android 串口扩展（wk2xxx）移植

1.驱动移植
将wk2xxx_i2c.c wk2xxx.h 放到lichee\linux-3.4\drivers\hwmon目录下
1.makefile
obj-$(CONFIG_SERIAL_I2C_WK2XXX) += wk2xxx_i2c.o
2. kconfig
config SERIAL_I2C_WK2XXX
tristate "i2c to 4 uart for wk2xxx chips "
select I2C
select SERIAL_CORE
depends on HWMON
default m
help
i2c to 4 uart for wk2xxx chips
说明：由于是串口扩展，所以需要选择 SERIAL_CORE，基于i2c，所以要select i2c

3.i2c irq中断配置
在sysconfig.fex中添加相关的io配置
;-------------------------------------------------------------------------------
;wk2 irq configuration
;-------------------------------------------------------------------------------
[wk2_para]
wk2_used = 1
wk2_twi_id = 1
wk2_twi_addr = 0x10
wk2_freq = 400000
wk2_irq_port = port:PI16<6><default><default><default>

4.驱动代码的移植
4.1. init函数
在这个函数中首先要获取sysconfig中的相关的配置，同时将设备注册到相应的i2c总线上
int ret;
printk("wk2xxx_init-------------------------\n");
int retval;
ret=wk2xxx_fetch_sysconfig_para();
if(ret < 0){
printk("wk2xxx_fetch_sysconfig_para failed in init \n");
}
// wk2xxx_i2c_driver.detect = wk2xxx_detect;
struct i2c_board_info info;
struct i2c_adapter *adapter;
struct i2c_client *client;
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = 0x10;
strlcpy(info.type, "wk2xxx_i2c", I2C_NAME_SIZE);
adapter = i2c_get_adapter(1);

if (!adapter) {
printk("*******get_adapter error!********\n");
}
client = i2c_new_device(adapter, &info);
wk2xxx_detect(client, &info);

/* i2c_add_driver(&msg21xx_ts_driver);
if (msg21xx_device_check == 0) {
i2c_del_driver(&msg21xx_ts_driver);
printk("msg21xx_device_check is 0 =========================\n");
}
return ret;
struct i2c_board_info bi = {I2C_BOARD_INFO("wk2xxx_i2c", 0x10),};
i2c_new_device(i2c_get_adapter( wk2xxx_i2c_pdata.bus_num), &bi);
*/
retval = i2c_add_driver(&wk2xxx_i2c_driver);
if (retval !=0)
{
printk("======wk2xxx_i2c_driver init fail, ret=0x%x======\n", retval);
i2c_del_driver(&wk2xxx_i2c_driver);
return ret;
}

static int wk2xxx_detect(struct i2c_client *client, struct i2c_board_info *info)
{
printk("wk2xxx_detect-----\n");
struct i2c_adapter *adapter = client->adapter;
int ret;

if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;

if(twi_id == adapter->nr){
printk("%s: addr= %x\n",__func__,client->addr);
ret = i2c_test(client);
if(!ret){
printk("%s:I2C connection might be something wrong \n",__func__);
return -ENODEV;

}else{
strlcpy(info->type, "wk2xxx_i2c", I2C_NAME_SIZE);
return 0;
}

}else{
return -ENODEV;
}
}

4.2 获取配置文件相关信息函数

static int wk2xxx_fetch_sysconfig_para(void){
printk("wk2xxx_fetch_sysconfig_para-------------------\n");
int ret = -1;
int i = -1;
int device_used = -1;
script_item_u val;
script_item_value_type_e type;
type = script_get_item("wk2_para", "wk2_used", &val);
if(SCIRPT_ITEM_VALUE_TYPE_INT != type){
printk("%s, type err device_used =%d \n", __func__, val.val);
goto script_get_err;
}
device_used = val.val;
if(1 == device_used){
type = script_get_item("wk2_para", "wk2_twi_id", &val);
if(SCIRPT_ITEM_VALUE_TYPE_INT != type){
printk("%s: type err twi_id = %d. \n", __func__, val.val);
goto script_get_err;
}
wk2xxx_i2c_pdata.bus_num = val.val;
printk("wk2xxx_i2c_pdata.bus_num =%d\n",wk2xxx_i2c_pdata.bus_num);

type = script_get_item("wk2_para", "wk2_twi_addr", &val);
if(SCIRPT_ITEM_VALUE_TYPE_INT != type){
printk("%s: type err twi_id = %d. \n", __func__, val.val);
goto script_get_err;
}
wk2xxx_i2c_pdata.slave_addr = val.val;

printk("wk2xxx_i2c_pdata.slave_addr =%d\n",wk2xxx_i2c_pdata.slave_addr);


type = script_get_item("wk2_para", "wk2_freq", &val);
if(SCIRPT_ITEM_VALUE_TYPE_INT != type){
printk("%s: type err twi_id = %d. \n", __func__, val.val);
goto script_get_err;
}
wk2xxx_i2c_pdata.frequency = val.val;
printk("wk2 frequency=%d\n",wk2xxx_i2c_pdata.frequency);

type = script_get_item("wk2_para", "wk2_irq_port", &val);
if (type != SCIRPT_ITEM_VALUE_TYPE_PIO) {
printk("get uarts IO(uart_irq) failed\n");
goto script_get_err;
}
int_number= val.gpio.gpio;
printk("wk2 int_number=%d\n",int_number);
/* i = i2c_register_board_info( wk2xxx_i2c_pdata.bus_num, wk2xxx_i2c_board_info,
ARRAY_SIZE(wk2xxx_i2c_board_info));
if(i < 0){
printk("wk2 register i2c device failed \n");
goto script_get_err;
}*/
printk("wk2xxx_fetch_sysconfig_para--is ok----------\n");
return 0;

}else{

printk("wk2xxx get sysconfig failed \n");
ret = -1;
}
script_get_err:
printk("get erro");
return ret;

}

4.3 构建board info
static struct wk2xxx_platform_data wk2xxx_i2c_pdata = {
.flag = 0,
};

4.4 中断函数的修改
由于a20对中断函数进行了重新的封装，所以要对应平台函数为
if(sw_gpio_irq_request(s->port.irq, TRIG_EDGE_NEGATIVE , (peint_handle)wk2xxx_irq, s) <0)
同时使能和关闭中断函数也要分别进行修改
//disable_irq_nosync(s->port.irq);
--------》 sw_gpio_eint_set_enable(s->port.irq, 0);

//enable_irq(s->port.irq);
===========》 sw_gpio_eint_set_enable(s->port.irq, 1);

/static irqreturn_t wk2xxx_irq(int irq, void *dev_id)//
----------------》static u32 wk2xxx_irq(struct wk2xxx_port *dev_id){
return 0；
}

4.5 还有就是一些头文件的修改了

4.6 编译成ko 或者build-in都ok，如果是ko，在android init 的时候记得要insod

5.总结的关键点
1.a20的对中断函数进行了重新的封装，对应于代码中要注意这一系列函数的参数以及
返回值的使用
2.其他就是一些细节问题了
3.最开始调试的是uart to uart 但是datasheet对于寄存器的设置流程基本无描述。
所以这个是非常难的一个部分

android 串口扩展（wk2xxx）移植

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