S3C2440 UDA1341声卡驱动分析（oos）


1，驱动架构：
驱动分两个层次，上层是平台设备驱动，底层是audio驱动与mixer驱动。

（1）标准的平台设备驱动结构，probe与remove两个函数。
probe：
获得平台资源->申请内存区域-io内存重映射->获得并使能时钟->设置gpio口->初始化iis总线-> 初始化uda1341->audio dma初始化->注册dsp和mixer->释放内存区域。
代码及注释：

static int s3c2410iis_probe(struct platform_device *pdev) {

struct resource *res;
unsigned long flags;
int ret;

DPRINTK("s3c2410iis_probe\n");

//获得平台设备资源

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
printk(KERN_INFO PFX "failed to get memory region resouce\n");
return -ENOENT;
}

//申请可用内存

res = request_mem_region(res->start, RESSIZE(res), pdev->name);
if(res == 0){
printk(KERN_INFO PFX "failed to request io memory region.\n");
return -ENOENT;
}

//io内存重映射

iis_base = ioremap(res->start, RESSIZE(res));
if(iis_base == 0){
printk(KERN_INFO PFX "failed to ioremap() io memory region.\n"); ret = -EINVAL;
goto free_mem_region;
}

//获得时钟资源

iis_clock = clk_get(&pdev->dev, "iis");
if (iis_clock == NULL) {
printk(KERN_INFO PFX "failed to find clock source\n");
return -ENOENT;
}
/**************************modify by lfc*****************************/
clk_enable(iis_clock);//使能时钟

/*****************************end add********************************/
//禁用本地中断，gpio口设置，恢复中断

local_irq_save(flags);

/* GPB 4: L3CLOCK, OUTPUT */
s3c2410_gpio_cfgpin(S3C2410_GPB4, S3C2410_GPB4_OUTP);
s3c2410_gpio_pullup(S3C2410_GPB4,1);
/* GPB 3: L3DATA, OUTPUT */
s3c2410_gpio_cfgpin(S3C2410_GPB3,S3C2410_GPB3_OUTP);
/* GPB 2: L3MODE, OUTPUT */
s3c2410_gpio_cfgpin(S3C2410_GPB2,S3C2410_GPB2_OUTP);
s3c2410_gpio_pullup(S3C2410_GPB2,1);
/* GPE 3: I2SSDI */
s3c2410_gpio_cfgpin(S3C2410_GPE3,S3C2410_GPE3_I2SSDI);
s3c2410_gpio_pullup(S3C2410_GPE3,1);
/* GPE 0: I2SLRCK */
s3c2410_gpio_cfgpin(S3C2410_GPE0,S3C2410_GPE0_I2SLRCK);
s3c2410_gpio_pullup(S3C2410_GPE0,1);
/* GPE 1: I2SSCLK */
s3c2410_gpio_cfgpin(S3C2410_GPE1,S3C2410_GPE1_I2SSCLK);
s3c2410_gpio_pullup(S3C2410_GPE1,1);
/* GPE 2: CDCLK */
s3c2410_gpio_cfgpin(S3C2410_GPE2,S3C2410_GPE2_CDCLK);
s3c2410_gpio_pullup(S3C2410_GPE2,1);
/* GPE 4: I2SSDO */
s3c2410_gpio_cfgpin(S3C2410_GPE4,S3C2410_GPE4_I2SSDO);
s3c2410_gpio_pullup(S3C2410_GPE4,1);

local_irq_restore(flags);

init_s3c2410_iis_bus();//初始化iis


init_uda1341();//初始化uda1341


//初始化dma ch1 ch2

output_stream.dma_ch = DMA_CH2;

if (!audio_init_dma(&output_stream, "UDA1341 out") & DMACH_LOW_LEVEL) {
audio_clear_dma(&output_stream,&s3c2410iis_dma_out);
printk( KERN_WARNING AUDIO_NAME_VERBOSE
": unable to get DMA channels\n" );
return -EBUSY;
}

input_stream.dma_ch = DMA_CH1;

if (!audio_init_dma(&input_stream, "UDA1341 in") & DMACH_LOW_LEVEL) {
audio_clear_dma(&input_stream,&s3c2410iis_dma_in);
printk( KERN_WARNING AUDIO_NAME_VERBOSE
": unable to get DMA channels\n" );
return -EBUSY;
}

//注册dsp及mixer

audio_dev_dsp = register_sound_dsp(&smdk2410_audio_fops, -1);
audio_dev_mixer = register_sound_mixer(&smdk2410_mixer_fops, -1);

printk(AUDIO_NAME_VERBOSE " initialized\n");

//释放内存区域

free_mem_region:
release_mem_region(res->start, RESSIZE(res));

return 0;
}

remove:
禁用时钟->取消dsp mixer注册->清除dma

static int s3c2410iis_remove(struct platform_device *dev) {
DPRINTK("s3c2410iis_remove\n");

if (iis_clock != NULL){
clk_disable(iis_clock);
clk_put(iis_clock);
iis_clock = NULL;
}

unregister_sound_dsp(audio_dev_dsp);
unregister_sound_mixer(audio_dev_mixer);
audio_clear_dma(&output_stream,&s3c2410iis_dma_out);
audio_clear_dma(&input_stream,&s3c2410iis_dma_in); /* input */
printk(AUDIO_NAME_VERBOSE " unloaded\n");

return 0;
}

uda1341的初始化：
设置gpio口->uda1341复位->uda1341设置

static void init_uda1341(void)
{

/* GPB 4: L3CLOCK */
/* GPB 3: L3DATA */
/* GPB 2: L3MODE */

unsigned long flags;

DPRINTK("init_uda1341\n");

uda1341_volume = 62 - ((DEF_VOLUME * 61) / 100);
uda1341_boost = 0;
// uda_sampling = DATA2_DEEMP_NONE;

// uda_sampling &= ~(DATA2_MUTE);



local_irq_save(flags);

s3c2410_gpio_setpin(S3C2410_GPB2,1);//L3MODE=1

s3c2410_gpio_setpin(S3C2410_GPB4,1);//L3CLOCK=1

local_irq_restore(flags);

uda1341_l3_address(UDA1341_REG_STATUS);
uda1341_l3_data(0x40 | STAT0_SC_384FS | STAT0_IF_MSB|STAT0_DC_FILTER); // reset uda1341

uda1341_l3_data(STAT1 | STAT1_ADC_ON | STAT1_DAC_ON);

uda1341_l3_address(UDA1341_REG_DATA0);
// uda1341_l3_data(DATA0 |DATA0_VOLUME(0x0)); // maximum volume

uda1341_l3_data(DATA0 | DATA0_VOLUME(uda1341_volume));//lfc

uda1341_l3_data(DATA1 |DATA1_BASS(uda1341_boost)| DATA1_TREBLE(0));
uda1341_l3_data((DATA2 |DATA2_DEEMP_NONE) &~(DATA2_MUTE));
uda1341_l3_data(EXTADDR(EXT2));
uda1341_l3_data(EXTDATA(EXT2_MIC_GAIN(0x6)) | EXT2_MIXMODE_CH1);//input channel 1 select(input channel 2 off)


}

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