SK-AM62: LED驱动编写

如何编译自己写的驱动文件

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define GPIOLED_CNT 1 /* 设备号个数 */
#define GPIOLED_NAME "gpioled" /* 名字 */
#define LEDOFF 0 /* 关灯 */
#define LEDON 1 /* 开灯 */

/* gpioled设备结构体 */
struct gpioled_dev{
dev_t devid; /* 设备号 */
struct cdev cdev; /* cdev */
struct class *class; /* 类 */
struct device *device; /* 设备 */
int major; /* 主设备号 */
int minor; /* 次设备号 */
struct device_node *nd; /* 设备节点 */
int led_gpio; /* led所使用的GPIO编号 */
};

struct gpioled_dev gpioled; /* led设备 */

/*
* @description : 打开设备
* @param – inode : 传递给驱动的inode
* @param – filp : 设备文件，file结构体有个叫做private_data的成员变量
* 一般在open的时候将private_data指向设备结构体。
* @return : 0 成功;其他 失败
*/
static int led_open(struct inode *inode, struct file *filp)
{
filp->private_data = &gpioled; /* 设置私有数据 */
return 0;
}

/*
* @description : 从设备读取数据 * @param – filp : 要打开的设备文件(文件描述符)
* @param – buf : 返回给用户空间的数据缓冲区
* @param – cnt : 要读取的数据长度
* @param – offt : 相对于文件首地址的偏移
* @return : 读取的字节数，如果为负值，表示读取失败
*/
static ssize_t led_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{
return 0;
}

/*
* @description : 向设备写数据 * @param – filp : 设备文件，表示打开的文件描述符
* @param – buf : 要写给设备写入的数据
* @param – cnt : 要写入的数据长度
* @param – offt : 相对于文件首地址的偏移
* @return : 写入的字节数，如果为负值，表示写入失败
*/
static ssize_t led_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offt)
{
int retvalue;
unsigned char databuf[1];
unsigned char ledstat;
struct gpioled_dev *dev = filp->private_data;

retvalue = copy_from_user(databuf, buf, cnt); /* 接收APP发送过来的数据 */
if(retvalue < 0) {
printk("kernel write failed!\r\n");
return -EFAULT;
}

ledstat = databuf[0]; /* 获取状态值 */

if(ledstat == LEDON) { gpio_set_value(dev->led_gpio, 0); /* 打开LED灯 */
} else if(ledstat == LEDOFF) {
gpio_set_value(dev->led_gpio, 1); /* 关闭LED灯 */
}
return 0;
}

/*
* @description : 关闭/释放设备
* @param – filp : 要关闭的设备文件(文件描述符)
* @return : 0 成功;其他 失败
*/
static int led_release(struct inode *inode, struct file *filp)
{
return 0;
}

/* 设备操作函数 */
static struct file_operations gpioled_fops = {
.owner = THIS_MODULE,
.open = led_open,
.read = led_read,
.write = led_write,
.release = led_release,
};

/*
* @description : 驱动出口函数
* @param : 无
* @return : 无
*/
static int __init led_init(void)
{
int ret = 0;
const char *str;

/* 设置LED所使用的GPIO */
/* 1、获取设备节点：gpioled */
gpioled.nd = of_find_node_by_path("/gpioled");
if(gpioled.nd == NULL) {
printk("gpioled node not find!\r\n");
return -EINVAL;
}

/* 2.读取status属性 */
ret = of_property_read_string(gpioled.nd, "status", &str);
if(ret < 0) return -EINVAL;

if (strcmp(str, "okay"))
return -EINVAL;
/* 3、获取compatible属性值并进行匹配 */
ret = of_property_read_string(gpioled.nd, "compatible", &str);
if(ret < 0) {
printk("gpioled: Failed to get compatible property\n");
return -EINVAL;
}

if (strcmp(str, "test,led")) {
printk("gpioled: Compatible match failed\n");
return -EINVAL;
}

/* 4、 获取设备树中的gpio属性，得到LED所使用的LED编号 */
gpioled.led_gpio = of_get_named_gpio(gpioled.nd, "led-gpio", 0);
if(gpioled.led_gpio < 0) {
printk("can't get led-gpio");
return -EINVAL;
}
printk("led-gpio num = %d\r\n", gpioled.led_gpio);

/* 5.向gpio子系统申请使用GPIO */
ret = gpio_request(gpioled.led_gpio, "LED-GPIO");
if (ret) {
printk(KERN_ERR "gpioled: Failed to request led-gpio\n");
return ret;
}

/* 6、设置PI0为输出，并且输出高电平，默认关闭LED灯 */
ret = gpio_direction_output(gpioled.led_gpio, 1);
if(ret < 0) {
printk("can't set gpio!\r\n");
}

/* 注册字符设备驱动 */
/* 1、创建设备号 */
if (gpioled.major) { /* 定义了设备号 */
gpioled.devid = MKDEV(gpioled.major, 0);
ret = register_chrdev_region(gpioled.devid, GPIOLED_CNT, GPIOLED_NAME);
if(ret < 0) {
pr_err("cannot register %s char driver [ret=%d]\n", GPIOLED_NAME, GPIOLED_CNT);
goto free_gpio;
}
} else { /* 没有定义设备号 */
ret = alloc_chrdev_region(&gpioled.devid, 0, GPIOLED_CNT, GPIOLED_NAME); /* 申请设备号 */
if(ret < 0) {
pr_err("%s Couldn't alloc_chrdev_region, ret=%d\r\n", GPIOLED_NAME, ret);
goto free_gpio;
}
gpioled.major = MAJOR(gpioled.devid); /* 获取分配号的主设备号 */
gpioled.minor = MINOR(gpioled.devid); /* 获取分配号的次设备号 */
}
printk("gpioled major=%d,minor=%d\r\n",gpioled.major, gpioled.minor); /* 2、初始化cdev */
gpioled.cdev.owner = THIS_MODULE;
cdev_init(&gpioled.cdev, &gpioled_fops);
/* 3、添加一个cdev */
cdev_add(&gpioled.cdev, gpioled.devid, GPIOLED_CNT);
if(ret < 0)
goto del_unregister;
/* 4、创建类 */
gpioled.class = class_create(THIS_MODULE, GPIOLED_NAME);
if (IS_ERR(gpioled.class)) {
goto del_cdev;
}

/* 5、创建设备 */
gpioled.device = device_create(gpioled.class, NULL, gpioled.devid, NULL, GPIOLED_NAME);
if (IS_ERR(gpioled.device)) {
goto destroy_class;
}
return 0;
destroy_class:
class_destroy(gpioled.class);
del_cdev:
cdev_del(&gpioled.cdev);
del_unregister:
unregister_chrdev_region(gpioled.devid, GPIOLED_CNT);
free_gpio:
gpio_free(gpioled.led_gpio);
return -EIO;
}

/*
* @description : 驱动出口函数
* @param : 无
* @return : 无
*/
static void __exit led_exit(void)
{
/* 注销字符设备驱动 */
cdev_del(&gpioled.cdev);/* 删除cdev */
unregister_chrdev_region(gpioled.devid, GPIOLED_CNT); /* 注销设备号 */
device_destroy(gpioled.class, gpioled.devid);/* 注销设备 */
class_destroy(gpioled.class);/* 注销类 */
gpio_free(gpioled.led_gpio); /* 释放GPIO */
}

module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("ALIENTEK");
MODULE_INFO(intree, "Y");

makefile文件如下

KERNELDIR := /home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/board-support/linux-5.10.168+gitAUTOINC+2c23e6c538-g2c23e6c538
CURRENT_PATH := $(shell pwd)

obj-m := gpioled.o

build: kernel_modules

kernel_modules:
$(MAKE) -C $(KERNELDIR) M=$(CURRENT_PATH) modules

clean:
$(MAKE) -C $(KERNELDIR) M=$(CURRENT_PATH) clean

运行报错

turing@ubuntu:~/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED$ make -j16
make -C /home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/board-support/linux-5.10.168+gitAUTOINC+2c23e6c538-g2c23e6c538 M=/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED modules
make[1]: Entering directory '/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/board-support/linux-5.10.168+gitAUTOINC+2c23e6c538-g2c23e6c538'
CC [M] /home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED/gpioled.o
In file included from <command-line>:0:0:
././include/linux/compiler_types.h:88:10: fatal error: asm/compiler.h: No such file or directory
#include <asm/compiler.h>
^~~~~~~~~~~~~~~~
compilation terminated.
scripts/Makefile.build:286: recipe for target '/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED/gpioled.o' failed
make[2]: *** [/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED/gpioled.o] Error 1
Makefile:1822: recipe for target '/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED' failed
make[1]: *** [/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED] Error 2
make[1]: Leaving directory '/home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/board-support/linux-5.10.168+gitAUTOINC+2c23e6c538-g2c23e6c538'
Makefile:9: recipe for target 'kernel_modules' failed
make: *** [kernel_modules] Error 2
turing@ubuntu:~/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/Drivers/LED$

Turing Alan：

修改Makefile,加入ARCH=arm64 CROSS_COMPILE=aarch64-none-linux-gnu-

KERNELDIR := /home/turing/ti-processor-sdk-linux-am62xx-evm-08.06.00.42/board-support/linux-5.10.168+gitAUTOINC+2c23e6c538-g2c23e6c538CURRENT_PATH := $(shell pwd)

obj-m := gpioled.o

build: kernel_modules

kernel_modules: $(MAKE) ARCH=arm64 CROSS_COMPILE=aarch64-none-linux-gnu- -C $(KERNELDIR) M=$(CURRENT_PATH) modules

clean: $(MAKE) ARCH=arm64 CROSS_COMPILE=aarch64-none-linux-gnu- -C $(KERNELDIR) M=$(CURRENT_PATH) clean