【驱动】第3课、分离分层驱动之学习笔记

开发环境
主 机：VMWare--Ubuntu-16.04.2-x64-100ask
开发板：Mini2440--256M NandFlash, 2M NorFlash, 64M SDRAM, LCD-TD35;
　　　　bootlorder:u-boot1.16, Kernel:2.6.22.6;
编译器：arm-linux-gcc-3.4.5

 

目录

1、问题1：关于驱动中device和driver的名字的问题

2、用platform_driver结构和platform_device结构分别注册驱动程序的操作部分和设备硬件部分

3、源码

 

1、问题1：关于驱动中device和driver的名字的问题？
<1>第一种分配方法如下，即视频源程序：
led_drvtest.c: fd = open("/dev/led", O_RDWR);
led_dev.c: static struct platform_device led_dev = {.name = "myled", ...};
led_drv.c:
static int led_probe(struct platform_device *pdev)
{ major = register_chrdev(0, "myled", &led_fops);
cls = class_create(THIS_MODULE, "myled");
class_device_create(cls, NULL, MKDEV(major, 0), NULL, "led"); /* /dev/led */
return 0;
}
static int led_remove(struct platform_device *pdev){... unregister_chrdev(major, "myled");...}
struct platform_driver led_drv = {.probe=led_probe, .remove=led_remove, .driver={.name= "myled",}};
<2>我自己的运行成功的程序：
led_drvtest.c: fd = open("/dev/myled_2", O_RDWR);
led_dev.c: static struct platform_device led_dev = {.name = "myled_2", ...};
led_drv.c:
static int led_probe(struct platform_device *pdev)
{ major = register_chrdev(0, "leds", &led_fops);
cls = class_create(THIS_MODULE, "leds");
class_device_create(cls, NULL, MKDEV(major, 0), NULL, "myled_2"); /* /dev/led */
return 0;
}
static int led_remove(struct platform_device *pdev){... unregister_chrdev(major, "leds");...}
struct platform_driver led_drv = {.probe=led_probe, .remove=led_remove, .driver={.name= "myled_2",}};
综上，platform_driver结构和platform_device结构中的 .name 名字和设备的结构体名字、设备节点的类名字及设备名字，没有
必须的联系，可以不一样！但是platform_driver结构和platform_device结构中的 .name 名字必须一样，方可配对！

2、用platform_driver结构和platform_device结构分别注册驱动程序的操作部分和设备硬件部分。
2.1、platform_driver部分（操作/较稳定的代码）：static int led_drv_init(void){ platform_driver_register(&s3c2440_led_drv); return 0;}
注册platform_driver平台结构体，然后程序即会调用其.probe元素对应的函数.probe = led_drv_probe,在函数led_drv_probe内完成
以前课程学习的驱动的xx_init()中需要完成的任务，即注册设备结构/设备节点的类/设备、映射寄存器的虚拟地址到内存。
其中，映射寄存器的虚拟地址到内存，需要调用驱动xx_driver.c对应的xx_device.c程序中的platform_device结构设备对应的设备资
源resource，对应代码如下：
static int led_drv_probe(struct platform_device *dev){...
/* 映射寄存器地址到虚拟地址 */
struct resource *res = platform_get_resource(dev, IORESOURCE_MEM, 0);
gpio_con = ioremap(res->start, res->end - res->start + 1);
gpio_dat = gpio_con + 1;
res = platform_get_resource(dev, IORESOURCE_IRQ, 0);
pin = res->start;
return 0;
}
2.2、platform_device部分（硬件）：主要就是struct platform_device结构及其元素的定义。

3、源码

 led_drv3.c
  1 /*
  2 2018-12-10
  3 File: led_drv3.c
  4 功能: 配置/注册 platform_device 结构体;
  5 说明: LED灯GPB5,6,7,8;
  6 */
  7 #include <linux/module.h>
  8 #include <linux/version.h>
  9 
 10 #include <linux/init.h>
 11 #include <linux/fs.h>
 12 #include <linux/interrupt.h>
 13 #include <linux/irq.h>
 14 #include <linux/sched.h>
 15 #include <linux/pm.h>
 16 #include <linux/sysctl.h>
 17 #include <linux/proc_fs.h>
 18 #include <linux/delay.h>
 19 #include <linux/platform_device.h>
 20 #include <linux/input.h>
 21 #include <linux/irq.h>
 22 #include <linux/gpio_keys.h>
 23 
 24 #include <asm/gpio.h>
 25 #include <asm/uaccess.h>
 26 #include <asm/irq.h>
 27 #include <asm/io.h>
 28 #include <asm/arch/regs-gpio.h>
 29 #include <asm/hardware.h>
 30 MODULE_LICENSE("GPL");
 31 
 32 static volatile int pin;    /* pin = 5/6/7/8 */
 33 static volatile int major;
 34 static struct class * cls;
 35 
 36 static volatile unsigned long * gpio_con;
 37 static volatile unsigned long * gpio_dat;
 38 
 39 /* LED模块的打开函数 */
 40 static int s3c2440_leds_open(struct inode *inode, struct file *file)
 41 {
 42     *gpio_con &= ~(3<<(pin*2));
 43     *gpio_con |=  (1<<(pin*2));
 44 
 45     return 0;
 46 }
 47 
 48 /* LED模块的写入操作函数 */
 49 static ssize_t s3c2440_leds_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 50 {
 51     char val;
 52     int ret;
 53 
 54     ret = copy_from_user(&val, buf, count);
 55     if(ret < 0)
 56     {
 57         printk("s3c2440_leds_write: Unable to copy_from_user !\n");
 58         return ret;
 59     }
 60 
 61     if(val == 0)
 62         *gpio_dat &= ~(1<<pin);
 63     if(val == 1)
 64         *gpio_dat |=  (1<<pin);
 65 
 66     return 0;
 67 }
 68 
 69 static struct file_operations  s3c2440_leds_fops =
 70 {
 71     .owner = THIS_MODULE,
 72     .open  = s3c2440_leds_open,
 73     .write = s3c2440_leds_write,
 74 };
 75 
 76 static int led_drv_probe(struct platform_device *dev)
 77 {
 78     struct resource * res;
 79     /* 注册设备 */
 80     major = register_chrdev(0, "leds", &s3c2440_leds_fops);
 81     cls = class_create(THIS_MODULE, "leds");
 82     class_device_create(cls, NULL, MKDEV(major, 0), NULL, "myled_3");
 83     /* 映射寄存器地址到虚拟地址 */
 84     res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 85     gpio_con = ioremap(res->start, res->end - res->start + 1);
 86     gpio_dat = gpio_con + 1;
 87     
 88     res = platform_get_resource(dev, IORESOURCE_IRQ, 0);
 89     pin = res->start;
 90 
 91     return 0;
 92 }
 93 
 94 static int led_drv_remove(struct platform_device *dev)
 95 {
 96     /* 注销设备 */
 97     class_device_destroy(cls, MKDEV(major, 0));
 98     class_destroy(cls);
 99     unregister_chrdev(major, "leds");
100     /* 释放虚拟内存 */
101     iounmap(gpio_con);
102 
103     return 0;
104 }
105 
106 struct platform_driver s3c2440_led_drv = {
107     .probe = led_drv_probe,
108     .remove = led_drv_remove,
109     .driver = {
110         .name = "myled_3",
111     }
112 };
113 
114 static int led_drv_init(void)
115 {
116     platform_driver_register(&s3c2440_led_drv);
117     return 0;
118 }
119 
120 static void led_drv_exit(void)
121 {
122     platform_driver_unregister(&s3c2440_led_drv);
123 }
124 
125 module_init(led_drv_init);
126 module_exit(led_drv_exit);

 1 /*
 2 2018-12-10
 3 File: led_dev3.c
 4 功能: 配置/注册 platform_device 结构体;
 5 说明: LED灯GPB5,6,7,8;
 6       GPBCON  0x56000010  
 7 */
 8 #include <linux/module.h>
 9 #include <linux/version.h>
10 
11 #include <linux/init.h>
12 #include <linux/fs.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/sched.h>
16 #include <linux/pm.h>
17 #include <linux/sysctl.h>
18 #include <linux/proc_fs.h>
19 #include <linux/delay.h>
20 #include <linux/platform_device.h>
21 #include <linux/input.h>
22 #include <linux/irq.h>
23 #include <linux/gpio_keys.h>
24 
25 #include <asm/gpio.h>
26 #include <asm/gpio.h>
27 #include <asm/uaccess.h>
28 #include <asm/irq.h>
29 #include <asm/io.h>
30 #include <asm/arch/regs-gpio.h>
31 #include <asm/hardware.h>
32 MODULE_LICENSE("GPL");
33 
34 /* 注册设备资源 */
35 static struct resource led_dev_resource[] = {
36     {
37         .start = 0x56000010,
38         .end   = 0x56000010 + 8 -1,
39         .flags = IORESOURCE_MEM
40     },
41     {
42         .start = 6,
43         .end   = 6,
44         .flags = IORESOURCE_IRQ
45     }
46 };
47 
48 static void led_dev_release(struct device * dev)
49 {
50 }
51 
52 static struct platform_device s3c2440_led_dev = {
53     .name = "myled_3",
54     .id = -1,
55     .dev = {
56         .release = led_dev_release,
57     },
58     .num_resources = ARRAY_SIZE(led_dev_resource),
59     .resource = led_dev_resource
60 };
61 
62 static int led_dev_init(void)
63 {
64     platform_device_register(&s3c2440_led_dev);
65     return 0;
66 }
67 
68 static void led_dev_exit(void)
69 {
70     platform_device_unregister(&s3c2440_led_dev);
71 }
72 
73 module_init(led_dev_init);
74 module_exit(led_dev_exit);
 1 /*
 2 2018-11-01
 3 File: led_4_drvteest.c
 4 功能: LED模块的测试文件;
 5 */
 6 #include <stdio.h>
 7 #include <fcntl.h>
 8 #include <unistd.h>
 9 #include <sys/types.h>
10 #include <sys/stat.h>
11 
12 void print_usage(char *file)
13 {
14     printf("Usage:\n");
15     printf("%s, <on|off>\n", file);
16     printf("eg.\n");
17     printf("%s, on\n",  file);
18     printf("%s, off\n", file);
19 }
20 
21 int main(int argc, char **argv)
22 {
23     int fd;
24     char val = 1;
25 
26     if(argc != 2)
27     {
28         print_usage(argv[0]);
29         return 0;
30     }
31 
32     fd = open("/dev/myled_3", O_RDWR);
33     if(fd < 0)
34     {
35         printf("Can't open /dev/myled_3!\n");
36         return 0;
37     }
38 
39     if(!strcmp(argv[1], "on"))
40     {
41         val = 0;
42         write(fd, &val, 1);
43     }
44     else if(!strcmp(argv[1], "off"))
45     {
46         val = 1;
47         write(fd, &val, 1);
48     }
49     else
50     {
51         print_usage(argv[0]);
52         return 0;
53     }
54 
55     return 0;
56 }

 1 
 1 ifneq ($(KERNELRELEASE),)
 2     obj-m := led_drv3.o
 3     obj-m += led_dev3.o
 4 else
 5     KERN_DIR ?= /home/book/workbook/mini2440/systems/linux-2.6.22.6
 6 
 7     PWD = $(shell pwd)
 8 all:
 9     $(MAKE) -C $(KERN_DIR) M=$(PWD) modules
10 clean:
11     $(MAKE) -C $(KERN_DIR) M=$(PWD) modules clean
12     rm -rf modules.order
13 
14 endif

 led_drv.c, led_dev.c, led_drvtest.c, Makefile

posted @ 2018-12-21 19:54  大秦长剑  阅读(223)  评论(0)  编辑  收藏  举报