[ALSA] ALSA sound driver for the AT73C213 DAC using Atmel SSC driver

This patch adds support for the AT73C213 DAC using the misc Atmel SSC driver in
I2S mode. The driver also requires a SPI to setup the registers and control
volume.
It has been tested with an AT32AP7000 on the ATSTK1000 development board. The
driver should also work with any Atmel device with an SSC module supported by
the Atmel SSC driver (atmel-ssc).
The atmel-ssc driver is just submitted to the Linux kernel. Please see mail
thread http://lkml.org/lkml/2007/7/16/32Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

include/linux/spi/at73c213.h

+/*
+ * Board-specific data used to set up AT73c213 audio DAC driver.
+ */
+
+#ifndef __LINUX_SPI_AT73C213_H
+#define __LINUX_SPI_AT73C213_H
+
+/**
+ * at73c213_board_info - how the external DAC is wired to the device.
+ *
+ * @ssc_id: SSC platform_driver id the DAC shall use to stream the audio.
+ * @dac_clk: the external clock used to provide master clock to the DAC.
+ * @shortname: a short discription for the DAC, seen by userspace tools.
+ *
+ * This struct contains the configuration of the hardware connection to the
+ * external DAC. The DAC needs a master clock and a I2S audio stream. It also
+ * provides a name which is used to identify it in userspace tools.
+ */
+struct at73c213_board_info {
+	int		ssc_id;
+	struct clk	*dac_clk;
+	char		shortname[32];
+};
+
+#endif /* __LINUX_SPI_AT73C213_H */

sound/spi/Kconfig

@@ -3,4 +3,29 @@
 menu "SPI devices"
 	depends on SND != n
 
+config SND_AT73C213
+	tristate "Atmel AT73C213 DAC driver"
+	depends on ATMEL_SSC
+	select SND_PCM
+	help
+	  Say Y here if you want to use the Atmel AT73C213 external DAC. This
+	  DAC can be found on Atmel development boards.
+
+	  This driver requires the Atmel SSC driver for sound sink, a
+	  peripheral found on most AT91 and AVR32 microprocessors.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called snd-at73c213.
+
+config SND_AT73C213_TARGET_BITRATE
+	int "Target bitrate for AT73C213"
+	depends on SND_AT73C213
+	default "48000"
+	range 8000 50000
+	help
+	  Sets the target bitrate for the bitrate calculator in the driver.
+	  Limited by hardware to be between 8000 Hz and 50000 Hz.
+
+	  Set to 48000 Hz by default.
+
 endmenu

sound/spi/Makefile

 # Makefile for SPI drivers
 
+snd-at73c213-objs		:= at73c213.o
+
+obj-$(CONFIG_SND_AT73C213)	+= snd-at73c213.o

sound/spi/at73c213.c

+/*
+ * Driver for AT73C213 16-bit stereo DAC connected to Atmel SSC
+ *
+ * Copyright (C) 2006-2007 Atmel Norway
+ *
+ * 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.
+ */
+
+/*#define DEBUG*/
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include <sound/driver.h>
+#include <sound/initval.h>
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+
+#include <linux/atmel-ssc.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/at73c213.h>
+
+#include "at73c213.h"
+
+#define BITRATE_MIN	 8000 /* Hardware limit? */
+#define BITRATE_TARGET	CONFIG_SND_AT73C213_TARGET_BITRATE
+#define BITRATE_MAX	50000 /* Hardware limit. */
+
+/* Initial (hardware reset) AT73C213 register values. */
+static u8 snd_at73c213_original_image[18] =
+{
+	0x00,	/* 00 - CTRL    */
+	0x05,	/* 01 - LLIG    */
+	0x05,	/* 02 - RLIG    */
+	0x08,	/* 03 - LPMG    */
+	0x08,	/* 04 - RPMG    */
+	0x00,	/* 05 - LLOG    */
+	0x00,	/* 06 - RLOG    */
+	0x22,	/* 07 - OLC     */
+	0x09,	/* 08 - MC      */
+	0x00,	/* 09 - CSFC    */
+	0x00,	/* 0A - MISC    */
+	0x00,	/* 0B -         */
+	0x00,	/* 0C - PRECH   */
+	0x05,	/* 0D - AUXG    */
+	0x00,	/* 0E -         */
+	0x00,	/* 0F -         */
+	0x00,	/* 10 - RST     */
+	0x00,	/* 11 - PA_CTRL */
+};
+
+struct snd_at73c213 {
+	struct snd_card			*card;
+	struct snd_pcm			*pcm;
+	struct snd_pcm_substream	*substream;
+	struct at73c213_board_info	*board;
+	int				irq;
+	int				period;
+	unsigned long			bitrate;
+	struct clk			*bitclk;
+	struct ssc_device		*ssc;
+	struct spi_device		*spi;
+	u8				spi_wbuffer[2];
+	u8				spi_rbuffer[2];
+	/* Image of the SPI registers in AT73C213. */
+	u8				reg_image[18];
+	/* Protect registers against concurrent access. */
+	spinlock_t			lock;
+};
+
+#define get_chip(card) ((struct snd_at73c213 *)card->private_data)
+
+static int
+snd_at73c213_write_reg(struct snd_at73c213 *chip, u8 reg, u8 val)
+{
+	struct spi_message msg;
+	struct spi_transfer msg_xfer = {
+		.len		= 2,
+		.cs_change	= 0,
+	};
+	int retval;
+
+	spi_message_init(&msg);
+
+	chip->spi_wbuffer[0] = reg;
+	chip->spi_wbuffer[1] = val;
+
+	msg_xfer.tx_buf = chip->spi_wbuffer;
+	msg_xfer.rx_buf = chip->spi_rbuffer;
+	spi_message_add_tail(&msg_xfer, &msg);
+
+	retval = spi_sync(chip->spi, &msg);
+
+	if (!retval)
+		chip->reg_image[reg] = val;
+
+	return retval;
+}
+
+static struct snd_pcm_hardware snd_at73c213_playback_hw = {
+	.info		= SNDRV_PCM_INFO_INTERLEAVED |
+			  SNDRV_PCM_INFO_BLOCK_TRANSFER,
+	.formats	= SNDRV_PCM_FMTBIT_S16_BE,
+	.rates		= SNDRV_PCM_RATE_CONTINUOUS,
+	.rate_min	= 8000,  /* Replaced by chip->bitrate later. */
+	.rate_max	= 50000, /* Replaced by chip->bitrate later. */
+	.channels_min	= 2,
+	.channels_max	= 2,
+	.buffer_bytes_max = 64 * 1024 - 1,
+	.period_bytes_min = 512,
+	.period_bytes_max = 64 * 1024 - 1,
+	.periods_min	= 4,
+	.periods_max	= 1024,
+};
+
+/*
+ * Calculate and set bitrate and divisions.
+ */
+static int snd_at73c213_set_bitrate(struct snd_at73c213 *chip)
+{
+	unsigned long ssc_rate = clk_get_rate(chip->ssc->clk);
+	unsigned long dac_rate_new, ssc_div, status;
+	unsigned long ssc_div_max, ssc_div_min;
+	int max_tries;
+
+	/*
+	 * We connect two clocks here, picking divisors so the I2S clocks
+	 * out data at the same rate the DAC clocks it in ... and as close
+	 * as practical to the desired target rate.
+	 *
+	 * The DAC master clock (MCLK) is programmable, and is either 256
+	 * or (not here) 384 times the I2S output clock (BCLK).
+	 */
+
+	/* SSC clock / (bitrate * stereo * 16-bit). */
+	ssc_div = ssc_rate / (BITRATE_TARGET * 2 * 16);
+	ssc_div_min = ssc_rate / (BITRATE_MAX * 2 * 16);
+	ssc_div_max = ssc_rate / (BITRATE_MIN * 2 * 16);
+	max_tries = (ssc_div_max - ssc_div_min) / 2;
+
+	if (max_tries < 1)
+		max_tries = 1;
+
+	/* ssc_div must be a power of 2. */
+	ssc_div = (ssc_div + 1) & ~1UL;
+
+	if ((ssc_rate / (ssc_div * 2 * 16)) < BITRATE_MIN) {
+		ssc_div -= 2;
+		if ((ssc_rate / (ssc_div * 2 * 16)) > BITRATE_MAX)
+			return -ENXIO;
+	}
+
+	/* Search for a possible bitrate. */
+	do {
+		/* SSC clock / (ssc divider * 16-bit * stereo). */
+		if ((ssc_rate / (ssc_div * 2 * 16)) < BITRATE_MIN)
+			return -ENXIO;
+
+		/* 256 / (2 * 16) = 8 */
+		dac_rate_new = 8 * (ssc_rate / ssc_div);
+
+		status = clk_round_rate(chip->board->dac_clk, dac_rate_new);
+		if (status < 0)
+			return status;
+
+		/* Ignore difference smaller than 256 Hz. */
+		if ((status/256) == (dac_rate_new/256))
+			goto set_rate;
+
+		ssc_div += 2;
+	} while (--max_tries);
+
+	/* Not able to find a valid bitrate. */
+	return -ENXIO;
+
+set_rate:
+	status = clk_set_rate(chip->board->dac_clk, status);
+	if (status < 0)
+		return status;
+
+	/* Set divider in SSC device. */
+	ssc_writel(chip->ssc->regs, CMR, ssc_div/2);
+
+	/* SSC clock / (ssc divider * 16-bit * stereo). */
+	chip->bitrate = ssc_rate / (ssc_div * 16 * 2);
+
+	dev_info(&chip->spi->dev,
+			"at73c213: supported bitrate is %lu (%lu divider)\n",
+			chip->bitrate, ssc_div);
+
+	return 0;
+}
+
+static int snd_at73c213_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	snd_at73c213_playback_hw.rate_min = chip->bitrate;
+	snd_at73c213_playback_hw.rate_max = chip->bitrate;
+	runtime->hw = snd_at73c213_playback_hw;
+	chip->substream = substream;
+
+	return 0;
+}
+
+static int snd_at73c213_pcm_close(struct snd_pcm_substream *substream)
+{
+	struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
+	chip->substream = NULL;
+	return 0;
+}
+
+static int snd_at73c213_pcm_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *hw_params)
+{
+	return snd_pcm_lib_malloc_pages(substream,
+					params_buffer_bytes(hw_params));
+}
+
+static int snd_at73c213_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int snd_at73c213_pcm_prepare(struct snd_pcm_substream *substream)
+{
+	struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int block_size;
+
+	block_size = frames_to_bytes(runtime, runtime->period_size);
+
+	chip->period = 0;
+
+	ssc_writel(chip->ssc->regs, PDC_TPR,
+			(long)runtime->dma_addr);
+	ssc_writel(chip->ssc->regs, PDC_TCR, runtime->period_size * 2);
+	ssc_writel(chip->ssc->regs, PDC_TNPR,
+			(long)runtime->dma_addr + block_size);
+	ssc_writel(chip->ssc->regs, PDC_TNCR, runtime->period_size * 2);
+
+	return 0;
+}
+
+static int snd_at73c213_pcm_trigger(struct snd_pcm_substream *substream,
+				   int cmd)
+{
+	struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
+	int retval = 0;
+
+	spin_lock(&chip->lock);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		ssc_writel(chip->ssc->regs, IER, SSC_BIT(IER_ENDTX));
+		ssc_writel(chip->ssc->regs, PDC_PTCR, SSC_BIT(PDC_PTCR_TXTEN));
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		ssc_writel(chip->ssc->regs, PDC_PTCR, SSC_BIT(PDC_PTCR_TXTDIS));
+		ssc_writel(chip->ssc->regs, IDR, SSC_BIT(IDR_ENDTX));
+		break;
+	default:
+		dev_dbg(&chip->spi->dev, "spurious command %x\n", cmd);
+		retval = -EINVAL;
+		break;
+	}
+
+	spin_unlock(&chip->lock);
+
+	return retval;
+}
+
+static snd_pcm_uframes_t
+snd_at73c213_pcm_pointer(struct snd_pcm_substream *substream)
+{
+	struct snd_at73c213 *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_uframes_t pos;
+	unsigned long bytes;
+
+	bytes = ssc_readl(chip->ssc->regs, PDC_TPR)
+		- (unsigned long)runtime->dma_addr;
+
+	pos = bytes_to_frames(runtime, bytes);
+	if (pos >= runtime->buffer_size)
+		pos -= runtime->buffer_size;
+
+	return pos;
+}
+
+static struct snd_pcm_ops at73c213_playback_ops = {
+	.open		= snd_at73c213_pcm_open,
+	.close		= snd_at73c213_pcm_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= snd_at73c213_pcm_hw_params,
+	.hw_free	= snd_at73c213_pcm_hw_free,
+	.prepare	= snd_at73c213_pcm_prepare,
+	.trigger	= snd_at73c213_pcm_trigger,
+	.pointer	= snd_at73c213_pcm_pointer,
+};
+
+static void snd_at73c213_pcm_free(struct snd_pcm *pcm)
+{
+	struct snd_at73c213 *chip = snd_pcm_chip(pcm);
+	if (chip->pcm) {
+		snd_pcm_lib_preallocate_free_for_all(chip->pcm);
+		chip->pcm = NULL;
+	}
+}
+
+static int __devinit snd_at73c213_pcm_new(struct snd_at73c213 *chip, int device)
+{
+	struct snd_pcm *pcm;
+	int retval;
+
+	retval = snd_pcm_new(chip->card, chip->card->shortname,
+			device, 1, 0, &pcm);
+	if (retval < 0)
+		goto out;
+
+	pcm->private_data = chip;
+	pcm->private_free = snd_at73c213_pcm_free;
+	pcm->info_flags = SNDRV_PCM_INFO_BLOCK_TRANSFER;
+	strcpy(pcm->name, "at73c213");
+	chip->pcm = pcm;
+
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &at73c213_playback_ops);
+
+	retval = snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
+			SNDRV_DMA_TYPE_DEV, &chip->ssc->pdev->dev,
+			64 * 1024, 64 * 1024);
+out:
+	return retval;
+}
+
+static irqreturn_t snd_at73c213_interrupt(int irq, void *dev_id)
+{
+	struct snd_at73c213 *chip = dev_id;
+	struct snd_pcm_runtime *runtime = chip->substream->runtime;
+	u32 status;
+	int offset;
+	int block_size;
+	int next_period;
+	int retval = IRQ_NONE;
+
+	spin_lock(&chip->lock);
+
+	block_size = frames_to_bytes(runtime, runtime->period_size);
+	status = ssc_readl(chip->ssc->regs, IMR);
+
+	if (status & SSC_BIT(IMR_ENDTX)) {
+		chip->period++;
+		if (chip->period == runtime->periods)
+			chip->period = 0;
+		next_period = chip->period + 1;
+		if (next_period == runtime->periods)
+			next_period = 0;
+
+		offset = block_size * next_period;
+
+		ssc_writel(chip->ssc->regs, PDC_TNPR,
+				(long)runtime->dma_addr + offset);
+		ssc_writel(chip->ssc->regs, PDC_TNCR, runtime->period_size * 2);
+		retval = IRQ_HANDLED;
+	}
+
+	ssc_readl(chip->ssc->regs, IMR);
+	spin_unlock(&chip->lock);
+
+	if (status & SSC_BIT(IMR_ENDTX))
+		snd_pcm_period_elapsed(chip->substream);
+
+	return retval;
+}
+
+/*
+ * Mixer functions.
+ */
+static int snd_at73c213_mono_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int reg = kcontrol->private_value & 0xff;
+	int shift = (kcontrol->private_value >> 8) & 0xff;
+	int mask = (kcontrol->private_value >> 16) & 0xff;
+	int invert = (kcontrol->private_value >> 24) & 0xff;
+
+	spin_lock_irq(&chip->lock);
+
+	ucontrol->value.integer.value[0] =
+		(chip->reg_image[reg] >> shift) & mask;
+
+	if (invert)
+		ucontrol->value.integer.value[0] =
+			mask - ucontrol->value.integer.value[0];
+
+	spin_unlock_irq(&chip->lock);
+
+	return 0;
+}
+
+static int snd_at73c213_mono_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int reg = kcontrol->private_value & 0xff;
+	int shift = (kcontrol->private_value >> 8) & 0xff;
+	int mask = (kcontrol->private_value >> 16) & 0xff;
+	int invert = (kcontrol->private_value >> 24) & 0xff;
+	int change, retval;
+	unsigned short val;
+
+	val = (ucontrol->value.integer.value[0] & mask);
+	if (invert)
+		val = mask - val;
+	val <<= shift;
+
+	spin_lock_irq(&chip->lock);
+
+	val = (chip->reg_image[reg] & ~(mask << shift)) | val;
+	change = val != chip->reg_image[reg];
+	retval = snd_at73c213_write_reg(chip, reg, val);
+
+	spin_unlock_irq(&chip->lock);
+
+	if (retval)
+		return retval;
+
+	return change;
+}
+
+static int snd_at73c213_stereo_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	int mask = (kcontrol->private_value >> 24) & 0xff;
+
+	if (mask == 1)
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	else
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+
+	uinfo->count = 2;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = mask;
+
+	return 0;
+}
+
+static int snd_at73c213_stereo_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int left_reg = kcontrol->private_value & 0xff;
+	int right_reg = (kcontrol->private_value >> 8) & 0xff;
+	int shift_left = (kcontrol->private_value >> 16) & 0x07;
+	int shift_right = (kcontrol->private_value >> 19) & 0x07;
+	int mask = (kcontrol->private_value >> 24) & 0xff;
+	int invert = (kcontrol->private_value >> 22) & 1;
+
+	spin_lock_irq(&chip->lock);
+
+	ucontrol->value.integer.value[0] =
+		(chip->reg_image[left_reg] >> shift_left) & mask;
+	ucontrol->value.integer.value[1] =
+		(chip->reg_image[right_reg] >> shift_right) & mask;
+
+	if (invert) {
+		ucontrol->value.integer.value[0] =
+			mask - ucontrol->value.integer.value[0];
+		ucontrol->value.integer.value[1] =
+			mask - ucontrol->value.integer.value[1];
+	}
+
+	spin_unlock_irq(&chip->lock);
+
+	return 0;
+}
+
+static int snd_at73c213_stereo_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int left_reg = kcontrol->private_value & 0xff;
+	int right_reg = (kcontrol->private_value >> 8) & 0xff;
+	int shift_left = (kcontrol->private_value >> 16) & 0x07;
+	int shift_right = (kcontrol->private_value >> 19) & 0x07;
+	int mask = (kcontrol->private_value >> 24) & 0xff;
+	int invert = (kcontrol->private_value >> 22) & 1;
+	int change, retval;
+	unsigned short val1, val2;
+
+	val1 = ucontrol->value.integer.value[0] & mask;
+	val2 = ucontrol->value.integer.value[1] & mask;
+	if (invert) {
+		val1 = mask - val1;
+		val2 = mask - val2;
+	}
+	val1 <<= shift_left;
+	val2 <<= shift_right;
+
+	spin_lock_irq(&chip->lock);
+
+	val1 = (chip->reg_image[left_reg] & ~(mask << shift_left)) | val1;
+	val2 = (chip->reg_image[right_reg] & ~(mask << shift_right)) | val2;
+	change = val1 != chip->reg_image[left_reg]
+		|| val2 != chip->reg_image[right_reg];
+	retval = snd_at73c213_write_reg(chip, left_reg, val1);
+	if (retval) {
+		spin_unlock_irq(&chip->lock);
+		goto out;
+	}
+	retval = snd_at73c213_write_reg(chip, right_reg, val2);
+	if (retval) {
+		spin_unlock_irq(&chip->lock);
+		goto out;
+	}
+
+	spin_unlock_irq(&chip->lock);
+
+	return change;
+
+out:
+	return retval;
+}
+
+static int snd_at73c213_mono_switch_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+
+	return 0;
+}
+
+static int snd_at73c213_mono_switch_get(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int reg = kcontrol->private_value & 0xff;
+	int shift = (kcontrol->private_value >> 8) & 0xff;
+	int invert = (kcontrol->private_value >> 24) & 0xff;
+
+	spin_lock_irq(&chip->lock);
+
+	ucontrol->value.integer.value[0] =
+		(chip->reg_image[reg] >> shift) & 0x01;
+
+	if (invert)
+		ucontrol->value.integer.value[0] =
+			0x01 - ucontrol->value.integer.value[0];
+
+	spin_unlock_irq(&chip->lock);
+
+	return 0;
+}
+
+static int snd_at73c213_mono_switch_put(struct snd_kcontrol *kcontrol,
+				 struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_at73c213 *chip = snd_kcontrol_chip(kcontrol);
+	int reg = kcontrol->private_value & 0xff;
+	int shift = (kcontrol->private_value >> 8) & 0xff;
+	int mask = (kcontrol->private_value >> 16) & 0xff;
+	int invert = (kcontrol->private_value >> 24) & 0xff;
+	int change, retval;
+	unsigned short val;
+
+	if (ucontrol->value.integer.value[0])
+		val = mask;
+	else
+		val = 0;
+
+	if (invert)
+		val = mask - val;
+	val <<= shift;
+
+	spin_lock_irq(&chip->lock);
+
+	val |= (chip->reg_image[reg] & ~(mask << shift));
+	change = val != chip->reg_image[reg];
+
+	retval = snd_at73c213_write_reg(chip, reg, val);
+
+	spin_unlock_irq(&chip->lock);
+
+	if (retval)
+		return retval;
+
+	return change;
+}
+
+static int snd_at73c213_pa_volume_info(struct snd_kcontrol *kcontrol,
+				  struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = ((kcontrol->private_value >> 16) & 0xff) - 1;
+
+	return 0;
+}
+
+static int snd_at73c213_line_capture_volume_info(
+		struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 2;
+	/* When inverted will give values 0x10001 => 0. */
+	uinfo->value.integer.min = 14;
+	uinfo->value.integer.max = 31;
+
+	return 0;
+}
+
+static int snd_at73c213_aux_capture_volume_info(
+		struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	/* When inverted will give values 0x10001 => 0. */
+	uinfo->value.integer.min = 14;
+	uinfo->value.integer.max = 31;
+
+	return 0;
+}
+
+#define AT73C213_MONO_SWITCH(xname, xindex, reg, shift, mask, invert)	\
+{									\
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,				\
+	.name = xname,							\
+	.index = xindex,						\
+	.info = snd_at73c213_mono_switch_info,				\
+	.get = snd_at73c213_mono_switch_get,				\
+	.put = snd_at73c213_mono_switch_put,				\
+	.private_value = (reg | (shift << 8) | (mask << 16) | (invert << 24)) \
+}
+
+#define AT73C213_STEREO(xname, xindex, left_reg, right_reg, shift_left, shift_right, mask, invert) \
+{									\
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,				\
+	.name = xname,							\
+	.index = xindex,						\
+	.info = snd_at73c213_stereo_info,				\
+	.get = snd_at73c213_stereo_get,					\
+	.put = snd_at73c213_stereo_put,					\
+	.private_value = (left_reg | (right_reg << 8)			\
+			| (shift_left << 16) | (shift_right << 19)	\
+			| (mask << 24) | (invert << 22))		\
+}
+
+static struct snd_kcontrol_new snd_at73c213_controls[] __devinitdata = {
+AT73C213_STEREO("Master Playback Volume", 0, DAC_LMPG, DAC_RMPG, 0, 0, 0x1f, 1),
+AT73C213_STEREO("Master Playback Switch", 0, DAC_LMPG, DAC_RMPG, 5, 5, 1, 1),
+AT73C213_STEREO("PCM Playback Volume", 0, DAC_LLOG, DAC_RLOG, 0, 0, 0x1f, 1),
+AT73C213_STEREO("PCM Playback Switch", 0, DAC_LLOG, DAC_RLOG, 5, 5, 1, 1),
+AT73C213_MONO_SWITCH("Mono PA Playback Switch", 0, DAC_CTRL, DAC_CTRL_ONPADRV,
+		     0x01, 0),
+{
+	.iface	= SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name	= "PA Playback Volume",
+	.index	= 0,
+	.info	= snd_at73c213_pa_volume_info,
+	.get	= snd_at73c213_mono_get,
+	.put	= snd_at73c213_mono_put,
+	.private_value	= PA_CTRL | (PA_CTRL_APAGAIN << 8) | \
+		(0x0f << 16) | (1 << 24),
+},
+AT73C213_MONO_SWITCH("PA High Gain Playback Switch", 0, PA_CTRL, PA_CTRL_APALP,
+		     0x01, 1),
+AT73C213_MONO_SWITCH("PA Playback Switch", 0, PA_CTRL, PA_CTRL_APAON, 0x01, 0),
+{
+	.iface	= SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name	= "Aux Capture Volume",
+	.index	= 0,
+	.info	= snd_at73c213_aux_capture_volume_info,
+	.get	= snd_at73c213_mono_get,
+	.put	= snd_at73c213_mono_put,
+	.private_value	= DAC_AUXG | (0 << 8) | (0x1f << 16) | (1 << 24),
+},
+AT73C213_MONO_SWITCH("Aux Capture Switch", 0, DAC_CTRL, DAC_CTRL_ONAUXIN,
+		     0x01, 0),
+{
+	.iface	= SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name	= "Line Capture Volume",
+	.index	= 0,
+	.info	= snd_at73c213_line_capture_volume_info,
+	.get	= snd_at73c213_stereo_get,
+	.put	= snd_at73c213_stereo_put,
+	.private_value	= DAC_LLIG | (DAC_RLIG << 8) | (0 << 16) | (0 << 19)
+		| (0x1f << 24) | (1 << 22),
+},
+AT73C213_MONO_SWITCH("Line Capture Switch", 0, DAC_CTRL, 0, 0x03, 0),
+};
+
+static int __devinit snd_at73c213_mixer(struct snd_at73c213 *chip)
+{
+	struct snd_card *card;
+	int errval, idx;
+
+	if (chip == NULL || chip->pcm == NULL)
+		return -EINVAL;
+
+	card = chip->card;
+
+	strcpy(card->mixername, chip->pcm->name);
+
+	for (idx = 0; idx < ARRAY_SIZE(snd_at73c213_controls); idx++) {
+		errval = snd_ctl_add(card,
+				snd_ctl_new1(&snd_at73c213_controls[idx],
+					chip));
+		if (errval < 0)
+			goto cleanup;
+	}
+
+	return 0;
+
+cleanup:
+	for (idx = 1; idx < ARRAY_SIZE(snd_at73c213_controls) + 1; idx++) {
+		struct snd_kcontrol *kctl;
+		kctl = snd_ctl_find_numid(card, idx);
+		if (kctl)
+			snd_ctl_remove(card, kctl);
+	}
+	return errval;
+}
+
+/*
+ * Device functions
+ */
+static int snd_at73c213_ssc_init(struct snd_at73c213 *chip)
+{
+	/*
+	 * Continuous clock output.
+	 * Starts on falling TF.
+	 * Delay 1 cycle (1 bit).
+	 * Periode is 16 bit (16 - 1).
+	 */
+	ssc_writel(chip->ssc->regs, TCMR,
+			SSC_BF(TCMR_CKO, 1)
+			| SSC_BF(TCMR_START, 4)
+			| SSC_BF(TCMR_STTDLY, 1)
+			| SSC_BF(TCMR_PERIOD, 16 - 1));
+	/*
+	 * Data length is 16 bit (16 - 1).
+	 * Transmit MSB first.
+	 * Transmit 2 words each transfer.
+	 * Frame sync length is 16 bit (16 - 1).
+	 * Frame starts on negative pulse.
+	 */
+	ssc_writel(chip->ssc->regs, TFMR,
+			SSC_BF(TFMR_DATLEN, 16 - 1)
+			| SSC_BIT(TFMR_MSBF)
+			| SSC_BF(TFMR_DATNB, 1)
+			| SSC_BF(TFMR_FSLEN, 16 - 1)
+			| SSC_BF(TFMR_FSOS, 1));
+
+	return 0;
+}
+
+static int snd_at73c213_chip_init(struct snd_at73c213 *chip)
+{
+	int retval;
+	unsigned char dac_ctrl = 0;
+
+	retval = snd_at73c213_set_bitrate(chip);
+	if (retval)
+		goto out;
+
+	/* Enable DAC master clock. */
+	clk_enable(chip->board->dac_clk);
+
+	/* Initialize at73c213 on SPI bus. */
+	retval = snd_at73c213_write_reg(chip, DAC_RST, 0x04);
+	if (retval)
+		goto out_clk;
+	msleep(1);
+	retval = snd_at73c213_write_reg(chip, DAC_RST, 0x03);
+	if (retval)
+		goto out_clk;
+
+	/* Precharge everything. */
+	retval = snd_at73c213_write_reg(chip, DAC_PRECH, 0xff);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, PA_CTRL, (1<<PA_CTRL_APAPRECH));
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_CTRL,
+			(1<<DAC_CTRL_ONLNOL) | (1<<DAC_CTRL_ONLNOR));
+	if (retval)
+		goto out_clk;
+
+	msleep(50);
+
+	/* Stop precharging PA. */
+	retval = snd_at73c213_write_reg(chip, PA_CTRL,
+			(1<<PA_CTRL_APALP) | 0x0f);
+	if (retval)
+		goto out_clk;
+
+	msleep(450);
+
+	/* Stop precharging DAC, turn on master power. */
+	retval = snd_at73c213_write_reg(chip, DAC_PRECH, (1<<DAC_PRECH_ONMSTR));
+	if (retval)
+		goto out_clk;
+
+	msleep(1);
+
+	/* Turn on DAC. */
+	dac_ctrl = (1<<DAC_CTRL_ONDACL) | (1<<DAC_CTRL_ONDACR)
+		| (1<<DAC_CTRL_ONLNOL) | (1<<DAC_CTRL_ONLNOR);
+
+	retval = snd_at73c213_write_reg(chip, DAC_CTRL, dac_ctrl);
+	if (retval)
+		goto out_clk;
+
+	/* Mute sound. */
+	retval = snd_at73c213_write_reg(chip, DAC_LMPG, 0x3f);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_RMPG, 0x3f);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_LLOG, 0x3f);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_RLOG, 0x3f);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_LLIG, 0x11);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_RLIG, 0x11);
+	if (retval)
+		goto out_clk;
+	retval = snd_at73c213_write_reg(chip, DAC_AUXG, 0x11);
+	if (retval)
+		goto out_clk;
+
+	/* Enable I2S device, i.e. clock output. */
+	ssc_writel(chip->ssc->regs, CR, SSC_BIT(CR_TXEN));
+
+	goto out;
+
+out_clk:
+	clk_disable(chip->board->dac_clk);
+out:
+	return retval;
+}
+
+static int snd_at73c213_dev_free(struct snd_device *device)
+{
+	struct snd_at73c213 *chip = device->device_data;
+
+	ssc_writel(chip->ssc->regs, CR, SSC_BIT(CR_TXDIS));
+	if (chip->irq >= 0) {
+		free_irq(chip->irq, chip);
+		chip->irq = -1;
+	}
+
+	return 0;
+}
+
+static int __devinit snd_at73c213_dev_init(struct snd_card *card,
+					 struct spi_device *spi)
+{
+	static struct snd_device_ops ops = {
+		.dev_free	= snd_at73c213_dev_free,
+	};
+	struct snd_at73c213 *chip = get_chip(card);
+	int irq, retval;
+
+	irq = chip->ssc->irq;
+	if (irq < 0)
+		return irq;
+
+	spin_lock_init(&chip->lock);
+	chip->card = card;
+	chip->irq = -1;
+
+	retval = request_irq(irq, snd_at73c213_interrupt, 0, "at73c213", chip);
+	if (retval) {
+		dev_dbg(&chip->spi->dev, "unable to request irq %d\n", irq);
+		goto out;
+	}
+	chip->irq = irq;
+
+	memcpy(&chip->reg_image, &snd_at73c213_original_image,
+			sizeof(snd_at73c213_original_image));
+
+	retval = snd_at73c213_ssc_init(chip);
+	if (retval)
+		goto out_irq;
+
+	retval = snd_at73c213_chip_init(chip);
+	if (retval)
+		goto out_irq;
+
+	retval = snd_at73c213_pcm_new(chip, 0);
+	if (retval)
+		goto out_irq;
+
+	retval = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
+	if (retval)
+		goto out_irq;
+
+	retval = snd_at73c213_mixer(chip);
+	if (retval)
+		goto out_snd_dev;
+
+	snd_card_set_dev(card, &spi->dev);
+
+	goto out;
+
+out_snd_dev:
+	snd_device_free(card, chip);
+out_irq:
+	free_irq(chip->irq, chip);
+	chip->irq = -1;
+out:
+	return retval;
+}
+
+static int snd_at73c213_probe(struct spi_device *spi)
+{
+	struct snd_card			*card;
+	struct snd_at73c213		*chip;
+	struct at73c213_board_info	*board;
+	int				retval;
+	char				id[16];
+
+	board = spi->dev.platform_data;
+	if (!board) {
+		dev_dbg(&spi->dev, "no platform_data\n");
+		return -ENXIO;
+	}
+
+	if (!board->dac_clk) {
+		dev_dbg(&spi->dev, "no DAC clk\n");
+		return -ENXIO;
+	}
+
+	if (IS_ERR(board->dac_clk)) {
+		dev_dbg(&spi->dev, "no DAC clk\n");
+		return PTR_ERR(board->dac_clk);
+	}
+
+	retval = -ENOMEM;
+
+	/* Allocate "card" using some unused identifiers. */
+	snprintf(id, sizeof id, "at73c213_%d", board->ssc_id);
+	card = snd_card_new(-1, id, THIS_MODULE, sizeof(struct snd_at73c213));
+	if (!card)
+		goto out;
+
+	chip = card->private_data;
+	chip->spi = spi;
+	chip->board = board;
+
+	chip->ssc = ssc_request(board->ssc_id);
+	if (IS_ERR(chip->ssc)) {
+		dev_dbg(&spi->dev, "could not get ssc%d device\n",
+				board->ssc_id);
+		retval = PTR_ERR(chip->ssc);
+		goto out_card;
+	}
+
+	retval = snd_at73c213_dev_init(card, spi);
+	if (retval)
+		goto out_ssc;
+
+	strcpy(card->driver, "at73c213");
+	strcpy(card->shortname, board->shortname);
+	sprintf(card->longname, "%s on irq %d", card->shortname, chip->irq);
+
+	retval = snd_card_register(card);
+	if (retval)
+		goto out_ssc;
+
+	dev_set_drvdata(&spi->dev, card);
+
+	goto out;
+
+out_ssc:
+	ssc_free(chip->ssc);
+out_card:
+	snd_card_free(card);
+out:
+	return retval;
+}
+
+static int __devexit snd_at73c213_remove(struct spi_device *spi)
+{
+	struct snd_card *card = dev_get_drvdata(&spi->dev);
+	struct snd_at73c213 *chip = card->private_data;
+	int retval;
+
+	/* Stop playback. */
+	ssc_writel(chip->ssc->regs, CR, SSC_BIT(CR_TXDIS));
+
+	/* Mute sound. */
+	retval = snd_at73c213_write_reg(chip, DAC_LMPG, 0x3f);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_RMPG, 0x3f);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_LLOG, 0x3f);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_RLOG, 0x3f);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_LLIG, 0x11);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_RLIG, 0x11);
+	if (retval)
+		goto out;
+	retval = snd_at73c213_write_reg(chip, DAC_AUXG, 0x11);
+	if (retval)
+		goto out;
+
+	/* Turn off PA. */
+	retval = snd_at73c213_write_reg(chip, PA_CTRL,
+					chip->reg_image[PA_CTRL] | 0x0f);
+	if (retval)
+		goto out;
+	msleep(10);
+	retval = snd_at73c213_write_reg(chip, PA_CTRL,
+					(1 << PA_CTRL_APALP) | 0x0f);
+	if (retval)
+		goto out;
+
+	/* Turn off external DAC. */
+	retval = snd_at73c213_write_reg(chip, DAC_CTRL, 0x0c);
+	if (retval)
+		goto out;
+	msleep(2);
+	retval = snd_at73c213_write_reg(chip, DAC_CTRL, 0x00);
+	if (retval)
+		goto out;
+
+	/* Turn off master power. */
+	retval = snd_at73c213_write_reg(chip, DAC_PRECH, 0x00);
+	if (retval)
+		goto out;
+
+out:
+	/* Stop DAC master clock. */
+	clk_disable(chip->board->dac_clk);
+
+	ssc_free(chip->ssc);
+	snd_card_free(card);
+	dev_set_drvdata(&spi->dev, NULL);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int snd_at73c213_suspend(struct spi_device *spi, pm_message_t msg)
+{
+	struct snd_card *card = dev_get_drvdata(&spi->dev);
+	struct snd_at73c213 *chip = card->private_data;
+
+	ssc_writel(chip->ssc->regs, CR, SSC_BIT(CR_TXDIS));
+	clk_disable(chip->board->dac_clk);
+
+	return 0;
+}
+
+static int snd_at73c213_resume(struct spi_device *spi)
+{
+	struct snd_card *card = dev_get_drvdata(&spi->dev);
+	struct snd_at73c213 *chip = card->private_data;
+
+	clk_enable(chip->board->dac_clk);
+	ssc_writel(chip->ssc->regs, CR, SSC_BIT(CR_TXEN));
+
+	return 0;
+}
+#else
+#define snd_at73c213_suspend NULL
+#define snd_at73c213_resume NULL
+#endif
+
+static struct spi_driver at73c213_driver = {
+	.driver		= {
+		.name	= "at73c213",
+	},
+	.probe		= snd_at73c213_probe,
+	.suspend	= snd_at73c213_suspend,
+	.resume		= snd_at73c213_resume,
+	.remove		= __devexit_p(snd_at73c213_remove),
+};
+
+static int __init at73c213_init(void)
+{
+	return spi_register_driver(&at73c213_driver);
+}
+module_init(at73c213_init);
+
+static void __exit at73c213_exit(void)
+{
+	spi_unregister_driver(&at73c213_driver);
+}
+module_exit(at73c213_exit);
+
+MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
+MODULE_DESCRIPTION("Sound driver for AT73C213 with Atmel SSC");
+MODULE_LICENSE("GPL");

sound/spi/at73c213.h

+/*
+ * Driver for the AT73C213 16-bit stereo DAC on Atmel ATSTK1000
+ *
+ * Copyright (C) 2006 - 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * The full GNU General Public License is included in this
+ * distribution in the file called COPYING.
+ */
+
+#ifndef _SND_AT73C213_H
+#define _SND_AT73C213_H
+
+/* DAC control register */
+#define DAC_CTRL		0x00
+#define DAC_CTRL_ONPADRV	7
+#define DAC_CTRL_ONAUXIN	6
+#define DAC_CTRL_ONDACR		5
+#define DAC_CTRL_ONDACL		4
+#define DAC_CTRL_ONLNOR		3
+#define DAC_CTRL_ONLNOL		2
+#define DAC_CTRL_ONLNIR		1
+#define DAC_CTRL_ONLNIL		0
+
+/* DAC left line in gain register */
+#define DAC_LLIG		0x01
+#define DAC_LLIG_LLIG		0
+
+/* DAC right line in gain register */
+#define DAC_RLIG		0x02
+#define DAC_RLIG_RLIG		0
+
+/* DAC Left Master Playback Gain Register */
+#define DAC_LMPG		0x03
+#define DAC_LMPG_LMPG		0
+
+/* DAC Right Master Playback Gain Register */
+#define DAC_RMPG		0x04
+#define DAC_RMPG_RMPG		0
+
+/* DAC Left Line Out Gain Register */
+#define DAC_LLOG		0x05
+#define DAC_LLOG_LLOG		0
+
+/* DAC Right Line Out Gain Register */
+#define DAC_RLOG		0x06
+#define DAC_RLOG_RLOG		0
+
+/* DAC Output Level Control Register */
+#define DAC_OLC			0x07
+#define DAC_OLC_RSHORT		7
+#define DAC_OLC_ROLC		4
+#define DAC_OLC_LSHORT		3
+#define DAC_OLC_LOLC		0
+
+/* DAC Mixer Control Register */
+#define DAC_MC			0x08
+#define DAC_MC_INVR		5
+#define DAC_MC_INVL		4
+#define DAC_MC_RMSMIN2		3
+#define DAC_MC_RMSMIN1		2
+#define DAC_MC_LMSMIN2		1
+#define DAC_MC_LMSMIN1		0
+
+/* DAC Clock and Sampling Frequency Control Register */
+#define DAC_CSFC		0x09
+#define DAC_CSFC_OVRSEL		4
+
+/* DAC Miscellaneous Register */
+#define DAC_MISC		0x0A
+#define DAC_MISC_VCMCAPSEL	7
+#define DAC_MISC_DINTSEL	4
+#define DAC_MISC_DITHEN		3
+#define DAC_MISC_DEEMPEN	2
+#define DAC_MISC_NBITS		0
+
+/* DAC Precharge Control Register */
+#define DAC_PRECH		0x0C
+#define DAC_PRECH_PRCHGPDRV	7
+#define DAC_PRECH_PRCHGAUX1	6
+#define DAC_PRECH_PRCHGLNOR	5
+#define DAC_PRECH_PRCHGLNOL	4
+#define DAC_PRECH_PRCHGLNIR	3
+#define DAC_PRECH_PRCHGLNIL	2
+#define DAC_PRECH_PRCHG		1
+#define DAC_PRECH_ONMSTR	0
+
+/* DAC Auxiliary Input Gain Control Register */
+#define DAC_AUXG		0x0D
+#define DAC_AUXG_AUXG		0
+
+/* DAC Reset Register */
+#define DAC_RST			0x10
+#define DAC_RST_RESMASK		2
+#define DAC_RST_RESFILZ		1
+#define DAC_RST_RSTZ		0
+
+/* Power Amplifier Control Register */
+#define PA_CTRL			0x11
+#define PA_CTRL_APAON		6
+#define PA_CTRL_APAPRECH	5
+#define PA_CTRL_APALP		4
+#define PA_CTRL_APAGAIN		0
+
+#endif /* _SND_AT73C213_H */