MTK平台-添加闪光灯测试节点

作者: c枫_撸码的日子 | 来源:发表于2018-10-24 11:04 被阅读0次

综述

项目需求：客户有一个老化apk，自动测试闪光灯。
新增以下节点，控制闪光灯亮灭。
/sys/devices/virtual/torch/torch/torch_level
写入1 ，后手电筒亮
写入0 ，后手电筒灭
/sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
写入1 ，前手电筒亮
写入0 ，前手电筒灭

实现思路
1.创建/sys/devices/virtual/torch/torch/torch_level节点
2.在写入1的时候，打开闪光灯，写入0的时候，关闭闪光灯
················································································
怎么在/sys/devices/virtual/路径下创建节点呢？很蒙逼
怎么在底层调用打开或者关闭闪光灯呢？很懵逼

学习本文，讲解决以上问题。

1.创建节点

这里以/sys/devices/virtual/torch/torch/torch_level节点创建为例子，

kernel-3.18/drivers/misc/mediatek/flashlight/src/mt6580/kd_flashlightlist.c

#define TORCH_DEVNAME "torch"//节点名称
static dev_t torch_devno;//设备号
static struct class *torch_class;//class类
static struct device *torch_device;//设备
static int main_torch_level = 0;

//show函数
static ssize_t torch_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
    logI("zcf torch_show is call,main_torch_level=%d\n",main_torch_level);
    return snprintf(buf, PAGE_SIZE, "%d\n", main_torch_level);
}
//store函数
static ssize_t torch_store(struct device *dev,
               struct device_attribute *attr, const char *buf, size_t count)
{
    //添加闪光灯控制逻辑
    return count;
}
//定义设备属性节点torch_level，和show函数，store函数
static DEVICE_ATTR(torch_level, S_IRUGO|S_IWUSR, torch_show, torch_store);

//初始化函数
static void torch_create(void)
{  
    int ret = 0;
    logI("zcf [%s] is init\n",__func__);
    //申请设备号--下面需要用的这个设备号
    ret = alloc_chrdev_region(&torch_devno, 0, 1, TORCH_DEVNAME);
    if (ret) {//申请成功
        logI("zcf [torch_init] alloc_chrdev_region fail: %d ~", ret);
        //goto torch_chrdev_error;   这里应该跳到unregister函数，懒得写
    } else {//申请失败
        logI("zcf [torch_init] major: %d, minor: %d ~", MAJOR(torch_devno),
             MINOR(torch_devno));
    } 
    //在sys/class创建torch_class 类
    torch_class = class_create(THIS_MODULE, TORCH_DEVNAME);
    if (IS_ERR(torch_class)) {//创建失败
        logI("zcf  Unable to create class:torch_class\n");
    }
    //在sys/class/torch_class/下创建设备节点
    torch_device =device_create(torch_class, NULL, torch_devno, 
                                                  NULL, TORCH_DEVNAME);
    if(NULL == torch_device)//创建失败
        logI("zcf [torch_init] device_create torch_device fail \n");
    //在sys/class/torch_class/torch_class下创建属性文件torch_level
    ret = device_create_file(torch_device,&dev_attr_torch_level);
    if(ret < 0)
        logI("zcf Failed to create attribute torch_levle\n");
}

static int flashlight_probe(struct platform_device *dev)
{
    //省略代码
    torch_create()；//创建节点
}

需要注意的地方
1.创建节点，最好在probe函数中创建！！！
2关于device_create_file函数
device_create_file(torch_device,&dev_attr_torch_level);
这个函数，前面的参数是device ，后面的参数加你要创建的节点名称dev_attr_xxxx。
device_create_file(torch_devicedev, &dev_attr_xxx);
dev_attr_xxx就是在xxx(要创建的节点)前加上dev_attr_

DEVICE_ATTR,device_create_file的使用

到此，我们的节点就创建出来了，有人可能会有疑问，上面代码中创建的节点是
sys/class/torch_class/torch_class/torch_level
但要求的节点路径是
/sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
不对劲啊！
实际上，我们创建sys/class/torch_class/torch_class/torch_level节点后，系统会默认也在/sys/devices/virtual/torch_class/torch_class/torch_level下创建一样的节点，使用adb命令可以查看！
（为啥会自动创建这个节点呢，这就需要跟踪源码啦）

adb命令查看节点

adb

可以看到，确实系统默认创建了/sys/devices/virtual/torch_class/torch_class/torch_level节点。

2.打开、关闭闪光灯

当我们获取torch_level节点的值(例如:使用adb命令 cat torch_level)时，就会调用show函数

//show函数
static ssize_t torch_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
    logI("zcf torch_show is call,main_torch_level=%d\n",main_torch_level);
    return snprintf(buf, PAGE_SIZE, "%d\n", main_torch_level);
}

当我们往torch_level节点写入值(例如:使用adb命令 echo 1 > torch_level)时，就会调用store函数

//store函数
static ssize_t torch_store(struct device *dev,
              struct device_attribute *attr, const char *buf, size_t count)
{
   //添加闪光灯控制逻辑
   return count;
}

因此，我们需要在store函数中添加闪光灯的控制逻辑，那么，如何打开或者关闭闪光灯呢？
kernel-3.18/drivers/misc/mediatek/flashlight/src/{平台}/{项目}/constant_flashlight/leds_strobe.c

int FL_Enable(void)//打开闪光灯
{
    if (g_duty>=1)
    {   
        mflash_set_gpio_output(GPIO_ENT,GPIO_OUT_ONE);
        mflash_set_gpio_output(GPIO_ENF,GPIO_OUT_ONE);
        FL_ALOGD(" FL_Enable enable in flash mode,duty=%d.", g_duty);
    }        
    else
    {   
        mflash_set_gpio_output(GPIO_ENT,GPIO_OUT_ONE);
        mflash_set_gpio_output(GPIO_ENF,GPIO_OUT_ZERO);
        FL_ALOGD(" FL_Enable enable in torch mode,duty=%d.", g_duty);
    }   

    return 0;
}

int FL_Disable(void)//关闭闪关灯
{
    FL_ALOGF();
    mflash_set_gpio_output(GPIO_ENT,GPIO_OUT_ZERO);
    mflash_set_gpio_output(GPIO_ENF,GPIO_OUT_ZERO);
    return 0;
}
//初始化GPIO引脚
void main_camera_flash_gpio_init(void) 
{
    static struct device_node *main_flash_node;
    FL_ALOGF();
    main_flash_node = of_find_compatible_node(NULL, NULL, 
                                                "mediatek,mainflashlight");
    GPIO_ENT = of_get_named_gpio(main_flash_node, 
                                                "flashlight_en_gpio", 0);
    GPIO_ENF = of_get_named_gpio(main_flash_node, 
                                                "flashlight_mode_gpio", 0);
}

从源码中，可以看到，调用了FL_Enable和FL_Disable去打开、关闭闪光灯，原理就是通过拉高相应的GPIO脚，使能闪光灯，拉低GPIO脚，关闭闪光灯。
需要注意的是，每次调用之前，我们需要先调用GPIO初始化函数，找到相应的GPIO引脚

extern int FL_Enable(void);//声明FL_Enable是外部函数
extern int FL_Disable(void);
extern void main_camera_flash_gpio_init(void);

static ssize_t torch_store(struct device *dev,
                 struct device_attribute *attr, const char *buf, size_t count)
{
    int temp;
    temp = simple_strtol(buf, NULL, 10);//把字符串转为数字
    main_torch_level = temp;
    main_camera_flash_gpio_init();//初始化gpio引脚
    if(main_torch_level == 1)//如果写1
    {   
        FL_Enable();//打开闪光灯
    }
    else if(main_torch_level == 0)//如果写0
        FL_Disable();//关闭闪光灯
    else//无效参数
        logI("zcf invalid parameter,the torch_level must be 1 or 0\n");

    logI("zcf  main_torch_level=%d , count =%d\n",main_torch_level,count);
    return count;
}

这样，我们在store函数中，就添加好了控制闪光灯的逻辑了。当然，仅仅这样，客户提供的第三方测试apk是无法访问节点的，会有selinux错误

 avc: denied { write } for name="torch_level" dev="sysfs" ino=9205 
scontext=u:r:system_app:s0 tcontext=u:object_r:sysfs:s0 
tclass=file permissive=0

avc错误

因此，我们要往系统加入相应的权限。

3.添加节点访问的权限

1.device/mediatek/mt6580/init.mt6580.rc
使所以用户对节点torch_level、sub_torch_level均有读写权限


    # start-add by zcf in 2018.10.23 for torch_test
    chmod 0666 /sys/devices/virtual/torch/torch/torch_level
    chown root system /sys/devices/virtual/torch/torch/torch_level

    chmod 0666 /sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
    chown root system /sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
    # end-add by zcf in 2018.10.23 for torch_test

2.device/mediatek/sepolicy/basic/non_plat/system_app.te

# add by zcf in 2018.10.23 for torch test
allow system_app sysfs:file { write read };

3.system/sepolicy/private/app.te
注释掉以下代码

app.te

以上这种添加SELinux权限的方式会导致GMS测试失败，因为改动了谷歌官方的逻辑-system/sepolicy/private/app.te。因此，换以下方式去改动：

1.device/mediatek/mt6580/init.mt6580.rc
使所以用户对节点torch_level、sub_torch_level均有读写权限

    # start-add by zcf in 2018.10.23 for torch_test
    chmod 0666 /sys/devices/virtual/torch/torch/torch_level
    chown root system /sys/devices/virtual/torch/torch/torch_level

    chmod 0666 /sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
    chown root system /sys/devices/virtual/sub_torch/sub_torch/sub_torch_level
    # end-add by zcf in 2018.10.23 for torch_test

2.自定义类型：定义torch SELinux type
device/mediatek/sepolicy/bsp/non_plat/file.te

#add by zcf in 2018.11.1 for flashilight test
type system_app_torch_file,fs_type,sysfs_type;
type system_app_sub_torch_file,fs_type,sysfs_type;

3.file_contexts 绑定 torch对应的label
注意对应的节点是实际节点，而不是链接.以及整个目录路径中也绝不能包含链接(无数同仁有犯这个错误，特意提醒)
device/mediatek/sepolicy/bsp/non_plat/file_contexts

#add by zcf in 2018.11.01 for torch test
/sys/devices/virtual/torch/torch/torch_level u:object_r:system_app_torch_file:s0
/sys/devices/virtual/sub_torch/sub_torch/sub_torch_level u:object_r:system_app_sub_torch_file:s0

4.申请相关的权限
device/mediatek/sepolicy/basic/non_plat/system_app.te

# add by zcf in 2018.10.23 for torch test
allow system_app system_app_torch_file:file rw_file_perms;
allow system_app system_app_sub_torch_file:file rw_file_perms;

4.完整源码

kernel-3.18/drivers/misc/mediatek/flashlight/src/mt6580/kd_flashlightlist.c

//start-add by zcf in 2018.10.23 for torch test
#define TORCH_DEVNAME "torch"
#define SUB_TORCH_DEVNAME "sub_torch"
static dev_t torch_devno,sub_torch_devno;
static struct class *torch_class,*sub_torch_class;
static struct device *torch_device,*sub_torch_device;

extern void main_camera_flash_gpio_init(void);
extern void sub_camera_flash_gpio_init(void);

extern int FL_Enable(void);
extern int FL_Disable(void);
extern int FL_Sub_Enable(void);
extern int FL_Sub_Disable(void);

static int main_torch_level = 0;
static int sub_torch_level = 0;
static ssize_t torch_show(struct device *dev,struct device_attribute *attr, char *buf)
{
    logI("zcf torch_show is call,main_torch_level=%d\n",main_torch_level);
    return snprintf(buf, PAGE_SIZE, "%d\n", main_torch_level);
}

static ssize_t torch_store(struct device *dev,struct device_attribute *attr, const char *buf, size_t count)
{
    int temp;
    temp = simple_strtol(buf, NULL, 10);
    main_torch_level = temp;
    main_camera_flash_gpio_init();
    if(main_torch_level == 1)
    {   
        FL_Enable();
    }
    else if(main_torch_level == 0)
        FL_Disable();
    else
        logI("zcf invalid parameter,the torch_level must be 1 or 0\n");

    logI("zcf torch_store is call,main_torch_level=%d , count =%d\n",main_torch_level,count);
    return count;
}
static DEVICE_ATTR(torch_level, S_IRUGO|S_IWUSR, torch_show, torch_store);


static ssize_t sub_torch_show(struct device *dev,struct device_attribute *attr, char *buf)
{
    logI("zcf torch_show is call,main_torch_level=%d\n",main_torch_level);
    return snprintf(buf, PAGE_SIZE, "%d\n", main_torch_level);
}

static ssize_t sub_torch_store(struct device *dev,struct device_attribute *attr, const char *buf, size_t count)
{
    int temp;
    temp = simple_strtol(buf, NULL, 10);
    sub_torch_level = temp;
    sub_camera_flash_gpio_init();
    if(sub_torch_level == 1)
    {   
        FL_Sub_Enable();
    }
    else if(sub_torch_level == 0)
        FL_Sub_Disable();
    else
        logI("zcf invalid parameter,the sub_torch_level must be 1 or 0\n");

    logI("zcf torch_store is call,sub_torch_level=%d , count =%d\n",sub_torch_level,count);
    return count;
}

static DEVICE_ATTR(sub_torch_level, S_IRUGO|S_IWUSR, sub_torch_show, sub_torch_store);

static void torch_create(void)
{   
    int ret = 0;
    logI("zcf [%s] is init\n",__func__);
    ret = alloc_chrdev_region(&torch_devno, 0, 1, TORCH_DEVNAME);
    if (ret) {
        logI("zcf [torch_init] alloc_chrdev_region fail: %d ~", ret);
        //goto torch_init_error;
    } else {
        logI("zcf [torch_init] major: %d, minor: %d ~", MAJOR(torch_devno),
             MINOR(torch_devno));
    } 
    ret = alloc_chrdev_region(&sub_torch_devno, 0, 1, SUB_TORCH_DEVNAME);

    if (ret) {
        logI("zcf [torch_init] alloc_chrdev_region fail: %d ~", ret);
        //goto torch_init_error;
        logI("zcf [torch_init] major: %d, minor: %d ~", MAJOR(sub_torch_devno),
             MINOR(sub_torch_devno));
    } 
    torch_class = class_create(THIS_MODULE, TORCH_DEVNAME);
    if (IS_ERR(torch_class)) {
        logI("zcf  Unable to create class:torch_class\n");
    }

    torch_device =device_create(torch_class, NULL, torch_devno, NULL, TORCH_DEVNAME);
    if(NULL == torch_device)
        logI("zcf [torch_init] device_create torch_device fail \n");
    ret = device_create_file(torch_device,&dev_attr_torch_level);
    if(ret < 0)
        logI("zcf Failed to create attribute torch_levle\n");
    
    sub_torch_class = class_create(THIS_MODULE, SUB_TORCH_DEVNAME);
    if (IS_ERR(sub_torch_class)) {
        logI("zcf  Unable to create class:sub_torch_class\n");
    }

    sub_torch_device =device_create(sub_torch_class, NULL, sub_torch_devno, NULL, SUB_TORCH_DEVNAME);
    if(NULL == sub_torch_device)
        logI("zcf [torch_init] device_create torch_device fail \n");
    ret = device_create_file(sub_torch_device,&dev_attr_sub_torch_level);
    if(ret < 0)
        logI("zcf Failed to create attribute sub_torch_levle\n");
}
//end-add by zcf in 2018.10.23 for torch test.

static int flashlight_probe(struct platform_device *dev)
{
    int ret = 0, err = 0;
    logI("[flashlight_probe] start ~")
    //省略部分代码
    torch_create();
}

荆轲刺秦王

MTK平台-添加闪光灯测试节点

综述

1.创建节点

2.打开、关闭闪光灯

3.添加节点访问的权限

4.完整源码

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MTK平台-添加闪光灯测试节点

综述

1.创建节点

2.打开、关闭 闪光灯

3.添加节点访问的权限

4.完整源码

相关文章

网友评论

延伸阅读

深度阅读

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热点阅读

2.打开、关闭闪光灯