audio_set_hw_channels(struct sun4i_hdmi *hdmi,
+					    struct snd_pcm_hw_params *params)
+{
+	u32 channels = params_channels(params);
+
+	if (channels > 8)
+		return -EINVAL;
+
+	hdmi->audio.channels = channels;
+
+	regmap_update_bits(hdmi->regmap,
+			   SUN4I_HDMI_AUDIO_FMT_REG,
+			   SUN4I_HDMI_AUDIO_FMT_LAYOUT,
+			   (channels > 2) ? SUN4I_HDMI_AUDIO_FMT_LAYOUT : 0);
+
+	regmap_update_bits(hdmi->regmap,
+			   SUN4I_HDMI_AUDIO_FMT_REG,
+			   SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK,
+			   SUN4I_HDMI_AUDIO_FMT_CH_CFG(channels));
+
+	regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_PCM_REG, 0x76543210);
+
+	/**
+	 * If only one channel is required, send the same sample
+	 * to the sink device as a left and right channel.
+	 */
+	if (channels == 1)
+		regmap_update_bits(hdmi->regmap,
+				   SUN4I_HDMI_AUDIO_PCM_REG,
+				   SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(1),
+				   SUN4I_HDMI_AUDIO_PCM_CH_MAP(1, 1));
+
+	return 0;
+}
+
+static int sun4i_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
+				      struct snd_pcm_hw_params *params,
+				      struct snd_soc_dai *dai)
+{
+	struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
+	struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
+	int ret;
+
+	ret = sun4i_hdmi_audio_set_hw_rate(hdmi, params);
+	if (ret < 0)
+		return ret;
+
+	ret = sun4i_hdmi_audio_set_hw_channels(hdmi, params);
+	if (ret < 0)
+		return ret;
+
+	sun4i_hdmi_audio_set_cts_n(hdmi, params);
+
+	return 0;
+}
+
+static int sun4i_hdmi_audio_trigger(struct snd_pcm_substream *substream,
+				    int cmd,
+				    struct snd_soc_dai *dai)
+{
+	struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
+	struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
+	int ret = 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		ret = sun4i_hdmi_setup_audio_infoframes(hdmi);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static const struct snd_soc_dai_ops sun4i_hdmi_audio_dai_ops = {
+	.startup = sun4i_hdmi_audio_startup,
+	.shutdown = sun4i_hdmi_audio_shutdown,
+	.hw_params = sun4i_hdmi_audio_hw_params,
+	.trigger = sun4i_hdmi_audio_trigger,
+};
+
+static int sun4i_hdmi_audio_dai_probe(struct snd_soc_dai *dai)
+{
+	struct snd_dmaengine_dai_dma_data *dma_data;
+
+	dma_data = devm_kzalloc(dai->dev, sizeof(*dma_data), GFP_KERNEL);
+	if (!dma_data)
+		return -ENOMEM;
+
+	dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dma_data->maxburst = 8;
+
+	snd_soc_dai_init_dma_data(dai, dma_data, NULL);
+
+	return 0;
+}
+
+static struct snd_soc_dai_driver sun4i_hdmi_audio_dai = {
+	.name = "HDMI",
+	.ops = &sun4i_hdmi_audio_dai_ops,
+	.probe = sun4i_hdmi_audio_dai_probe,
+	.playback = {
+		.stream_name	= "Playback",
+		.channels_min	= 1,
+		.channels_max	= 8,
+		.formats	= SNDRV_PCM_FMTBIT_S16_LE,
+		.rates		= SNDRV_PCM_RATE_8000_192000,
+	},
+};
+
+static const struct snd_pcm_hardware sun4i_hdmi_audio_pcm_hardware = {
+	.info			= SNDRV_PCM_INFO_INTERLEAVED |
+				  SNDRV_PCM_INFO_BLOCK_TRANSFER |
+				  SNDRV_PCM_INFO_MMAP |
+				  SNDRV_PCM_INFO_MMAP_VALID |
+				  SNDRV_PCM_INFO_PAUSE |
+				  SNDRV_PCM_INFO_RESUME,
+	.formats		= SNDRV_PCM_FMTBIT_S16_LE,
+	.rates                  = SNDRV_PCM_RATE_8000_192000,
+	.rate_min               = 8000,
+	.rate_max               = 192000,
+	.channels_min           = 1,
+	.channels_max           = 8,
+	.buffer_bytes_max	= 128 * 1024,
+	.period_bytes_min	= 4 * 1024,
+	.period_bytes_max	= 32 * 1024,
+	.periods_min		= 2,
+	.periods_max		= 8,
+	.fifo_size		= 128,
+};
+
+static const struct snd_dmaengine_pcm_config sun4i_hdmi_audio_pcm_config = {
+	.chan_names[SNDRV_PCM_STREAM_PLAYBACK] = "audio-tx",
+	.pcm_hardware = &sun4i_hdmi_audio_pcm_hardware,
+	.prealloc_buffer_size = 128 * 1024,
+	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
+};
+
+struct snd_soc_card sun4i_hdmi_audio_card = {
+	.name = "sun4i-hdmi",
+};
+
+int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi)
+{
+	struct snd_soc_card *card = &sun4i_hdmi_audio_card;
+	struct snd_soc_dai_link_component *comp;
+	struct snd_soc_dai_link *link;
+	int ret;
+
+	ret = snd_dmaengine_pcm_register(hdmi->dev,
+					 &sun4i_hdmi_audio_pcm_config, 0);
+	if (ret < 0) {
+		DRM_ERROR("Could not register PCM\n");
+		return ret;
+	}
+
+	ret = snd_soc_register_component(hdmi->dev,
+					 &sun4i_hdmi_audio_component,
+					 &sun4i_hdmi_audio_dai, 1);
+	if (ret < 0) {
+		DRM_ERROR("Could not register DAI\n");
+		goto unregister_pcm;
+	}
+
+	link = devm_kzalloc(hdmi->dev, sizeof(*link), GFP_KERNEL);
+	if (!link) {
+		ret = -ENOMEM;
+		goto unregister_component;
+	}
+
+	comp = devm_kzalloc(hdmi->dev, sizeof(*comp) * 3, GFP_KERNEL);
+	if (!comp) {
+		ret = -ENOMEM;
+		goto unregister_component;
+	}
+
+	link->cpus = &comp[0];
+	link->codecs = &comp[1];
+	link->platforms = &comp[2];
+
+	link->num_cpus = 1;
+	link->num_codecs = 1;
+	link->num_platforms = 1;
+
+	link->playback_only = 1;
+
+	link->name = "SUN4I-HDMI";
+	link->stream_name = "SUN4I-HDMI PCM";
+
+	link->codecs->name = dev_name(hdmi->dev);
+	link->codecs->dai_name	= sun4i_hdmi_audio_dai.name;
+
+	link->cpus->dai_name = dev_name(hdmi->dev);
+
+	link->platforms->name = dev_name(hdmi->dev);
+
+	link->dai_fmt = SND_SOC_DAIFMT_I2S;
+
+	card->dai_link = link;
+	card->num_links = 1;
+	card->dev = hdmi->dev;
+
+	hdmi->audio.card = card;
+
+	/**
+	 * snd_soc_register_card() will overwrite the driver_data pointer.
+	 * So before registering the card, store the original pointer in
+	 * card->drvdata.
+	 */
+	snd_soc_card_set_drvdata(card, hdmi);
+	ret = snd_soc_register_card(card);
+	if (ret)
+		goto unregister_component;
+
+	return 0;
+
+unregister_component:
+	snd_soc_unregister_component(hdmi->dev);
+unregister_pcm:
+	snd_dmaengine_pcm_unregister(hdmi->dev);
+	return ret;
+}
+
+void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi)
+{
+	struct snd_soc_card *card = hdmi->audio.card;
+	void *data;
+
+	/**
+	 * Before removing the card, restore the previously stored driver_data.
+	 * This will ensure proper removal of the sun4i-hdmi module, since it
+	 * uses dev_get_drvdata() in the unbind function.
+	 */
+	data = snd_soc_card_get_drvdata(card);
+
+	snd_soc_unregister_card(card);
+	snd_soc_unregister_component(hdmi->dev);
+	snd_dmaengine_pcm_unregister(hdmi->dev);
+
+	dev_set_drvdata(hdmi->dev, data);
+}
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
index 68d4644ac2dc..4cd35c97c503 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
@@ -23,6 +23,8 @@
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 
+#include <sound/soc.h>
+
 #include "sun4i_backend.h"
 #include "sun4i_crtc.h"
 #include "sun4i_drv.h"
@@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
 
 	DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
 
+#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
+	sun4i_hdmi_audio_destroy(hdmi);
+#endif
+
 	val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
 	val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
 	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
@@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
 		val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
 
 	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
+
+#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
+	if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
+		DRM_ERROR("Couldn't create the HDMI audio adapter\n");
+#endif
 }
 
 static void sun4i_hdmi_mode_set(struct drm_encoder *encoder,
@@ -218,6 +229,9 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
 	if (!edid)
 		return 0;
 
+#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
+	hdmi->hdmi_audio = drm_detect_monitor_audio(edid);
+#endif
 	hdmi->hdmi_monitor = drm_detect_hdmi_monitor(edid);
 	DRM_DEBUG_DRIVER("Monitor is %s monitor\n",
 			 hdmi->hdmi_monitor ? "an HDMI" : "a DVI");
-- 
2.17.1

Re: [linux-sunxi] [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Chen-Yu Tsai]

On Tue, Jan 28, 2020 at 10:07 PM Stefan Mavrodiev <stefan@olimex.com> wrote:
>
> Add HDMI audio support for the sun4i-hdmi encoder, used on
> the older Allwinner chips - A10, A20, A31.
>
> Most of the code is based on the BSP implementation. In it
> dditional formats are supported (S20_3LE and S24_LE), however
> there where some problems with them and only S16_LE is left.
>
> Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
> ---
> Changes for v3:
>  - Instead of platfrom_driver dynammicly register/unregister card
>  - Add Kconfig dependencies
>  - Restrore drvdata after card unregistering
>
> Changes for v2:
>  - Create a new platform driver instead of using the HDMI encoder
>  - Expose a new kcontrol to the userspace holding the ELD data
>  - Wrap all macro arguments in parentheses
>
>  drivers/gpu/drm/sun4i/Kconfig            |  11 +
>  drivers/gpu/drm/sun4i/Makefile           |   3 +
>  drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
>  drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
>  drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
>  5 files changed, 515 insertions(+)
>  create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c

Since this is actually an audio driver, please include all the ALSA / ASoC
maintainers and mailing lists (CC-ed).

> diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
> index 37e90e42943f..ca2ab5d53dd4 100644
> --- a/drivers/gpu/drm/sun4i/Kconfig
> +++ b/drivers/gpu/drm/sun4i/Kconfig
> @@ -23,6 +23,17 @@ config DRM_SUN4I_HDMI
>           Choose this option if you have an Allwinner SoC with an HDMI
>           controller.
>
> +config DRM_SUN4I_HDMI_AUDIO
> +       bool "Allwinner A10 HDMI Audio Support"
> +       default y
> +       depends on DRM_SUN4I_HDMI
> +       depends on SND_SOC=y || SND_SOC=DRM_SUN4I_HDMI
> +       select SND_PCM_ELD
> +       select SND_SOC_GENERIC_DMAENGINE_PCM
> +       help
> +         Choose this option if you have an Allwinner SoC with an HDMI
> +         controller and want to use audio.
> +
>  config DRM_SUN4I_HDMI_CEC
>         bool "Allwinner A10 HDMI CEC Support"
>         depends on DRM_SUN4I_HDMI
> diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
> index 0d04f2447b01..492bfd28ad2e 100644
> --- a/drivers/gpu/drm/sun4i/Makefile
> +++ b/drivers/gpu/drm/sun4i/Makefile
> @@ -5,6 +5,9 @@ sun4i-frontend-y                += sun4i_frontend.o
>  sun4i-drm-y                    += sun4i_drv.o
>  sun4i-drm-y                    += sun4i_framebuffer.o
>
> +ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +sun4i-drm-hdmi-y               += sun4i_hdmi_audio.o
> +endif
>  sun4i-drm-hdmi-y               += sun4i_hdmi_ddc_clk.o
>  sun4i-drm-hdmi-y               += sun4i_hdmi_enc.o
>  sun4i-drm-hdmi-y               += sun4i_hdmi_i2c.o
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> index 7ad3f06c127e..28621d289655 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> @@ -42,7 +42,32 @@
>  #define SUN4I_HDMI_VID_TIMING_POL_VSYNC                BIT(1)
>  #define SUN4I_HDMI_VID_TIMING_POL_HSYNC                BIT(0)
>
> +#define SUN4I_HDMI_AUDIO_CTRL_REG      0x040
> +#define SUN4I_HDMI_AUDIO_CTRL_ENABLE           BIT(31)
> +#define SUN4I_HDMI_AUDIO_CTRL_RESET            BIT(30)
> +
> +#define SUN4I_HDMI_AUDIO_FMT_REG       0x048
> +#define SUN4I_HDMI_AUDIO_FMT_SRC               BIT(31)
> +#define SUN4I_HDMI_AUDIO_FMT_LAYOUT            BIT(3)
> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG(n)         ((n) - 1)
> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK       GENMASK(2, 0)
> +
> +#define SUN4I_HDMI_AUDIO_PCM_REG       0x4c
> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP(n, m)      (((m) - 1) << ((n) * 4))
> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(n)    (GENMASK(2, 0) << ((n) * 4))
> +
> +#define SUN4I_HDMI_AUDIO_CTS_REG       0x050
> +#define SUN4I_HDMI_AUDIO_CTS(n)                        ((n) & GENMASK(19, 0))
> +
> +#define SUN4I_HDMI_AUDIO_N_REG         0x054
> +#define SUN4I_HDMI_AUDIO_N(n)                  ((n) & GENMASK(19, 0))
> +
> +#define SUN4I_HDMI_AUDIO_STAT0_REG     0x58
> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ(n)         ((n) << 24)
> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK       GENMASK(27, 24)
> +
>  #define SUN4I_HDMI_AVI_INFOFRAME_REG(n)        (0x080 + (n))
> +#define SUN4I_HDMI_AUDIO_INFOFRAME_REG(n)      (0x0a0 + (n))
>
>  #define SUN4I_HDMI_PAD_CTRL0_REG       0x200
>  #define SUN4I_HDMI_PAD_CTRL0_BIASEN            BIT(31)
> @@ -242,6 +267,11 @@ struct sun4i_hdmi_variant {
>         bool                    ddc_fifo_has_dir;
>  };
>
> +struct sun4i_hdmi_audio {
> +       struct snd_soc_card             *card;
> +       u8                              channels;
> +};
> +
>  struct sun4i_hdmi {
>         struct drm_connector    connector;
>         struct drm_encoder      encoder;
> @@ -283,9 +313,14 @@ struct sun4i_hdmi {
>         struct regmap_field     *field_ddc_sda_en;
>         struct regmap_field     *field_ddc_sck_en;
>
> +
>         struct sun4i_drv        *drv;
>
>         bool                    hdmi_monitor;
> +       bool                    hdmi_audio;
> +
> +       struct sun4i_hdmi_audio audio;
> +
>         struct cec_adapter      *cec_adap;
>
>         const struct sun4i_hdmi_variant *variant;
> @@ -294,5 +329,7 @@ struct sun4i_hdmi {
>  int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
>  int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
>  int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi);
> +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi);
>
>  #endif /* _SUN4I_HDMI_H_ */
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> new file mode 100644
> index 000000000000..f42f2cea4e9e
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> @@ -0,0 +1,450 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2020 Olimex Ltd.
> + *   Author: Stefan Mavrodiev <stefan@olimex.com>
> + */
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/module.h>
> +#include <linux/of_dma.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/drm_print.h>
> +
> +#include <sound/dmaengine_pcm.h>
> +#include <sound/pcm_drm_eld.h>
> +#include <sound/pcm_params.h>
> +#include <sound/soc.h>
> +
> +#include "sun4i_hdmi.h"
> +
> +static int sun4i_hdmi_audio_ctl_eld_info(struct snd_kcontrol *kcontrol,
> +                                        struct snd_ctl_elem_info *uinfo)
> +{
> +       uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
> +       uinfo->count = MAX_ELD_BYTES;
> +       return 0;
> +}
> +
> +static int sun4i_hdmi_audio_ctl_eld_get(struct snd_kcontrol *kcontrol,
> +                                       struct snd_ctl_elem_value *ucontrol)
> +{
> +       struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
> +       struct snd_soc_card *card = snd_soc_component_get_drvdata(component);
> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> +
> +       memcpy(ucontrol->value.bytes.data,
> +              hdmi->connector.eld,
> +              MAX_ELD_BYTES);
> +
> +       return 0;
> +}
> +
> +static const struct snd_kcontrol_new sun4i_hdmi_audio_controls[] = {
> +       {
> +               .access = SNDRV_CTL_ELEM_ACCESS_READ |
> +                         SNDRV_CTL_ELEM_ACCESS_VOLATILE,
> +               .iface = SNDRV_CTL_ELEM_IFACE_PCM,
> +               .name = "ELD",
> +               .info = sun4i_hdmi_audio_ctl_eld_info,
> +               .get = sun4i_hdmi_audio_ctl_eld_get,
> +       },
> +};
> +
> +static const struct snd_soc_dapm_widget sun4i_hdmi_audio_widgets[] = {
> +       SND_SOC_DAPM_OUTPUT("TX"),
> +};
> +
> +static const struct snd_soc_dapm_route sun4i_hdmi_audio_routes[] = {
> +       { "TX", NULL, "Playback" },
> +};
> +
> +static const struct snd_soc_component_driver sun4i_hdmi_audio_component = {
> +       .controls               = sun4i_hdmi_audio_controls,
> +       .num_controls           = ARRAY_SIZE(sun4i_hdmi_audio_controls),
> +       .dapm_widgets           = sun4i_hdmi_audio_widgets,
> +       .num_dapm_widgets       = ARRAY_SIZE(sun4i_hdmi_audio_widgets),
> +       .dapm_routes            = sun4i_hdmi_audio_routes,
> +       .num_dapm_routes        = ARRAY_SIZE(sun4i_hdmi_audio_routes),
> +};
> +
> +static int sun4i_hdmi_audio_startup(struct snd_pcm_substream *substream,
> +                                   struct snd_soc_dai *dai)
> +{
> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> +       u32 reg;
> +       int ret;
> +
> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
> +       regmap_write(hdmi->regmap,
> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
> +                    SUN4I_HDMI_AUDIO_CTRL_RESET);
> +       ret = regmap_read_poll_timeout(hdmi->regmap,
> +                                      SUN4I_HDMI_AUDIO_CTRL_REG,
> +                                      reg, !reg, 100, 50000);
> +       if (ret < 0) {
> +               DRM_ERROR("Failed to reset HDMI Audio\n");
> +               return ret;
> +       }
> +
> +       regmap_write(hdmi->regmap,
> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
> +                    SUN4I_HDMI_AUDIO_CTRL_ENABLE);
> +
> +       return snd_pcm_hw_constraint_eld(substream->runtime,
> +                                       hdmi->connector.eld);
> +}
> +
> +static void sun4i_hdmi_audio_shutdown(struct snd_pcm_substream *substream,
> +                                     struct snd_soc_dai *dai)
> +{
> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> +
> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
> +}
> +
> +static int sun4i_hdmi_setup_audio_infoframes(struct sun4i_hdmi *hdmi)
> +{
> +       union hdmi_infoframe frame;
> +       u8 buffer[14];
> +       int i, ret;
> +
> +       ret = hdmi_audio_infoframe_init(&frame.audio);
> +       if (ret < 0) {
> +               DRM_ERROR("Failed to init HDMI audio infoframe\n");
> +               return ret;
> +       }
> +
> +       frame.audio.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
> +       frame.audio.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
> +       frame.audio.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
> +       frame.audio.channels = hdmi->audio.channels;
> +
> +       ret = hdmi_infoframe_pack(&frame, buffer, sizeof(buffer));
> +       if (ret < 0) {
> +               DRM_ERROR("Failed to pack HDMI audio infoframe\n");
> +               return ret;
> +       }
> +
> +       for (i = 0; i < sizeof(buffer); i++)
> +               writeb(buffer[i],
> +                      hdmi->base + SUN4I_HDMI_AUDIO_INFOFRAME_REG(i));
> +
> +       return 0;
> +}
> +
> +static void sun4i_hdmi_audio_set_cts_n(struct sun4i_hdmi *hdmi,
> +                                      struct snd_pcm_hw_params *params)
> +{
> +       struct drm_encoder *encoder = &hdmi->encoder;
> +       struct drm_crtc *crtc = encoder->crtc;
> +       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> +       u32 rate = params_rate(params);
> +       u32 n, cts;
> +       u64 tmp;
> +
> +       /**
> +        * Calculate Cycle Time Stamp (CTS) and Numerator (N):
> +        *
> +        * N = 128 * Samplerate / 1000
> +        * CTS = (Ftdms * N) / (128 * Samplerate)
> +        */
> +
> +       n = 128 * rate / 1000;
> +       tmp = (u64)(mode->clock * 1000) * n;
> +       do_div(tmp, 128 * rate);
> +       cts = tmp;
> +
> +       regmap_write(hdmi->regmap,
> +                    SUN4I_HDMI_AUDIO_CTS_REG,
> +                    SUN4I_HDMI_AUDIO_CTS(cts));
> +
> +       regmap_write(hdmi->regmap,
> +                    SUN4I_HDMI_AUDIO_N_REG,
> +                    SUN4I_HDMI_AUDIO_N(n));
> +}
> +
> +static int sun4i_hdmi_audio_set_hw_rate(struct sun4i_hdmi *hdmi,
> +                                       struct snd_pcm_hw_params *params)
> +{
> +       u32 rate = params_rate(params);
> +       u32 val;
> +
> +       switch (rate) {
> +       case 44100:
> +               val = 0x0;
> +               break;
> +       case 48000:
> +               val = 0x2;
> +               break;
> +       case 32000:
> +               val = 0x3;
> +               break;
> +       case 88200:
> +               val = 0x8;
> +               break;
> +       case 96000:
> +               val = 0x9;
> +               break;
> +       case 176400:
> +               val = 0xc;
> +               break;
> +       case 192000:
> +               val = 0xe;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       regmap_update_bits(hdmi->regmap,
> +                          SUN4I_HDMI_AUDIO_STAT0_REG,
> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK,
> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ(val));
> +
> +       return 0;
> +}
> +
> +static int sun4i_hdmi_audio_set_hw_channels(struct sun4i_hdmi *hdmi,
> +                                           struct snd_pcm_hw_params *params)
> +{
> +       u32 channels = params_channels(params);
> +
> +       if (channels > 8)
> +               return -EINVAL;
> +
> +       hdmi->audio.channels = channels;
> +
> +       regmap_update_bits(hdmi->regmap,
> +                          SUN4I_HDMI_AUDIO_FMT_REG,
> +                          SUN4I_HDMI_AUDIO_FMT_LAYOUT,
> +                          (channels > 2) ? SUN4I_HDMI_AUDIO_FMT_LAYOUT : 0);
> +
> +       regmap_update_bits(hdmi->regmap,
> +                          SUN4I_HDMI_AUDIO_FMT_REG,
> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK,
> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG(channels));
> +
> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_PCM_REG, 0x76543210);
> +
> +       /**
> +        * If only one channel is required, send the same sample
> +        * to the sink device as a left and right channel.
> +        */
> +       if (channels == 1)
> +               regmap_update_bits(hdmi->regmap,
> +                                  SUN4I_HDMI_AUDIO_PCM_REG,
> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(1),
> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP(1, 1));
> +
> +       return 0;
> +}
> +
> +static int sun4i_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
> +                                     struct snd_pcm_hw_params *params,
> +                                     struct snd_soc_dai *dai)
> +{
> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> +       int ret;
> +
> +       ret = sun4i_hdmi_audio_set_hw_rate(hdmi, params);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = sun4i_hdmi_audio_set_hw_channels(hdmi, params);
> +       if (ret < 0)
> +               return ret;
> +
> +       sun4i_hdmi_audio_set_cts_n(hdmi, params);
> +
> +       return 0;
> +}
> +
> +static int sun4i_hdmi_audio_trigger(struct snd_pcm_substream *substream,
> +                                   int cmd,
> +                                   struct snd_soc_dai *dai)
> +{
> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> +       int ret = 0;
> +
> +       switch (cmd) {
> +       case SNDRV_PCM_TRIGGER_START:
> +               ret = sun4i_hdmi_setup_audio_infoframes(hdmi);
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       return ret;
> +}
> +
> +static const struct snd_soc_dai_ops sun4i_hdmi_audio_dai_ops = {
> +       .startup = sun4i_hdmi_audio_startup,
> +       .shutdown = sun4i_hdmi_audio_shutdown,
> +       .hw_params = sun4i_hdmi_audio_hw_params,
> +       .trigger = sun4i_hdmi_audio_trigger,
> +};
> +
> +static int sun4i_hdmi_audio_dai_probe(struct snd_soc_dai *dai)
> +{
> +       struct snd_dmaengine_dai_dma_data *dma_data;
> +
> +       dma_data = devm_kzalloc(dai->dev, sizeof(*dma_data), GFP_KERNEL);
> +       if (!dma_data)
> +               return -ENOMEM;
> +
> +       dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +       dma_data->maxburst = 8;
> +
> +       snd_soc_dai_init_dma_data(dai, dma_data, NULL);
> +
> +       return 0;
> +}
> +
> +static struct snd_soc_dai_driver sun4i_hdmi_audio_dai = {
> +       .name = "HDMI",
> +       .ops = &sun4i_hdmi_audio_dai_ops,
> +       .probe = sun4i_hdmi_audio_dai_probe,
> +       .playback = {
> +               .stream_name    = "Playback",
> +               .channels_min   = 1,
> +               .channels_max   = 8,
> +               .formats        = SNDRV_PCM_FMTBIT_S16_LE,
> +               .rates          = SNDRV_PCM_RATE_8000_192000,
> +       },
> +};
> +
> +static const struct snd_pcm_hardware sun4i_hdmi_audio_pcm_hardware = {
> +       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
> +                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
> +                                 SNDRV_PCM_INFO_MMAP |
> +                                 SNDRV_PCM_INFO_MMAP_VALID |
> +                                 SNDRV_PCM_INFO_PAUSE |
> +                                 SNDRV_PCM_INFO_RESUME,
> +       .formats                = SNDRV_PCM_FMTBIT_S16_LE,
> +       .rates                  = SNDRV_PCM_RATE_8000_192000,
> +       .rate_min               = 8000,
> +       .rate_max               = 192000,
> +       .channels_min           = 1,
> +       .channels_max           = 8,
> +       .buffer_bytes_max       = 128 * 1024,
> +       .period_bytes_min       = 4 * 1024,
> +       .period_bytes_max       = 32 * 1024,
> +       .periods_min            = 2,
> +       .periods_max            = 8,
> +       .fifo_size              = 128,
> +};
> +
> +static const struct snd_dmaengine_pcm_config sun4i_hdmi_audio_pcm_config = {
> +       .chan_names[SNDRV_PCM_STREAM_PLAYBACK] = "audio-tx",
> +       .pcm_hardware = &sun4i_hdmi_audio_pcm_hardware,
> +       .prealloc_buffer_size = 128 * 1024,
> +       .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
> +};
> +
> +struct snd_soc_card sun4i_hdmi_audio_card = {
> +       .name = "sun4i-hdmi",
> +};
> +
> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi)
> +{
> +       struct snd_soc_card *card = &sun4i_hdmi_audio_card;
> +       struct snd_soc_dai_link_component *comp;
> +       struct snd_soc_dai_link *link;
> +       int ret;
> +
> +       ret = snd_dmaengine_pcm_register(hdmi->dev,
> +                                        &sun4i_hdmi_audio_pcm_config, 0);
> +       if (ret < 0) {
> +               DRM_ERROR("Could not register PCM\n");
> +               return ret;
> +       }
> +
> +       ret = snd_soc_register_component(hdmi->dev,
> +                                        &sun4i_hdmi_audio_component,
> +                                        &sun4i_hdmi_audio_dai, 1);
> +       if (ret < 0) {
> +               DRM_ERROR("Could not register DAI\n");
> +               goto unregister_pcm;
> +       }
> +
> +       link = devm_kzalloc(hdmi->dev, sizeof(*link), GFP_KERNEL);
> +       if (!link) {
> +               ret = -ENOMEM;
> +               goto unregister_component;
> +       }
> +
> +       comp = devm_kzalloc(hdmi->dev, sizeof(*comp) * 3, GFP_KERNEL);
> +       if (!comp) {
> +               ret = -ENOMEM;
> +               goto unregister_component;
> +       }
> +
> +       link->cpus = &comp[0];
> +       link->codecs = &comp[1];
> +       link->platforms = &comp[2];
> +
> +       link->num_cpus = 1;
> +       link->num_codecs = 1;
> +       link->num_platforms = 1;
> +
> +       link->playback_only = 1;
> +
> +       link->name = "SUN4I-HDMI";
> +       link->stream_name = "SUN4I-HDMI PCM";
> +
> +       link->codecs->name = dev_name(hdmi->dev);
> +       link->codecs->dai_name  = sun4i_hdmi_audio_dai.name;
> +
> +       link->cpus->dai_name = dev_name(hdmi->dev);
> +
> +       link->platforms->name = dev_name(hdmi->dev);
> +
> +       link->dai_fmt = SND_SOC_DAIFMT_I2S;
> +
> +       card->dai_link = link;
> +       card->num_links = 1;
> +       card->dev = hdmi->dev;
> +
> +       hdmi->audio.card = card;
> +
> +       /**
> +        * snd_soc_register_card() will overwrite the driver_data pointer.
> +        * So before registering the card, store the original pointer in
> +        * card->drvdata.
> +        */
> +       snd_soc_card_set_drvdata(card, hdmi);
> +       ret = snd_soc_register_card(card);
> +       if (ret)
> +               goto unregister_component;

So using ASoC with all the components IMHO is just adding dead weight. The
audio interface for this particular hardware is just a FIFO that needs to
be written to by an external DMA engine, and a bunch of controls to setup
the parameters of the HDMI audio stream. There's no power sequencing to do,
and no actual individual components to control. There's no reason you couldn't
use just the ALSA DMAENGINE helpers to create a simple ALSA sound card.

(Maybe we could clean it up after it's merged? Would there be any issues
 with backward compatibility?)

I think the only example of this besides ASoC is the PXA2xx sound library
and AC97 driver:

  - sound/arm/pxa2xx-pcm-lib.c
  - sound/arm/pxa2xx-ac97.c

Regards
ChenYu



> +
> +       return 0;
> +
> +unregister_component:
> +       snd_soc_unregister_component(hdmi->dev);
> +unregister_pcm:
> +       snd_dmaengine_pcm_unregister(hdmi->dev);
> +       return ret;
> +}
> +
> +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi)
> +{
> +       struct snd_soc_card *card = hdmi->audio.card;
> +       void *data;
> +
> +       /**
> +        * Before removing the card, restore the previously stored driver_data.
> +        * This will ensure proper removal of the sun4i-hdmi module, since it
> +        * uses dev_get_drvdata() in the unbind function.
> +        */
> +       data = snd_soc_card_get_drvdata(card);
> +
> +       snd_soc_unregister_card(card);
> +       snd_soc_unregister_component(hdmi->dev);
> +       snd_dmaengine_pcm_unregister(hdmi->dev);
> +
> +       dev_set_drvdata(hdmi->dev, data);
> +}
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> index 68d4644ac2dc..4cd35c97c503 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> @@ -23,6 +23,8 @@
>  #include <drm/drm_print.h>
>  #include <drm/drm_probe_helper.h>
>
> +#include <sound/soc.h>
> +
>  #include "sun4i_backend.h"
>  #include "sun4i_crtc.h"
>  #include "sun4i_drv.h"
> @@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
>
>         DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
>
> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +       sun4i_hdmi_audio_destroy(hdmi);
> +#endif
> +
>         val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>         val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
>         writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> @@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
>                 val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
>
>         writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> +
> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +       if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
> +               DRM_ERROR("Couldn't create the HDMI audio adapter\n");
> +#endif
>  }
>
>  static void sun4i_hdmi_mode_set(struct drm_encoder *encoder,
> @@ -218,6 +229,9 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
>         if (!edid)
>                 return 0;
>
> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +       hdmi->hdmi_audio = drm_detect_monitor_audio(edid);
> +#endif
>         hdmi->hdmi_monitor = drm_detect_hdmi_monitor(edid);
>         DRM_DEBUG_DRIVER("Monitor is %s monitor\n",
>                          hdmi->hdmi_monitor ? "an HDMI" : "a DVI");
> --
> 2.17.1
>
> --
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Re: [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Maxime Ripard]

Hi,

On Tue, Jan 28, 2020 at 04:06:42PM +0200, Stefan Mavrodiev wrote:
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> index 68d4644ac2dc..4cd35c97c503 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> @@ -23,6 +23,8 @@
>  #include <drm/drm_print.h>
>  #include <drm/drm_probe_helper.h>
>
> +#include <sound/soc.h>
> +
>  #include "sun4i_backend.h"
>  #include "sun4i_crtc.h"
>  #include "sun4i_drv.h"
> @@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
>
>  	DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
>
> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +	sun4i_hdmi_audio_destroy(hdmi);
> +#endif
> +
>  	val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>  	val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
>  	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> @@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
>  		val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
>
>  	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> +
> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> +	if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
> +		DRM_ERROR("Couldn't create the HDMI audio adapter\n");
> +#endif

I really don't think we should be creating / removing the audio card
at enable / disable time.

To fix the drvdata pointer, you just need to use the card pointer in
the unbind, and that's it.

Maxime

Re: [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Stefan Mavrodiev]

Hi,

On 1/29/20 6:43 PM, Maxime Ripard wrote:
> Hi,
>
> On Tue, Jan 28, 2020 at 04:06:42PM +0200, Stefan Mavrodiev wrote:
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> index 68d4644ac2dc..4cd35c97c503 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> @@ -23,6 +23,8 @@
>>   #include <drm/drm_print.h>
>>   #include <drm/drm_probe_helper.h>
>>
>> +#include <sound/soc.h>
>> +
>>   #include "sun4i_backend.h"
>>   #include "sun4i_crtc.h"
>>   #include "sun4i_drv.h"
>> @@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
>>
>>   	DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
>>
>> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +	sun4i_hdmi_audio_destroy(hdmi);
>> +#endif
>> +
>>   	val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>>   	val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
>>   	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>> @@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
>>   		val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
>>
>>   	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>> +
>> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +	if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
>> +		DRM_ERROR("Couldn't create the HDMI audio adapter\n");
>> +#endif
> I really don't think we should be creating / removing the audio card
> at enable / disable time.

For me it's unnatural to have sound card all the time, even when the HDMI
is not plugged-in.

I'll follow your suggestion. Besides it's easier for me just to drop this
register/unregister mechanism.

Best regards,
Stefan Mavrodiev

>
> To fix the drvdata pointer, you just need to use the card pointer in
> the unbind, and that's it.
>
> Maxime

Re: [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 2535 bytes --]

Hi,

On Thu, Jan 30, 2020 at 08:20:55AM +0200, Stefan Mavrodiev wrote:
> On 1/29/20 6:43 PM, Maxime Ripard wrote:
> > On Tue, Jan 28, 2020 at 04:06:42PM +0200, Stefan Mavrodiev wrote:
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> > > index 68d4644ac2dc..4cd35c97c503 100644
> > > --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> > > @@ -23,6 +23,8 @@
> > >   #include <drm/drm_print.h>
> > >   #include <drm/drm_probe_helper.h>
> > >
> > > +#include <sound/soc.h>
> > > +
> > >   #include "sun4i_backend.h"
> > >   #include "sun4i_crtc.h"
> > >   #include "sun4i_drv.h"
> > > @@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
> > >
> > >   	DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
> > >
> > > +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> > > +	sun4i_hdmi_audio_destroy(hdmi);
> > > +#endif
> > > +
> > >   	val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> > >   	val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
> > >   	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> > > @@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
> > >   		val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
> > >
> > >   	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
> > > +
> > > +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> > > +	if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
> > > +		DRM_ERROR("Couldn't create the HDMI audio adapter\n");
> > > +#endif
> > I really don't think we should be creating / removing the audio card
> > at enable / disable time.
>
> For me it's unnatural to have sound card all the time, even when the HDMI
> is not plugged-in.

It's also a matter of being consistent: pretty much everyone else is
doing it:
  * vc4 (RaspberryPi)
    https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/vc4/vc4_hdmi.c#L1437

  * omap
    https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/omapdrm/dss/hdmi4.c#L620

  * sti
    https://elixir.bootlin.com/linux/v5.5.1/source/drivers/gpu/drm/sti/sti_hdmi.c#L1310

  * msm
    https://elixir.bootlin.com/linux/v5.5.1/source/drivers/gpu/drm/msm/hdmi/hdmi.c#L597

etc...

If we were to think about this at a more theorical level though, it's
pretty much the same case than having a sound card but no headphone
attached, or having a display engine but no display attached. In both
case, you register the driver before having a sink, you just let the
userspace know that there's nothing connected on the other end.

Maxime

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Re: [linux-sunxi] [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Stefan Mavrodiev]

On 1/29/20 6:34 PM, Chen-Yu Tsai wrote:
> On Tue, Jan 28, 2020 at 10:07 PM Stefan Mavrodiev <stefan@olimex.com> wrote:
>> Add HDMI audio support for the sun4i-hdmi encoder, used on
>> the older Allwinner chips - A10, A20, A31.
>>
>> Most of the code is based on the BSP implementation. In it
>> dditional formats are supported (S20_3LE and S24_LE), however
>> there where some problems with them and only S16_LE is left.
>>
>> Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
>> ---
>> Changes for v3:
>>   - Instead of platfrom_driver dynammicly register/unregister card
>>   - Add Kconfig dependencies
>>   - Restrore drvdata after card unregistering
>>
>> Changes for v2:
>>   - Create a new platform driver instead of using the HDMI encoder
>>   - Expose a new kcontrol to the userspace holding the ELD data
>>   - Wrap all macro arguments in parentheses
>>
>>   drivers/gpu/drm/sun4i/Kconfig            |  11 +
>>   drivers/gpu/drm/sun4i/Makefile           |   3 +
>>   drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
>>   drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
>>   drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
>>   5 files changed, 515 insertions(+)
>>   create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> Since this is actually an audio driver, please include all the ALSA / ASoC
> maintainers and mailing lists (CC-ed).
>
>> diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
>> index 37e90e42943f..ca2ab5d53dd4 100644
>> --- a/drivers/gpu/drm/sun4i/Kconfig
>> +++ b/drivers/gpu/drm/sun4i/Kconfig
>> @@ -23,6 +23,17 @@ config DRM_SUN4I_HDMI
>>            Choose this option if you have an Allwinner SoC with an HDMI
>>            controller.
>>
>> +config DRM_SUN4I_HDMI_AUDIO
>> +       bool "Allwinner A10 HDMI Audio Support"
>> +       default y
>> +       depends on DRM_SUN4I_HDMI
>> +       depends on SND_SOC=y || SND_SOC=DRM_SUN4I_HDMI
>> +       select SND_PCM_ELD
>> +       select SND_SOC_GENERIC_DMAENGINE_PCM
>> +       help
>> +         Choose this option if you have an Allwinner SoC with an HDMI
>> +         controller and want to use audio.
>> +
>>   config DRM_SUN4I_HDMI_CEC
>>          bool "Allwinner A10 HDMI CEC Support"
>>          depends on DRM_SUN4I_HDMI
>> diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
>> index 0d04f2447b01..492bfd28ad2e 100644
>> --- a/drivers/gpu/drm/sun4i/Makefile
>> +++ b/drivers/gpu/drm/sun4i/Makefile
>> @@ -5,6 +5,9 @@ sun4i-frontend-y                += sun4i_frontend.o
>>   sun4i-drm-y                    += sun4i_drv.o
>>   sun4i-drm-y                    += sun4i_framebuffer.o
>>
>> +ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +sun4i-drm-hdmi-y               += sun4i_hdmi_audio.o
>> +endif
>>   sun4i-drm-hdmi-y               += sun4i_hdmi_ddc_clk.o
>>   sun4i-drm-hdmi-y               += sun4i_hdmi_enc.o
>>   sun4i-drm-hdmi-y               += sun4i_hdmi_i2c.o
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>> index 7ad3f06c127e..28621d289655 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>> @@ -42,7 +42,32 @@
>>   #define SUN4I_HDMI_VID_TIMING_POL_VSYNC                BIT(1)
>>   #define SUN4I_HDMI_VID_TIMING_POL_HSYNC                BIT(0)
>>
>> +#define SUN4I_HDMI_AUDIO_CTRL_REG      0x040
>> +#define SUN4I_HDMI_AUDIO_CTRL_ENABLE           BIT(31)
>> +#define SUN4I_HDMI_AUDIO_CTRL_RESET            BIT(30)
>> +
>> +#define SUN4I_HDMI_AUDIO_FMT_REG       0x048
>> +#define SUN4I_HDMI_AUDIO_FMT_SRC               BIT(31)
>> +#define SUN4I_HDMI_AUDIO_FMT_LAYOUT            BIT(3)
>> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG(n)         ((n) - 1)
>> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK       GENMASK(2, 0)
>> +
>> +#define SUN4I_HDMI_AUDIO_PCM_REG       0x4c
>> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP(n, m)      (((m) - 1) << ((n) * 4))
>> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(n)    (GENMASK(2, 0) << ((n) * 4))
>> +
>> +#define SUN4I_HDMI_AUDIO_CTS_REG       0x050
>> +#define SUN4I_HDMI_AUDIO_CTS(n)                        ((n) & GENMASK(19, 0))
>> +
>> +#define SUN4I_HDMI_AUDIO_N_REG         0x054
>> +#define SUN4I_HDMI_AUDIO_N(n)                  ((n) & GENMASK(19, 0))
>> +
>> +#define SUN4I_HDMI_AUDIO_STAT0_REG     0x58
>> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ(n)         ((n) << 24)
>> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK       GENMASK(27, 24)
>> +
>>   #define SUN4I_HDMI_AVI_INFOFRAME_REG(n)        (0x080 + (n))
>> +#define SUN4I_HDMI_AUDIO_INFOFRAME_REG(n)      (0x0a0 + (n))
>>
>>   #define SUN4I_HDMI_PAD_CTRL0_REG       0x200
>>   #define SUN4I_HDMI_PAD_CTRL0_BIASEN            BIT(31)
>> @@ -242,6 +267,11 @@ struct sun4i_hdmi_variant {
>>          bool                    ddc_fifo_has_dir;
>>   };
>>
>> +struct sun4i_hdmi_audio {
>> +       struct snd_soc_card             *card;
>> +       u8                              channels;
>> +};
>> +
>>   struct sun4i_hdmi {
>>          struct drm_connector    connector;
>>          struct drm_encoder      encoder;
>> @@ -283,9 +313,14 @@ struct sun4i_hdmi {
>>          struct regmap_field     *field_ddc_sda_en;
>>          struct regmap_field     *field_ddc_sck_en;
>>
>> +
>>          struct sun4i_drv        *drv;
>>
>>          bool                    hdmi_monitor;
>> +       bool                    hdmi_audio;
>> +
>> +       struct sun4i_hdmi_audio audio;
>> +
>>          struct cec_adapter      *cec_adap;
>>
>>          const struct sun4i_hdmi_variant *variant;
>> @@ -294,5 +329,7 @@ struct sun4i_hdmi {
>>   int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
>>   int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
>>   int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
>> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi);
>> +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi);
>>
>>   #endif /* _SUN4I_HDMI_H_ */
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
>> new file mode 100644
>> index 000000000000..f42f2cea4e9e
>> --- /dev/null
>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
>> @@ -0,0 +1,450 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (C) 2020 Olimex Ltd.
>> + *   Author: Stefan Mavrodiev <stefan@olimex.com>
>> + */
>> +#include <linux/dma-mapping.h>
>> +#include <linux/dmaengine.h>
>> +#include <linux/module.h>
>> +#include <linux/of_dma.h>
>> +#include <linux/regmap.h>
>> +
>> +#include <drm/drm_print.h>
>> +
>> +#include <sound/dmaengine_pcm.h>
>> +#include <sound/pcm_drm_eld.h>
>> +#include <sound/pcm_params.h>
>> +#include <sound/soc.h>
>> +
>> +#include "sun4i_hdmi.h"
>> +
>> +static int sun4i_hdmi_audio_ctl_eld_info(struct snd_kcontrol *kcontrol,
>> +                                        struct snd_ctl_elem_info *uinfo)
>> +{
>> +       uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
>> +       uinfo->count = MAX_ELD_BYTES;
>> +       return 0;
>> +}
>> +
>> +static int sun4i_hdmi_audio_ctl_eld_get(struct snd_kcontrol *kcontrol,
>> +                                       struct snd_ctl_elem_value *ucontrol)
>> +{
>> +       struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
>> +       struct snd_soc_card *card = snd_soc_component_get_drvdata(component);
>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>> +
>> +       memcpy(ucontrol->value.bytes.data,
>> +              hdmi->connector.eld,
>> +              MAX_ELD_BYTES);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct snd_kcontrol_new sun4i_hdmi_audio_controls[] = {
>> +       {
>> +               .access = SNDRV_CTL_ELEM_ACCESS_READ |
>> +                         SNDRV_CTL_ELEM_ACCESS_VOLATILE,
>> +               .iface = SNDRV_CTL_ELEM_IFACE_PCM,
>> +               .name = "ELD",
>> +               .info = sun4i_hdmi_audio_ctl_eld_info,
>> +               .get = sun4i_hdmi_audio_ctl_eld_get,
>> +       },
>> +};
>> +
>> +static const struct snd_soc_dapm_widget sun4i_hdmi_audio_widgets[] = {
>> +       SND_SOC_DAPM_OUTPUT("TX"),
>> +};
>> +
>> +static const struct snd_soc_dapm_route sun4i_hdmi_audio_routes[] = {
>> +       { "TX", NULL, "Playback" },
>> +};
>> +
>> +static const struct snd_soc_component_driver sun4i_hdmi_audio_component = {
>> +       .controls               = sun4i_hdmi_audio_controls,
>> +       .num_controls           = ARRAY_SIZE(sun4i_hdmi_audio_controls),
>> +       .dapm_widgets           = sun4i_hdmi_audio_widgets,
>> +       .num_dapm_widgets       = ARRAY_SIZE(sun4i_hdmi_audio_widgets),
>> +       .dapm_routes            = sun4i_hdmi_audio_routes,
>> +       .num_dapm_routes        = ARRAY_SIZE(sun4i_hdmi_audio_routes),
>> +};
>> +
>> +static int sun4i_hdmi_audio_startup(struct snd_pcm_substream *substream,
>> +                                   struct snd_soc_dai *dai)
>> +{
>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>> +       u32 reg;
>> +       int ret;
>> +
>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
>> +       regmap_write(hdmi->regmap,
>> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
>> +                    SUN4I_HDMI_AUDIO_CTRL_RESET);
>> +       ret = regmap_read_poll_timeout(hdmi->regmap,
>> +                                      SUN4I_HDMI_AUDIO_CTRL_REG,
>> +                                      reg, !reg, 100, 50000);
>> +       if (ret < 0) {
>> +               DRM_ERROR("Failed to reset HDMI Audio\n");
>> +               return ret;
>> +       }
>> +
>> +       regmap_write(hdmi->regmap,
>> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
>> +                    SUN4I_HDMI_AUDIO_CTRL_ENABLE);
>> +
>> +       return snd_pcm_hw_constraint_eld(substream->runtime,
>> +                                       hdmi->connector.eld);
>> +}
>> +
>> +static void sun4i_hdmi_audio_shutdown(struct snd_pcm_substream *substream,
>> +                                     struct snd_soc_dai *dai)
>> +{
>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>> +
>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
>> +}
>> +
>> +static int sun4i_hdmi_setup_audio_infoframes(struct sun4i_hdmi *hdmi)
>> +{
>> +       union hdmi_infoframe frame;
>> +       u8 buffer[14];
>> +       int i, ret;
>> +
>> +       ret = hdmi_audio_infoframe_init(&frame.audio);
>> +       if (ret < 0) {
>> +               DRM_ERROR("Failed to init HDMI audio infoframe\n");
>> +               return ret;
>> +       }
>> +
>> +       frame.audio.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
>> +       frame.audio.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
>> +       frame.audio.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
>> +       frame.audio.channels = hdmi->audio.channels;
>> +
>> +       ret = hdmi_infoframe_pack(&frame, buffer, sizeof(buffer));
>> +       if (ret < 0) {
>> +               DRM_ERROR("Failed to pack HDMI audio infoframe\n");
>> +               return ret;
>> +       }
>> +
>> +       for (i = 0; i < sizeof(buffer); i++)
>> +               writeb(buffer[i],
>> +                      hdmi->base + SUN4I_HDMI_AUDIO_INFOFRAME_REG(i));
>> +
>> +       return 0;
>> +}
>> +
>> +static void sun4i_hdmi_audio_set_cts_n(struct sun4i_hdmi *hdmi,
>> +                                      struct snd_pcm_hw_params *params)
>> +{
>> +       struct drm_encoder *encoder = &hdmi->encoder;
>> +       struct drm_crtc *crtc = encoder->crtc;
>> +       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>> +       u32 rate = params_rate(params);
>> +       u32 n, cts;
>> +       u64 tmp;
>> +
>> +       /**
>> +        * Calculate Cycle Time Stamp (CTS) and Numerator (N):
>> +        *
>> +        * N = 128 * Samplerate / 1000
>> +        * CTS = (Ftdms * N) / (128 * Samplerate)
>> +        */
>> +
>> +       n = 128 * rate / 1000;
>> +       tmp = (u64)(mode->clock * 1000) * n;
>> +       do_div(tmp, 128 * rate);
>> +       cts = tmp;
>> +
>> +       regmap_write(hdmi->regmap,
>> +                    SUN4I_HDMI_AUDIO_CTS_REG,
>> +                    SUN4I_HDMI_AUDIO_CTS(cts));
>> +
>> +       regmap_write(hdmi->regmap,
>> +                    SUN4I_HDMI_AUDIO_N_REG,
>> +                    SUN4I_HDMI_AUDIO_N(n));
>> +}
>> +
>> +static int sun4i_hdmi_audio_set_hw_rate(struct sun4i_hdmi *hdmi,
>> +                                       struct snd_pcm_hw_params *params)
>> +{
>> +       u32 rate = params_rate(params);
>> +       u32 val;
>> +
>> +       switch (rate) {
>> +       case 44100:
>> +               val = 0x0;
>> +               break;
>> +       case 48000:
>> +               val = 0x2;
>> +               break;
>> +       case 32000:
>> +               val = 0x3;
>> +               break;
>> +       case 88200:
>> +               val = 0x8;
>> +               break;
>> +       case 96000:
>> +               val = 0x9;
>> +               break;
>> +       case 176400:
>> +               val = 0xc;
>> +               break;
>> +       case 192000:
>> +               val = 0xe;
>> +               break;
>> +       default:
>> +               return -EINVAL;
>> +       }
>> +
>> +       regmap_update_bits(hdmi->regmap,
>> +                          SUN4I_HDMI_AUDIO_STAT0_REG,
>> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK,
>> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ(val));
>> +
>> +       return 0;
>> +}
>> +
>> +static int sun4i_hdmi_audio_set_hw_channels(struct sun4i_hdmi *hdmi,
>> +                                           struct snd_pcm_hw_params *params)
>> +{
>> +       u32 channels = params_channels(params);
>> +
>> +       if (channels > 8)
>> +               return -EINVAL;
>> +
>> +       hdmi->audio.channels = channels;
>> +
>> +       regmap_update_bits(hdmi->regmap,
>> +                          SUN4I_HDMI_AUDIO_FMT_REG,
>> +                          SUN4I_HDMI_AUDIO_FMT_LAYOUT,
>> +                          (channels > 2) ? SUN4I_HDMI_AUDIO_FMT_LAYOUT : 0);
>> +
>> +       regmap_update_bits(hdmi->regmap,
>> +                          SUN4I_HDMI_AUDIO_FMT_REG,
>> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK,
>> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG(channels));
>> +
>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_PCM_REG, 0x76543210);
>> +
>> +       /**
>> +        * If only one channel is required, send the same sample
>> +        * to the sink device as a left and right channel.
>> +        */
>> +       if (channels == 1)
>> +               regmap_update_bits(hdmi->regmap,
>> +                                  SUN4I_HDMI_AUDIO_PCM_REG,
>> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(1),
>> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP(1, 1));
>> +
>> +       return 0;
>> +}
>> +
>> +static int sun4i_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
>> +                                     struct snd_pcm_hw_params *params,
>> +                                     struct snd_soc_dai *dai)
>> +{
>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>> +       int ret;
>> +
>> +       ret = sun4i_hdmi_audio_set_hw_rate(hdmi, params);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       ret = sun4i_hdmi_audio_set_hw_channels(hdmi, params);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       sun4i_hdmi_audio_set_cts_n(hdmi, params);
>> +
>> +       return 0;
>> +}
>> +
>> +static int sun4i_hdmi_audio_trigger(struct snd_pcm_substream *substream,
>> +                                   int cmd,
>> +                                   struct snd_soc_dai *dai)
>> +{
>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>> +       int ret = 0;
>> +
>> +       switch (cmd) {
>> +       case SNDRV_PCM_TRIGGER_START:
>> +               ret = sun4i_hdmi_setup_audio_infoframes(hdmi);
>> +               break;
>> +       default:
>> +               break;
>> +       }
>> +
>> +       return ret;
>> +}
>> +
>> +static const struct snd_soc_dai_ops sun4i_hdmi_audio_dai_ops = {
>> +       .startup = sun4i_hdmi_audio_startup,
>> +       .shutdown = sun4i_hdmi_audio_shutdown,
>> +       .hw_params = sun4i_hdmi_audio_hw_params,
>> +       .trigger = sun4i_hdmi_audio_trigger,
>> +};
>> +
>> +static int sun4i_hdmi_audio_dai_probe(struct snd_soc_dai *dai)
>> +{
>> +       struct snd_dmaengine_dai_dma_data *dma_data;
>> +
>> +       dma_data = devm_kzalloc(dai->dev, sizeof(*dma_data), GFP_KERNEL);
>> +       if (!dma_data)
>> +               return -ENOMEM;
>> +
>> +       dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>> +       dma_data->maxburst = 8;
>> +
>> +       snd_soc_dai_init_dma_data(dai, dma_data, NULL);
>> +
>> +       return 0;
>> +}
>> +
>> +static struct snd_soc_dai_driver sun4i_hdmi_audio_dai = {
>> +       .name = "HDMI",
>> +       .ops = &sun4i_hdmi_audio_dai_ops,
>> +       .probe = sun4i_hdmi_audio_dai_probe,
>> +       .playback = {
>> +               .stream_name    = "Playback",
>> +               .channels_min   = 1,
>> +               .channels_max   = 8,
>> +               .formats        = SNDRV_PCM_FMTBIT_S16_LE,
>> +               .rates          = SNDRV_PCM_RATE_8000_192000,
>> +       },
>> +};
>> +
>> +static const struct snd_pcm_hardware sun4i_hdmi_audio_pcm_hardware = {
>> +       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
>> +                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
>> +                                 SNDRV_PCM_INFO_MMAP |
>> +                                 SNDRV_PCM_INFO_MMAP_VALID |
>> +                                 SNDRV_PCM_INFO_PAUSE |
>> +                                 SNDRV_PCM_INFO_RESUME,
>> +       .formats                = SNDRV_PCM_FMTBIT_S16_LE,
>> +       .rates                  = SNDRV_PCM_RATE_8000_192000,
>> +       .rate_min               = 8000,
>> +       .rate_max               = 192000,
>> +       .channels_min           = 1,
>> +       .channels_max           = 8,
>> +       .buffer_bytes_max       = 128 * 1024,
>> +       .period_bytes_min       = 4 * 1024,
>> +       .period_bytes_max       = 32 * 1024,
>> +       .periods_min            = 2,
>> +       .periods_max            = 8,
>> +       .fifo_size              = 128,
>> +};
>> +
>> +static const struct snd_dmaengine_pcm_config sun4i_hdmi_audio_pcm_config = {
>> +       .chan_names[SNDRV_PCM_STREAM_PLAYBACK] = "audio-tx",
>> +       .pcm_hardware = &sun4i_hdmi_audio_pcm_hardware,
>> +       .prealloc_buffer_size = 128 * 1024,
>> +       .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
>> +};
>> +
>> +struct snd_soc_card sun4i_hdmi_audio_card = {
>> +       .name = "sun4i-hdmi",
>> +};
>> +
>> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi)
>> +{
>> +       struct snd_soc_card *card = &sun4i_hdmi_audio_card;
>> +       struct snd_soc_dai_link_component *comp;
>> +       struct snd_soc_dai_link *link;
>> +       int ret;
>> +
>> +       ret = snd_dmaengine_pcm_register(hdmi->dev,
>> +                                        &sun4i_hdmi_audio_pcm_config, 0);
>> +       if (ret < 0) {
>> +               DRM_ERROR("Could not register PCM\n");
>> +               return ret;
>> +       }
>> +
>> +       ret = snd_soc_register_component(hdmi->dev,
>> +                                        &sun4i_hdmi_audio_component,
>> +                                        &sun4i_hdmi_audio_dai, 1);
>> +       if (ret < 0) {
>> +               DRM_ERROR("Could not register DAI\n");
>> +               goto unregister_pcm;
>> +       }
>> +
>> +       link = devm_kzalloc(hdmi->dev, sizeof(*link), GFP_KERNEL);
>> +       if (!link) {
>> +               ret = -ENOMEM;
>> +               goto unregister_component;
>> +       }
>> +
>> +       comp = devm_kzalloc(hdmi->dev, sizeof(*comp) * 3, GFP_KERNEL);
>> +       if (!comp) {
>> +               ret = -ENOMEM;
>> +               goto unregister_component;
>> +       }
>> +
>> +       link->cpus = &comp[0];
>> +       link->codecs = &comp[1];
>> +       link->platforms = &comp[2];
>> +
>> +       link->num_cpus = 1;
>> +       link->num_codecs = 1;
>> +       link->num_platforms = 1;
>> +
>> +       link->playback_only = 1;
>> +
>> +       link->name = "SUN4I-HDMI";
>> +       link->stream_name = "SUN4I-HDMI PCM";
>> +
>> +       link->codecs->name = dev_name(hdmi->dev);
>> +       link->codecs->dai_name  = sun4i_hdmi_audio_dai.name;
>> +
>> +       link->cpus->dai_name = dev_name(hdmi->dev);
>> +
>> +       link->platforms->name = dev_name(hdmi->dev);
>> +
>> +       link->dai_fmt = SND_SOC_DAIFMT_I2S;
>> +
>> +       card->dai_link = link;
>> +       card->num_links = 1;
>> +       card->dev = hdmi->dev;
>> +
>> +       hdmi->audio.card = card;
>> +
>> +       /**
>> +        * snd_soc_register_card() will overwrite the driver_data pointer.
>> +        * So before registering the card, store the original pointer in
>> +        * card->drvdata.
>> +        */
>> +       snd_soc_card_set_drvdata(card, hdmi);
>> +       ret = snd_soc_register_card(card);
>> +       if (ret)
>> +               goto unregister_component;
> So using ASoC with all the components IMHO is just adding dead weight. The
> audio interface for this particular hardware is just a FIFO that needs to
> be written to by an external DMA engine, and a bunch of controls to setup
> the parameters of the HDMI audio stream. There's no power sequencing to do,
> and no actual individual components to control. There's no reason you couldn't
> use just the ALSA DMAENGINE helpers to create a simple ALSA sound card.
>
> (Maybe we could clean it up after it's merged? Would there be any issues
>   with backward compatibility?)
>
> I think the only example of this besides ASoC is the PXA2xx sound library
> and AC97 driver:
>
>    - sound/arm/pxa2xx-pcm-lib.c
>    - sound/arm/pxa2xx-ac97.c
>
> Regards
> ChenYu
>
>
Hi,

I'd like to hear Maxime opinion on this. I get it why it's overkill to 
use ASoC.
However it will take only couple of lines to make the changes for v4. On 
the other
side with dropping the ASoC, the driver must be almost rewritten. It's 
not such a big deal,
but I want to know that this is the right thing to do.

Best regards,
Stefan Mavrodiev


P.S. Sorry for the long break.

>> +
>> +       return 0;
>> +
>> +unregister_component:
>> +       snd_soc_unregister_component(hdmi->dev);
>> +unregister_pcm:
>> +       snd_dmaengine_pcm_unregister(hdmi->dev);
>> +       return ret;
>> +}
>> +
>> +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi)
>> +{
>> +       struct snd_soc_card *card = hdmi->audio.card;
>> +       void *data;
>> +
>> +       /**
>> +        * Before removing the card, restore the previously stored driver_data.
>> +        * This will ensure proper removal of the sun4i-hdmi module, since it
>> +        * uses dev_get_drvdata() in the unbind function.
>> +        */
>> +       data = snd_soc_card_get_drvdata(card);
>> +
>> +       snd_soc_unregister_card(card);
>> +       snd_soc_unregister_component(hdmi->dev);
>> +       snd_dmaengine_pcm_unregister(hdmi->dev);
>> +
>> +       dev_set_drvdata(hdmi->dev, data);
>> +}
>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> index 68d4644ac2dc..4cd35c97c503 100644
>> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
>> @@ -23,6 +23,8 @@
>>   #include <drm/drm_print.h>
>>   #include <drm/drm_probe_helper.h>
>>
>> +#include <sound/soc.h>
>> +
>>   #include "sun4i_backend.h"
>>   #include "sun4i_crtc.h"
>>   #include "sun4i_drv.h"
>> @@ -87,6 +89,10 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
>>
>>          DRM_DEBUG_DRIVER("Disabling the HDMI Output\n");
>>
>> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +       sun4i_hdmi_audio_destroy(hdmi);
>> +#endif
>> +
>>          val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>>          val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
>>          writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>> @@ -114,6 +120,11 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
>>                  val |= SUN4I_HDMI_VID_CTRL_HDMI_MODE;
>>
>>          writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
>> +
>> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +       if (hdmi->hdmi_audio && sun4i_hdmi_audio_create(hdmi))
>> +               DRM_ERROR("Couldn't create the HDMI audio adapter\n");
>> +#endif
>>   }
>>
>>   static void sun4i_hdmi_mode_set(struct drm_encoder *encoder,
>> @@ -218,6 +229,9 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
>>          if (!edid)
>>                  return 0;
>>
>> +#ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>> +       hdmi->hdmi_audio = drm_detect_monitor_audio(edid);
>> +#endif
>>          hdmi->hdmi_monitor = drm_detect_hdmi_monitor(edid);
>>          DRM_DEBUG_DRIVER("Monitor is %s monitor\n",
>>                           hdmi->hdmi_monitor ? "an HDMI" : "a DVI");
>> --
>> 2.17.1
>>
>> --
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Re: [linux-sunxi] [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 24357 bytes --]

On Tue, Feb 25, 2020 at 11:45:28AM +0200, Stefan Mavrodiev wrote:
>
> On 1/29/20 6:34 PM, Chen-Yu Tsai wrote:
> > On Tue, Jan 28, 2020 at 10:07 PM Stefan Mavrodiev <stefan@olimex.com> wrote:
> > > Add HDMI audio support for the sun4i-hdmi encoder, used on
> > > the older Allwinner chips - A10, A20, A31.
> > >
> > > Most of the code is based on the BSP implementation. In it
> > > dditional formats are supported (S20_3LE and S24_LE), however
> > > there where some problems with them and only S16_LE is left.
> > >
> > > Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
> > > ---
> > > Changes for v3:
> > >   - Instead of platfrom_driver dynammicly register/unregister card
> > >   - Add Kconfig dependencies
> > >   - Restrore drvdata after card unregistering
> > >
> > > Changes for v2:
> > >   - Create a new platform driver instead of using the HDMI encoder
> > >   - Expose a new kcontrol to the userspace holding the ELD data
> > >   - Wrap all macro arguments in parentheses
> > >
> > >   drivers/gpu/drm/sun4i/Kconfig            |  11 +
> > >   drivers/gpu/drm/sun4i/Makefile           |   3 +
> > >   drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
> > >   drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
> > >   drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
> > >   5 files changed, 515 insertions(+)
> > >   create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> > Since this is actually an audio driver, please include all the ALSA / ASoC
> > maintainers and mailing lists (CC-ed).
> >
> > > diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
> > > index 37e90e42943f..ca2ab5d53dd4 100644
> > > --- a/drivers/gpu/drm/sun4i/Kconfig
> > > +++ b/drivers/gpu/drm/sun4i/Kconfig
> > > @@ -23,6 +23,17 @@ config DRM_SUN4I_HDMI
> > >            Choose this option if you have an Allwinner SoC with an HDMI
> > >            controller.
> > >
> > > +config DRM_SUN4I_HDMI_AUDIO
> > > +       bool "Allwinner A10 HDMI Audio Support"
> > > +       default y
> > > +       depends on DRM_SUN4I_HDMI
> > > +       depends on SND_SOC=y || SND_SOC=DRM_SUN4I_HDMI
> > > +       select SND_PCM_ELD
> > > +       select SND_SOC_GENERIC_DMAENGINE_PCM
> > > +       help
> > > +         Choose this option if you have an Allwinner SoC with an HDMI
> > > +         controller and want to use audio.
> > > +
> > >   config DRM_SUN4I_HDMI_CEC
> > >          bool "Allwinner A10 HDMI CEC Support"
> > >          depends on DRM_SUN4I_HDMI
> > > diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
> > > index 0d04f2447b01..492bfd28ad2e 100644
> > > --- a/drivers/gpu/drm/sun4i/Makefile
> > > +++ b/drivers/gpu/drm/sun4i/Makefile
> > > @@ -5,6 +5,9 @@ sun4i-frontend-y                += sun4i_frontend.o
> > >   sun4i-drm-y                    += sun4i_drv.o
> > >   sun4i-drm-y                    += sun4i_framebuffer.o
> > >
> > > +ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
> > > +sun4i-drm-hdmi-y               += sun4i_hdmi_audio.o
> > > +endif
> > >   sun4i-drm-hdmi-y               += sun4i_hdmi_ddc_clk.o
> > >   sun4i-drm-hdmi-y               += sun4i_hdmi_enc.o
> > >   sun4i-drm-hdmi-y               += sun4i_hdmi_i2c.o
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> > > index 7ad3f06c127e..28621d289655 100644
> > > --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> > > @@ -42,7 +42,32 @@
> > >   #define SUN4I_HDMI_VID_TIMING_POL_VSYNC                BIT(1)
> > >   #define SUN4I_HDMI_VID_TIMING_POL_HSYNC                BIT(0)
> > >
> > > +#define SUN4I_HDMI_AUDIO_CTRL_REG      0x040
> > > +#define SUN4I_HDMI_AUDIO_CTRL_ENABLE           BIT(31)
> > > +#define SUN4I_HDMI_AUDIO_CTRL_RESET            BIT(30)
> > > +
> > > +#define SUN4I_HDMI_AUDIO_FMT_REG       0x048
> > > +#define SUN4I_HDMI_AUDIO_FMT_SRC               BIT(31)
> > > +#define SUN4I_HDMI_AUDIO_FMT_LAYOUT            BIT(3)
> > > +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG(n)         ((n) - 1)
> > > +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK       GENMASK(2, 0)
> > > +
> > > +#define SUN4I_HDMI_AUDIO_PCM_REG       0x4c
> > > +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP(n, m)      (((m) - 1) << ((n) * 4))
> > > +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(n)    (GENMASK(2, 0) << ((n) * 4))
> > > +
> > > +#define SUN4I_HDMI_AUDIO_CTS_REG       0x050
> > > +#define SUN4I_HDMI_AUDIO_CTS(n)                        ((n) & GENMASK(19, 0))
> > > +
> > > +#define SUN4I_HDMI_AUDIO_N_REG         0x054
> > > +#define SUN4I_HDMI_AUDIO_N(n)                  ((n) & GENMASK(19, 0))
> > > +
> > > +#define SUN4I_HDMI_AUDIO_STAT0_REG     0x58
> > > +#define SUN4I_HDMI_AUDIO_STAT0_FREQ(n)         ((n) << 24)
> > > +#define SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK       GENMASK(27, 24)
> > > +
> > >   #define SUN4I_HDMI_AVI_INFOFRAME_REG(n)        (0x080 + (n))
> > > +#define SUN4I_HDMI_AUDIO_INFOFRAME_REG(n)      (0x0a0 + (n))
> > >
> > >   #define SUN4I_HDMI_PAD_CTRL0_REG       0x200
> > >   #define SUN4I_HDMI_PAD_CTRL0_BIASEN            BIT(31)
> > > @@ -242,6 +267,11 @@ struct sun4i_hdmi_variant {
> > >          bool                    ddc_fifo_has_dir;
> > >   };
> > >
> > > +struct sun4i_hdmi_audio {
> > > +       struct snd_soc_card             *card;
> > > +       u8                              channels;
> > > +};
> > > +
> > >   struct sun4i_hdmi {
> > >          struct drm_connector    connector;
> > >          struct drm_encoder      encoder;
> > > @@ -283,9 +313,14 @@ struct sun4i_hdmi {
> > >          struct regmap_field     *field_ddc_sda_en;
> > >          struct regmap_field     *field_ddc_sck_en;
> > >
> > > +
> > >          struct sun4i_drv        *drv;
> > >
> > >          bool                    hdmi_monitor;
> > > +       bool                    hdmi_audio;
> > > +
> > > +       struct sun4i_hdmi_audio audio;
> > > +
> > >          struct cec_adapter      *cec_adap;
> > >
> > >          const struct sun4i_hdmi_variant *variant;
> > > @@ -294,5 +329,7 @@ struct sun4i_hdmi {
> > >   int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
> > >   int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
> > >   int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
> > > +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi);
> > > +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi);
> > >
> > >   #endif /* _SUN4I_HDMI_H_ */
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> > > new file mode 100644
> > > index 000000000000..f42f2cea4e9e
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
> > > @@ -0,0 +1,450 @@
> > > +// SPDX-License-Identifier: GPL-2.0-or-later
> > > +/*
> > > + * Copyright (C) 2020 Olimex Ltd.
> > > + *   Author: Stefan Mavrodiev <stefan@olimex.com>
> > > + */
> > > +#include <linux/dma-mapping.h>
> > > +#include <linux/dmaengine.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of_dma.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include <drm/drm_print.h>
> > > +
> > > +#include <sound/dmaengine_pcm.h>
> > > +#include <sound/pcm_drm_eld.h>
> > > +#include <sound/pcm_params.h>
> > > +#include <sound/soc.h>
> > > +
> > > +#include "sun4i_hdmi.h"
> > > +
> > > +static int sun4i_hdmi_audio_ctl_eld_info(struct snd_kcontrol *kcontrol,
> > > +                                        struct snd_ctl_elem_info *uinfo)
> > > +{
> > > +       uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
> > > +       uinfo->count = MAX_ELD_BYTES;
> > > +       return 0;
> > > +}
> > > +
> > > +static int sun4i_hdmi_audio_ctl_eld_get(struct snd_kcontrol *kcontrol,
> > > +                                       struct snd_ctl_elem_value *ucontrol)
> > > +{
> > > +       struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
> > > +       struct snd_soc_card *card = snd_soc_component_get_drvdata(component);
> > > +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> > > +
> > > +       memcpy(ucontrol->value.bytes.data,
> > > +              hdmi->connector.eld,
> > > +              MAX_ELD_BYTES);
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static const struct snd_kcontrol_new sun4i_hdmi_audio_controls[] = {
> > > +       {
> > > +               .access = SNDRV_CTL_ELEM_ACCESS_READ |
> > > +                         SNDRV_CTL_ELEM_ACCESS_VOLATILE,
> > > +               .iface = SNDRV_CTL_ELEM_IFACE_PCM,
> > > +               .name = "ELD",
> > > +               .info = sun4i_hdmi_audio_ctl_eld_info,
> > > +               .get = sun4i_hdmi_audio_ctl_eld_get,
> > > +       },
> > > +};
> > > +
> > > +static const struct snd_soc_dapm_widget sun4i_hdmi_audio_widgets[] = {
> > > +       SND_SOC_DAPM_OUTPUT("TX"),
> > > +};
> > > +
> > > +static const struct snd_soc_dapm_route sun4i_hdmi_audio_routes[] = {
> > > +       { "TX", NULL, "Playback" },
> > > +};
> > > +
> > > +static const struct snd_soc_component_driver sun4i_hdmi_audio_component = {
> > > +       .controls               = sun4i_hdmi_audio_controls,
> > > +       .num_controls           = ARRAY_SIZE(sun4i_hdmi_audio_controls),
> > > +       .dapm_widgets           = sun4i_hdmi_audio_widgets,
> > > +       .num_dapm_widgets       = ARRAY_SIZE(sun4i_hdmi_audio_widgets),
> > > +       .dapm_routes            = sun4i_hdmi_audio_routes,
> > > +       .num_dapm_routes        = ARRAY_SIZE(sun4i_hdmi_audio_routes),
> > > +};
> > > +
> > > +static int sun4i_hdmi_audio_startup(struct snd_pcm_substream *substream,
> > > +                                   struct snd_soc_dai *dai)
> > > +{
> > > +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> > > +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> > > +       u32 reg;
> > > +       int ret;
> > > +
> > > +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
> > > +       regmap_write(hdmi->regmap,
> > > +                    SUN4I_HDMI_AUDIO_CTRL_REG,
> > > +                    SUN4I_HDMI_AUDIO_CTRL_RESET);
> > > +       ret = regmap_read_poll_timeout(hdmi->regmap,
> > > +                                      SUN4I_HDMI_AUDIO_CTRL_REG,
> > > +                                      reg, !reg, 100, 50000);
> > > +       if (ret < 0) {
> > > +               DRM_ERROR("Failed to reset HDMI Audio\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       regmap_write(hdmi->regmap,
> > > +                    SUN4I_HDMI_AUDIO_CTRL_REG,
> > > +                    SUN4I_HDMI_AUDIO_CTRL_ENABLE);
> > > +
> > > +       return snd_pcm_hw_constraint_eld(substream->runtime,
> > > +                                       hdmi->connector.eld);
> > > +}
> > > +
> > > +static void sun4i_hdmi_audio_shutdown(struct snd_pcm_substream *substream,
> > > +                                     struct snd_soc_dai *dai)
> > > +{
> > > +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> > > +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> > > +
> > > +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
> > > +}
> > > +
> > > +static int sun4i_hdmi_setup_audio_infoframes(struct sun4i_hdmi *hdmi)
> > > +{
> > > +       union hdmi_infoframe frame;
> > > +       u8 buffer[14];
> > > +       int i, ret;
> > > +
> > > +       ret = hdmi_audio_infoframe_init(&frame.audio);
> > > +       if (ret < 0) {
> > > +               DRM_ERROR("Failed to init HDMI audio infoframe\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       frame.audio.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
> > > +       frame.audio.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
> > > +       frame.audio.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
> > > +       frame.audio.channels = hdmi->audio.channels;
> > > +
> > > +       ret = hdmi_infoframe_pack(&frame, buffer, sizeof(buffer));
> > > +       if (ret < 0) {
> > > +               DRM_ERROR("Failed to pack HDMI audio infoframe\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       for (i = 0; i < sizeof(buffer); i++)
> > > +               writeb(buffer[i],
> > > +                      hdmi->base + SUN4I_HDMI_AUDIO_INFOFRAME_REG(i));
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static void sun4i_hdmi_audio_set_cts_n(struct sun4i_hdmi *hdmi,
> > > +                                      struct snd_pcm_hw_params *params)
> > > +{
> > > +       struct drm_encoder *encoder = &hdmi->encoder;
> > > +       struct drm_crtc *crtc = encoder->crtc;
> > > +       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> > > +       u32 rate = params_rate(params);
> > > +       u32 n, cts;
> > > +       u64 tmp;
> > > +
> > > +       /**
> > > +        * Calculate Cycle Time Stamp (CTS) and Numerator (N):
> > > +        *
> > > +        * N = 128 * Samplerate / 1000
> > > +        * CTS = (Ftdms * N) / (128 * Samplerate)
> > > +        */
> > > +
> > > +       n = 128 * rate / 1000;
> > > +       tmp = (u64)(mode->clock * 1000) * n;
> > > +       do_div(tmp, 128 * rate);
> > > +       cts = tmp;
> > > +
> > > +       regmap_write(hdmi->regmap,
> > > +                    SUN4I_HDMI_AUDIO_CTS_REG,
> > > +                    SUN4I_HDMI_AUDIO_CTS(cts));
> > > +
> > > +       regmap_write(hdmi->regmap,
> > > +                    SUN4I_HDMI_AUDIO_N_REG,
> > > +                    SUN4I_HDMI_AUDIO_N(n));
> > > +}
> > > +
> > > +static int sun4i_hdmi_audio_set_hw_rate(struct sun4i_hdmi *hdmi,
> > > +                                       struct snd_pcm_hw_params *params)
> > > +{
> > > +       u32 rate = params_rate(params);
> > > +       u32 val;
> > > +
> > > +       switch (rate) {
> > > +       case 44100:
> > > +               val = 0x0;
> > > +               break;
> > > +       case 48000:
> > > +               val = 0x2;
> > > +               break;
> > > +       case 32000:
> > > +               val = 0x3;
> > > +               break;
> > > +       case 88200:
> > > +               val = 0x8;
> > > +               break;
> > > +       case 96000:
> > > +               val = 0x9;
> > > +               break;
> > > +       case 176400:
> > > +               val = 0xc;
> > > +               break;
> > > +       case 192000:
> > > +               val = 0xe;
> > > +               break;
> > > +       default:
> > > +               return -EINVAL;
> > > +       }
> > > +
> > > +       regmap_update_bits(hdmi->regmap,
> > > +                          SUN4I_HDMI_AUDIO_STAT0_REG,
> > > +                          SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK,
> > > +                          SUN4I_HDMI_AUDIO_STAT0_FREQ(val));
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int sun4i_hdmi_audio_set_hw_channels(struct sun4i_hdmi *hdmi,
> > > +                                           struct snd_pcm_hw_params *params)
> > > +{
> > > +       u32 channels = params_channels(params);
> > > +
> > > +       if (channels > 8)
> > > +               return -EINVAL;
> > > +
> > > +       hdmi->audio.channels = channels;
> > > +
> > > +       regmap_update_bits(hdmi->regmap,
> > > +                          SUN4I_HDMI_AUDIO_FMT_REG,
> > > +                          SUN4I_HDMI_AUDIO_FMT_LAYOUT,
> > > +                          (channels > 2) ? SUN4I_HDMI_AUDIO_FMT_LAYOUT : 0);
> > > +
> > > +       regmap_update_bits(hdmi->regmap,
> > > +                          SUN4I_HDMI_AUDIO_FMT_REG,
> > > +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK,
> > > +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG(channels));
> > > +
> > > +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_PCM_REG, 0x76543210);
> > > +
> > > +       /**
> > > +        * If only one channel is required, send the same sample
> > > +        * to the sink device as a left and right channel.
> > > +        */
> > > +       if (channels == 1)
> > > +               regmap_update_bits(hdmi->regmap,
> > > +                                  SUN4I_HDMI_AUDIO_PCM_REG,
> > > +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(1),
> > > +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP(1, 1));
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int sun4i_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
> > > +                                     struct snd_pcm_hw_params *params,
> > > +                                     struct snd_soc_dai *dai)
> > > +{
> > > +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> > > +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> > > +       int ret;
> > > +
> > > +       ret = sun4i_hdmi_audio_set_hw_rate(hdmi, params);
> > > +       if (ret < 0)
> > > +               return ret;
> > > +
> > > +       ret = sun4i_hdmi_audio_set_hw_channels(hdmi, params);
> > > +       if (ret < 0)
> > > +               return ret;
> > > +
> > > +       sun4i_hdmi_audio_set_cts_n(hdmi, params);
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static int sun4i_hdmi_audio_trigger(struct snd_pcm_substream *substream,
> > > +                                   int cmd,
> > > +                                   struct snd_soc_dai *dai)
> > > +{
> > > +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
> > > +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
> > > +       int ret = 0;
> > > +
> > > +       switch (cmd) {
> > > +       case SNDRV_PCM_TRIGGER_START:
> > > +               ret = sun4i_hdmi_setup_audio_infoframes(hdmi);
> > > +               break;
> > > +       default:
> > > +               break;
> > > +       }
> > > +
> > > +       return ret;
> > > +}
> > > +
> > > +static const struct snd_soc_dai_ops sun4i_hdmi_audio_dai_ops = {
> > > +       .startup = sun4i_hdmi_audio_startup,
> > > +       .shutdown = sun4i_hdmi_audio_shutdown,
> > > +       .hw_params = sun4i_hdmi_audio_hw_params,
> > > +       .trigger = sun4i_hdmi_audio_trigger,
> > > +};
> > > +
> > > +static int sun4i_hdmi_audio_dai_probe(struct snd_soc_dai *dai)
> > > +{
> > > +       struct snd_dmaengine_dai_dma_data *dma_data;
> > > +
> > > +       dma_data = devm_kzalloc(dai->dev, sizeof(*dma_data), GFP_KERNEL);
> > > +       if (!dma_data)
> > > +               return -ENOMEM;
> > > +
> > > +       dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> > > +       dma_data->maxburst = 8;
> > > +
> > > +       snd_soc_dai_init_dma_data(dai, dma_data, NULL);
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static struct snd_soc_dai_driver sun4i_hdmi_audio_dai = {
> > > +       .name = "HDMI",
> > > +       .ops = &sun4i_hdmi_audio_dai_ops,
> > > +       .probe = sun4i_hdmi_audio_dai_probe,
> > > +       .playback = {
> > > +               .stream_name    = "Playback",
> > > +               .channels_min   = 1,
> > > +               .channels_max   = 8,
> > > +               .formats        = SNDRV_PCM_FMTBIT_S16_LE,
> > > +               .rates          = SNDRV_PCM_RATE_8000_192000,
> > > +       },
> > > +};
> > > +
> > > +static const struct snd_pcm_hardware sun4i_hdmi_audio_pcm_hardware = {
> > > +       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
> > > +                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
> > > +                                 SNDRV_PCM_INFO_MMAP |
> > > +                                 SNDRV_PCM_INFO_MMAP_VALID |
> > > +                                 SNDRV_PCM_INFO_PAUSE |
> > > +                                 SNDRV_PCM_INFO_RESUME,
> > > +       .formats                = SNDRV_PCM_FMTBIT_S16_LE,
> > > +       .rates                  = SNDRV_PCM_RATE_8000_192000,
> > > +       .rate_min               = 8000,
> > > +       .rate_max               = 192000,
> > > +       .channels_min           = 1,
> > > +       .channels_max           = 8,
> > > +       .buffer_bytes_max       = 128 * 1024,
> > > +       .period_bytes_min       = 4 * 1024,
> > > +       .period_bytes_max       = 32 * 1024,
> > > +       .periods_min            = 2,
> > > +       .periods_max            = 8,
> > > +       .fifo_size              = 128,
> > > +};
> > > +
> > > +static const struct snd_dmaengine_pcm_config sun4i_hdmi_audio_pcm_config = {
> > > +       .chan_names[SNDRV_PCM_STREAM_PLAYBACK] = "audio-tx",
> > > +       .pcm_hardware = &sun4i_hdmi_audio_pcm_hardware,
> > > +       .prealloc_buffer_size = 128 * 1024,
> > > +       .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
> > > +};
> > > +
> > > +struct snd_soc_card sun4i_hdmi_audio_card = {
> > > +       .name = "sun4i-hdmi",
> > > +};
> > > +
> > > +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi)
> > > +{
> > > +       struct snd_soc_card *card = &sun4i_hdmi_audio_card;
> > > +       struct snd_soc_dai_link_component *comp;
> > > +       struct snd_soc_dai_link *link;
> > > +       int ret;
> > > +
> > > +       ret = snd_dmaengine_pcm_register(hdmi->dev,
> > > +                                        &sun4i_hdmi_audio_pcm_config, 0);
> > > +       if (ret < 0) {
> > > +               DRM_ERROR("Could not register PCM\n");
> > > +               return ret;
> > > +       }
> > > +
> > > +       ret = snd_soc_register_component(hdmi->dev,
> > > +                                        &sun4i_hdmi_audio_component,
> > > +                                        &sun4i_hdmi_audio_dai, 1);
> > > +       if (ret < 0) {
> > > +               DRM_ERROR("Could not register DAI\n");
> > > +               goto unregister_pcm;
> > > +       }
> > > +
> > > +       link = devm_kzalloc(hdmi->dev, sizeof(*link), GFP_KERNEL);
> > > +       if (!link) {
> > > +               ret = -ENOMEM;
> > > +               goto unregister_component;
> > > +       }
> > > +
> > > +       comp = devm_kzalloc(hdmi->dev, sizeof(*comp) * 3, GFP_KERNEL);
> > > +       if (!comp) {
> > > +               ret = -ENOMEM;
> > > +               goto unregister_component;
> > > +       }
> > > +
> > > +       link->cpus = &comp[0];
> > > +       link->codecs = &comp[1];
> > > +       link->platforms = &comp[2];
> > > +
> > > +       link->num_cpus = 1;
> > > +       link->num_codecs = 1;
> > > +       link->num_platforms = 1;
> > > +
> > > +       link->playback_only = 1;
> > > +
> > > +       link->name = "SUN4I-HDMI";
> > > +       link->stream_name = "SUN4I-HDMI PCM";
> > > +
> > > +       link->codecs->name = dev_name(hdmi->dev);
> > > +       link->codecs->dai_name  = sun4i_hdmi_audio_dai.name;
> > > +
> > > +       link->cpus->dai_name = dev_name(hdmi->dev);
> > > +
> > > +       link->platforms->name = dev_name(hdmi->dev);
> > > +
> > > +       link->dai_fmt = SND_SOC_DAIFMT_I2S;
> > > +
> > > +       card->dai_link = link;
> > > +       card->num_links = 1;
> > > +       card->dev = hdmi->dev;
> > > +
> > > +       hdmi->audio.card = card;
> > > +
> > > +       /**
> > > +        * snd_soc_register_card() will overwrite the driver_data pointer.
> > > +        * So before registering the card, store the original pointer in
> > > +        * card->drvdata.
> > > +        */
> > > +       snd_soc_card_set_drvdata(card, hdmi);
> > > +       ret = snd_soc_register_card(card);
> > > +       if (ret)
> > > +               goto unregister_component;
> > So using ASoC with all the components IMHO is just adding dead weight. The
> > audio interface for this particular hardware is just a FIFO that needs to
> > be written to by an external DMA engine, and a bunch of controls to setup
> > the parameters of the HDMI audio stream. There's no power sequencing to do,
> > and no actual individual components to control. There's no reason you couldn't
> > use just the ALSA DMAENGINE helpers to create a simple ALSA sound card.
> >
> > (Maybe we could clean it up after it's merged? Would there be any issues
> >   with backward compatibility?)
> >
> > I think the only example of this besides ASoC is the PXA2xx sound library
> > and AC97 driver:
> >
> >    - sound/arm/pxa2xx-pcm-lib.c
> >    - sound/arm/pxa2xx-ac97.c
>
> I'd like to hear Maxime opinion on this. I get it why it's overkill to use
> ASoC.
> However it will take only couple of lines to make the changes for v4. On the
> other
> side with dropping the ASoC, the driver must be almost rewritten. It's not
> such a big deal,
> but I want to know that this is the right thing to do.

I don't really have an opinion on this, either way is fine for me, so
if it's simpler to go for ALSA, then let's do it :)

Maxime

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Re: [linux-sunxi] [PATCH v3 1/1] drm: sun4i: hdmi: Add support for sun4i HDMI encoder audio

[Stefan Mavrodiev]

On 2/25/20 11:58 AM, Maxime Ripard wrote:
> On Tue, Feb 25, 2020 at 11:45:28AM +0200, Stefan Mavrodiev wrote:
>> On 1/29/20 6:34 PM, Chen-Yu Tsai wrote:
>>> On Tue, Jan 28, 2020 at 10:07 PM Stefan Mavrodiev <stefan@olimex.com> wrote:
>>>> Add HDMI audio support for the sun4i-hdmi encoder, used on
>>>> the older Allwinner chips - A10, A20, A31.
>>>>
>>>> Most of the code is based on the BSP implementation. In it
>>>> dditional formats are supported (S20_3LE and S24_LE), however
>>>> there where some problems with them and only S16_LE is left.
>>>>
>>>> Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
>>>> ---
>>>> Changes for v3:
>>>>    - Instead of platfrom_driver dynammicly register/unregister card
>>>>    - Add Kconfig dependencies
>>>>    - Restrore drvdata after card unregistering
>>>>
>>>> Changes for v2:
>>>>    - Create a new platform driver instead of using the HDMI encoder
>>>>    - Expose a new kcontrol to the userspace holding the ELD data
>>>>    - Wrap all macro arguments in parentheses
>>>>
>>>>    drivers/gpu/drm/sun4i/Kconfig            |  11 +
>>>>    drivers/gpu/drm/sun4i/Makefile           |   3 +
>>>>    drivers/gpu/drm/sun4i/sun4i_hdmi.h       |  37 ++
>>>>    drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c | 450 +++++++++++++++++++++++
>>>>    drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c   |  14 +
>>>>    5 files changed, 515 insertions(+)
>>>>    create mode 100644 drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
>>> Since this is actually an audio driver, please include all the ALSA / ASoC
>>> maintainers and mailing lists (CC-ed).
>>>
>>>> diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
>>>> index 37e90e42943f..ca2ab5d53dd4 100644
>>>> --- a/drivers/gpu/drm/sun4i/Kconfig
>>>> +++ b/drivers/gpu/drm/sun4i/Kconfig
>>>> @@ -23,6 +23,17 @@ config DRM_SUN4I_HDMI
>>>>             Choose this option if you have an Allwinner SoC with an HDMI
>>>>             controller.
>>>>
>>>> +config DRM_SUN4I_HDMI_AUDIO
>>>> +       bool "Allwinner A10 HDMI Audio Support"
>>>> +       default y
>>>> +       depends on DRM_SUN4I_HDMI
>>>> +       depends on SND_SOC=y || SND_SOC=DRM_SUN4I_HDMI
>>>> +       select SND_PCM_ELD
>>>> +       select SND_SOC_GENERIC_DMAENGINE_PCM
>>>> +       help
>>>> +         Choose this option if you have an Allwinner SoC with an HDMI
>>>> +         controller and want to use audio.
>>>> +
>>>>    config DRM_SUN4I_HDMI_CEC
>>>>           bool "Allwinner A10 HDMI CEC Support"
>>>>           depends on DRM_SUN4I_HDMI
>>>> diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
>>>> index 0d04f2447b01..492bfd28ad2e 100644
>>>> --- a/drivers/gpu/drm/sun4i/Makefile
>>>> +++ b/drivers/gpu/drm/sun4i/Makefile
>>>> @@ -5,6 +5,9 @@ sun4i-frontend-y                += sun4i_frontend.o
>>>>    sun4i-drm-y                    += sun4i_drv.o
>>>>    sun4i-drm-y                    += sun4i_framebuffer.o
>>>>
>>>> +ifdef CONFIG_DRM_SUN4I_HDMI_AUDIO
>>>> +sun4i-drm-hdmi-y               += sun4i_hdmi_audio.o
>>>> +endif
>>>>    sun4i-drm-hdmi-y               += sun4i_hdmi_ddc_clk.o
>>>>    sun4i-drm-hdmi-y               += sun4i_hdmi_enc.o
>>>>    sun4i-drm-hdmi-y               += sun4i_hdmi_i2c.o
>>>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>>>> index 7ad3f06c127e..28621d289655 100644
>>>> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>>>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
>>>> @@ -42,7 +42,32 @@
>>>>    #define SUN4I_HDMI_VID_TIMING_POL_VSYNC                BIT(1)
>>>>    #define SUN4I_HDMI_VID_TIMING_POL_HSYNC                BIT(0)
>>>>
>>>> +#define SUN4I_HDMI_AUDIO_CTRL_REG      0x040
>>>> +#define SUN4I_HDMI_AUDIO_CTRL_ENABLE           BIT(31)
>>>> +#define SUN4I_HDMI_AUDIO_CTRL_RESET            BIT(30)
>>>> +
>>>> +#define SUN4I_HDMI_AUDIO_FMT_REG       0x048
>>>> +#define SUN4I_HDMI_AUDIO_FMT_SRC               BIT(31)
>>>> +#define SUN4I_HDMI_AUDIO_FMT_LAYOUT            BIT(3)
>>>> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG(n)         ((n) - 1)
>>>> +#define SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK       GENMASK(2, 0)
>>>> +
>>>> +#define SUN4I_HDMI_AUDIO_PCM_REG       0x4c
>>>> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP(n, m)      (((m) - 1) << ((n) * 4))
>>>> +#define SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(n)    (GENMASK(2, 0) << ((n) * 4))
>>>> +
>>>> +#define SUN4I_HDMI_AUDIO_CTS_REG       0x050
>>>> +#define SUN4I_HDMI_AUDIO_CTS(n)                        ((n) & GENMASK(19, 0))
>>>> +
>>>> +#define SUN4I_HDMI_AUDIO_N_REG         0x054
>>>> +#define SUN4I_HDMI_AUDIO_N(n)                  ((n) & GENMASK(19, 0))
>>>> +
>>>> +#define SUN4I_HDMI_AUDIO_STAT0_REG     0x58
>>>> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ(n)         ((n) << 24)
>>>> +#define SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK       GENMASK(27, 24)
>>>> +
>>>>    #define SUN4I_HDMI_AVI_INFOFRAME_REG(n)        (0x080 + (n))
>>>> +#define SUN4I_HDMI_AUDIO_INFOFRAME_REG(n)      (0x0a0 + (n))
>>>>
>>>>    #define SUN4I_HDMI_PAD_CTRL0_REG       0x200
>>>>    #define SUN4I_HDMI_PAD_CTRL0_BIASEN            BIT(31)
>>>> @@ -242,6 +267,11 @@ struct sun4i_hdmi_variant {
>>>>           bool                    ddc_fifo_has_dir;
>>>>    };
>>>>
>>>> +struct sun4i_hdmi_audio {
>>>> +       struct snd_soc_card             *card;
>>>> +       u8                              channels;
>>>> +};
>>>> +
>>>>    struct sun4i_hdmi {
>>>>           struct drm_connector    connector;
>>>>           struct drm_encoder      encoder;
>>>> @@ -283,9 +313,14 @@ struct sun4i_hdmi {
>>>>           struct regmap_field     *field_ddc_sda_en;
>>>>           struct regmap_field     *field_ddc_sck_en;
>>>>
>>>> +
>>>>           struct sun4i_drv        *drv;
>>>>
>>>>           bool                    hdmi_monitor;
>>>> +       bool                    hdmi_audio;
>>>> +
>>>> +       struct sun4i_hdmi_audio audio;
>>>> +
>>>>           struct cec_adapter      *cec_adap;
>>>>
>>>>           const struct sun4i_hdmi_variant *variant;
>>>> @@ -294,5 +329,7 @@ struct sun4i_hdmi {
>>>>    int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
>>>>    int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
>>>>    int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
>>>> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi);
>>>> +void sun4i_hdmi_audio_destroy(struct sun4i_hdmi *hdmi);
>>>>
>>>>    #endif /* _SUN4I_HDMI_H_ */
>>>> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
>>>> new file mode 100644
>>>> index 000000000000..f42f2cea4e9e
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_audio.c
>>>> @@ -0,0 +1,450 @@
>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>>> +/*
>>>> + * Copyright (C) 2020 Olimex Ltd.
>>>> + *   Author: Stefan Mavrodiev <stefan@olimex.com>
>>>> + */
>>>> +#include <linux/dma-mapping.h>
>>>> +#include <linux/dmaengine.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_dma.h>
>>>> +#include <linux/regmap.h>
>>>> +
>>>> +#include <drm/drm_print.h>
>>>> +
>>>> +#include <sound/dmaengine_pcm.h>
>>>> +#include <sound/pcm_drm_eld.h>
>>>> +#include <sound/pcm_params.h>
>>>> +#include <sound/soc.h>
>>>> +
>>>> +#include "sun4i_hdmi.h"
>>>> +
>>>> +static int sun4i_hdmi_audio_ctl_eld_info(struct snd_kcontrol *kcontrol,
>>>> +                                        struct snd_ctl_elem_info *uinfo)
>>>> +{
>>>> +       uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
>>>> +       uinfo->count = MAX_ELD_BYTES;
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_audio_ctl_eld_get(struct snd_kcontrol *kcontrol,
>>>> +                                       struct snd_ctl_elem_value *ucontrol)
>>>> +{
>>>> +       struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
>>>> +       struct snd_soc_card *card = snd_soc_component_get_drvdata(component);
>>>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>>>> +
>>>> +       memcpy(ucontrol->value.bytes.data,
>>>> +              hdmi->connector.eld,
>>>> +              MAX_ELD_BYTES);
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static const struct snd_kcontrol_new sun4i_hdmi_audio_controls[] = {
>>>> +       {
>>>> +               .access = SNDRV_CTL_ELEM_ACCESS_READ |
>>>> +                         SNDRV_CTL_ELEM_ACCESS_VOLATILE,
>>>> +               .iface = SNDRV_CTL_ELEM_IFACE_PCM,
>>>> +               .name = "ELD",
>>>> +               .info = sun4i_hdmi_audio_ctl_eld_info,
>>>> +               .get = sun4i_hdmi_audio_ctl_eld_get,
>>>> +       },
>>>> +};
>>>> +
>>>> +static const struct snd_soc_dapm_widget sun4i_hdmi_audio_widgets[] = {
>>>> +       SND_SOC_DAPM_OUTPUT("TX"),
>>>> +};
>>>> +
>>>> +static const struct snd_soc_dapm_route sun4i_hdmi_audio_routes[] = {
>>>> +       { "TX", NULL, "Playback" },
>>>> +};
>>>> +
>>>> +static const struct snd_soc_component_driver sun4i_hdmi_audio_component = {
>>>> +       .controls               = sun4i_hdmi_audio_controls,
>>>> +       .num_controls           = ARRAY_SIZE(sun4i_hdmi_audio_controls),
>>>> +       .dapm_widgets           = sun4i_hdmi_audio_widgets,
>>>> +       .num_dapm_widgets       = ARRAY_SIZE(sun4i_hdmi_audio_widgets),
>>>> +       .dapm_routes            = sun4i_hdmi_audio_routes,
>>>> +       .num_dapm_routes        = ARRAY_SIZE(sun4i_hdmi_audio_routes),
>>>> +};
>>>> +
>>>> +static int sun4i_hdmi_audio_startup(struct snd_pcm_substream *substream,
>>>> +                                   struct snd_soc_dai *dai)
>>>> +{
>>>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>>>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>>>> +       u32 reg;
>>>> +       int ret;
>>>> +
>>>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
>>>> +       regmap_write(hdmi->regmap,
>>>> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
>>>> +                    SUN4I_HDMI_AUDIO_CTRL_RESET);
>>>> +       ret = regmap_read_poll_timeout(hdmi->regmap,
>>>> +                                      SUN4I_HDMI_AUDIO_CTRL_REG,
>>>> +                                      reg, !reg, 100, 50000);
>>>> +       if (ret < 0) {
>>>> +               DRM_ERROR("Failed to reset HDMI Audio\n");
>>>> +               return ret;
>>>> +       }
>>>> +
>>>> +       regmap_write(hdmi->regmap,
>>>> +                    SUN4I_HDMI_AUDIO_CTRL_REG,
>>>> +                    SUN4I_HDMI_AUDIO_CTRL_ENABLE);
>>>> +
>>>> +       return snd_pcm_hw_constraint_eld(substream->runtime,
>>>> +                                       hdmi->connector.eld);
>>>> +}
>>>> +
>>>> +static void sun4i_hdmi_audio_shutdown(struct snd_pcm_substream *substream,
>>>> +                                     struct snd_soc_dai *dai)
>>>> +{
>>>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>>>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>>>> +
>>>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_CTRL_REG, 0);
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_setup_audio_infoframes(struct sun4i_hdmi *hdmi)
>>>> +{
>>>> +       union hdmi_infoframe frame;
>>>> +       u8 buffer[14];
>>>> +       int i, ret;
>>>> +
>>>> +       ret = hdmi_audio_infoframe_init(&frame.audio);
>>>> +       if (ret < 0) {
>>>> +               DRM_ERROR("Failed to init HDMI audio infoframe\n");
>>>> +               return ret;
>>>> +       }
>>>> +
>>>> +       frame.audio.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
>>>> +       frame.audio.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
>>>> +       frame.audio.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
>>>> +       frame.audio.channels = hdmi->audio.channels;
>>>> +
>>>> +       ret = hdmi_infoframe_pack(&frame, buffer, sizeof(buffer));
>>>> +       if (ret < 0) {
>>>> +               DRM_ERROR("Failed to pack HDMI audio infoframe\n");
>>>> +               return ret;
>>>> +       }
>>>> +
>>>> +       for (i = 0; i < sizeof(buffer); i++)
>>>> +               writeb(buffer[i],
>>>> +                      hdmi->base + SUN4I_HDMI_AUDIO_INFOFRAME_REG(i));
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static void sun4i_hdmi_audio_set_cts_n(struct sun4i_hdmi *hdmi,
>>>> +                                      struct snd_pcm_hw_params *params)
>>>> +{
>>>> +       struct drm_encoder *encoder = &hdmi->encoder;
>>>> +       struct drm_crtc *crtc = encoder->crtc;
>>>> +       const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>>>> +       u32 rate = params_rate(params);
>>>> +       u32 n, cts;
>>>> +       u64 tmp;
>>>> +
>>>> +       /**
>>>> +        * Calculate Cycle Time Stamp (CTS) and Numerator (N):
>>>> +        *
>>>> +        * N = 128 * Samplerate / 1000
>>>> +        * CTS = (Ftdms * N) / (128 * Samplerate)
>>>> +        */
>>>> +
>>>> +       n = 128 * rate / 1000;
>>>> +       tmp = (u64)(mode->clock * 1000) * n;
>>>> +       do_div(tmp, 128 * rate);
>>>> +       cts = tmp;
>>>> +
>>>> +       regmap_write(hdmi->regmap,
>>>> +                    SUN4I_HDMI_AUDIO_CTS_REG,
>>>> +                    SUN4I_HDMI_AUDIO_CTS(cts));
>>>> +
>>>> +       regmap_write(hdmi->regmap,
>>>> +                    SUN4I_HDMI_AUDIO_N_REG,
>>>> +                    SUN4I_HDMI_AUDIO_N(n));
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_audio_set_hw_rate(struct sun4i_hdmi *hdmi,
>>>> +                                       struct snd_pcm_hw_params *params)
>>>> +{
>>>> +       u32 rate = params_rate(params);
>>>> +       u32 val;
>>>> +
>>>> +       switch (rate) {
>>>> +       case 44100:
>>>> +               val = 0x0;
>>>> +               break;
>>>> +       case 48000:
>>>> +               val = 0x2;
>>>> +               break;
>>>> +       case 32000:
>>>> +               val = 0x3;
>>>> +               break;
>>>> +       case 88200:
>>>> +               val = 0x8;
>>>> +               break;
>>>> +       case 96000:
>>>> +               val = 0x9;
>>>> +               break;
>>>> +       case 176400:
>>>> +               val = 0xc;
>>>> +               break;
>>>> +       case 192000:
>>>> +               val = 0xe;
>>>> +               break;
>>>> +       default:
>>>> +               return -EINVAL;
>>>> +       }
>>>> +
>>>> +       regmap_update_bits(hdmi->regmap,
>>>> +                          SUN4I_HDMI_AUDIO_STAT0_REG,
>>>> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ_MASK,
>>>> +                          SUN4I_HDMI_AUDIO_STAT0_FREQ(val));
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_audio_set_hw_channels(struct sun4i_hdmi *hdmi,
>>>> +                                           struct snd_pcm_hw_params *params)
>>>> +{
>>>> +       u32 channels = params_channels(params);
>>>> +
>>>> +       if (channels > 8)
>>>> +               return -EINVAL;
>>>> +
>>>> +       hdmi->audio.channels = channels;
>>>> +
>>>> +       regmap_update_bits(hdmi->regmap,
>>>> +                          SUN4I_HDMI_AUDIO_FMT_REG,
>>>> +                          SUN4I_HDMI_AUDIO_FMT_LAYOUT,
>>>> +                          (channels > 2) ? SUN4I_HDMI_AUDIO_FMT_LAYOUT : 0);
>>>> +
>>>> +       regmap_update_bits(hdmi->regmap,
>>>> +                          SUN4I_HDMI_AUDIO_FMT_REG,
>>>> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG_MASK,
>>>> +                          SUN4I_HDMI_AUDIO_FMT_CH_CFG(channels));
>>>> +
>>>> +       regmap_write(hdmi->regmap, SUN4I_HDMI_AUDIO_PCM_REG, 0x76543210);
>>>> +
>>>> +       /**
>>>> +        * If only one channel is required, send the same sample
>>>> +        * to the sink device as a left and right channel.
>>>> +        */
>>>> +       if (channels == 1)
>>>> +               regmap_update_bits(hdmi->regmap,
>>>> +                                  SUN4I_HDMI_AUDIO_PCM_REG,
>>>> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP_MASK(1),
>>>> +                                  SUN4I_HDMI_AUDIO_PCM_CH_MAP(1, 1));
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_audio_hw_params(struct snd_pcm_substream *substream,
>>>> +                                     struct snd_pcm_hw_params *params,
>>>> +                                     struct snd_soc_dai *dai)
>>>> +{
>>>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>>>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>>>> +       int ret;
>>>> +
>>>> +       ret = sun4i_hdmi_audio_set_hw_rate(hdmi, params);
>>>> +       if (ret < 0)
>>>> +               return ret;
>>>> +
>>>> +       ret = sun4i_hdmi_audio_set_hw_channels(hdmi, params);
>>>> +       if (ret < 0)
>>>> +               return ret;
>>>> +
>>>> +       sun4i_hdmi_audio_set_cts_n(hdmi, params);
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static int sun4i_hdmi_audio_trigger(struct snd_pcm_substream *substream,
>>>> +                                   int cmd,
>>>> +                                   struct snd_soc_dai *dai)
>>>> +{
>>>> +       struct snd_soc_card *card = snd_soc_dai_get_drvdata(dai);
>>>> +       struct sun4i_hdmi *hdmi = snd_soc_card_get_drvdata(card);
>>>> +       int ret = 0;
>>>> +
>>>> +       switch (cmd) {
>>>> +       case SNDRV_PCM_TRIGGER_START:
>>>> +               ret = sun4i_hdmi_setup_audio_infoframes(hdmi);
>>>> +               break;
>>>> +       default:
>>>> +               break;
>>>> +       }
>>>> +
>>>> +       return ret;
>>>> +}
>>>> +
>>>> +static const struct snd_soc_dai_ops sun4i_hdmi_audio_dai_ops = {
>>>> +       .startup = sun4i_hdmi_audio_startup,
>>>> +       .shutdown = sun4i_hdmi_audio_shutdown,
>>>> +       .hw_params = sun4i_hdmi_audio_hw_params,
>>>> +       .trigger = sun4i_hdmi_audio_trigger,
>>>> +};
>>>> +
>>>> +static int sun4i_hdmi_audio_dai_probe(struct snd_soc_dai *dai)
>>>> +{
>>>> +       struct snd_dmaengine_dai_dma_data *dma_data;
>>>> +
>>>> +       dma_data = devm_kzalloc(dai->dev, sizeof(*dma_data), GFP_KERNEL);
>>>> +       if (!dma_data)
>>>> +               return -ENOMEM;
>>>> +
>>>> +       dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>>>> +       dma_data->maxburst = 8;
>>>> +
>>>> +       snd_soc_dai_init_dma_data(dai, dma_data, NULL);
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static struct snd_soc_dai_driver sun4i_hdmi_audio_dai = {
>>>> +       .name = "HDMI",
>>>> +       .ops = &sun4i_hdmi_audio_dai_ops,
>>>> +       .probe = sun4i_hdmi_audio_dai_probe,
>>>> +       .playback = {
>>>> +               .stream_name    = "Playback",
>>>> +               .channels_min   = 1,
>>>> +               .channels_max   = 8,
>>>> +               .formats        = SNDRV_PCM_FMTBIT_S16_LE,
>>>> +               .rates          = SNDRV_PCM_RATE_8000_192000,
>>>> +       },
>>>> +};
>>>> +
>>>> +static const struct snd_pcm_hardware sun4i_hdmi_audio_pcm_hardware = {
>>>> +       .info                   = SNDRV_PCM_INFO_INTERLEAVED |
>>>> +                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
>>>> +                                 SNDRV_PCM_INFO_MMAP |
>>>> +                                 SNDRV_PCM_INFO_MMAP_VALID |
>>>> +                                 SNDRV_PCM_INFO_PAUSE |
>>>> +                                 SNDRV_PCM_INFO_RESUME,
>>>> +       .formats                = SNDRV_PCM_FMTBIT_S16_LE,
>>>> +       .rates                  = SNDRV_PCM_RATE_8000_192000,
>>>> +       .rate_min               = 8000,
>>>> +       .rate_max               = 192000,
>>>> +       .channels_min           = 1,
>>>> +       .channels_max           = 8,
>>>> +       .buffer_bytes_max       = 128 * 1024,
>>>> +       .period_bytes_min       = 4 * 1024,
>>>> +       .period_bytes_max       = 32 * 1024,
>>>> +       .periods_min            = 2,
>>>> +       .periods_max            = 8,
>>>> +       .fifo_size              = 128,
>>>> +};
>>>> +
>>>> +static const struct snd_dmaengine_pcm_config sun4i_hdmi_audio_pcm_config = {
>>>> +       .chan_names[SNDRV_PCM_STREAM_PLAYBACK] = "audio-tx",
>>>> +       .pcm_hardware = &sun4i_hdmi_audio_pcm_hardware,
>>>> +       .prealloc_buffer_size = 128 * 1024,
>>>> +       .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
>>>> +};
>>>> +
>>>> +struct snd_soc_card sun4i_hdmi_audio_card = {
>>>> +       .name = "sun4i-hdmi",
>>>> +};
>>>> +
>>>> +int sun4i_hdmi_audio_create(struct sun4i_hdmi *hdmi)
>>>> +{
>>>> +       struct snd_soc_card *card = &sun4i_hdmi_audio_card;
>>>> +       struct snd_soc_dai_link_component *comp;
>>>> +       struct snd_soc_dai_link *link;
>>>> +       int ret;
>>>> +
>>>> +       ret = snd_dmaengine_pcm_register(hdmi->dev,
>>>> +                                        &sun4i_hdmi_audio_pcm_config, 0);
>>>> +       if (ret < 0) {
>>>> +               DRM_ERROR("Could not register PCM\n");
>>>> +               return ret;
>>>> +       }
>>>> +
>>>> +       ret = snd_soc_register_component(hdmi->dev,
>>>> +                                        &sun4i_hdmi_audio_component,
>>>> +                                        &sun4i_hdmi_audio_dai, 1);
>>>> +       if (ret < 0) {
>>>> +               DRM_ERROR("Could not register DAI\n");
>>>> +               goto unregister_pcm;
>>>> +       }
>>>> +
>>>> +       link = devm_kzalloc(hdmi->dev, sizeof(*link), GFP_KERNEL);
>>>> +       if (!link) {
>>>> +               ret = -ENOMEM;
>>>> +               goto unregister_component;
>>>> +       }
>>>> +
>>>> +       comp = devm_kzalloc(hdmi->dev, sizeof(*comp) * 3, GFP_KERNEL);
>>>> +       if (!comp) {
>>>> +               ret = -ENOMEM;
>>>> +               goto unregister_component;
>>>> +       }
>>>> +
>>>> +       link->cpus = &comp[0];
>>>> +       link->codecs = &comp[1];
>>>> +       link->platforms = &comp[2];
>>>> +
>>>> +       link->num_cpus = 1;
>>>> +       link->num_codecs = 1;
>>>> +       link->num_platforms = 1;
>>>> +
>>>> +       link->playback_only = 1;
>>>> +
>>>> +       link->name = "SUN4I-HDMI";
>>>> +       link->stream_name = "SUN4I-HDMI PCM";
>>>> +
>>>> +       link->codecs->name = dev_name(hdmi->dev);
>>>> +       link->codecs->dai_name  = sun4i_hdmi_audio_dai.name;
>>>> +
>>>> +       link->cpus->dai_name = dev_name(hdmi->dev);
>>>> +
>>>> +       link->platforms->name = dev_name(hdmi->dev);
>>>> +
>>>> +       link->dai_fmt = SND_SOC_DAIFMT_I2S;
>>>> +
>>>> +       card->dai_link = link;
>>>> +       card->num_links = 1;
>>>> +       card->dev = hdmi->dev;
>>>> +
>>>> +       hdmi->audio.card = card;
>>>> +
>>>> +       /**
>>>> +        * snd_soc_register_card() will overwrite the driver_data pointer.
>>>> +        * So before registering the card, store the original pointer in
>>>> +        * card->drvdata.
>>>> +        */
>>>> +       snd_soc_card_set_drvdata(card, hdmi);
>>>> +       ret = snd_soc_register_card(card);
>>>> +       if (ret)
>>>> +               goto unregister_component;
>>> So using ASoC with all the components IMHO is just adding dead weight. The
>>> audio interface for this particular hardware is just a FIFO that needs to
>>> be written to by an external DMA engine, and a bunch of controls to setup
>>> the parameters of the HDMI audio stream. There's no power sequencing to do,
>>> and no actual individual components to control. There's no reason you couldn't
>>> use just the ALSA DMAENGINE helpers to create a simple ALSA sound card.
>>>
>>> (Maybe we could clean it up after it's merged? Would there be any issues
>>>    with backward compatibility?)
>>>
>>> I think the only example of this besides ASoC is the PXA2xx sound library
>>> and AC97 driver:
>>>
>>>     - sound/arm/pxa2xx-pcm-lib.c
>>>     - sound/arm/pxa2xx-ac97.c
>> I'd like to hear Maxime opinion on this. I get it why it's overkill to use
>> ASoC.
>> However it will take only couple of lines to make the changes for v4. On the
>> other
>> side with dropping the ASoC, the driver must be almost rewritten. It's not
>> such a big deal,
>> but I want to know that this is the right thing to do.
> I don't really have an opinion on this, either way is fine for me, so
> if it's simpler to go for ALSA, then let's do it :)

Then ALSA will be. Thanks :)

Stefan

>
> Maxime