Date:   Mon, 3 Aug 2020 13:06:56 +0000
From:   <Claudiu.Beznea@...rochip.com>
To:     <Codrin.Ciubotariu@...rochip.com>, <alsa-devel@...a-project.org>,
        <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     <alexandre.belloni@...tlin.com>, <lgirdwood@...il.com>,
        <robh+dt@...nel.org>, <tiwai@...e.com>,
        <Ludovic.Desroches@...rochip.com>, <broonie@...nel.org>,
        <perex@...ex.cz>
Subject: Re: [PATCH v3 2/2] ASoC: mchp-spdiftx: add driver for S/PDIF TX
 Controller



On 03.08.2020 11:18, Codrin Ciubotariu wrote:
> The new SPDIF TX controller is a serial port compliant with the IEC-
> 60958 standard. It also supports programmable User Data and Channel
> Status fields.
> 
> This IP is embedded in Microchip's sama7g5 SoC.
> 
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
> ---
> 
> Changes in v2, v3:
>  - none;
> 
>  sound/soc/atmel/Kconfig        |  12 +
>  sound/soc/atmel/Makefile       |   2 +
>  sound/soc/atmel/mchp-spdiftx.c | 864 +++++++++++++++++++++++++++++++++
>  3 files changed, 878 insertions(+)
>  create mode 100644 sound/soc/atmel/mchp-spdiftx.c
> 
> diff --git a/sound/soc/atmel/Kconfig b/sound/soc/atmel/Kconfig
> index 71f2d42188c4..93beb7d670a3 100644
> --- a/sound/soc/atmel/Kconfig
> +++ b/sound/soc/atmel/Kconfig
> @@ -132,4 +132,16 @@ config SND_MCHP_SOC_I2S_MCC
>  	  and supports a Time Division Multiplexed (TDM) interface with
>  	  external multi-channel audio codecs.
>  
> +config SND_MCHP_SOC_SPDIFTX
> +	tristate "Microchip ASoC driver for boards using S/PDIF TX"
> +	depends on OF && (ARCH_AT91 || COMPILE_TEST)
> +	select SND_SOC_GENERIC_DMAENGINE_PCM
> +	select REGMAP_MMIO
> +	help
> +	  Say Y or M if you want to add support for Microchip S/PDIF TX ASoc
> +	  driver on the following Microchip platforms:
> +	  - sama7g5
> +
> +	  This S/PDIF TX driver is compliant with IEC-60958 standard and
> +	  includes programable User Data and Channel Status fields.
>  endif
> diff --git a/sound/soc/atmel/Makefile b/sound/soc/atmel/Makefile
> index c7d2989791be..3fd89a0063df 100644
> --- a/sound/soc/atmel/Makefile
> +++ b/sound/soc/atmel/Makefile
> @@ -5,6 +5,7 @@ snd-soc-atmel-pcm-dma-objs := atmel-pcm-dma.o
>  snd-soc-atmel_ssc_dai-objs := atmel_ssc_dai.o
>  snd-soc-atmel-i2s-objs := atmel-i2s.o
>  snd-soc-mchp-i2s-mcc-objs := mchp-i2s-mcc.o
> +snd-soc-mchp-spdiftx-objs := mchp-spdiftx.o
>  
>  # pdc and dma need to both be built-in if any user of
>  # ssc is built-in.
> @@ -17,6 +18,7 @@ endif
>  obj-$(CONFIG_SND_ATMEL_SOC_SSC) += snd-soc-atmel_ssc_dai.o
>  obj-$(CONFIG_SND_ATMEL_SOC_I2S) += snd-soc-atmel-i2s.o
>  obj-$(CONFIG_SND_MCHP_SOC_I2S_MCC) += snd-soc-mchp-i2s-mcc.o
> +obj-$(CONFIG_SND_MCHP_SOC_SPDIFTX) += snd-soc-mchp-spdiftx.o
>  
>  # AT91 Machine Support
>  snd-soc-sam9g20-wm8731-objs := sam9g20_wm8731.o
> diff --git a/sound/soc/atmel/mchp-spdiftx.c b/sound/soc/atmel/mchp-spdiftx.c
> new file mode 100644
> index 000000000000..738f6788212e
> --- /dev/null
> +++ b/sound/soc/atmel/mchp-spdiftx.c
> @@ -0,0 +1,864 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Driver for Microchip S/PDIF TX Controller
> +//
> +// Copyright (C) 2020 Microchip Technology Inc. and its subsidiaries
> +//
> +// Author: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/spinlock.h>
> +
> +#include <sound/asoundef.h>
> +#include <sound/dmaengine_pcm.h>
> +#include <sound/pcm_params.h>
> +#include <sound/soc.h>
> +
> +/*
> + * ---- S/PDIF Transmitter Controller Register map ----
> + */
> +#define SPDIFTX_CR			0x00	/* Control Register */
> +#define SPDIFTX_MR			0x04	/* Mode Register */

This register is read/write either in atomic and non-atomic contextes but
not protected everywhere the same way.

> +#define SPDIFTX_CDR			0x0C	/* Common Data Register */
> +
> +#define SPDIFTX_IER			0x14	/* Interrupt Enable Register */
> +#define SPDIFTX_IDR			0x18	/* Interrupt Disable Register */
> +#define SPDIFTX_IMR			0x1C	/* Interrupt Mask Register */
> +#define SPDIFTX_ISR			0x20	/* Interrupt Status Register */
> +
> +#define SPDIFTX_CH1UD(reg)	(0x50 + (reg) * 4)	/* User Data 1 Register x */
> +#define SPDIFTX_CH1S(reg)	(0x80 + (reg) * 4)	/* Channel Status 1 Register x */
> +
> +#define SPDIFTX_VERSION			0xF0
> +
> +/*
> + * ---- Control Register (Write-only) ----
> + */
> +#define SPDIFTX_CR_SWRST		BIT(0)	/* Software Reset */
> +#define SPDIFTX_CR_FCLR			BIT(1)	/* FIFO clear */
> +
> +/*
> + * ---- Mode Register (Read/Write) ----
> + */
> +/* Transmit Enable */
> +#define SPDIFTX_MR_TXEN_MASK		GENMASK(0, 0)
> +#define SPDIFTX_MR_TXEN_DISABLE		(0 << 0)
> +#define SPDIFTX_MR_TXEN_ENABLE		(1 << 0)
> +
> +/* Multichannel Transfer */
> +#define SPDIFTX_MR_MULTICH_MASK		GENAMSK(1, 1)
> +#define SPDIFTX_MR_MULTICH_MONO		(0 << 1)
> +#define SPDIFTX_MR_MULTICH_DUAL		(1 << 1)
> +
> +/* Data Word Endian Mode */
> +#define SPDIFTX_MR_ENDIAN_MASK		GENMASK(2, 2)
> +#define SPDIFTX_MR_ENDIAN_LITTLE	(0 << 2)
> +#define SPDIFTX_MR_ENDIAN_BIG		(1 << 2)
> +
> +/* Data Justification */
> +#define SPDIFTX_MR_JUSTIFY_MASK		GENMASK(3, 3)
> +#define SPDIFTX_MR_JUSTIFY_LSB		(0 << 3)
> +#define SPDIFTX_MR_JUSTIFY_MSB		(1 << 3)
> +
> +/* Common Audio Register Transfer Mode */
> +#define SPDIFTX_MR_CMODE_MASK			GENMASK(5, 4)
> +#define SPDIFTX_MR_CMODE_INDEX_ACCESS		(0 << 4)
> +#define SPDIFTX_MR_CMODE_TOGGLE_ACCESS		(1 << 4)
> +#define SPDIFTX_MR_CMODE_INTERLVD_ACCESS	(2 << 4)
> +
> +/* Valid Bits per Sample */
> +#define SPDIFTX_MR_VBPS_MASK		GENMASK(13, 8)
> +#define SPDIFTX_MR_VBPS(bps)		(((bps) << 8) & SPDIFTX_MR_VBPS_MASK)
> +
> +/* Chunk Size */
> +#define SPDIFTX_MR_CHUNK_MASK		GENMASK(19, 16)
> +#define SPDIFTX_MR_CHUNK(size)		(((size) << 16) & SPDIFTX_MR_CHUNK_MASK)
> +
> +/* Validity Bits for Channels 1 and 2 */
> +#define SPDIFTX_MR_VALID1			BIT(24)
> +#define SPDIFTX_MR_VALID2			BIT(25)
> +
> +/* Disable Null Frame on underrrun */
> +#define SPDIFTX_MR_DNFR_MASK		GENMASK(27, 27)
> +#define SPDIFTX_MR_DNFR_INVALID		(0 << 27)
> +#define SPDIFTX_MR_DNFR_VALID		(1 << 27)
> +
> +/* Bytes per Sample */
> +#define SPDIFTX_MR_BPS_MASK		GENMASK(29, 28)
> +#define SPDIFTX_MR_BPS(bytes) \
> +	((((bytes) - 1) << 28) & SPDIFTX_MR_BPS_MASK)
> +
> +/*
> + * ---- Interrupt Enable/Disable/Mask/Status Register (Write/Read-only) ----
> + */
> +#define SPDIFTX_IR_TXRDY		BIT(0)
> +#define SPDIFTX_IR_TXEMPTY		BIT(1)
> +#define SPDIFTX_IR_TXFULL		BIT(2)
> +#define SPDIFTX_IR_TXCHUNK		BIT(3)
> +#define SPDIFTX_IR_TXUDR		BIT(4)
> +#define SPDIFTX_IR_TXOVR		BIT(5)
> +#define SPDIFTX_IR_CSRDY		BIT(6)
> +#define SPDIFTX_IR_UDRDY		BIT(7)
> +#define SPDIFTX_IR_TXRDYCH(ch)		BIT((ch) + 8)
> +#define SPDIFTX_IR_SECE			BIT(10)
> +#define SPDIFTX_IR_TXUDRCH(ch)		BIT((ch) + 11)
> +#define SPDIFTX_IR_BEND			BIT(13)
> +
> +static bool mchp_spdiftx_readable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPDIFTX_MR:
> +	case SPDIFTX_IMR:
> +	case SPDIFTX_ISR:
> +	case SPDIFTX_CH1UD(0):
> +	case SPDIFTX_CH1UD(1):
> +	case SPDIFTX_CH1UD(2):
> +	case SPDIFTX_CH1UD(3):
> +	case SPDIFTX_CH1UD(4):
> +	case SPDIFTX_CH1UD(5):
> +	case SPDIFTX_CH1S(0):
> +	case SPDIFTX_CH1S(1):
> +	case SPDIFTX_CH1S(2):
> +	case SPDIFTX_CH1S(3):
> +	case SPDIFTX_CH1S(4):
> +	case SPDIFTX_CH1S(5):
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool mchp_spdiftx_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPDIFTX_CR:
> +	case SPDIFTX_MR:
> +	case SPDIFTX_CDR:
> +	case SPDIFTX_IER:
> +	case SPDIFTX_IDR:
> +	case SPDIFTX_CH1UD(0):
> +	case SPDIFTX_CH1UD(1):
> +	case SPDIFTX_CH1UD(2):
> +	case SPDIFTX_CH1UD(3):
> +	case SPDIFTX_CH1UD(4):
> +	case SPDIFTX_CH1UD(5):
> +	case SPDIFTX_CH1S(0):
> +	case SPDIFTX_CH1S(1):
> +	case SPDIFTX_CH1S(2):
> +	case SPDIFTX_CH1S(3):
> +	case SPDIFTX_CH1S(4):
> +	case SPDIFTX_CH1S(5):
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool mchp_spdiftx_precious_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPDIFTX_CDR:
> +	case SPDIFTX_ISR:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config mchp_spdiftx_regmap_config = {
> +	.reg_bits = 32,
> +	.reg_stride = 4,
> +	.val_bits = 32,
> +	.max_register = SPDIFTX_VERSION,
> +	.readable_reg = mchp_spdiftx_readable_reg,
> +	.writeable_reg = mchp_spdiftx_writeable_reg,
> +	.precious_reg = mchp_spdiftx_precious_reg,
> +};
> +
> +#define SPDIFTX_GCLK_RATIO	128
> +
> +#define SPDIFTX_CS_BITS		192
> +#define SPDIFTX_UD_BITS		192
> +
> +struct mchp_spdiftx_mixer_control {
> +	unsigned char				ch_stat[SPDIFTX_CS_BITS / 8];
> +	unsigned char				user_data[SPDIFTX_UD_BITS / 8];
> +	spinlock_t				lock;
> +};
> +
> +struct mchp_spdiftx_dev {
> +	struct mchp_spdiftx_mixer_control	control;
> +	struct snd_dmaengine_dai_dma_data	playback;
> +	struct device				*dev;
> +	struct regmap				*regmap;
> +	struct clk				*pclk;
> +	struct clk				*gclk;
> +	unsigned int				fmt;
> +	const struct mchp_i2s_caps		*caps;
> +	int					gclk_enabled:1;
> +};
> +
> +static inline int mchp_spdiftx_is_running(struct mchp_spdiftx_dev *dev)
> +{
> +	u32 mr;
> +
> +	regmap_read(dev->regmap, SPDIFTX_MR, &mr);
> +	return !!(mr & SPDIFTX_MR_TXEN_ENABLE);
> +}
> +
> +static void mchp_spdiftx_channel_status_write(struct mchp_spdiftx_dev *dev)
> +{
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	u32 val;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ctrl->ch_stat) / 4; i++) {
> +		val = (ctrl->ch_stat[(i * 4) + 0] << 0) |
> +		      (ctrl->ch_stat[(i * 4) + 1] << 8) |
> +		      (ctrl->ch_stat[(i * 4) + 2] << 16) |
> +		      (ctrl->ch_stat[(i * 4) + 3] << 24);
> +
> +		regmap_write(dev->regmap, SPDIFTX_CH1S(i), val);
> +	}
> +}
> +
> +static void mchp_spdiftx_user_data_write(struct mchp_spdiftx_dev *dev)
> +{
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	u32 val;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ctrl->user_data) / 4; i++) {
> +		val = (ctrl->user_data[(i * 4) + 0] << 0) |
> +		      (ctrl->user_data[(i * 4) + 1] << 8) |
> +		      (ctrl->user_data[(i * 4) + 2] << 16) |
> +		      (ctrl->user_data[(i * 4) + 3] << 24);
> +
> +		regmap_write(dev->regmap, SPDIFTX_CH1UD(i), val);
> +	}
> +}
> +
> +static irqreturn_t mchp_spdiftx_interrupt(int irq, void *dev_id)
> +{
> +	struct mchp_spdiftx_dev *dev = dev_id;
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	u32 sr, imr, pending, idr = 0;
> +
> +	regmap_read(dev->regmap, SPDIFTX_ISR, &sr);
> +	regmap_read(dev->regmap, SPDIFTX_IMR, &imr);
> +	pending = sr & imr;
> +
> +	if (!pending)
> +		return IRQ_NONE;
> +
> +	if (pending & SPDIFTX_IR_TXUDR) {
> +		dev_warn(dev->dev, "underflow detected\n");
> +		idr |= SPDIFTX_IR_TXUDR;
> +	}
> +
> +	if (pending & SPDIFTX_IR_TXOVR) {
> +		dev_warn(dev->dev, "overflow detected\n");
> +		idr |= SPDIFTX_IR_TXOVR;
> +	}
> +
> +	if (pending & SPDIFTX_IR_UDRDY) {
> +		spin_lock(&ctrl->lock);
> +		mchp_spdiftx_user_data_write(dev);
> +		spin_unlock(&ctrl->lock);
> +		idr |= SPDIFTX_IR_UDRDY;
> +	}
> +
> +	if (pending & SPDIFTX_IR_CSRDY) {
> +		spin_lock(&ctrl->lock);
> +		mchp_spdiftx_channel_status_write(dev);
> +		spin_unlock(&ctrl->lock);
> +		idr |= SPDIFTX_IR_CSRDY;
> +	}
> +
> +	regmap_write(dev->regmap, SPDIFTX_IDR, idr);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int mchp_spdiftx_dai_startup(struct snd_pcm_substream *substream,
> +				    struct snd_soc_dai *dai)
> +{
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	int err;
> +
> +	err = clk_prepare_enable(dev->pclk);
> +	if (err) {
> +		dev_err(dev->dev,
> +			"failed to enable the peripheral clock: %d\n", err);
> +		return err;
> +	}
> +
> +	/* Software reset the IP */
> +	regmap_write(dev->regmap, SPDIFTX_CR,
> +		     SPDIFTX_CR_SWRST | SPDIFTX_CR_FCLR);
> +
> +	return 0;
> +}
> +
> +static void mchp_spdiftx_dai_shutdown(struct snd_pcm_substream *substream,
> +				      struct snd_soc_dai *dai)
> +{
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +
> +	/* Disable interrupts */
> +	regmap_write(dev->regmap, SPDIFTX_IDR, 0xffffffff);
> +
> +	clk_disable_unprepare(dev->pclk);
> +}
> +
> +static int mchp_spdiftx_trigger(struct snd_pcm_substream *substream, int cmd,
> +				struct snd_soc_dai *dai)
> +{
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	u32 mr;
> +	int running;
> +	int ret;
> +
> +	/* do not start/stop while channel status or user data is updated */
> +	spin_lock(&ctrl->lock);
> +	regmap_read(dev->regmap, SPDIFTX_MR, &mr);

Here, atomic, for instance.

> +	running = !!(mr & SPDIFTX_MR_TXEN_ENABLE);
> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		if (!running) {
> +			mr &= ~SPDIFTX_MR_TXEN_MASK;
> +			mr |= SPDIFTX_MR_TXEN_ENABLE;
> +		}
> +		break;
> +	case SNDRV_PCM_TRIGGER_STOP:
> +	case SNDRV_PCM_TRIGGER_SUSPEND:
> +	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +		if (running) {
> +			mr &= ~SPDIFTX_MR_TXEN_MASK;
> +			mr |= SPDIFTX_MR_TXEN_DISABLE;
> +		}
> +		break;
> +	default:
> +		spin_unlock(&ctrl->lock);
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_write(dev->regmap, SPDIFTX_MR, mr);
> +	spin_unlock(&ctrl->lock);
> +	if (ret) {
> +		dev_err(dev->dev, "unable to disable TX: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_hw_params(struct snd_pcm_substream *substream,
> +				  struct snd_pcm_hw_params *params,
> +				  struct snd_soc_dai *dai)
> +{
> +	unsigned long flags;
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	u32 mr;
> +	unsigned int bps = params_physical_width(params) / 8;
> +	int ret;
> +
> +	dev_dbg(dev->dev, "%s() rate=%u format=%#x width=%u channels=%u\n",
> +		__func__, params_rate(params), params_format(params),
> +		params_width(params), params_channels(params));
> +
> +	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
> +		dev_err(dev->dev, "Capture is not supported\n");
> +		return -EINVAL;
> +	}
> +
> +	regmap_read(dev->regmap, SPDIFTX_MR, &mr);

Here non-atomic.

> +
> +	if (mr & SPDIFTX_MR_TXEN_ENABLE) {
> +		dev_err(dev->dev, "PCM already running\n");
> +		return -EBUSY;
> +	}
> +
> +	/* Defaults: Toggle mode, justify to LSB, chunksize 1 */
> +	mr = SPDIFTX_MR_CMODE_TOGGLE_ACCESS | SPDIFTX_MR_JUSTIFY_LSB;
> +	dev->playback.maxburst = 1;
> +	switch (params_channels(params)) {
> +	case 1:
> +		mr |= SPDIFTX_MR_MULTICH_MONO;
> +		break;
> +	case 2:
> +		mr |= SPDIFTX_MR_MULTICH_DUAL;
> +		if (bps > 2)
> +			dev->playback.maxburst = 2;
> +		break;
> +	default:
> +		dev_err(dev->dev, "unsupported number of channels: %d\n",
> +			params_channels(params));
> +		return -EINVAL;
> +	}
> +	mr |= SPDIFTX_MR_CHUNK(dev->playback.maxburst);
> +
> +	switch (params_format(params)) {
> +	case SNDRV_PCM_FORMAT_S8:
> +		mr |= SPDIFTX_MR_VBPS(8);
> +		break;
> +	case SNDRV_PCM_FORMAT_S16_BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S16_LE:
> +		mr |= SPDIFTX_MR_VBPS(16);
> +		break;
> +	case SNDRV_PCM_FORMAT_S18_3BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S18_3LE:
> +		mr |= SPDIFTX_MR_VBPS(18);
> +		break;
> +	case SNDRV_PCM_FORMAT_S20_3BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S20_3LE:
> +		mr |= SPDIFTX_MR_VBPS(20);
> +		break;
> +	case SNDRV_PCM_FORMAT_S24_3BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S24_3LE:
> +		mr |= SPDIFTX_MR_VBPS(24);
> +		break;
> +	case SNDRV_PCM_FORMAT_S24_BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S24_LE:
> +		mr |= SPDIFTX_MR_VBPS(24);
> +		break;
> +	case SNDRV_PCM_FORMAT_S32_BE:
> +		mr |= SPDIFTX_MR_ENDIAN_BIG;
> +		fallthrough;
> +	case SNDRV_PCM_FORMAT_S32_LE:
> +		mr |= SPDIFTX_MR_VBPS(32);
> +		break;
> +	default:
> +		dev_err(dev->dev, "unsupported PCM format: %d\n",
> +			params_format(params));
> +		return -EINVAL;
> +	}
> +
> +	mr |= SPDIFTX_MR_BPS(bps);
> +
> +	spin_lock_irqsave(&ctrl->lock, flags);
> +	ctrl->ch_stat[3] &= ~IEC958_AES3_CON_FS;
> +	switch (params_rate(params)) {
> +	case 22050:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_22050;
> +		break;
> +	case 24000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_24000;
> +		break;
> +	case 32000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_32000;
> +		break;
> +	case 44100:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_44100;
> +		break;
> +	case 48000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_48000;
> +		break;
> +	case 88200:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_88200;
> +		break;
> +	case 96000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_96000;
> +		break;
> +	case 176400:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_176400;
> +		break;
> +	case 192000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_192000;
> +		break;
> +	case 8000:
> +	case 11025:
> +	case 16000:
> +	case 64000:
> +		ctrl->ch_stat[3] |= IEC958_AES3_CON_FS_NOTID;
> +		break;
> +	default:
> +		dev_err(dev->dev, "unsupported sample frequency: %u\n",
> +			params_rate(params));
> +		spin_unlock_irqrestore(&ctrl->lock, flags);
> +		return -EINVAL;
> +	}
> +	mchp_spdiftx_channel_status_write(dev);
> +	spin_unlock_irqrestore(&ctrl->lock, flags);
> +	mr |= SPDIFTX_MR_VALID1 | SPDIFTX_MR_VALID2;
> +
> +	if (dev->gclk_enabled) {
> +		clk_disable_unprepare(dev->gclk);
> +		dev->gclk_enabled = 0;
> +	}
> +	ret = clk_set_rate(dev->gclk, params_rate(params) *
> +				      SPDIFTX_GCLK_RATIO);
> +	if (ret) {
> +		dev_err(dev->dev,
> +			"unable to change gclk rate to: rate %u * ratio %u\n",
> +			params_rate(params), SPDIFTX_GCLK_RATIO);
> +		return ret;
> +	}
> +	ret = clk_prepare_enable(dev->gclk);
> +	if (ret) {
> +		dev_err(dev->dev, "unable to enable gclk: %d\n", ret);
> +		return ret;
> +	}
> +	dev->gclk_enabled = 1;
> +	dev_dbg(dev->dev, "%s(): GCLK set to %d\n", __func__,
> +		params_rate(params) * SPDIFTX_GCLK_RATIO);
> +
> +	/* Enable interrupts */
> +	regmap_write(dev->regmap, SPDIFTX_IER,
> +		     SPDIFTX_IR_TXUDR | SPDIFTX_IR_TXOVR);
> +
> +	regmap_write(dev->regmap, SPDIFTX_MR, mr);

Same here.

> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_hw_free(struct snd_pcm_substream *substream,
> +				struct snd_soc_dai *dai)
> +{
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +
> +	regmap_write(dev->regmap, SPDIFTX_IDR,
> +		     SPDIFTX_IR_TXUDR | SPDIFTX_IR_TXOVR);
> +	if (dev->gclk_enabled) {
> +		clk_disable_unprepare(dev->gclk);
> +		dev->gclk_enabled = 0;
> +	}
> +
> +	return regmap_write(dev->regmap, SPDIFTX_CR,
> +			    SPDIFTX_CR_SWRST | SPDIFTX_CR_FCLR);
> +}
> +
> +
> +static const struct snd_soc_dai_ops mchp_spdiftx_dai_ops = {
> +	.startup	= mchp_spdiftx_dai_startup,
> +	.shutdown	= mchp_spdiftx_dai_shutdown,
> +	.trigger	= mchp_spdiftx_trigger,
> +	.hw_params	= mchp_spdiftx_hw_params,
> +	.hw_free	= mchp_spdiftx_hw_free,
> +};
> +
> +#define MCHP_SPDIFTX_RATES	SNDRV_PCM_RATE_8000_192000
> +
> +#define MCHP_SPDIFTX_FORMATS	(SNDRV_PCM_FMTBIT_S8 |		\
> +				 SNDRV_PCM_FMTBIT_S16_LE |	\
> +				 SNDRV_PCM_FMTBIT_U16_BE |	\
> +				 SNDRV_PCM_FMTBIT_S18_3LE |	\
> +				 SNDRV_PCM_FMTBIT_S18_3BE |	\
> +				 SNDRV_PCM_FMTBIT_S20_3LE |	\
> +				 SNDRV_PCM_FMTBIT_S20_3BE |	\
> +				 SNDRV_PCM_FMTBIT_S24_3LE |	\
> +				 SNDRV_PCM_FMTBIT_S24_3BE |	\
> +				 SNDRV_PCM_FMTBIT_S24_LE |	\
> +				 SNDRV_PCM_FMTBIT_S24_BE |	\
> +				 SNDRV_PCM_FMTBIT_S32_LE |	\
> +				 SNDRV_PCM_FMTBIT_S32_BE	\
> +				 )
> +
> +static int mchp_spdiftx_info(struct snd_kcontrol *kcontrol,
> +			     struct snd_ctl_elem_info *uinfo)
> +{
> +	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
> +	uinfo->count = 1;
> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_cs_get(struct snd_kcontrol *kcontrol,
> +			       struct snd_ctl_elem_value *uvalue)
> +{
> +	unsigned long flags;
> +	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +
> +	spin_lock_irqsave(&ctrl->lock, flags);
> +	memcpy(uvalue->value.iec958.status, ctrl->ch_stat,
> +	       sizeof(ctrl->ch_stat));
> +	spin_unlock_irqrestore(&ctrl->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_cs_put(struct snd_kcontrol *kcontrol,
> +			       struct snd_ctl_elem_value *uvalue)
> +{
> +	unsigned long flags;
> +	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	int changed = 0;
> +	int i;
> +
> +	spin_lock_irqsave(&ctrl->lock, flags);
> +	for (i = 0; i < ARRAY_SIZE(ctrl->ch_stat); i++) {
> +		if (ctrl->ch_stat[i] != uvalue->value.iec958.status[i])
> +			changed = 1;
> +		ctrl->ch_stat[i] = uvalue->value.iec958.status[i];
> +	}
> +
> +	if (changed) {
> +		/* don't enable IP while we copy the channel status */
> +		if (mchp_spdiftx_is_running(dev)) {
> +			/*
> +			 * if SPDIF is running, wait for interrupt to write
> +			 * channel status
> +			 */
> +			regmap_write(dev->regmap, SPDIFTX_IER,
> +				     SPDIFTX_IR_CSRDY);
> +		} else {
> +			mchp_spdiftx_channel_status_write(dev);
> +		}
> +	}
> +	spin_unlock_irqrestore(&ctrl->lock, flags);
> +
> +	return changed;
> +}
> +
> +static int mchp_spdiftx_cs_mask(struct snd_kcontrol *kcontrol,
> +				struct snd_ctl_elem_value *uvalue)
> +{
> +	memset(uvalue->value.iec958.status, 0xff,
> +	       sizeof(uvalue->value.iec958.status));
> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_subcode_get(struct snd_kcontrol *kcontrol,
> +				    struct snd_ctl_elem_value *uvalue)
> +{
> +	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&ctrl->lock, flags);
> +	memcpy(uvalue->value.iec958.subcode, ctrl->user_data,
> +	       sizeof(ctrl->user_data));
> +	spin_unlock_irqrestore(&ctrl->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int mchp_spdiftx_subcode_put(struct snd_kcontrol *kcontrol,
> +				    struct snd_ctl_elem_value *uvalue)
> +{
> +	unsigned long flags;
> +	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +	struct mchp_spdiftx_mixer_control *ctrl = &dev->control;
> +	int changed = 0;
> +	int i;
> +
> +	spin_lock_irqsave(&ctrl->lock, flags);
> +	for (i = 0; i < ARRAY_SIZE(ctrl->user_data); i++) {
> +		if (ctrl->user_data[i] != uvalue->value.iec958.subcode[i])
> +			changed = 1;
> +
> +		ctrl->user_data[i] = uvalue->value.iec958.subcode[i];
> +	}
> +	if (changed) {
> +		if (mchp_spdiftx_is_running(dev)) {
> +			/*
> +			 * if SPDIF is running, wait for interrupt to write
> +			 * user data
> +			 */
> +			regmap_write(dev->regmap, SPDIFTX_IER,
> +				     SPDIFTX_IR_UDRDY);
> +		} else {
> +			mchp_spdiftx_user_data_write(dev);
> +		}
> +	}
> +	spin_unlock_irqrestore(&ctrl->lock, flags);
> +
> +	return changed;
> +}
> +
> +static struct snd_kcontrol_new mchp_spdiftx_ctrls[] = {
> +	/* Channel status controller */
> +	{
> +		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
> +		.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
> +		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
> +			SNDRV_CTL_ELEM_ACCESS_VOLATILE,
> +		.info = mchp_spdiftx_info,
> +		.get = mchp_spdiftx_cs_get,
> +		.put = mchp_spdiftx_cs_put,
> +	},
> +	{
> +		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
> +		.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, MASK),
> +		.access = SNDRV_CTL_ELEM_ACCESS_READ,
> +			SNDRV_CTL_ELEM_ACCESS_VOLATILE,
> +		.info = mchp_spdiftx_info,
> +		.get = mchp_spdiftx_cs_mask,
> +	},
> +	/* User bits controller */
> +	{
> +		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
> +		.name = "IEC958 Subcode Playback Default",
> +		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
> +		.info = mchp_spdiftx_info,
> +		.get = mchp_spdiftx_subcode_get,
> +		.put = mchp_spdiftx_subcode_put,
> +	},
> +};
> +
> +static int mchp_spdiftx_dai_probe(struct snd_soc_dai *dai)
> +{
> +	struct mchp_spdiftx_dev *dev = snd_soc_dai_get_drvdata(dai);
> +
> +	snd_soc_dai_init_dma_data(dai, &dev->playback, NULL);
> +
> +	/* Add controls */
> +	snd_soc_add_dai_controls(dai, mchp_spdiftx_ctrls,
> +				 ARRAY_SIZE(mchp_spdiftx_ctrls));
> +
> +	return 0;
> +}
> +
> +static struct snd_soc_dai_driver mchp_spdiftx_dai = {
> +	.name = "mchp-spdiftx",
> +	.probe	= mchp_spdiftx_dai_probe,
> +	.playback = {
> +		.stream_name = "S/PDIF TX Playback",
> +		.channels_min = 1,
> +		.channels_max = 2,
> +		.rates = MCHP_SPDIFTX_RATES,
> +		.formats = MCHP_SPDIFTX_FORMATS,
> +	},
> +	.ops = &mchp_spdiftx_dai_ops,
> +};
> +
> +static const struct snd_soc_component_driver mchp_spdiftx_component = {
> +	.name		= "mchp-spdiftx",
> +};
> +
> +static const struct of_device_id mchp_spdiftx_dt_ids[] = {
> +	{
> +		.compatible = "microchip,sama7g5-spdiftx",
> +	},
> +	{ /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, mchp_spdiftx_dt_ids);
> +static int mchp_spdiftx_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	const struct of_device_id *match;
> +	struct mchp_spdiftx_dev *dev;
> +	struct resource *mem;
> +	struct regmap *regmap;
> +	void __iomem *base;
> +	struct mchp_spdiftx_mixer_control *ctrl;
> +	int irq;
> +	int err;
> +
> +	/* Get memory for driver data. */
> +	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	/* Get hardware capabilities. */
> +	match = of_match_node(mchp_spdiftx_dt_ids, np);
> +	if (match)
> +		dev->caps = match->data;
> +
> +	/* Map I/O registers. */
> +	base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	regmap = devm_regmap_init_mmio(&pdev->dev, base,
> +				       &mchp_spdiftx_regmap_config);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	/* Request IRQ */
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	err = devm_request_irq(&pdev->dev, irq, mchp_spdiftx_interrupt, 0,
> +			       dev_name(&pdev->dev), dev);
> +	if (err)
> +		return err;
> +
> +	/* Get the peripheral clock */
> +	dev->pclk = devm_clk_get(&pdev->dev, "pclk");
> +	if (IS_ERR(dev->pclk)) {
> +		err = PTR_ERR(dev->pclk);
> +		dev_err(&pdev->dev,
> +			"failed to get the peripheral clock: %d\n", err);
> +		return err;
> +	}
> +
> +	/* Get the generic clock */
> +	dev->gclk = devm_clk_get(&pdev->dev, "gclk");
> +	if (IS_ERR(dev->gclk)) {
> +		err = PTR_ERR(dev->gclk);
> +		dev_err(&pdev->dev,
> +			"failed to get the PMC generic clock: %d\n", err);
> +		return err;
> +	}
> +
> +	ctrl = &dev->control;
> +	spin_lock_init(&ctrl->lock);
> +
> +	/* Init channel status */
> +	ctrl->ch_stat[0] = IEC958_AES0_CON_NOT_COPYRIGHT |
> +			   IEC958_AES0_CON_EMPHASIS_NONE;
> +
> +	dev->dev = &pdev->dev;
> +	dev->regmap = regmap;
> +	platform_set_drvdata(pdev, dev);
> +
> +	dev->playback.addr = (dma_addr_t)mem->start + SPDIFTX_CDR;
> +	dev->playback.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +
> +	err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed to register PMC: %d\n", err);
> +		return err;
> +	}
> +
> +	err = devm_snd_soc_register_component(&pdev->dev,
> +					      &mchp_spdiftx_component,
> +					      &mchp_spdiftx_dai, 1);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed to register component: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct platform_driver mchp_spdiftx_driver = {
> +	.probe	= mchp_spdiftx_probe,
> +	.driver	= {
> +		.name	= "mchp_spdiftx",
> +		.of_match_table = of_match_ptr(mchp_spdiftx_dt_ids),
> +	},
> +};
> +
> +module_platform_driver(mchp_spdiftx_driver);
> +
> +MODULE_AUTHOR("Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>");
> +MODULE_DESCRIPTION("Microchip S/PDIF TX Controller Driver");
> +MODULE_LICENSE("GPL v2");
> 

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