综述

项目需求：传音客户
新增TP版本号节点：
/sys/devices/platform/miki-tpd/tp_firmware_version
自己编写一个简单的platform设备驱动
kernel-3.18/drivers/misc/mediatek/mikinode/
---mikinode.c
---Kconfig
---Makefile

1.mikinode.c

#include <linux/init.h> 
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/fs.h>

#define MIKI_TP_ATTR_NAME "tp_firmware_version"

u8 tp_fw_ver_factory = 0x01; 
static ssize_t show_tp_version(struct device *dev,struct device_attribute *attr,char *buf)
{
    printk("show_tp_version is call \n");
    return snprintf(buf, PAGE_SIZE, "0x%02x\n", tp_fw_ver_factory);
}

static ssize_t store_tp_version(struct device *dev,struct device_attribute *attr,const char *buf,size_t size)
{
    printk("store_tp_version is call \n");
    return size;
}
static DEVICE_ATTR(tp_firmware_version,0664,show_tp_version,store_tp_version);


static int mikinode_probe(struct platform_device *dev)
{
    int ret = 0;
    printk("zcf mikinode_probe is call\n");
    ret = device_create_file(&(dev->dev),&dev_attr_tp_firmware_version);
    if(ret)
    {
        printk("zcf device_create_file failed\n");
    }
    return ret;
}
static struct platform_driver mikinode_driver = {
    .driver = {
        .name = "miki-tpd",
        .owner = THIS_MODULE,
    },
    .probe = mikinode_probe,

};
#ifdef CONFIG_OF
static struct platform_device mikinode_device = {
    .name = "miki-tpd",
    .id = -1,
};
#endif
static int __init mikinode_init(void)
{
    int err;
    err = platform_device_register(&mikinode_device);
    if(err)
    {
        printk("zcf failed to register device\n");
        return -ENODEV;
    }
    err = platform_driver_register(&mikinode_driver);
    if(err)
    {
        printk("zcf failed to register driver\n");
        return -ENODEV;
    }
    return err;
}

static void __exit mikinode_exit(void)
{
    platform_device_unregister(&mikinode_device);
}

module_init(mikinode_init);
module_exit(mikinode_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("miki tp node driver");
MODULE_AUTHOR("zengcf@mikimobile.com");

2.Kconfig

config MIKI_TP_SYS_NODE
    bool "MIKI_TP_NODE for MediaTek package"
    default n
    help
       It support to query TP version infomation.
       If this option is set,it will support MIKI_TP_SYS_NODE.

3.Makefile

obj-y=mikinode.o

4.添加以下修改

kernel-3.18/drivers/misc/mediatek/Kconfig

obj-y += mikinode/

device/mediatek/mt6580/init.mt6580.rc

    #start-add by zcf in 2018.11.26 for tp_node     
    chmod 0666 /sys/devices/platform/miki-tpd/tp_firmware_version
    chown root system /sys/devices/platform/miki-tpd/tp_firmware_version
    #end-add by zcf in 2018.11.26 for tp_node