path: root/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/mutex.h>
#include <linux/platform_device.h>
#include <linux/io.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 SSC registers against concurrent access. */
	spinlock_t			lock;
	/* Protect mixer registers against concurrent access. */
	struct mutex			mixer_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	= 1,
	.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;
	int statu