at73c213.c

linux 内核源代码

/*
 * 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];