[PATCH 1/9] drm: bridge/dw_hdmi-ahb-audio: add audio driver

[Takashi Iwai]

On Sat, 08 Aug 2015 18:10:06 +0200,
Russell King wrote:
> 
> Add ALSA based HDMI AHB audio driver for dw_hdmi.  The only buffer
> format supported by the hardware is its own special IEC958 based format,
> which is not compatible with any ALSA format.  To avoid doing too much
> data manipulation within the driver, we support only ALSAs IEC958 LE and
> 24-bit PCM formats for 2 to 6 channels, which we convert to its hardware
> format.
> 
> A more desirable solution would be to have this conversion in userspace,
> but ALSA does not appear to allow such transformations outside of
> libasound itself.
> 
> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> ---
>  drivers/gpu/drm/bridge/Kconfig             |  10 +
>  drivers/gpu/drm/bridge/Makefile            |   1 +
>  drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c | 561 +++++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/dw_hdmi-audio.h     |  13 +
>  drivers/gpu/drm/bridge/dw_hdmi.c           |  24 ++
>  drivers/gpu/drm/bridge/dw_hdmi.h           |   3 +
>  6 files changed, 612 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
>  create mode 100644 drivers/gpu/drm/bridge/dw_hdmi-audio.h
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index acef3223772c..56ed35fe0734 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -3,6 +3,16 @@ config DRM_DW_HDMI
>  	depends on DRM
>  	select DRM_KMS_HELPER
>  
> +config DRM_DW_HDMI_AHB_AUDIO
> +	tristate "Synopsis Designware AHB Audio interface"
> +	depends on DRM_DW_HDMI && SND
> +	select SND_PCM
> +	select SND_PCM_IEC958
> +	help
> +	  Support the AHB Audio interface which is part of the Synopsis
> +	  Designware HDMI block.  This is used in conjunction with
> +	  the i.MX6 HDMI driver.
> +
>  config DRM_PTN3460
>  	tristate "PTN3460 DP/LVDS bridge"
>  	depends on DRM
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 8dfebd984370..eb80dbbb8365 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -3,3 +3,4 @@ ccflags-y := -Iinclude/drm
>  obj-$(CONFIG_DRM_PS8622) += ps8622.o
>  obj-$(CONFIG_DRM_PTN3460) += ptn3460.o
>  obj-$(CONFIG_DRM_DW_HDMI) += dw_hdmi.o
> +obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw_hdmi-ahb-audio.o
> diff --git a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
> new file mode 100644
> index 000000000000..22bbbc5c2393
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
> @@ -0,0 +1,561 @@
> +/*
> + * DesignWare HDMI audio driver
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * Written and tested against the Designware HDMI Tx found in iMX6.
> + */
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <drm/bridge/dw_hdmi.h>
> +
> +#include <sound/asoundef.h>
> +#include <sound/core.h>
> +#include <sound/initval.h>
> +#include <sound/pcm.h>
> +#include <sound/pcm_iec958.h>
> +
> +#include "dw_hdmi-audio.h"
> +
> +#define DRIVER_NAME "dw-hdmi-ahb-audio"
> +
> +/* Provide some bits rather than bit offsets */
> +enum {
> +	HDMI_AHB_DMA_CONF0_SW_FIFO_RST = BIT(7),
> +	HDMI_AHB_DMA_CONF0_EN_HLOCK = BIT(3),
> +	HDMI_AHB_DMA_START_START = BIT(0),
> +	HDMI_AHB_DMA_STOP_STOP = BIT(0),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_ERROR = BIT(5),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_LOST = BIT(4),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_RETRY = BIT(3),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_DONE = BIT(2),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_BUFFFULL = BIT(1),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_BUFFEMPTY = BIT(0),
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0_ALL =
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_ERROR |
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_LOST |
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_RETRY |
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_DONE |
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_BUFFFULL |
> +		HDMI_IH_MUTE_AHBDMAAUD_STAT0_BUFFEMPTY,
> +	HDMI_IH_AHBDMAAUD_STAT0_ERROR = BIT(5),
> +	HDMI_IH_AHBDMAAUD_STAT0_LOST = BIT(4),
> +	HDMI_IH_AHBDMAAUD_STAT0_RETRY = BIT(3),
> +	HDMI_IH_AHBDMAAUD_STAT0_DONE = BIT(2),
> +	HDMI_IH_AHBDMAAUD_STAT0_BUFFFULL = BIT(1),
> +	HDMI_IH_AHBDMAAUD_STAT0_BUFFEMPTY = BIT(0),
> +	HDMI_IH_AHBDMAAUD_STAT0_ALL =
> +		HDMI_IH_AHBDMAAUD_STAT0_ERROR |
> +		HDMI_IH_AHBDMAAUD_STAT0_LOST |
> +		HDMI_IH_AHBDMAAUD_STAT0_RETRY |
> +		HDMI_IH_AHBDMAAUD_STAT0_DONE |
> +		HDMI_IH_AHBDMAAUD_STAT0_BUFFFULL |
> +		HDMI_IH_AHBDMAAUD_STAT0_BUFFEMPTY,
> +	HDMI_AHB_DMA_CONF0_INCR16 = 2 << 1,
> +	HDMI_AHB_DMA_CONF0_INCR8 = 1 << 1,
> +	HDMI_AHB_DMA_CONF0_INCR4 = 0,
> +	HDMI_AHB_DMA_CONF0_BURST_MODE = BIT(0),
> +	HDMI_AHB_DMA_MASK_DONE = BIT(7),
> +	HDMI_REVISION_ID = 0x0001,
> +	HDMI_IH_AHBDMAAUD_STAT0 = 0x0109,
> +	HDMI_IH_MUTE_AHBDMAAUD_STAT0 = 0x0189,
> +	HDMI_AHB_DMA_CONF0 = 0x3600,
> +	HDMI_AHB_DMA_START = 0x3601,
> +	HDMI_AHB_DMA_STOP = 0x3602,
> +	HDMI_AHB_DMA_THRSLD = 0x3603,
> +	HDMI_AHB_DMA_STRADDR0 = 0x3604,
> +	HDMI_AHB_DMA_STPADDR0 = 0x3608,
> +	HDMI_AHB_DMA_MASK = 0x3614,
> +	HDMI_AHB_DMA_POL = 0x3615,
> +	HDMI_AHB_DMA_CONF1 = 0x3616,
> +	HDMI_AHB_DMA_BUFFPOL = 0x361a,
> +};
> +
> +struct snd_dw_hdmi {
> +	struct snd_card *card;
> +	struct snd_pcm *pcm;
> +	struct dw_hdmi_audio_data data;
> +	struct snd_pcm_substream *substream;
> +	void (*reformat)(struct snd_dw_hdmi *, size_t, size_t);
> +	void *buf_src;
> +	void *buf_dst;
> +	dma_addr_t buf_addr;
> +	unsigned buf_offset;
> +	unsigned buf_period;
> +	unsigned buf_size;
> +	unsigned channels;
> +	u8 revision;
> +	u8 iec_offset;
> +	u8 cs[192][8];
> +};
> +
> +static void dw_hdmi_writel(unsigned long val, void __iomem *ptr)

Better to be u32 instead of unsigned long in general.

> +{
> +	writeb_relaxed(val, ptr);
> +	writeb_relaxed(val >> 8, ptr + 1);
> +	writeb_relaxed(val >> 16, ptr + 2);
> +	writeb_relaxed(val >> 24, ptr + 3);
> +}
> +
> +/*
> + * Convert to hardware format: The userspace buffer contains IEC958 samples,
> + * with the PCUV bits in bits 31..28 and audio samples in bits 27..4.  We
> + * need these to be in bits 27..24, with the IEC B bit in bit 28, and audio
> + * samples in 23..0.
> + *
> + * Default preamble in bits 3..0: 8 = block start, 4 = even 2 = odd
> + *
> + * Ideally, we could do with having the data properly formatted in userspace.
> + */
> +static void dw_hdmi_reformat_iec958(struct snd_dw_hdmi *dw,
> +	size_t offset, size_t bytes)
> +{
> +	u32 *src = dw->buf_src + offset;
> +	u32 *dst = dw->buf_dst + offset;
> +	u32 *end = dw->buf_src + offset + bytes;
> +
> +	do {
> +		u32 b, sample = *src++;
> +
> +		b = (sample & 8) << (28 - 3);
> +
> +		sample >>= 4;
> +
> +		*dst++ = sample | b;
> +	} while (src < end);
> +}
> +
> +static u32 parity(u32 sample)
> +{
> +	sample ^= sample >> 16;
> +	sample ^= sample >> 8;
> +	sample ^= sample >> 4;
> +	sample ^= sample >> 2;
> +	sample ^= sample >> 1;
> +	return (sample & 1) << 27;
> +}
> +
> +static void dw_hdmi_reformat_s24(struct snd_dw_hdmi *dw,
> +	size_t offset, size_t bytes)
> +{
> +	u32 *src = dw->buf_src + offset;
> +	u32 *dst = dw->buf_dst + offset;
> +	u32 *end = dw->buf_src + offset + bytes;
> +
> +	do {
> +		unsigned i;
> +		u8 *cs;
> +
> +		cs = dw->cs[dw->iec_offset++];
> +		if (dw->iec_offset >= 192)
> +			dw->iec_offset = 0;
> +
> +		i = dw->channels;
> +		do {
> +			u32 sample = *src++;
> +
> +			sample &= ~0xff000000;
> +			sample |= *cs++ << 24;
> +			sample |= parity(sample & ~0xf8000000);
> +
> +			*dst++ = sample;
> +		} while (--i);
> +	} while (src < end);
> +}
> +
> +static void dw_hdmi_create_cs(struct snd_dw_hdmi *dw,
> +	struct snd_pcm_runtime *runtime)
> +{
> +	u8 cs[4];
> +	unsigned ch, i, j;
> +
> +	snd_pcm_create_iec958_consumer(runtime, cs, sizeof(cs));
> +
> +	memset(dw->cs, 0, sizeof(dw->cs));
> +
> +	for (ch = 0; ch < 8; ch++) {
> +		cs[2] &= ~IEC958_AES2_CON_CHANNEL;
> +		cs[2] |= (ch + 1) << 4;
> +
> +		for (i = 0; i < ARRAY_SIZE(cs); i++) {
> +			unsigned c = cs[i];
> +
> +			for (j = 0; j < 8; j++, c >>= 1)
> +				dw->cs[i * 8 + j][ch] = (c & 1) << 2;
> +		}
> +	}
> +	dw->cs[0][0] |= BIT(4);
> +}
> +
> +static void dw_hdmi_start_dma(struct snd_dw_hdmi *dw)
> +{
> +	void __iomem *base = dw->data.base;
> +	unsigned offset = dw->buf_offset;
> +	unsigned period = dw->buf_period;
> +	u32 start, stop;
> +
> +	dw->reformat(dw, offset, period);
> +
> +	/* Clear all irqs before enabling irqs and starting DMA */
> +	writeb_relaxed(HDMI_IH_AHBDMAAUD_STAT0_ALL,
> +		       base + HDMI_IH_AHBDMAAUD_STAT0);
> +
> +	start = dw->buf_addr + offset;
> +	stop = start + period - 1;
> +
> +	/* Setup the hardware start/stop addresses */
> +	dw_hdmi_writel(start, base + HDMI_AHB_DMA_STRADDR0);
> +	dw_hdmi_writel(stop, base + HDMI_AHB_DMA_STPADDR0);
> +
> +	writeb_relaxed((u8)~HDMI_AHB_DMA_MASK_DONE, base + HDMI_AHB_DMA_MASK);
> +	writeb(HDMI_AHB_DMA_START_START, base + HDMI_AHB_DMA_START);
> +
> +	offset += period;
> +	if (offset >= dw->buf_size)
> +		offset = 0;
> +	dw->buf_offset = offset;
> +}
> +
> +static void dw_hdmi_stop_dma(struct snd_dw_hdmi *dw)
> +{
> +	dw->substream = NULL;
> +
> +	/* Disable interrupts before disabling DMA */
> +	writeb_relaxed(~0, dw->data.base + HDMI_AHB_DMA_MASK);
> +	writeb_relaxed(HDMI_AHB_DMA_STOP_STOP, dw->data.base + HDMI_AHB_DMA_STOP);
> +}
> +
> +static irqreturn_t snd_dw_hdmi_irq(int irq, void *data)
> +{
> +	struct snd_dw_hdmi *dw = data;
> +	struct snd_pcm_substream *substream;
> +	unsigned stat;
> +
> +	stat = readb_relaxed(dw->data.base + HDMI_IH_AHBDMAAUD_STAT0);
> +	if (!stat)
> +		return IRQ_NONE;
> +
> +	writeb_relaxed(stat, dw->data.base + HDMI_IH_AHBDMAAUD_STAT0);
> +
> +	substream = dw->substream;
> +	if (stat & HDMI_IH_AHBDMAAUD_STAT0_DONE && substream) {
> +		snd_pcm_period_elapsed(substream);
> +		if (dw->substream)
> +			dw_hdmi_start_dma(dw);
> +	}

Don't we need locking?  In theory, the trigger can be issued while the
irq is being handled.

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static struct snd_pcm_hardware dw_hdmi_hw = {
> +	.info = SNDRV_PCM_INFO_INTERLEAVED |
> +		SNDRV_PCM_INFO_BLOCK_TRANSFER |
> +		SNDRV_PCM_INFO_MMAP |
> +		SNDRV_PCM_INFO_MMAP_VALID,
> +	.formats = SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE |
> +		   SNDRV_PCM_FMTBIT_S24_LE,
> +	.rates = SNDRV_PCM_RATE_32000 |
> +		 SNDRV_PCM_RATE_44100 |
> +		 SNDRV_PCM_RATE_48000 |
> +		 SNDRV_PCM_RATE_88200 |
> +		 SNDRV_PCM_RATE_96000 |
> +		 SNDRV_PCM_RATE_176400 |
> +		 SNDRV_PCM_RATE_192000,
> +	.channels_min = 2,
> +	.channels_max = 8,
> +	.buffer_bytes_max = 64 * 1024,
> +	.period_bytes_min = 256,
> +	.period_bytes_max = 8192,	/* ERR004323: must limit to 8k */
> +	.periods_min = 2,
> +	.periods_max = 16,
> +	.fifo_size = 0,
> +};
> +
> +static int dw_hdmi_open(struct snd_pcm_substream *substream)
> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	struct snd_dw_hdmi *dw = substream->private_data;
> +	void __iomem *base = dw->data.base;
> +	int ret;
> +
> +	runtime->hw = dw_hdmi_hw;
> +
> +	ret = snd_pcm_limit_hw_rates(runtime);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Clear FIFO */
> +	writeb_relaxed(HDMI_AHB_DMA_CONF0_SW_FIFO_RST,
> +		       base + HDMI_AHB_DMA_CONF0);
> +
> +	/* Configure interrupt polarities */
> +	writeb_relaxed(~0, base + HDMI_AHB_DMA_POL);
> +	writeb_relaxed(~0, base + HDMI_AHB_DMA_BUFFPOL);
> +
> +	/* Keep interrupts masked, and clear any pending */
> +	writeb_relaxed(~0, base + HDMI_AHB_DMA_MASK);
> +	writeb_relaxed(~0, base + HDMI_IH_AHBDMAAUD_STAT0);
> +
> +	ret = request_irq(dw->data.irq, snd_dw_hdmi_irq, IRQF_SHARED,
> +			  "dw-hdmi-audio", dw);
> +	if (ret)
> +		return ret;
> +
> +	/* Un-mute done interrupt */
> +	writeb_relaxed(HDMI_IH_MUTE_AHBDMAAUD_STAT0_ALL &
> +		       ~HDMI_IH_MUTE_AHBDMAAUD_STAT0_DONE,
> +		       base + HDMI_IH_MUTE_AHBDMAAUD_STAT0);
> +
> +	return 0;
> +}
> +
> +static int dw_hdmi_close(struct snd_pcm_substream *substream)
> +{
> +	struct snd_dw_hdmi *dw = substream->private_data;
> +
> +	/* Mute all interrupts */
> +	writeb_relaxed(HDMI_IH_MUTE_AHBDMAAUD_STAT0_ALL,
> +		       dw->data.base + HDMI_IH_MUTE_AHBDMAAUD_STAT0);
> +
> +	free_irq(dw->data.irq, dw);
> +
> +	return 0;
> +}
> +
> +static int dw_hdmi_hw_free(struct snd_pcm_substream *substream)
> +{
> +	return snd_pcm_lib_free_vmalloc_buffer(substream);
> +}
> +
> +static int dw_hdmi_hw_params(struct snd_pcm_substream *substream,
> +	struct snd_pcm_hw_params *params)
> +{
> +	return snd_pcm_lib_alloc_vmalloc_buffer(substream,
> +						params_buffer_bytes(params));
> +}
> +
> +static int dw_hdmi_prepare(struct snd_pcm_substream *substream)
> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	struct snd_dw_hdmi *dw = substream->private_data;
> +	u8 threshold, conf0, conf1;
> +
> +	/* Setup as per 3.0.5 FSL 4.1.0 BSP */
> +	switch (dw->revision) {
> +	case 0x0a:
> +		conf0 = HDMI_AHB_DMA_CONF0_BURST_MODE |
> +			HDMI_AHB_DMA_CONF0_INCR4;
> +		if (runtime->channels == 2)
> +			threshold = 126;
> +		else
> +			threshold = 124;
> +		break;
> +	case 0x1a:
> +		conf0 = HDMI_AHB_DMA_CONF0_BURST_MODE |
> +			HDMI_AHB_DMA_CONF0_INCR8;
> +		threshold = 128;
> +		break;
> +	default:
> +		/* NOTREACHED */
> +		return -EINVAL;
> +	}
> +
> +	dw_hdmi_set_sample_rate(dw->data.hdmi, runtime->rate);
> +
> +	/* Minimum number of bytes in the fifo. */
> +	runtime->hw.fifo_size = threshold * 32;
> +
> +	conf0 |= HDMI_AHB_DMA_CONF0_EN_HLOCK;
> +	conf1 = (1 << runtime->channels) - 1;
> +
> +	writeb_relaxed(threshold, dw->data.base + HDMI_AHB_DMA_THRSLD);
> +	writeb_relaxed(conf0, dw->data.base + HDMI_AHB_DMA_CONF0);
> +	writeb_relaxed(conf1, dw->data.base + HDMI_AHB_DMA_CONF1);
> +
> +	switch (runtime->format) {
> +	case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
> +		dw->reformat = dw_hdmi_reformat_iec958;
> +		break;
> +	case SNDRV_PCM_FORMAT_S24_LE:
> +		dw_hdmi_create_cs(dw, runtime);
> +		dw->reformat = dw_hdmi_reformat_s24;
> +		break;
> +	}
> +	dw->iec_offset = 0;
> +	dw->channels = runtime->channels;
> +	dw->buf_src  = runtime->dma_area;
> +	dw->buf_dst  = substream->dma_buffer.area;
> +	dw->buf_addr = substream->dma_buffer.addr;
> +	dw->buf_period = snd_pcm_lib_period_bytes(substream);
> +	dw->buf_size = snd_pcm_lib_buffer_bytes(substream);
> +
> +	return 0;
> +}
> +
> +static int dw_hdmi_trigger(struct snd_pcm_substream *substream, int cmd)
> +{
> +	struct snd_dw_hdmi *dw = substream->private_data;
> +	int ret = 0;
> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +		dw->buf_offset = 0;
> +		dw->substream = substream;
> +		dw_hdmi_start_dma(dw);
> +		dw_hdmi_audio_enable(dw->data.hdmi);
> +		substream->runtime->delay = substream->runtime->period_size;
> +		break;
> +
> +	case SNDRV_PCM_TRIGGER_STOP:
> +		dw_hdmi_stop_dma(dw);
> +		dw_hdmi_audio_disable(dw->data.hdmi);
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +		break;

SNDRV_PCM_TRIGGER_SUSPEND may be passed at suspend, too.


> +	}
> +
> +	return ret;
> +}
> +
> +static snd_pcm_uframes_t dw_hdmi_pointer(struct snd_pcm_substream *substream)
> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	struct snd_dw_hdmi *dw = substream->private_data;
> +
> +	return bytes_to_frames(runtime, dw->buf_offset);

So, this returns the offset that has been reformatted.  Does the
hardware support any better position reporting?  We may give the delay
from the driver if possible.


thanks,

Takashi


> +}
> +
> +static struct snd_pcm_ops snd_dw_hdmi_ops = {
> +	.open = dw_hdmi_open,
> +	.close = dw_hdmi_close,
> +	.ioctl = snd_pcm_lib_ioctl,
> +	.hw_params = dw_hdmi_hw_params,
> +	.hw_free = dw_hdmi_hw_free,
> +	.prepare = dw_hdmi_prepare,
> +	.trigger = dw_hdmi_trigger,
> +	.pointer = dw_hdmi_pointer,
> +	.page = snd_pcm_lib_get_vmalloc_page,
> +};
> +
> +static int snd_dw_hdmi_probe(struct platform_device *pdev)
> +{
> +	const struct dw_hdmi_audio_data *data = pdev->dev.platform_data;
> +	struct device *dev = pdev->dev.parent;
> +	struct snd_dw_hdmi *dw;
> +	struct snd_card *card;
> +	struct snd_pcm *pcm;
> +	unsigned revision;
> +	int ret;
> +
> +	writeb_relaxed(HDMI_IH_MUTE_AHBDMAAUD_STAT0_ALL,
> +		       data->base + HDMI_IH_MUTE_AHBDMAAUD_STAT0);
> +	revision = readb_relaxed(data->base + HDMI_REVISION_ID);
> +	if (revision != 0x0a && revision != 0x1a) {
> +		dev_err(dev, "dw-hdmi-audio: unknown revision 0x%02x\n",
> +			revision);
> +		return -ENXIO;
> +	}
> +
> +	ret = snd_card_new(dev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
> +			      THIS_MODULE, sizeof(struct snd_dw_hdmi), &card);
> +	if (ret < 0)
> +		return ret;
> +
> +	strlcpy(card->driver, DRIVER_NAME, sizeof(card->driver));
> +	strlcpy(card->shortname, "DW-HDMI", sizeof(card->shortname));
> +	snprintf(card->longname, sizeof(card->longname),
> +		 "%s rev 0x%02x, irq %d", card->shortname, revision,
> +		 data->irq);
> +
> +	dw = card->private_data;
> +	dw->card = card;
> +	dw->data = *data;
> +	dw->revision = revision;
> +
> +	ret = snd_pcm_new(card, "DW HDMI", 0, 1, 0, &pcm);
> +	if (ret < 0)
> +		goto err;
> +
> +	dw->pcm = pcm;
> +	pcm->private_data = dw;
> +	strlcpy(pcm->name, DRIVER_NAME, sizeof(pcm->name));
> +	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_dw_hdmi_ops);
> +
> +	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
> +			dev, 64 * 1024, 64 * 1024);
> +
> +	ret = snd_card_register(card);
> +	if (ret < 0)
> +		goto err;
> +
> +	platform_set_drvdata(pdev, dw);
> +
> +	return 0;
> +
> +err:
> +	snd_card_free(card);
> +	return ret;
> +}
> +
> +static int snd_dw_hdmi_remove(struct platform_device *pdev)
> +{
> +	struct snd_dw_hdmi *dw = platform_get_drvdata(pdev);
> +
> +	snd_card_free(dw->card);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int snd_dw_hdmi_suspend(struct device *dev)
> +{
> +	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
> +
> +	snd_power_change_state(dw->card, SNDRV_CTL_POWER_D3cold);
> +	snd_pcm_suspend_all(dw->pcm);
> +
> +	return 0;
> +}
> +
> +static int snd_dw_hdmi_resume(struct device *dev)
> +{
> +	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
> +
> +	snd_power_change_state(dw->card, SNDRV_CTL_POWER_D0);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(snd_dw_hdmi_pm, snd_dw_hdmi_suspend,
> +			 snd_dw_hdmi_resume);
> +#define PM_OPS &snd_dw_hdmi_pm
> +#else
> +#define PM_OPS NULL
> +#endif
> +
> +static struct platform_driver snd_dw_hdmi_driver = {
> +	.probe	= snd_dw_hdmi_probe,
> +	.remove	= snd_dw_hdmi_remove,
> +	.driver	= {
> +		.name = DRIVER_NAME,
> +		.owner = THIS_MODULE,
> +		.pm = PM_OPS,
> +	},
> +};
> +
> +module_platform_driver(snd_dw_hdmi_driver);
> +
> +MODULE_AUTHOR("Russell King <rmk+kernel at arm.linux.org.uk>");
> +MODULE_DESCRIPTION("Synopsis Designware HDMI AHB ALSA interface");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> diff --git a/drivers/gpu/drm/bridge/dw_hdmi-audio.h b/drivers/gpu/drm/bridge/dw_hdmi-audio.h
> new file mode 100644
> index 000000000000..1e840118d90a
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/dw_hdmi-audio.h
> @@ -0,0 +1,13 @@
> +#ifndef DW_HDMI_AUDIO_H
> +#define DW_HDMI_AUDIO_H
> +
> +struct dw_hdmi;
> +
> +struct dw_hdmi_audio_data {
> +	phys_addr_t phys;
> +	void __iomem *base;
> +	int irq;
> +	struct dw_hdmi *hdmi;
> +};
> +
> +#endif
> diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
> index fba25607ef88..b65464789fbd 100644
> --- a/drivers/gpu/drm/bridge/dw_hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw_hdmi.c
> @@ -28,6 +28,7 @@
>  #include <drm/bridge/dw_hdmi.h>
>  
>  #include "dw_hdmi.h"
> +#include "dw_hdmi-audio.h"
>  
>  #define HDMI_EDID_LEN		512
>  
> @@ -104,6 +105,7 @@ struct dw_hdmi {
>  	struct drm_encoder *encoder;
>  	struct drm_bridge *bridge;
>  
> +	struct platform_device *audio;
>  	enum dw_hdmi_devtype dev_type;
>  	struct device *dev;
>  	struct clk *isfr_clk;
> @@ -1732,7 +1734,9 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
>  {
>  	struct drm_device *drm = data;
>  	struct device_node *np = dev->of_node;
> +	struct platform_device_info pdevinfo;
>  	struct device_node *ddc_node;
> +	struct dw_hdmi_audio_data audio;
>  	struct dw_hdmi *hdmi;
>  	int ret;
>  	u32 val = 1;
> @@ -1860,6 +1864,23 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
>  	hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE),
>  		    HDMI_IH_MUTE_PHY_STAT0);
>  
> +	memset(&pdevinfo, 0, sizeof(pdevinfo));
> +	pdevinfo.parent = dev;
> +	pdevinfo.id = PLATFORM_DEVID_AUTO;
> +
> +	if (hdmi_readb(hdmi, HDMI_CONFIG1_ID) & HDMI_CONFIG1_AHB) {
> +		audio.phys = iores->start;
> +		audio.base = hdmi->regs;
> +		audio.irq = irq;
> +		audio.hdmi = hdmi;
> +
> +		pdevinfo.name = "dw-hdmi-ahb-audio";
> +		pdevinfo.data = &audio;
> +		pdevinfo.size_data = sizeof(audio);
> +		pdevinfo.dma_mask = DMA_BIT_MASK(32);
> +		hdmi->audio = platform_device_register_full(&pdevinfo);
> +	}
> +
>  	dev_set_drvdata(dev, hdmi);
>  
>  	return 0;
> @@ -1877,6 +1898,9 @@ void dw_hdmi_unbind(struct device *dev, struct device *master, void *data)
>  {
>  	struct dw_hdmi *hdmi = dev_get_drvdata(dev);
>  
> +	if (hdmi->audio && !IS_ERR(hdmi->audio))
> +		platform_device_unregister(hdmi->audio);
> +
>  	/* Disable all interrupts */
>  	hdmi_writeb(hdmi, ~0, HDMI_IH_MUTE_PHY_STAT0);
>  
> diff --git a/drivers/gpu/drm/bridge/dw_hdmi.h b/drivers/gpu/drm/bridge/dw_hdmi.h
> index 175dbc89a824..78e54e813212 100644
> --- a/drivers/gpu/drm/bridge/dw_hdmi.h
> +++ b/drivers/gpu/drm/bridge/dw_hdmi.h
> @@ -545,6 +545,9 @@
>  #define HDMI_I2CM_FS_SCL_LCNT_0_ADDR            0x7E12
>  
>  enum {
> +/* CONFIG1_ID field values */
> +	HDMI_CONFIG1_AHB = 0x01,
> +
>  /* IH_FC_INT2 field values */
>  	HDMI_IH_FC_INT2_OVERFLOW_MASK = 0x03,
>  	HDMI_IH_FC_INT2_LOW_PRIORITY_OVERFLOW = 0x02,
> -- 
> 2.1.0
>