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(a)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(a)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(a)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
