linux-- input子系统分析

二 设备驱动层

本节将讲述一个简单的输入设备驱动实例。
这个输入设备只有一个按键,按键被连接到一条中断线上,当按键被按下时,将产生一个中断,内核将检测到这个中

断,并对其进行处理。该实例的代码如下:

#include <asm/irq.h>

#include <asm/io.h>

static struct input_dev *button_dev;   /*输入设备结构体*/

static irqreturn_t button_interrupt(int irq, void *dummy)     /*中断处理函数*/
{
input_report_key(button_dev, BTN_0, inb(BUTTON_PORT) & 1);  /*向输入子系统报告产生按键事件*/

input_sync(button_dev);    /*通知接收者,一个报告发送完毕*/

return IRQ_HANDLED;

}

static int __init button_init(void)      /*加载函数*/
{

int error;

if (request_irq(BUTTON_IRQ, button_interrupt, 0, "button", NULL))  /*申请中断，绑定中断处理函数*/
{
printk(KERN_ERR "button.c: Can't allocate irq %d\n", button_irq);

return -EBUSY;
}

button_dev = input_allocate_device();     /*分配一个设备结构体*/

//input_allocate_device()函
4000
数在内存中为输入设备结构体分配一个空间,并对其主要的成员进行了初始化.

if (!button_dev)
{
printk(KERN_ERR "button.c: Not enough memory\n");
error = -ENOMEM;

goto err_free_irq;

}

button_dev->evbit[0] = BIT_MASK(EV_KEY);    /*设置按键信息*/

button_dev->keybit[BIT_WORD(BTN_0)] = BIT_MASK(BTN_0);

//分别用来设置设备所产生的事件以及上报的按键值。Struct iput_dev中有两个成员，一个是evbit.一个是keybit.分别用

//表示设备所支持的动作和键值。

error = input_register_device(button_dev);      /*注册一个输入设备*/
if (error)
{
printk(KERN_ERR "button.c: Failed to register device\n");
goto err_free_dev;
}

return 0;

err_free_dev:

input_free_device(button_dev);

err_free_irq:
free_irq(BUTTON_IRQ, button_interrupt);
return error;

}

static void __exit button_exit(void)      /*卸载函数*/
{
input_unregister_device(button_dev);          /*注销按键设备*/
free_irq(BUTTON_IRQ, button_interrupt);        /*释放按键占用的中断线*/
}
module_init(button_init);
module_exit(button_exit);

这个实例程序代码比较简单,在初始化函数 button_init()中注册了一个中断处理函数,然后调用input_allocate_device()函数分配了一个 input_dev 结构体,并调用 input_register_device()函数对其进行了注册。在中断处理函数 button_interrupt()中,实例将接收到的按键信息上报给 input 子系统。从而通过 input 子系统,向用户态程序提供按键输入信息。本实例采用了中断方式,除了中断相关的代码外,实例中包含了一些 input 子系统提供的函数,现对其中一些重要的函数进行分析。

三 核心层

input_allocate_device()函数,驱动开发人员为了更深入的了解 input 子系统,应该对其代码有一点的认识,该函数的代码

如下:

struct input_dev *input_allocate_device(void)
{
struct input_dev *dev;

dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);  /*分配一个 input_dev 结构体,并初始化为 0*/

if (dev)

{
dev->dev.type = &input_dev_type;   /*初始化设备的类型*/

dev->dev.class = &input_class;

device_initialize(&dev->dev);

mutex_init(&dev->mutex);   // 初始话互斥锁

spin_lock_init(&dev->event_lock);  // 初始化自旋锁

INIT_LIST_HEAD(&dev->h_list);   //初始化链表

INIT_LIST_HEAD(&dev->node);

__module_get(THIS_MODULE);
}

return dev;

}

该函数返回一个指向 input_dev 类型的指针,该结构体是一个输入设备结构体,包含了输入设备的一些相关信息,如

设备支持的按键码、设备的名称、设备支持的事件等。

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Input设备注册的接口为：input_register_device()。代码如下：

int input_register_device(struct input_dev *dev)
{
static atomic_t input_no = ATOMIC_INIT(0);
struct input_handler *handler;
const char *path;
int error;

__set_bit(EV_SYN, dev->evbit);

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调用__set_bit()函数设置 input_dev 所支持的事件类型。事件类型由 input_dev 的evbit 成员来表示,在这里将其 EV_SYN 置位,表示设

备支持所有的事件。注意,一个设备可以支持一种或者多种事件类型。常用的事件类型如下:

1. #define EV_SYN     0x00   /*表示设备支持所有的事件*/
2. #define EV_KEY     0x01  /*键盘或者按键,表示一个键码*/
3. #define EV_REL     0x02  /*鼠标设备,表示一个相对的光标位置结果*/
4. #define EV_ABS     0x03  /*手写板产生的值,其是一个绝对整数值*/
5. #define EV_MSC     0x04  /*其他类型*/
6. #define EV_LED     0x11   /*LED 灯设备*/
7. #define EV_SND     0x12  /*蜂鸣器,输入声音*/
8. #define EV_REP     0x14   /*允许重复按键类型*/
9. #define EV_PWR     0x16   /*电源管理事件*/

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/*

* If delay and period are pre-set by the driver, then autorepeating

* is handled by the driver itself and we don’t do it in input.c.

*/

init_timer(&dev->timer);  //初始化一个 timer 定时器,这个定时器是为处理重复击键而定义的。
if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
dev->timer.data = (long) dev;
dev->timer.function = input_repeat_key;
dev->rep[REP_DELAY] = 250;
dev->rep[REP_PERIOD] = 33;
}

//如果dev->rep[REP_DELAY]和dev->rep[REP_PERIOD]没有设值，则将其赋默认值。这主要是处理重复按键的.

if (!dev->getkeycode)
dev->getkeycode = input_default_getkeycode;

if (!dev->setkeycode)

dev->setkeycode = input_default_setkeycode;

//检查 getkeycode()函数和 setkeycode()函数是否被定义,如果没定义,则使用默认的处理函数,这两个函数为

//input_default_getkeycode()和 input_default_setkeycode()。input_default_getkeycode()函数用来得到指定位置的键

//值。input_default_setkeycode()函数用来设置键值。具体啥用处，我也没搞清楚？

snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
"input%ld", (unsigned long) atomic_inc_return(&input_no) - 1);

//设置 input_dev 中的 device 的名字,名字以 input0、input1、input2、input3、input4等的形式出现在 sysfs

//文件系统中.

error = device_add(&dev->dev);
if (error)

return error;

//使用 device_add()函数将 input_dev 包含的 device 结构注册到 Linux 设备模型中,并可以在 sysfs

//文件系统中表现出来。

path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
printk(KERN_INFO "input: %s as %s/n",
dev->name ? dev->name : "Unspecified device", path ? path : "N/A");
kfree(path);

error = mutex_lock_interruptible(&input_mutex);
if (error) {
device_del(&dev->dev);
return error;
}

list_add_tail(&dev->node, &input_dev_list);

//调用 list_add_tail()函数将 input_dev 加入 input_dev_list 链表中,input_dev_list 链

//表中包含了系统中所有的 input_dev 设备。

list_for_each_entry(handler, &input_handler_list, node)

input_attach_handler(dev, handler);

//将input device 挂到input_dev_list链表上.然后，对每一个挂在input_handler_list的handler调用

//input_attach_handler().在这里的情况有好比设备模型中的device和driver的匹配。所有的input device都挂在

//input_dev_list链上。所有的handler都挂在input_handler_list上。

input_wakeup_procfs_readers();

mutex_unlock(&input_mutex);

return 0;

}

====================================================================================

匹配是在input_attach_handler()中完成的。代码如下：

static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)

{

const struct input_device_id *id;

int error;

if (handler->blacklist && input_match_device(handler->blacklist, dev))
return -ENODEV;

//首先判断 handler的 blacklist 是否被赋值,如果被赋值,则匹配 blacklist 中的数据跟 dev->id 的数据是否匹配。blacklist

//是一个 input_device_id*的类型,其指向 input_device_ids的一个表,这个表中存放了驱动程序应该忽略的设备。即使在

//id_table 中找到支持的项,也应该忽略这种设备。

id = input_match_device(handler->id_table, dev);

//调用 input_match_device()函数匹配 handler->>id_table 和 dev->id 中的数据。如果不成功则返回。

handle->id_table 也是一个 input_device_id 类型的指针,其表示驱动支持的设备列表。

if (!id)
return -ENODEV;

error = handler->connect(handler, dev, id);

//如果匹配成功,则调用 handler->connect()函数将 handler 与 input_dev 连接起来。

// 在connect() 中会调用input_register_handle，而这些都需要handler的注册。

if (error && error != -ENODEV)
printk(KERN_ERR
"input: failed to attach handler %s to device %s, "
"error: %d/n",
handler->name, kobject_name(&dev->dev.kobj), error);

return error;

}

//如果handler的blacklist被赋值。要先匹配blacklist中的数据跟dev->id的数据是否匹配。匹配成功过后再来匹配

//handle->id和dev->id中的数据。如果匹配成功，则调用handler->connect().

====================================================================================

input_match_device()代码如下：

static const struct input_device_id *input_match_device(const struct input_device_id *id,

struct input_dev *dev)

{

int i;

for (; id->flags || id->driver_info; id++) {

//匹配设备厂商的信息,设备号的信息。

if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)

if (id->bustype != dev->id.bustype)

continue;

if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
if (id->vendor != dev->id.vendor)
continue;

if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
if (id->product != dev->id.product)
continue;

if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
if (id->version != dev->id.version)
continue;

MATCH_BIT(evbit,  EV_MAX);
MATCH_BIT(,, KEY_MAX);
MATCH_BIT(relbit, REL_MAX);
MATCH_BIT(absbit, ABS_MAX);
MATCH_BIT(mscbit, MSC_MAX);
MATCH_BIT(ledbit, LED_MAX);
MATCH_BIT(sndbit, SND_MAX);
MATCH_BIT(ffbit,  FF_MAX);

MATCH_BIT(swbit,  SW_MAX);

MATCH_BIT宏的定义如下：
#define MATCH_BIT(bit, max)
for (i = 0; i < BITS_TO_LONGS(max); i++)
if ((id->bit[i] & dev->bit[i]) != id->bit[i])
break;
if (i != BITS_TO_LONGS(max))
continue;

--------------------------------------------------------------------------------------------------------------------------------------
return id;
}
return NULL;
}

//从MATCH_BIT宏的定义可以看出。只有当iput device和input handler的id成员在evbit, keybit,… swbit项相同才会匹//配成功。而且匹配的顺序是从evbit, keybit到swbit.只要有一项不同，就会循环到id中的下一项进行比较.

//简而言之,注册input device的过程就是为input device设置默认值，并将其挂以input_dev_list.与挂载在//input_handler_list中的handler相匹配。如果匹配成功，就会调用handler的connect函数.

=========
216b3
===========================================================================

这一条线先讲到这里因为接下去就要讲handler ，那就是事件层的东西了， 我们先把核心层的东西讲完，

在前面的设备驱动层中的中断响应函数里面，有input_report_key 函数 ，下面我们来看看他。

input_report_key()函数向输入子系统报告发生的事件,这里就是一个按键事件。在 button_interrupt()中断函数中,

不需要考虑重复按键的重复点击情况,input_report_key()函数会自动检查这个问题,并报告一次事件给输入子系统。该

函数的代码如下:
static inline void input_report_key(struct input_dev *dev, unsigned int code, int value)

{
input_event(dev, EV_KEY, code, !!value);

}

该函数的第 1 个参数是产生事件的输入设备, 2 个参数是产生的事件, 3 个参数是事件的值。需要注意的是, 第2 个

参数可以取类似 BTN_0、 BTN_1、BTN_LEFT、BTN_RIGHT 等值,这些键值被定义在 include/linux/input.h 文件中。

当第 2 个参数为按键时,第 3 个参数表示按键的状态,value 值为 0 表示按键释放,非 0 表示按键按下。

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在 input_report_key()函数中正在起作用的函数是 input_event()函数,该函数用来向输入子系统报告输入设备产生

的事件,这个函数非常重要,它的代码如下:

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)) {  //检查输入设备是否支持该事件

spin_lock_irqsave(&dev->event_lock, flags);

add_input_randomness(type, code, value);

//函数对事件发送没有一点用处,只是用来对随机数熵池增加一些贡献,因为按键输入是一种随机事件,

//所以对熵池是有贡献的。

input_handle_event(dev, type, code, value);

//调用 input_handle_event()函数来继续输入子系统的相关模块发送数据。

spin_unlock_irqrestore(&dev->event_lock, flags);
}

====================================================================================

input_handle_event()函数向输入子系统传送事件信息。第 1 个参数是输入设备 input_dev,第 2 个参数是事件的类

型,第 3 个参数是键码,第 4 个参数是键值。

浏览一下该函数的大部分代码,主要由一个 switch 结构组成。该结构用来对不同的事件类型,分别处理。其中 case

语句包含了 EV_SYN、 EV_KEY、EV_SW、EV_SW、EV_SND 等事件类型。在这么多事件中,本例只要关注

EV_KEY 事件,因为本节的实例发送的是键盘事件。其实,只要对一个事件的处理过程了解后,对其他事件的处理过程也

就清楚了。该函数的代码如下:

static void input_handle_event(struct input_dev *dev,
{
unsigned int type, unsigned int code, int value)
int disposition = INPUT_IGNORE_EVENT;

//定义了一个 disposition 变量,该变量表示使用什么样的方式处理事件

switch (type) {
case EV_SYN:
switch (code)

{
case SYN_CONFIG:
disposition = INPUT_PASS_TO_ALL;
break;
case SYN_REPORT:
if (!dev->sync)

{
dev->sync = 1;
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
}
break;
case EV_KEY:
if (is_event_supported(code, dev->keybit, KEY_MAX) &&!!test_bit(code, dev->key) != value)

//函数判断是否支持该按键

{
if (value != 2)

{
__change_bit(code, dev->key);
if (value)
input_start_autorepeat(dev, code);   //处理重复按键的情况
}
disposition = INPUT_PASS_TO_HANDLERS;

//将 disposition变量设置为 INPUT_PASS_TO_HANDLERS,表示事件需要 handler 来处理。

---------------------------------------------------------------------------------------------------------------------

disposition 的取值有如下几种:
1. #define INPUT_IGNORE_EVENT           0
2. #define INPUT_PASS_TO_HANDLERS         1
3. #define INPUT_PASS_TO_DEVICE         2
4. #define INPUT_PASS_TO_ALL                 (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)

INPUT_IGNORE_EVENT  表示忽略事件,不对其进行处理。

INPUT_PASS_ TO_HANDLERS  表示将事件交给 handler 处理。
INPUT_PASS_TO_DEVICE  表示将事件交给 input_dev 处理。
INPUT_PASS_TO_ALL 表示将事件交给 handler 和 input_dev 共同处理。

--------------------------------------------------------------------------------------------------------------------

}
break;
case EV_SW:
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))

{
value = input_defuzz_abs_event(value,
dev->abs[code], dev->absfuzz[code]);
if (dev->abs[code] != value)

{
dev->abs[code] = value;
disposition = INPUT_PASS_TO_HANDLERS;

}

}

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 = 0;
if ((disposition &INPUT_PASS_TO_DEVICE) && dev->event)
dev->event(dev, type, code, value);

//首先判断 disposition 等于 INPUT_PASS_TO_DEVICE,然后判断 dev->event 是否对其指定了一个处理函数,如果这些

//条件都满足,则调用自定义的 dev->event()函数处理事件。

//有些事件是发送给设备,而不是发送给 handler 处理的。event()函数用来向输入子系统报告一个将要发送给设备的事

//件,例如让 LED 灯点亮事件、蜂鸣器鸣叫事件等。当事件报告给输入子系统后,就要求设备处理这个事件。

if (disposition & INPUT_PASS_TO_HANDLERS)
input_pass_event(dev, type, code, value);
}

====================================================================================

input_pass_event()函数将事件传递到合适的函数,然后对其进行处理,该函数的代码如下:

static void input_pass_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{

struct input_handle *handle;

rcu_read_lock();

handle = rcu_dereference(dev->grab);

//得到 dev->grab 的指针。grab 是强制为 input device 的 handler,这时要调用 handler的 event 函数。

if (handle)

handle->handler->event(handle, type, code, value);
else

list_for_each_entry_rcu(handle, &dev->h_list, d_node)  //一般情况下走这里

if (handle->open)

handle->handler->event(handle,type, code, value);

//如果该 handle 被打开,表示该设备已经被一个用户进程使用。就会调用与输入设备对应的 handler 的 event()函数。

//注意,只有在 handle 被打开的情况下才会接收到事件,这就是说,只有设备被用户程序使用时,才有必要向用户空间导出

//信息

//此处亦是用到了handle ，核心层就到此为止，前面也讲过在device和handler  connect() 时会调用

//input_register_handle，而这些都需要handler的注册,所以接下来我们看看事件层
rcu_read_unlock();
}

四   事件层

input_handler 是输入子系统的主要数据结构,一般将其称为 handler 处理器,表示对输入事件的具体处理。

input_handler 为输入设备的功能实现了一个接口,输入事件最终传递到handler 处理器,handler 处理器根据一定的规则,

然后对事件进行处理,具体的规则将在下面详细介绍。

输入子系统由驱动层、输入子系统核心层(Input Core)和事件处理层(Event Handler)3 部分组成。一个输入事件,

如鼠标移动,键盘按键按下等通过驱动层->系统核心层->事件处理层->用户空间的顺序到达用户空间并传给应用程序使

用。其中 Input Core 即输入子系统核心层由 driver/input/input.c 及相关头文件实现。其对下提供了设备驱动的接口,对

上提供了事件处理层的编程接口。输入子系统主要设计 input_dev、input_handler、input_handle 等数据结构.

struct input_dev物理输入设备的基本数据结构,包含设备相关的一些信息

struct input_handler 事件处理结构体,定义怎么处理事件的逻辑
struct input_handle用来创建 input_dev 和 input_handler 之间关系的结构体

在evdev.c 中：
static struct input_handler evdev_handler = {
.event        = evdev_event,  // 前面讲的传递信息是调用，在 input_pass_event 中
.connect    = evdev_connect,  //device 和 handler 匹配时调用
.disconnect    = evdev_disconnect,
.fops        = &evdev_fops,                        //  event 、connect、 fops 会在后面详细讲
.minor        = EVDEV_MINOR_BASE,
.name        = "evdev",
.id_table    = evdev_ids,
};

--------------------------------------------------------------------------------------------------------------------------------

struct input_handler {

void *private;

void (*event)(struct input_handle *handle, unsigned int type,

unsigned int code, int value);
int (*connect)(struct input_handler *handler, struct input_dev* dev, const struct input_device_id *id);

void (*disconnect)(struct input_handle *handle);

void (*start)(struct input_handle *handle);

const struct file_operations *fops;

int minor;  //表示设备的次设备号

const char *name;

const struct input_device_id *id_table; //定义了一个 name, 表示 handler 的名字,显示在/proc/bus/input/handlers 目录

//中。
const struct input_device_id *blacklist; //指向一个 input_device_id 表,这个表包含 handler 应该忽略的设备

struct list_head h_list;

struct list_head node;
};

--------------------------------------------------------------------------------------------------------------------------------

//事件层注册
static int __init evdev_init(void)
{
return input_register_handler(&evdev_handler);
}

====================================================================================

int input_register_handler(struct input_handler *handler)
{
struct input_dev *dev;

int retval;
retval = mutex_lock_interruptible(&input_mutex);
if (retval)
return retval;

INIT_LIST_HEAD(&handler->h_list);

//其中的 handler->minor 表示对应 input 设备结点的次设备号。 handler->minor以右移 5 位作为索引值插入到 //input_table[ ]中

if (handler->fops != NULL)

{

if (input_table[handler->minor >> 5])

{
retval = -EBUSY;
goto out;
}
input_table[handler->minor >> 5] = handler;

}

list_add_tail(&handler->node, &input_handler_list);

//调用 list_add_tail()函数,将 handler 加入全局的 input_handler_list 链表中,该链表包含了系统中所有的 input_handler
list_for_each_entry(dev, &input_dev_list, node)

input_attach_handler(dev, handler);

//主 要 调 用 了 input_attach_handler() 函 数 。 该 函 数 在 input_register_device()函数的第 35 行曾详细的介绍过。//input_attach_handler()函数的作用是匹配 input_dev_list 链表中的 input_dev 与 handler。如果成功会将 input_dev

//与 handler 联系起来。也就是说在注册handler和dev时都会去调用该函数。
input_wakeup_procfs_readers();
out:
mutex_unlock(&input_mutex);
return retval;
}

====================================================================================

ok下面我们来看下handle的注册，在前面evdev_handler结构体中，有一个.connect    = evdev_connect, 在

connect里面会注册handle，在前面注册dev，匹配成功后调用。

static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
const struct input_device_id *id)
{
struct evdev *evdev;
int minor;
int error;

for (minor = 0; minor < EVDEV_MINORS; minor++)
if (!evdev_table[minor])
break;

if (minor == EVDEV_MINORS) {
printk(KERN_ERR "evdev: no more free evdev devices/n");
return -ENFILE;
}

evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
if (!evdev)
return -ENOMEM;

INIT_LIST_HEAD(&evdev->client_list);
spin_lock_init(&evdev->client_lock);
mutex_init(&evdev->mutex);
init_waitqueue_head(&evdev->wait);

snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
evdev->exist = 1;
evdev->minor = minor;

evdev->handle.dev = input_get_device(dev);
evdev->handle.name = evdev->name;
evdev->handle.handler = handler;
evdev->handle.private = evdev;

//分配了一个 evdev结构 ,并对这个结构进行初始化 .在这里我们可以看到 ,这个结构封装了一个 handle结构 ,这结构与

//我们之前所讨论的 handler是不相同的 .注意有一个字母的差别哦 .我们可以把 handle看成是 handler和 input device

//的信息集合体 .在这个结构里集合了匹配成功的 handler和 input device

strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
evdev->dev.class = &input_class;
evdev->dev.parent = &dev->dev;
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);

//在这段代码里主要完成 evdev封装的 device的初始化 .注意在这里 ,使它所属的类指向 input_class.这样在 /sysfs中创

//建的设备目录就会在 /sys/class/input/下面显示 .

error = input_register_handle(&evdev->handle);
if (error)
goto err_free_evdev;
error = evdev_install_chrdev(evdev);
if (error)
goto err_unregister_handle;

error = device_add(&evdev->dev);
if (error)
goto err_cleanup_evdev;

return 0;

err_cleanup_evdev:
evdev_cleanup(evdev);
err_unregister_handle:
input_unregister_handle(&evdev->handle);
err_free_evdev:
put_device(&evdev->dev);
return error;
}

====================================================================================

int input_register_handle(struct input_handle *handle)
{
struct input_handler *handler = handle->handler;
struct input_dev *dev = handle->dev;
int error;

/*
* We take dev->mutex here to prevent race with
* input_release_device().
*/
error = mutex_lock_interruptible(&dev->mutex);
if (error)
return error;
list_add_tail_rcu(&handle->d_node, &dev->h_list);
mutex_unlock(&dev->mutex);
synchronize_rcu();

/*
* Since we are supposed to be called from ->connect()
* which is mutually exclusive with ->disconnect()
* we can't be racing with input_unregister_handle()
* and so separate lock is not needed here.
*/
list_add_tail(&handle->h_node, &handler->h_list);

if (handler->start)
handler->start(handle);

return 0;
}
将handle挂到所对应input device的h_list链表上.还将handle挂到对应的handler的hlist链表上.如果handler定

义了start函数,将调用之. 到这里,我们已经看到了input device, handler和handle是怎么关联起来的了

====================================================================================

接下来我们看看上报信息是调用的  .event        = evdev_event       。

每当input device上报一个事件时,会将其交给和它匹配的handler的event函数处理.在evdev中.这个event函数

对应的代码为:

static void evdev_event(struct input_handle *handle,
unsigned int type, unsigned int code, int value)
{
struct evdev *evdev = handle->private;
struct evdev_client *client;
struct input_event event;

do_gettimeofday(&event.time);
event.type = type;
event.code = code;
event.value = value;

rcu_read_lock();

client = rcu_dereference(evdev->grab);
if (client)
evdev_pass_event(client, &event);
else
list_for_each_entry_rcu(client, &evdev->client_list, node)
evdev_pass_event(client, &event);

rcu_read_unlock();

wake_up_interruptible(&evdev->wait);
}

===================================================================================

static void evdev_pass_event(struct evdev_client *client,
struct input_event *event)
{
/*
* Interrupts are disabled, just acquire the lock
*/
spin_lock(&client->buffer_lock);
client->buffer[client->head++] = *event;
client->head &= EVDEV_BUFFER_SIZE - 1;
spin_unlock(&client->buffer_lock);

kill_fasync(&client->fasync, SIGIO, POLL_IN);
}

这里的操作很简单.就是将event(上传数据)保存到client->buffer中.而client->head就是当前的数据位置.注意这里

是一个环形缓存区.写数据是从client->head写.而读数据则是从client->tail中读.

====================================================================================

最后我们看下handler的相关操作函数    .fops        = &evdev_fops,

我们知道.对主设备号为INPUT_MAJOR的设备节点进行操作,会将操作集转换成handler的操作集.在evdev中,这个

操作集就是evdev_fops.对应的open函数如下示:

static int evdev_open(struct inode *inode, struct file *file)
{
struct evdev *evdev;
struct evdev_client *client;
int i = iminor(inode) - EVDEV_MINOR_BASE;
int error;

if (i >= EVDEV_MINORS)
return -ENODEV;

error = mutex_lock_interruptible(&evdev_table_mutex);
if (error)
return error;
evdev = evdev_table[i];
if (evdev)
get_device(&evdev->dev);
mutex_unlock(&evdev_table_mutex);

if (!evdev)
return -ENODEV;

client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
if (!client) {
error = -ENOMEM;
goto err_put_evdev;
}
spin_lock_init(&client->buffer_lock);
client->evdev = evdev;
evdev_attach_client(evdev, client);

error = evdev_open_device(evdev);
if (error)
goto err_free_client;

file->private_data = client;
return 0;

err_free_client:
evdev_detach_client(evdev, client);
kfree(client);
err_put_evdev:
put_device(&evdev->dev);
return error;
}

====================================================================================

evdev_open_device()函数用来打开相应的输入设备，使设备准备好接收或者发送数据。evdev_open_device()函

数先获得互斥锁，然后检查设备是否存在，并判断设备是否已经被打开。如果没有打开，则调用 input_open_device()

函数打开设备.

static int evdev_open_device(struct evdev *evdev)
{
int retval;

retval = mutex_lock_interruptible(&evdev->mutex);
if (retval)
return retval;

if (!evdev->exist)
retval = -ENODEV;
else if (!evdev->open++) {
retval = input_open_device(&evdev->handle);
if (retval)
evdev->open--;
}

mutex_unlock(&evdev->mutex);
return retval;
}

====================================================================================

对于evdev设备节点的read操作都会由evdev_read()完成.它的代码如下:

static ssize_t evdev_read(struct file *file, char __user *buffer,
size_t count, loff_t *ppos)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
struct input_event event;
int retval;

if (count < evdev_event_size())
return -EINVAL;

if (client->head == client->tail && evdev->exist &&
(file->f_flags & O_NONBLOCK))
return -EAGAIN;

retval = wait_event_interruptible(evdev->wait,
client->head != client->tail || !evdev->exist);
if (retval)
return retval;

if (!evdev->exist)
return -ENODEV;

while (retval + evdev_event_size() <= count &&
evdev_fetch_next_event(client, &event)) {

if (evdev_event_to_user(buffer + retval, &event))
return -EFAULT;

retval += evdev_event_size();
}

return retval;
}

首先,它判断缓存区大小是否足够.在读取数据的情况下,可能当前缓存区内没有数据可读.在这里先睡眠等待缓存

区中有数据.如果在睡眠的时候,.条件满足.是不会进行睡眠状态而直接返回的. 然后根据read()提够的缓存区大小.将

client中的数据写入到用户空间的缓存区中.

五  用户空间

到这就没啥讲的了， ok到此为止吧！！！

以下为电磁笔驱动程序：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/version.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/ioctl.h>
#include <linux/regulator/consumer.h>
#ifdef CONFIG_HAS_EARLYSUSPEND
#include <linux/earlysuspend.h>
#endif
#include <asm/uaccess.h>
#include <mach/sys_config.h>
#include <linux/delay.h>
#define CHIP_NAME                       "Hanvon0868"
#define HANVON_NAME                     "hanvon_0868_i2c"
#define HANVON_NAME_SIZE                16
#define MAX_EVENTS                      10
#define SCR_X                           800
#define SCR_Y                           1280
#define MAX_X                           0x1cfe
#define MAX_Y                           0x27de
#define MAX_PRESSURE                    1024
#define MAX_PACKET_SIZE                 7

/* if uncomment this definition, calibrate function is enabled. */
//#define HW0868_CALIBRATE

#define DEBUG_SHOW_RAW                  0X00000001
#define DEBUG_SHOW_COORD                0X00000010

#define UPDATE_SLAVE_ADDR               0x34
/*
#define HW0868_GPIO_RESET               TEGRA_GPIO_PU3
#define HW0868_GPIO_CONFIG              TEGRA_GPIO_PV4
#define HW0868_GPIO_POWER               TEGRA_GPIO_PS2
*/

#define HW0868_CMD_RESET                0x08680000
#define HW0868_CMD_CONFIG_HIGH          0x08680001
#define HW0868_CMD_CONFIG_LOW           0x08680002
#define HW0868_CMD_UPDATE               0x08680003
#define HW0868_CMD_GET_VERSION          0x08680004
#define HW0868_CMD_CALIBRATE            0x08680005

/* define pen flags, 7-bytes protocal. */
#define PEN_POINTER_UP                  0xa0
#define PEN_POINTER_DOWN                0xa1
#define PEN_BUTTON_UP                   0xa2
#define PEN_BUTTON_DOWN                 0xa3
#define PEN_RUBBER_UP                   0xa4
#define PEN_RUBBER_DOWN                 0xa5
#define PEN_ALL_LEAVE                   0xe0

struct hanvon_pen_data
{
u16         x;
u16         y;
u16         pressure;
u8          flag;
};

struct hanvon_i2c_chip {
unsigned char * chipname;
struct workqueue_struct *ktouch_wq;
struct work_struct work_irq;
struct mutex mutex_wq;
struct i2c_client *client;
unsigned char work_state;
struct input_dev *p_inputdev;
struct early_suspend early_suspend;
};

/* global I2C client. */
static struct i2c_client *g_client;
static int epen_rst_gpio;
static int epen_irq_number;
static int epen_twi_id;
static int epen_power_name;
static int epen_power_vol;
static int epen_ldo;

/* when pen detected, this flag is set 1 */
static volatile int isPenDetected = 0;

/* DEBUG micro, for user interface. */
static unsigned int debug = 0;//DEBUG_SHOW_COORD | DEBUG_SHOW_RAW;

/* version number buffer */
static unsigned char ver_info[9] = {0};
static int ver_size = 9;

/* calibration parameter */
static bool isCalibrated = false;
static int a[7];
static int A = 65535, B = 0, C = 16, D = 0, E = 65535, F = 0, scale = 65536;

/*Enable the Touchscreen */
int enTouchscreen = 1;
EXPORT_SYMBOL(enTouchscreen);
static int flagTouchscreen=0;
static int debugTouchscreen=0;
struct hanvon_pen_data infoTouchscreen = {0};
#define hw0868_dbg_raw(fmt, args...)        \
if(debug & DEBUG_SHOW_RAW) \
printk(KERN_INFO "[HW0868 raw]: "fmt, ##args);
#define hw0868_dbg_coord(fmt, args...)  \
if(debug & DEBUG_SHOW_COORD) \
printk(KERN_INFO "[HW0868 coord]: "fmt, ##args);

static struct i2c_device_id hanvon_i2c_idtable[] = {
{ HANVON_NAME, 0 },
{ }
};

static void hw0868_reset()
{
printk(KERN_INFO "Hanvon 0868 reset!\n");
//tegra_gpio_enable(HW0868_GPIO_RESET);
//gpio_direction_output(HW0868_GPIO_RESET, 0);
__gpio_set_value(epen_rst_gpio, 1);
mdelay(10);
__gpio_set_value(epen_rst_gpio, 0);
mdelay(50);
//gpio_direction_output(HW0868_GPIO_RESET, 1);
__gpio_set_value(epen_rst_gpio, 1);
mdelay(50);
}

static void hw0868_set_power(int enable)
{
printk(KERN_INFO "Hanvon 0868 set power (%d)\n", enable);
if(enable) {
regulator_enable(epen_ldo);
} else {
if (regulator_is_enabled(epen_ldo))
regulator_disable(epen_ldo);
}
msleep(10);
}

static void hw0868_set_config_pin(int i)
{
printk(KERN_INFO "Config pin status(%d)\n", i);
/*
tegra_gpio_enable(HW0868_GPIO_CONFIG);
if (i == 0)
gpio_direction_output(HW0868_GPIO_CONFIG, 0);
if (i == 1)
gpio_direction_output(HW0868_GPIO_CONFIG, 1);
*/
}

static int hw0868_get_version(struct i2c_client *client)
{
int ret = -1;
unsigned char ver_cmd[] = {0xcd, 0x5f};
//hw0868_reset();
ret = i2c_master_send(client, ver_cmd, 2);
if (ret < 0)
{
printk(KERN_INFO "Get version ERROR!\n");
return ret;
}
return ret;
}

static int read_calibrate_param()
{
int ret = -1;
mm_segment_t old_fs;
struct file *file = NULL;
printk(KERN_INFO "kernel read calibrate param.\n");
old_fs = get_fs();
set_fs(get_ds());
file = filp_open("/data/calibrate", O_RDONLY, 0);
if (file == NULL)
return -1;
if (file->f_op->read == NULL)
return -1;

// TODO: read file
if (file->f_op->read(file, (unsigned char*)a, sizeof(int)*7, &file->f_pos) == 28)
{
printk(KERN_INFO "calibrate param: %d, %d, %d, %d, %d, %d, %d\n", a[0], a[1], a[2], a[3], a[4], a[5], a[6]);
A = a[1];
B = a[2];
C = a[0];
D = a[4];
E = a[5];
F = a[3];
scale = a[6];
isCalibrated = true;
}
else
{
filp_close(file, NULL);
set_fs(old_fs);
return -1;
}

filp_close(file, NULL);
set_fs(old_fs);
return 0;
}

int fw_i2c_master_send(const struct i2c_client *client, const char *buf, int count)
{
int ret;
struct i2c_adapter *adap = client->adapter;
struct i2c_msg msg;

msg.addr = UPDATE_SLAVE_ADDR;
msg.flags = client->flags & I2C_M_TEN;
msg.len = count;
msg.buf = (char *)buf;

ret = i2c_transfer(adap, &msg, 1);
printk(KERN_INFO "[hanvon 0868 update] fw_i2c_master_send  ret = %d\n", ret);
/*
* If everything went ok (i.e. 1 msg transmitted), return #bytes
* transmitted, else error code.
*/
return (ret == 1) ? count : ret;
}

int fw_i2c_master_recv(const struct i2c_client *client, char *buf, int count)
{
struct i2c_adapter *adap = client->adapter;
struct i2c_msg msg;
int ret;

msg.addr = UPDATE_SLAVE_ADDR;
msg.flags = client->flags & I2C_M_TEN;
msg.flags |= I2C_M_RD;
msg.len = count;
msg.buf = buf;

ret = i2c_transfer(adap, &msg, 1);
printk(KERN_INFO "[hanvon 0868 update] fw_i2c_master_recv  ret = %d\n", ret);
/*
* If everything went ok (i.e. 1 msg received), return #bytes received,
* else error code.
*/
return (ret == 1) ? count : ret;
}

ssize_t hw0868_i2c_show(struct device *dev, struct device_attribute *attr, char *buf)
{
int count, i;
unsigned char csw_packet[13] = {1};
printk(KERN_INFO "Receive CSW package.\n");
count = fw_i2c_master_recv(g_client, csw_packet, 13);
if (count < 0)
{
return -1;
}
printk(KERN_INFO "[num 01] read %d bytes.\n", count);
for(i = 0; i < count; i++)
{
printk(KERN_INFO "%.2x \n", csw_packet[i]);
}
return sprintf(buf, "%s", csw_packet);
}

ssize_t hw0868_i2c_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
int ret = 0;
printk(KERN_INFO "%x\n", buf[3]);
printk(KERN_INFO "%x\n", buf[2]);
printk(KERN_INFO "%x\n", buf[1]);
printk(KERN_INFO "%x\n", buf[0]);
printk(KERN_INFO "%s is called, count=%d.\n", __func__, count);
if ((count == 31) && (buf[1] == 0x57) && (buf[0] == 0x48))
{
printk(KERN_INFO "Send CBW package.\n");
ret = fw_i2c_master_send(g_client, buf, count);
return ret;
}

/* transfer file */
if (count == 32)
{
printk(KERN_INFO "Transfer file.\n");
ret = fw_i2c_master_send(g_client, buf, count);
return ret;
}

int cmd = *((int *)buf);
if ((cmd & 0x08680000) != 0x08680000)
{
printk(KERN_INFO "Invalid command (0x%08x).\n", cmd);
return -1;
}

switch(cmd)
{
case HW0868_CMD_RESET:
printk(KERN_INFO "Command: reset.\n");
hw0868_reset();
break;
case HW0868_CMD_CONFIG_HIGH:
printk(KERN_INFO "Command: set config pin high.\n");
hw0868_set_config_pin(1);
break;
case HW0868_CMD_CONFIG_LOW:
printk(KERN_INFO "Command: set config pin low.\n");
hw0868_set_config_pin(0);
break;
case HW0868_CMD_GET_VERSION:
printk(KERN_INFO "Command: get firmware version.\n");
hw0868_get_version(g_client);
break;
case HW0868_CMD_CALIBRATE:
printk(KERN_INFO "Command: Calibrate.\n");
read_calibrate_param();
break;
}
return count;
}

DEVICE_ATTR(hw0868_entry, 0666, hw0868_i2c_show, hw0868_i2c_store);

/* get version */
ssize_t hw0868_version_show(struct device *dev, struct device_attribute *attr,char *buf)
{
return sprintf(buf, "version number: %.2x %.2x %.2x %.2x %.2x %.2x\n",
ver_info[1], ver_info[2], ver_info[3],ver_info[4], ver_info[5], ver_info[6]);
}

ssize_t hw0868_version_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
return count;
}
DEVICE_ATTR(version, 0666, hw0868_version_show, hw0868_version_store);

MODULE_DEVICE_TABLE(i2c, hanvon_i2c_idtable);

static long hw0868_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
return 0;
}

static struct file_operations hanvon_cdev_fops = {
.owner= THIS_MODULE,
.unlocked_ioctl= hw0868_ioctl,
};

static struct miscdevice hanvon_misc_dev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "hw0868",
.fops = &hanvon_cdev_fops,
};

static struct input_dev * allocate_hanvon_input_dev(void)
{
int ret;
struct input_dev *p_inputdev=NULL;

p_inputdev = input_allocate_device();
if(p_inputdev == NULL)
{
return NULL;
}

p_inputdev->name = "Hanvon electromagnetic pen";
p_inputdev->phys = "I2C";
p_inputdev->id.bustype = BUS_I2C;

set_bit(EV_ABS, p_inputdev->evbit);
__set_bit(INPUT_PROP_DIRECT, p_inputdev->propbit);
__set_bit(EV_ABS, p_inputdev->evbit);
__set_bit(EV_KEY, p_inputdev->evbit);
__set_bit(BTN_TOUCH, p_inputdev->keybit);
__set_bit(BTN_STYLUS, p_inputdev->keybit);
__set_bit(BTN_TOOL_PEN, p_inputdev->keybit);
__set_bit(BTN_TOOL_RUBBER, p_inputdev->keybit);

#ifdef HW0868_CALIBRATE
input_set_abs_params(p_inputdev, ABS_X, 0, SCR_X, 0, 0);
input_set_abs_params(p_inputdev, ABS_Y, 0, SCR_Y, 0, 0);
#else
input_set_abs_params(p_inputdev, ABS_X, 0, MAX_X, 0, 0);
input_set_abs_params(p_inputdev, ABS_Y, 0, MAX_Y, 0, 0);
#endif

input_set_abs_params(p_inputdev, ABS_PRESSURE, 0, MAX_PRESSURE, 0, 0);

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,36)
input_set_events_per_packet(p_inputdev, MAX_EVENTS);
#endif

ret = input_register_device(p_inputdev);
if(ret)
{
printk(KERN_INFO "Unable to register input device.\n");
input_free_device(p_inputdev);
p_inputdev = NULL;
}

return p_inputdev;
}

static struct hanvon_pen_data hanvon_get_packet(struct hanvon_i2c_chip *phic)
{
struct hanvon_pen_data data = {0};
struct i2c_client *client = phic->client;
u8 x_buf[MAX_PACKET_SIZE];
int count;
int tmp;
int sum_x, sum_y;

do {
//mdelay(2);
count = i2c_master_recv(client, x_buf, MAX_PACKET_SIZE);
}
while(count == EAGAIN);
/*
printk(KERN_INFO "Reading data. %.2x %.2x %.2x %.2x %.2x %.2x %.2x, count=%d\n",
x_buf[0], x_buf[1], x_buf[2], x_buf[3], x_buf[4],
x_buf[5], x_buf[6], count);
*/

if (x_buf[0] == 0x80)
{
printk(KERN_INFO "Get version number ok!\n");
memcpy(ver_info, x_buf, ver_size);
}
data.flag = x_buf[0];
data.x |= ((x_buf[1]&0x7f) << 9) | (x_buf[2] << 2) | (x_buf[6] >> 5); // x
data.y |= ((x_buf[3]&0x7f) << 9) | (x_buf[4] << 2) | ((x_buf[6] >> 3)&0x03); // y
data.pressure |= ((x_buf[6]&0x07) << 7) | (x_buf[5]);  // pressure

//    data.x = MAX_X - data.x;
//    data.y = MAX_Y - data.y;
/* transform x y */
tmp=data.x;data.x=data.y;data.y=tmp;
#ifdef HW0868_CALIBRATE
/* transform raw coordinate to srceen coord */
data.x = data.x / MAX_X * SCR_X;
data.y = data.y / MAX_Y * SCR_Y;

/* perform calibrate */
if (isCalibrated)
{
sum_x = data.x*A + data.y*B + C;
if ((sum_x % scale) > 32768)
{
data.x = (sum_x >> 16) + 1;
}
else
{
data.x = sum_x >> 16;
}

sum_y = data.x*D + data.y*E + F;
if ((sum_y % scale) > 32768)
{
data.y = (sum_y >> 16) + 1;
}
else
{
data.y = sum_y >> 16;
}
}
#endif

return data;
}

static int hanvon_report_event(struct hanvon_i2c_chip *phic)
{
struct hanvon_pen_data data = {0};
data = hanvon_get_packet(phic);

if (data.flag == 0x80)
{
return 0;
}
//hw0868_dbg_coord(KERN_INFO "x=%d\ty=%d\tpressure=%d\tflag=%d\n",
//                          data.x, data.y, data.pressure, data.flag);
//printk("x=%d\ty=%d\tpressure=%d\tflag=%d\n", data.x, data.y, data.pressure, data.flag);
//

switch(data.flag)
{
/* side key events */
case PEN_BUTTON_DOWN:
{
infoTouchscreen = data;
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 1);
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 1);
input_report_key(phic->p_inputdev, BTN_STYLUS, 1);
break;
}
case PEN_BUTTON_UP:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 0);
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 0);
input_report_key(phic->p_inputdev, BTN_STYLUS, 0);
break;
}
/* rubber events */
case PEN_RUBBER_DOWN:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 1);
input_report_key(phic->p_inputdev, BTN_TOOL_RUBBER, 1);
break;
}
case PEN_RUBBER_UP:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 0);
input_report_key(phic->p_inputdev, BTN_TOOL_RUBBER, 0);
break;
}
/* pen pointer events */
case PEN_POINTER_DOWN:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 1);
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 1);
break;
}
case PEN_POINTER_UP:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 0);
if (isPenDetected == 0)
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 1);
isPenDetected = 1;
break;
}
/* Leave the induction area. */
case PEN_ALL_LEAVE:
{
input_report_abs(phic->p_inputdev, ABS_X, data.x);
input_report_abs(phic->p_inputdev, ABS_Y, data.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, data.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 0);
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 0);
input_report_key(phic->p_inputdev, BTN_STYLUS, 0);
isPenDetected = 0;
break;
}
default:
if(!debugTouchscreen){
input_report_abs(phic->p_inputdev, ABS_X, infoTouchscreen.x);
input_report_abs(phic->p_inputdev, ABS_Y, infoTouchscreen.y);
input_report_abs(phic->p_inputdev, ABS_PRESSURE, infoTouchscreen.pressure);
input_report_key(phic->p_inputdev, BTN_TOUCH, 1);
input_report_key(phic->p_inputdev, BTN_TOOL_PEN, 1);
input_report_key(phic->p_inputdev, BTN_STYLUS, 1);
break;
}
printk(KERN_ERR "Hanvon stylus device[0868,I2C]: Invalid input event.\n");
}
input_sync(phic->p_inputdev);
return 0;
}

static void hanvon_i2c_wq(struct work_struct *work)
{
struct hanvon_i2c_chip *phid = container_of(work, struct hanvon_i2c_chip, work_irq);
struct i2c_client *client = phid->client;
int cnt = 0;
debugTouchscreen=1;
mutex_lock(&phid->mutex_wq);

hanvon_report_event(phid);
schedule();
//printk(KERN_INFO "%s:Now ,handled enTouchscreen is %d .\n", __func__, enTouchscreen);
mutex_unlock(&phid->mutex_wq);

enable_irq(client->irq);
/*enable the touchscreen */
flagTouchscreen=1;

while(flagTouchscreen==1 && cnt <15 ){
msleep(1);
cnt++;
}
//    printk("===========cnt=%d\n",cnt);
if(cnt>=15){
//if(enTouchscreen==0)
enTouchscreen =1;

}
else{
//if(enTouchscreen==1)
enTouchscreen = 0;
}

}

static irqreturn_t hanvon_i2c_interrupt(int irq, void *dev_id)
{
struct hanvon_i2c_chip *phid = (struct hanvon_i2c_chip *)dev_id;

disable_irq_nosync(irq);
/*disable the Touchscreen*/
flagTouchscreen = 0;
debugTouchscreen=0;
printk("%s:Interrupt handled.\n", __func__);
queue_work(phid->ktouch_wq, &phid->work_irq);
printk("%s:Interrupt handled.\n", __func__);

return IRQ_HANDLED;
}

#ifdef CONFIG_HAS_EARLYSUSPEND
static void hanvon_i2c_early_suspend(struct early_suspend *h)
{
printk(KERN_INFO "%s\n", __func__);
hw0868_set_power(0);
}

static void hanvon_i2c_late_resume(struct early_suspend *h)
{
printk(KERN_INFO "%s\n", __func__);
hw0868_set_power(1);
hw0868_reset();
}
#endif

static int hanvon_i2c_probe(struct i2c_client * client, const struct i2c_device_id * idp)
{
int result = -1;
struct device *pdev = NULL;
client->irq = epen_irq_number;

//int gpio = irq_to_gpio(client->irq);
g_client = client;
//printk(KERN_INFO "starting %s, irq(%d).\n", __func__, gpio);
struct hanvon_i2c_chip *hidp = NULL;
hidp = (struct hanvon_i2c_chip*)kzalloc(sizeof(struct hanvon_i2c_chip), GFP_KERNEL);
if(!hidp)
{
printk(KERN_INFO "request memory failed.\n");
result = -ENOMEM;
goto fail1;
}

/* setup input device. */
hidp->p_inputdev = allocate_hanvon_input_dev();

/* setup work queue. */
hidp->client = client;
hidp->ktouch_wq = create_singlethread_workqueue("hanvon0868");
mutex_init(&hidp->mutex_wq);
INIT_WORK(&hidp->work_irq, hanvon_i2c_wq);
i2c_set_clientdata(client, hidp);

/* request irq. */
result = request_irq(client->irq, hanvon_i2c_interrupt, IRQF_DISABLED | IRQF_TRIGGER_FALLING /*IRQF_TRIGGER_LOW*/, client->name, hidp);
if(result)
{
printk(KERN_INFO " Request irq(%d) failed\n", client->irq);
goto fail1;
}

/*  define a entry for update use.
*  register misc device  */
result = misc_register(&hanvon_misc_dev);
device_create_file(hanvon_misc_dev.this_device, &dev_attr_hw0868_entry);
device_create_file(hanvon_misc_dev.this_device, &dev_attr_version);

#ifdef CONFIG_HAS_EARLYSUSPEND
hidp->early_suspend.level = EARLY_SUSPEND_LEVEL_BLANK_SCREEN - 1;
hidp->early_suspend.suspend = hanvon_i2c_early_suspend;
hidp->early_suspend.resume = hanvon_i2c_late_resume;
register_early_suspend(&hidp->early_suspend);
#endif

printk(KERN_INFO "%s done.\n", __func__);
printk(KERN_INFO "Name of device: %s.\n", client->dev.kobj.name);

//Try to get firmware version here!
//hw0868_get_version(client);

return 0;
fail2:
i2c_set_clientdata(client, NULL);
destroy_workqueue(hidp->ktouch_wq);
free_irq(client->irq, hidp);
input_unregister_device(hidp->p_inputdev);
hidp->p_inputdev = NULL;
fail1:
kfree(hidp);
hidp = NULL;
return result;
}

static int hanvon_i2c_remove(struct i2c_client * client)
{
/*
struct hanvon_i2c_chip *hidp = container_of(client, struct hanvon_i2c_chip, client);
printk("%s, i2c client name: %s\n", __func__, client->name);

if (0 != strncmp(client->name, HANVON_NAME, HANVON_NAME_SIZE-1)) {
return 0;
}

#ifdef CONFIG_HAS_EARLYSUSPEND
unregister_early_suspend(&hidp->early_suspend);
#endif
i2c_set_clientdata(client, NULL);
destroy_workqueue(hidp->ktouch_wq);
free_irq(client->irq, hidp);
input_unregister_device(hidp->p_inputdev);
hidp->p_inputdev = NULL;
kfree(hidp);
*/
return 0;
}

static int hanvon_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
{
/* reset hw0868 chip */
printk("%s\n", __func__);
hw0868_reset();
return 0;
}

static int hanvon_i2c_resume(struct i2c_client *client)
{
/* reset hw0868 chip */
printk("%s\n", __func__);
hw0868_reset();
return 0;
}

/**
* fetch epen sysconfig
* return
*     = 0: success
*     < 0: error
*/
static int fetch_epen_sysconfig() {

script_item_u   val;
script_item_value_type_e  type;

type = script_get_item("epen", "epen_used", &val);
if (SCIRPT_ITEM_VALUE_TYPE_INT != type) {
pr_err("%s: epen_used script_get_item  err. \n", __func__);
goto script_get_item_err;
}
if(val.val != 1) {
pr_err("%s: epen_unused. \n",  __func__);
goto script_get_item_err;
}

type = script_get_item("epen", "epen_twi_id", &val);
if (SCIRPT_ITEM_VALUE_TYPE_INT != type) {
pr_err("%s: epen_twi_id script_get_item err. \n",__func__ );
goto script_get_item_err;
}
epen_twi_id = val.val;

type = script_get_item("epen", "epen_rst", &val);
if (SCIRPT_ITEM_VALUE_TYPE_PIO != type) {
pr_err("script_get_item epen_rst err\n");
goto script_get_item_err;
}
epen_rst_gpio = val.gpio.gpio;

type = script_get_item("epen", "epen_int", &val);
if (SCIRPT_ITEM_VALUE_TYPE_PIO != type) {
pr_err("script_get_item epen_int err\n");
goto script_get_item_err;
}
epen_irq_number = gpio_to_irq(val.gpio.gpio);
if (IS_ERR_VALUE(epen_irq_number)) {
pr_warn("map gpio [%d] to virq failed, errno = %d\n", val.gpio.gpio, epen_irq_number);
goto script_get_item_err;
}

// get epen power config
type = script_get_item("epen", "epen_power", &val);
if (SCIRPT_ITEM_VALUE_TYPE_STR != type) {
pr_err("%s: epen power script_get_item err. \n",__func__ );
goto script_get_item_err;
}
else
epen_power_name = val.str;

type = script_get_item("epen", "epen_power_vol", &val);
if (SCIRPT_ITEM_VALUE_TYPE_INT != type) {
pr_err("%s: epen_power_vol script_get_item err. \n",__func__ );
goto script_get_item_err;
}
else
epen_power_vol = val.val;

return 0;
script_get_item_err:
return -1;

}

static int hanvon_request_resource()
{
if(0 != gpio_request(epen_rst_gpio, NULL)) {
pr_err("gpio_request is failed(%d)\n", epen_rst_gpio);
return -1;
}
if (0 != gpio_direction_output(epen_rst_gpio, 0)) {
pr_err("wakeup gpio set err!");
return -1;
}

// init epen power
epen_ldo = regulator_get(NULL, epen_power_name);
if(!epen_ldo) {
pr_err("%s: could not get epen ldo '%s' , check"
"if ctp independent power supply by ldo,ignore"
"firstly\n",__func__,epen_power_name);
} else {
regulator_set_voltage(epen_ldo,
(int)(epen_power_vol)*1000,
(int)(epen_power_vol)*1000);
}

return 0;
}

static int hanvon_free_resource()
{
if(epen_ldo) {
regulator_put(epen_ldo);
epen_ldo = NULL;
}

gpio_free(epen_rst_gpio);
return 0;
}

/**
* hanvon_i2c_detect - Device detection callback for automatic device creation
* return value:
*                    = 0; success;
*                    < 0; err
*/
static int hanvon_i2c_detect(struct i2c_client *client, struct i2c_board_info *info)
{
int ret;
printk(KERN_INFO "hw0868 detect ....\n");
if(epen_twi_id != client->adapter->nr)
return -ENODEV;

//Try to get firmware version here!
ret = hw0868_get_version(client);
if(ret < 0) {
printk(KERN_INFO "can not read version, detect failed!!\n");
//return ret;
}
strlcpy(info->type, HANVON_NAME, HANVON_NAME_SIZE);
printk(KERN_INFO "hw0868 detect success at i2c%d....\n", epen_twi_id);
return 0;
}

static const unsigned short normal_i2c[2] = {0x18, I2C_CLIENT_END};

static struct i2c_driver hanvon_i2c_driver = {
.class          = I2C_CLASS_HWMON,
.driver = {
.name   = HANVON_NAME,
},
.id_table   = hanvon_i2c_idtable,
.probe      = hanvon_i2c_probe,
.remove     = __devexit_p(hanvon_i2c_remove),
.detect     = hanvon_i2c_detect,
.address_list   = normal_i2c,
};

static int hw0868_i2c_init(void)
{
printk(KERN_INFO "hw0868 chip initializing ....\n");

//1. fetch params from sysconfig
if(fetch_epen_sysconfig() != 0) {
printk("fetch epen config error!!!\n");
return -1;
}
if(0 != hanvon_request_resource()) {
printk("request resource error, exit driver!!!\n");
return -1;
}

hw0868_set_power(1);
hw0868_reset();

//2. register i2c device
//hw0868_i2c_boardinfo.irq = epen_irq_number;
//i2c_register_board_info(epen_twi_id, &hw0868_i2c_boardinfo, 1);

//3. register i2c driver
return i2c_add_driver(&hanvon_i2c_driver);
}

static void hw0868_i2c_exit(void)
{
printk(KERN_INFO "hw0868 driver exit.\n");
i2c_del_driver(&hanvon_i2c_driver);
hanvon_free_resource();
}

module_init(hw0868_i2c_init);
module_exit(hw0868_i2c_exit);

module_param(debug, uint, S_IRUGO | S_IWUSR);

MODULE_AUTHOR("hello world");
MODULE_DESCRIPTION("Hanvon Electromagnetic Pen");
MODULE_LICENSE("GPL");