搞定s3c6410 wm9714的驱动

    2.6.33的内核，在内核自带的s3c2443-ac97.c上移植的s3c6410-ac97.c，把开发板的smdk6400_wm9713.c配置搬过来的。
    改动不大，遇到的主要几个问题是：
    1、开始的时候"AC97 Playback" preallocate_dma_buffer成功，"AC97 Capture"的失败。后来发现是FB用的DMA太多了, s3c_fb_pd_win 的 max_bpp我们使用的16bits，但我们设成32bits，FB申请DMA的时候是按max_bpp申请的。改完max_bpp就OK了。
    2、warm reset函数里面最后把AC97给关了，就没打开，cold reset的最后就打开了。但wm9713初始化的时候是先cold reset，再warm reset。我就把cold reset的最后一点搬上来了，代码如下。
static void s3c6410_ac97_warm_reset(struct snd_ac97 *ac97)
{
    u32 ac_glbctrl;

    ac_glbctrl = readl(s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    ac_glbctrl = S3C_AC97_GLBCTRL_WARMRESET;
    writel(ac_glbctrl, s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    msleep(1);

    ac_glbctrl = 0;
    writel(ac_glbctrl, s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    msleep(1);

    /************** wy! add *****************/
    ac_glbctrl = S3C_AC97_GLBCTRL_ACLINKON;
    writel(ac_glbctrl, s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    msleep(1);

    ac_glbctrl |= S3C_AC97_GLBCTRL_TRANSFERDATAENABLE;
    writel(ac_glbctrl, s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    msleep(1);

    ac_glbctrl |= S3C_AC97_GLBCTRL_PCMOUTTM_DMA |
        S3C_AC97_GLBCTRL_PCMINTM_DMA | S3C_AC97_GLBCTRL_MICINTM_DMA;
    writel(ac_glbctrl, s3c24xx_ac97.regs + S3C_AC97_GLBCTRL);
    /************** wy! add *****************/
}
    3、开始的时候没有声音，后来参考开发板的代码。发现开发板的代码里面的 snd_soc_dai_ops多了个.prepare的初始化。没看过AC97，感觉是在调音量。
static struct snd_soc_dai_ops s3c6410_ac97_dai_ops = {
    .hw_params    = s3c6410_ac97_hw_params,
    .trigger    = s3c6410_ac97_trigger,
    .prepare    = s3c6410_ac97_hifi_prepare,      //wy ! add from kfb
};

static int s3c6410_ac97_hifi_prepare(struct snd_pcm_substream *substream,
                                     struct snd_soc_dai *dai)      
{
    /*
     * To support full duplex 
     * Tested by cat /dev/dsp > /dev/dsp
     */
    s3c6410_ac97_write(0,0x26,0x0);
    s3c6410_ac97_write(0, 0x0c, 0x0808);
    s3c6410_ac97_write(0,0x3c, 0xf803);
    s3c6410_ac97_write(0,0x3e,0xb990);

    if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
        //s3c6400_ac97_write(0,0x02, 0x8080);    //modify by kfb
        s3c6410_ac97_write(0,0x02, 0x0404);
        s3c6410_ac97_write(0, 0x04, 0x0606);   
        //s3c6400_ac97_write(0,0x1c, 0x00aa);  //modify by kfb
        s3c6410_ac97_write(0,0x1c, 0x12aa);
    }
    else
    {
        s3c6410_ac97_write(0, 0x12, 0x0f0f);
#ifdef CONFIG_SOUND_WM9713_INPUT_STREAM_MIC
        s3c6410_ac97_write(0,0x5c,0x2);
        s3c6410_ac97_write(0,0x10,0x68);
        s3c6410_ac97_write(0,0x14,0xfe00);
#else /* Input Stream is LINE-IN */
        s3c6410_ac97_write(0, 0x14, 0xd612);
#endif
    }

    return 0;
}

     4、smdk6400_wm9713.c的初始化和 smdk2443_wm9710.c的初始化不一样，最后在开发板的基础上做了一点改动。代码如下：
/*
 * smdk6400_wm9713.c  --  SoC audio for smdk6400
 *
 * Copyright (C) 2007, Ryu Euiyoul
 *
 * Copyright 2007 Wolfson Microelectronics PLC.
 * Author: Graeme Gregory
 *         [e-mail] or [e-mail]
 *
 *  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.
 *
 *  Revision history
 *    8th  Mar 2007   Initial version.
 *    20th Sep 2007   Apply at smdk6400
 *
 */

#include
#include
//#include
#include
#include
#include
#include

#include "../codecs/wm9713.h"
#include "s3c-pcm.h"
#include "s3c-dma.h"
#include "s3c24xx-ac97.h"

static struct snd_soc_card s3c6410;

static struct snd_soc_dai_link s3c6410_dai[] = {
{
    .name = "AC97",
    .stream_name = "AC97 HiFi",
    .cpu_dai = &s3c6410_ac97_dai[0],
    .codec_dai = &wm9713_dai[WM9713_DAI_AC97_HIFI],
},
};

static struct snd_soc_card s3c6410 = {
    .name = "S3C6410",
    .dai_link = s3c6410_dai,
    .num_links = ARRAY_SIZE(s3c6410_dai),
    .platform = &s3c24xx_soc_platform,      //wy ! add from smdk6400_snd_ac97_devdata
};

static struct snd_soc_device s3c6410_snd_ac97_devdata = {
    //.machine = &s3c6410,      //wy ! modify
    .card = &s3c6410,      //wy ! add
    //.platform = &s3c24xx_soc_platform,
    .codec_dev = &soc_codec_dev_wm9713,
};

static struct platform_device *s3c6410_snd_ac97_device;

static int __init s3c6410_init(void)
{
    int ret;

    s3c6410_snd_ac97_device = platform_device_alloc("soc-audio", -1);
    if (!s3c6410_snd_ac97_device)
        return -ENOMEM;

    platform_set_drvdata(s3c6410_snd_ac97_device,
                &s3c6410_snd_ac97_devdata);
    s3c6410_snd_ac97_devdata.dev = &s3c6410_snd_ac97_device->dev;
    ret = platform_device_add(s3c6410_snd_ac97_device);

    if (ret)
        platform_device_put(s3c6410_snd_ac97_device);

    return ret;
}

static void __exit s3c6410_exit(void)
{
    platform_device_unregister(s3c6410_snd_ac97_device);
}

module_init(s3c6410_init);
module_exit(s3c6410_exit);

/* Module information */
MODULE_AUTHOR("Samsung: Ryu");
MODULE_DESCRIPTION("ALSA SoC WM9713 S3C6410");
MODULE_LICENSE("GPL");

PS：s3c6410-ac97.c的MIC的部分我没用，全注释了，具体就不知道能不能用了。capture我也没试过是否正常。我们只用播放声音。