input设备使用方法和input_event说明
1.定义的结构体继承input_dev
struct bma150_data {
struct i2c_client *bma150_client;
struct bma150_platform_data *platform_data;
int IRQ;
atomic_t delay;
unsigned char mode;
struct input_dev *input;
struct bma150acc value;
struct mutex value_mutex;
struct mutex mode_mutex;
struct delayed_work work;
struct work_struct irq_work;
};2.给input_dev指定名字和总线类型，对input事件类型可以参考下面代码
EV_MSC 类型参考下面的
set_bit(EV_MSC, dev->evbit);
set_bit(MSC_RAW, dev->mscbit);
EV_ABS类型参考下面的
input->evbit[0] = BIT(EV_ABS);
input->absbit[0] = BIT(ABS_X) | BIT(ABS_Y) | BIT(ABS_Z);
input_set_capability实际调用的也是__set_bit,
input_set_abs_params调用实际上也是set_bit,对于参数（dev,axis,min,max,fuzz,flat） fuzz有滤波作用，min，max代表范围，axis表示了坐标轴，flat暂时不知到用途
3.通过input_register_device(dev)注册input设备
static int bma150_input_init(struct bma150_data *bma150)
{
struct input_dev *dev;
int err;
dev = input_allocate_device();
if (!dev)
return -ENOMEM;
dev->name = SENSOR_NAME;
dev->id.bustype = BUS_I2C;
input_set_capability(dev, EV_ABS, ABS_MISC);
input_set_abs_params(dev, ABS_X, ABSMIN_2G, ABSMAX_2G, 0, 0);
input_set_abs_params(dev, ABS_Y, ABSMIN_2G, ABSMAX_2G, 0, 0);
input_set_abs_params(dev, ABS_Z, ABSMIN_2G, ABSMAX_2G, 0, 0);
input_set_drvdata(dev, bma150);
err = input_register_device(dev);
if (err < 0) {
input_free_device(dev);
return err;
}
bma150->input = dev;
return 0;
}
据说可以指定input号
dev->phys = "bma150/input0";
dev->id.bustype = BUS_HOST;
4.在中断函数或者工作队列中调用input_event上报事件
static inline void input_report_abs(struct input_dev *dev, unsigned int code, int value)
{
input_event(dev, EV_ABS, code, value);
}
input_event函数说明,input调用input_handle_event
对各种事件类型的处理主要体现在input_handle_event函数上
static void input_handle_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
int disposition = INPUT_IGNORE_EVENT;//忽略事件
switch (type) {
case EV_SYN:
switch (code) {
case SYN_CONFIG:
disposition = INPUT_PASS_TO_ALL;//传给设备和handle处理
break;
case SYN_REPORT:
if (!dev->sync) {
dev->sync = true;
disposition = INPUT_PASS_TO_HANDLERS;//传给handle处理 同步事件
}
break;
case SYN_MT_REPORT:
dev->sync = false;
disposition = INPUT_PASS_TO_HANDLERS;//传给handle处理 多点触摸
break;
}
break;
case EV_KEY:
if (is_event_supported(code, dev->keybit, KEY_MAX) &&
!!test_bit(code, dev->key) != value) {
if (value != 2) {
__change_bit(code, dev->key);
if (value)
input_start_autorepeat(dev, code);
else
input_stop_autorepeat(dev);
}
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
case EV_SW://耳机事件
if (is_event_supported(code, dev->swbit, SW_MAX) &&
!!test_bit(code, dev->sw) != value) {
__change_bit(code, dev->sw);
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
case EV_ABS:
if (is_event_supported(code, dev->absbit, ABS_MAX))
disposition = input_handle_abs_event(dev, code, &value);//这里调用的input_handle_abs_event会将上次值和这次值相同的事件过滤掉
break;
case EV_REL:
if (is_event_supported(code, dev->relbit, REL_MAX) && value)
disposition = INPUT_PASS_TO_HANDLERS;
break;
case EV_MSC:
if (is_event_supported(code, dev->mscbit, MSC_MAX))
disposition = INPUT_PASS_TO_ALL;
break;
case EV_LED:
if (is_event_supported(code, dev->ledbit, LED_MAX) &&
!!test_bit(code, dev->led) != value) {
__change_bit(code, dev->led);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_SND:
if (is_event_supported(code, dev->sndbit, SND_MAX)) {
if (!!test_bit(code, dev->snd) != !!value)
__change_bit(code, dev->snd);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_REP:
if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
dev->rep[code] = value;
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_FF:
if (value >= 0)
disposition = INPUT_PASS_TO_ALL;
break;
case EV_PWR:
disposition = INPUT_PASS_TO_ALL;
break;
}
if (disposition != INPUT_IGNORE_EVENT && type != EV_SYN)
dev->sync = false;
if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
dev->event(dev, type, code, value);
if (disposition & INPUT_PASS_TO_HANDLERS)
input_pass_event(dev, type, code, value);
}
/**
* input_event() - report new input event
* @dev: device that generated the event
* @type: type of the event
* @code: event code
* @value: value of the event
*
* This function should be used by drivers implementing various input
* devices to report input events. See also input_inject_event().
*
* NOTE: input_event() may be safely used right after input device was
* allocated with input_allocate_device(), even before it is registered
* with input_register_device(), but the event will not reach any of the
* input handlers. Such early invocation of input_event() may be used
* to 'seed' initial state of a switch or initial position of absolute
* axis, etc.
*/
void input_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
unsigned long flags;
if (is_event_supported(type, dev->evbit, EV_MAX)) {
spin_lock_irqsave(&dev->event_lock, flags);
add_input_randomness(type, code, value);
input_handle_event(dev, type, code, value);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_event);
static int input_handle_abs_event(struct input_dev *dev,
unsigned int code, int *pval)
{
bool is_mt_event;
int *pold;
if (code == ABS_MT_SLOT) {//多点触摸信号？？
/*
* "Stage" the event; we'll flush it later, when we
* get actual touch data.
*/
if (*pval >= 0 && *pval < dev->mtsize)
dev->slot = *pval;
return INPUT_IGNORE_EVENT;
}
is_mt_event = code >= ABS_MT_FIRST && code <= ABS_MT_LAST;//多点触摸事件值
if (!is_mt_event) {//不是多点触摸值，旧将上次值保存在pold里面
pold = &dev->absinfo[code].value;
} else if (dev->mt) {
struct input_mt_slot *mtslot = &dev->mt[dev->slot];
pold = &mtslot->abs[code - ABS_MT_FIRST];
} else {
/*
* Bypass filtering for multi-touch events when
* not employing slots.
*/
pold = NULL;
}
if (pold) {
*pval = input_defuzz_abs_event(*pval, *pold,//fuzz为0时，返回值为pold本身
dev->absinfo[code].fuzz);//这里fuzz是在2中设置类型时传入的参数input_set_abs_params(dev,axis,min,max.fuzz,flat)
if (*pold == *pval)
return INPUT_IGNORE_EVENT;
*pold = *pval;
}
/* Flush pending "slot" event */
if (is_mt_event && dev->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
input_abs_set_val(dev, ABS_MT_SLOT, dev->slot);
input_pass_event(dev, EV_ABS, ABS_MT_SLOT, dev->slot);
}
return INPUT_PASS_TO_HANDLERS;
}