AM335x Multiple Audio Channels on MCASP0 Linux

/*
 * ASoC driver for TI DAVINCI EVM platform
 *
 * Author:      Vladimir Barinov, <vbarinov@embeddedalley.com>
 * Copyright:   (C) 2007 MontaVista Software, Inc., <source@mvista.com>
 *
 * 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.
 */
//Includes
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/soc.h>
#include <sound/pcm_params.h>

#include <asm/dma.h>
#include <asm/mach-types.h>

#include <asm/hardware/asp.h>
#include <mach/edma.h>
#include <mach/board-am335xevm.h>

#include "../codecs/wm8580.h"
#include "davinci-pcm.h"
#include "davinci-i2s.h"
#include "davinci-mcasp.h"

//Defines
/* Board has a 12MHZ crystal attached to WM8580 */
#define EVM_WM8580_FREQ 12000000		//!< Board has a 12MHz crystal attached to WM8580
#define AUDIO_FORMAT (SND_SOC_DAIFMT_DSP_B | SND_SOC_DAIFMT_CBM_CFM | SND_SOC_DAIFMT_IB_NF)	//!< MCASP Communication format, codec = master, mode = DSP Mode B

//Enumerations and Structs
/*!
* Defines the different interfaces available on the codec
*/
enum {
	PRI_PLAYBACK = 0,	//!< Playback over the primary interface
	PRI_CAPTURE,		//!< Capture over the primary interface
	SEC_PLAYBACK,		//!< Playback over the secondary interface (not used)
};

/*!
* Define the different output interfaces of the card (3 out 1 in)
*/
static const struct snd_soc_dapm_widget evm_wm8580_dapm_widgets[] = {
	SND_SOC_DAPM_HP("Front", NULL),					//!< Front Speakers (VOUT1)
	SND_SOC_DAPM_HP("Center+Sub", NULL),			//!< Center and Sub Speakers (VOUT2)
	SND_SOC_DAPM_HP("Rear", NULL),					//!< Rear Speakers (VOUT3)

	SND_SOC_DAPM_MIC("MicIn", NULL),				//!< Microphone In (AINL)
	SND_SOC_DAPM_LINE("LineIn", NULL),				//!< Line In (AIN)
};

/*!
* Define all the connection routes for the different interfaces
*/
static const struct snd_soc_dapm_route evm_wm8580_audio_map[] = {
	{"AINL", NULL, "MicIn"},			//!< MicIn feeds AINL

	{"AINL", NULL, "LineIn"},			//!< LineIn feeds AINL
	{"AINR", NULL, "LineIn"},			//!< LineIn feeds AINR

	{"Front", NULL, "VOUT1L"},			//!< Front Left is fed by VOUT1L
	{"Front", NULL, "VOUT1R"},			//!< Front Right is fed VOUT1R

	{"Center+Sub", NULL, "VOUT2L"},		//!< Center is fed by VOUT2L
	{"Center+Sub", NULL, "VOUT2R"},		//!< Sub is fed by VOUT2R

	{"Rear", NULL, "VOUT3L"},			//!< Rear Left is fed by VOUT3L
	{"Rear", NULL, "VOUT3R"},			//!< Rear Right is fed by VOUT3R
};

//Local Variables
static struct platform_device *evm_snd_device;		//!< For storing a reference to the device so it can be closed on exit

//Functions+
/*!
* @name evm_hw_params
* @brief Setup the parameters for playing the requested track
*
* Called before playback/capture is started to setup the peices to
* correctly perform the requested operations.
*
* @param substream the stream to play/capture the data on
* @param params the parameters for use in playback/capture
*
* @returns 0 returned if succesful, otherwise error code
*/
static int evm_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
	struct snd_soc_dai *codec_dai = rtd->codec_dai;
	unsigned int pll_out;
	int rfs;
	int ret;

	/* The Fvco for WM8580 PLLs must fall within [90,100]MHz.
	 * This criterion can't be met if we request PLL output
	 * as {8000x256, 64000x256, 11025x256}Hz.
	 * As a wayout, we rather change rfs to a minimum value that
	 * results in (params_rate(params) * rfs), and itself, acceptable
	 * to both - the CODEC and the CPU.
	 */
	switch (params_rate(params)) {
	case 16000:
	case 22050:
	case 32000:
	case 44100:
	case 48000:
	case 88200:
	case 96000:
		rfs = 256;
		break;
	case 64000:
		rfs = 384;
		break;
	case 8000:
	case 11025:
		rfs = 512;
		break;
	default:
		return -EINVAL;
	}
	//Calculate pll_out value
	pll_out = params_rate(params) * rfs;

	// Set the Codec DAI configuration 
	ret = snd_soc_dai_set_fmt(codec_dai, AUDIO_FORMAT);
	if (ret < 0)
		return ret;

	// Set the AP DAI configuration 
	ret = snd_soc_dai_set_fmt(cpu_dai, AUDIO_FORMAT);
	if (ret < 0)
		return ret;

	// Set WM8580 to drive MCLK from its PLLA 
	ret = snd_soc_dai_set_clkdiv(codec_dai, WM8580_MCLK, WM8580_CLKSRC_PLLA);
	if (ret < 0)
		return ret;

	// Make nothing drive the clkout pin 
	ret = snd_soc_dai_set_clkdiv(codec_dai, WM8580_CLKOUTSRC, WM8580_CLKSRC_NONE);
	if (ret < 0)
		return ret;

	//Set the Codec's PLL
	ret = snd_soc_dai_set_pll(codec_dai, WM8580_PLLA, 0, EVM_WM8580_FREQ, pll_out);
	if (ret < 0)
		return ret;

	//Set the codecs system clock
	ret = snd_soc_dai_set_sysclk(codec_dai, WM8580_CLKSRC_PLLA, pll_out, SND_SOC_CLOCK_IN);
	if (ret < 0)
		return ret;

	return 0;
}

/*!
* @name evm_wm8580_init_paiftx
* @brief Initializes capturing by enabling/disabling the correct pins
*
* Called to setup the card for capturing audio.  Basically just disables
* the mic since there isn't one hooked in.
*
* @param rtd The current runtime
*
* @returns 0 returned if succesful, otherwise error code
*/
static int evm_wm8580_init_paiftx(struct snd_soc_pcm_runtime *rtd)
{
	struct snd_soc_codec *codec = rtd->codec;
	struct snd_soc_dapm_context *dapm = &codec->dapm;

	/* Enabling the microphone requires the connecting of
	 * and actual microphone jack to audio in left.
	 */
	snd_soc_dapm_disable_pin(dapm, "MicIn");

	return 0;
}

/*!
* Define the operations for the audio card (hw params setup)
*/
static struct snd_soc_ops evm_ops = {
	.hw_params = evm_hw_params,			//!< Function to setup hardware for audio format
};

/*!
* Defines the different interfaces available on the card
*/
static struct snd_soc_dai_link evm_dai[] = {
	[PRI_PLAYBACK] = { /* Primary Playback i/f */
		.name = "WM8580 PAIF RX",
		.stream_name = "Playback",
		.cpu_dai_name = "davinci-mcasp.0",
		.codec_dai_name = "wm8580-hifi-playback",
		.platform_name = "davinci-pcm-audio",
		.codec_name = "wm8580.1-001b",
		.ops = &evm_ops,
	},
	[PRI_CAPTURE] = { /* Primary Capture i/f */
		.name = "WM8580 PAIF TX",
		.stream_name = "Capture",
		.cpu_dai_name = "davinci-mcasp.0",
		.codec_dai_name = "wm8580-hifi-capture",
		.platform_name = "davinci-pcm-audio",
		.codec_name = "wm8580.1-001b",
		.init = evm_wm8580_init_paiftx,
		.ops = &evm_ops,
	},
	[SEC_PLAYBACK] = { /* Sec_Fifo Playback i/f */
		.name = "Sec_FIFO TX",
		.stream_name = "Playback",
		.cpu_dai_name = "davinci-mcasp.0",
		.codec_dai_name = "wm8580-hifi-playback",
		.platform_name = "davinci-pcm-audio",
		.codec_name = "wm8580.1-001b",
		.ops = &evm_ops,
	},
};

/*!
* Define the card, its available interfaces, and its mapping
*/
static struct snd_soc_card evm_snd_soc_card = {
	.name = "EVM WM8580",
	.dai_link = evm_dai,
	.num_links = 2,

	.dapm_widgets = evm_wm8580_dapm_widgets,
	.num_dapm_widgets = ARRAY_SIZE(evm_wm8580_dapm_widgets),
	.dapm_routes = evm_wm8580_audio_map,
	.num_dapm_routes = ARRAY_SIZE(evm_wm8580_audio_map),
};

/*!
* @name evm_init
* @brief Initializes the sound device
*
* Called when module is loaded to initialize the audio interface
* for use.
*
* @returns 0 returned if succesful, otherwise error code
*/
static int __init evm_init(void)
{
	int ret;

	evm_snd_device = platform_device_alloc("soc-audio", -1);
	if (!evm_snd_device)
		return -ENOMEM;

	platform_set_drvdata(evm_snd_device, &evm_snd_soc_card);
	ret = platform_device_add(evm_snd_device);
	if (ret)
		platform_device_put(evm_snd_device);

	return ret;
}

/*!
* @name evm_exit
* @brief DeInitializes the sound device
*
* Called when module is unloaded to unregister the
* audio interface from further use.
*
* @returns 0 returned if succesful, otherwise error code
*/
static void __exit evm_exit(void)
{
	platform_device_unregister(evm_snd_device);
}

//REGISTER THE MODULE
module_init(evm_init);
module_exit(evm_exit);

MODULE_AUTHOR("Vladimir Barinov");
MODULE_DESCRIPTION("TI DAVINCI EVM ASoC driver");
MODULE_LICENSE("GPL");