linux ASOC(3)—— jack framwork & drv

1.涉及文件

kernel/sound/soc/soc-jack.c
kernel/sound/soc/codes/wm8996.c
kernel\cht\sound\soc\intel\board\Cht_bl_dpcm_rt5672.c

2.framwork

2.1重要结构

/**
* struct snd_soc_jack_gpio - Describes a gpio pin for jack detection
*
* @gpio:         gpio number
* @name:         gpio name
* @report:       value to report when jack detected
* @invert:       report presence in low state
* @debouce_time: debouce time in ms
* @wake:     enable as wake source
* @jack_status_check: callback function which overrides the detection
*             to provide more complex checks (eg, reading an
*             ADC).
*/
struct snd_soc_jack_gpio {
unsigned int gpio;
const char *name;
int report;
int invert;
int debounce_time;
bool wake;

struct snd_soc_jack *jack;
struct delayed_work work;

void *data;

/* drv中需要实现的重要回调函数，耳机的插入、拔出、按键的按下工作都需要从这个函数调度，
jack按键中断处理函数也会调用这个函数（整个jack drv都围绕着这个回调函数进行）!!!!!
*/
int (*jack_status_check)(void *data);
};

2.2涉及函数

// 1.Create a new jack
snd_soc_jack_new(struct snd_soc_codec *codec, const char *id, int type, struct snd_soc_jack *jack)

----------
// 2.Set a key mapping on a jack，设置键值对应关系,
snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_3, KEY_PREVIOUSSONG);

----------

/* 3.(核心函数) Associate GPIO pins with an ASoC jack，并且设置对应的gpio功能，设为中断模式
参数3：核心结构
*/
snd_soc_jack_add_gpios(struct snd_soc_jack *jack, int count,struct snd_soc_jack_gpio *gpios)

----------
/* 4.上报键值*/
snd_soc_jack_report(struct snd_soc_jack *jack, int status, int mask)

(1)snd_jack_set_key 函数

snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_0, KEY_MEDIA);
snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_1, KEY_VOLUMEUP);
snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_2, KEY_VOLUMEDOWN);
//changed by chen.lv,20161010
snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_3, KEY_PREVIOUSSONG);
snd_jack_set_key(ctx->jack.jack, SND_JACK_BTN_4, KEY_NEXTSONG);

（2）snd_soc_jack_add_gpios 核心函数

snd_soc_jack_add_gpios(struct snd_soc_jack *jack, int count,struct snd_soc_jack_gpio *gpios)

// 1. 初始化gpio的 work

INIT_DELAYED_WORK(&gpios[i].work, gpio_work);

gpio_work

snd_soc_jack_gpio_detect

report = gpio->jack_status_check(gpio->data); // drv回调函数

/*---------------------from drv 回调----------------------*/

// 耳机的插入、拔出、按键的按下工作都需要从这个函数调度
snd_soc_jack_gpio->jack_status_check = cht_hs_detection

/*-------------------------end -------------------------*/

// 2. 中断注册

ret = request_any_context_irq(gpio_to_irq(gpios[i].gpio),

gpio_handler, // 中断处理函数

IRQF_TRIGGER_RISING |

IRQF_TRIGGER_FALLING,

gpios[i].name,

&gpios[i]);

**// 中断处理函数中调度了 gpio的 work**
queue_delayed_work(system_power_efficient_wq, &gpio->work, msecs_to_jiffies(gpio->debounce_time));