Platform: Rockchip
OS: Android 6.0
Kernel: 3.10.92

rk的pmu模組只提供了每次單個暫存器的讀寫，驅動提供了這個節點供使用：/sys/rk818/rk818_test
舉例：

• 讀取：

echo r 0x23 > /sys/rk818/rk818_test: 讀取地址 0x23 的值，r 表示讀；

• 寫入：

echo w 0x23 0x7f > /sys/rk818/rk818_test: 對地址 0x23 賦值為 0x7f, w 表示寫。

程式碼實現部分：
rk818.c

static struct rk818_attribute rk818_attrs[] = {
    /*     node_name    permision       show_func   store_func */
 

    __ATTR(rk818_test,  S_IRUGO | S_IWUSR,  rk818_test_show,    rk818_test_store),
};

static ssize_t rk818_test_store(struct kobject *kobj, struct kobj_attribute *attr,
                                const char *buf, size_t n)
{
    u32 getdata[8];
    u8 regAddr;
    u8 data;
    char cmd;
    const
 
 char *buftmp = buf;
    struct rk818 *rk818 = g_rk818;
    /**
     * W Addr(8Bit) regAddr(8Bit) data0(8Bit) data1(8Bit) data2(8Bit) data3(8Bit)
     *      :data can be less than 4 byte
     * R regAddr(8Bit)
     * C gpio_name(poweron/powerhold/sleep/boot0/boot1) value(H/L)
     */
    sscanf(buftmp, "%c "
 
, &cmd);
    printk("------zhangqing: get cmd = %c\n", cmd);
    switch (cmd) {
    case 'w':
        sscanf(buftmp, "%c %x %x ", &cmd, &getdata[0], &getdata[1]);
        regAddr = (u8)(getdata[0] & 0xff);
        data = (u8)(getdata[1] & 0xff);
        printk("get value = %x\n", data);

        rk818_i2c_write(rk818, regAddr, 1, data);
        rk818_i2c_read(rk818, regAddr, 1, &data);
        printk("%x   %x\n", getdata[1], data);
        break;
    case 'r':
        sscanf(buftmp, "%c %x ", &cmd, &getdata[0]);
        printk("CMD : %c %x\n", cmd, getdata[0]);

        regAddr = (u8)(getdata[0] & 0xff);
        rk818_i2c_read(rk818, regAddr, 1, &data);
        printk("%x %x\n", getdata[0], data);
        break;
    default:
        printk("Unknown command\n");
        break;
    }
    return n;

}

如果要實現所有暫存器dump,可以新增一個選項，其他pmu模組方法一樣。