常用 API

 常用API

1.根据compatible找到对应的devicenode结构

struct device_node*of_find_compatible_node(struct device_node *from,

         constchar *type, const char *compatible)

 

更加full path 找到对应的device node

struct device_node*of_find_node_by_path(const char *path)

 

2. 在device node 中获取属性值

struct property *of_find_property(conststruct device_node *np,

                                       const char *name,

                                       int *lenp)

3. 检查device node的是否与compa匹配

int of_device_is_compatible(const structdevice_node *device,

                   constchar *compat)

4. 读取属性值

static inline intof_property_read_u32(const struct device_node *np,

                                            const char *propname,

                                            u32 *out_value)

5. 通过phandle引用node

struct device_node *of_parse_phandle(conststruct device_node *np,

                                          const char *phandle_name, int index)

6.映射中断

unsigned int irq_of_

5. 使用案例

以触摸屏为来说明如何使用.

另外i2c设备必须是i2c控制器的子设备才能顺利添加到系统中.

Dts文件如下：

/{

  bus{

         I2C2@0x11009000{

          status="okay";

          #size-cells = <0>;

     synaptics_touch@20{

          compatible = "synaptics,touch" ;

        reg= <0x20>;

        touch_irq=<2>;

       }；

 

  };

};

驱动中添加：

static struct i2c_driversynaptics_i2c_driver = {

       .driver = {

                .name =  TPD_DEVICE,

                .owner = THIS_MODULE,

               #ifdef CONFIG_OF

                .of_match_table = &of_match,

               #endif

       },

       .probe = synaptics_rmi4_probe,

       .remove = synaptics_rmi4_remove,

       .id_table = tp_id,

};

static const struct of_device_id of_match[]= {

         {.compatible = "synaptics,touch",},/* 要和dts中的compatible匹配*/

         {/*sentinel */},

};