1.LED总线驱动源码
led_opr.h
#ifndef _LED_OPR_H #define _LED_OPR_H struct led_operations { int (*init) (int which); /* 初始化LED, which-哪个LED */ int (*ctl) (int which, char status); /* 控制LED, which-哪个LED, status:1-亮,0-灭 */ }; struct led_operations *get_board_led_opr(void); #endif
led_source.h
#ifndef _LED_RESOURCE_H #define _LED_RESOURCE_H /* GPIO3_0 */ /* bit[31:16] = group */ /* bit[15:0] = which pin */ #define GROUP(x) (x>>16) #define PIN(x) (x&0xFFFF) #define GROUP_PIN(g,p) ((g<<16) | (p)) #endif
leddrv.c
#include <linux/module.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/stat.h> #include <linux/init.h> #include <linux/device.h> #include <linux/tty.h> #include <linux/kmod.h> #include <linux/gfp.h> #include "led_opr.h" /* 1. 确定主设备号 */ static int major = 0; static struct class *led_class; struct led_operations *p_led_opr; #define MIN(a, b) (a < b ? a : b) void led_class_create_device(int minor) { device_create(led_class, NULL, MKDEV(major, minor), NULL, "100ask_led%d", minor); /* /dev/100ask_led0,1,... */ } void led_class_destroy_device(int minor) { device_destroy(led_class, MKDEV(major, minor)); } void register_led_operations(struct led_operations *opr) { p_led_opr = opr; } EXPORT_SYMBOL(led_class_create_device); EXPORT_SYMBOL(led_class_destroy_device); EXPORT_SYMBOL(register_led_operations); /* 3. 实现对应的open/read/write等函数，填入file_operations结构体 */ static ssize_t led_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); return 0; } /* write(fd, &val, 1); */ static ssize_t led_drv_write (struct file *file, const char __user *buf, size_t size, loff_t *offset) { int err; char status; struct inode *inode = file_inode(file); int minor = iminor(inode); printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); err = copy_from_user(&status, buf, 1); /* 根据次设备号和status控制LED */ p_led_opr->ctl(minor, status); return 1; } static int led_drv_open (struct inode *node, struct file *file) { int minor = iminor(node); printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); /* 根据次设备号初始化LED */ p_led_opr->init(minor); return 0; } static int led_drv_close (struct inode *node, struct file *file) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); return 0; } /* 2. 定义自己的file_operations结构体 */ static struct file_operations led_drv = { .owner = THIS_MODULE, .open = led_drv_open, .read = led_drv_read, .write = led_drv_write, .release = led_drv_close, }; /* 4. 把file_operations结构体告诉内核：注册驱动程序 */ /* 5. 谁来注册驱动程序啊？得有一个入口函数：安装驱动程序时，就会去调用这个入口函数 */ static int __init led_init(void) { int err; printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); major = register_chrdev(0, "100ask_led", &led_drv); /* /dev/led */ led_class = class_create(THIS_MODULE, "100ask_led_class"); err = PTR_ERR(led_class); if (IS_ERR(led_class)) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); unregister_chrdev(major, "led"); return -1; } /* 本来函数是向底层获取结构体，但是由于EXPORT_SYMBOL(led_class_create_device);的关系， 也就是leddrv这个驱动要先加载，然后再加载chip_demo_gpio。 但是这个下面这个函数是在底层定义，也就是要先加载底层的驱动，然后再加载上层驱动。这样就会 存在交叉加载。所以现在不用这个函数。 EXPORT_SYMBOL(register_led_operations); 通过这个函数，让底层主动向上层注册结构体。*/ // p_led_opr = get_board_led_opr(); return 0; } /* 6. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数 */ static void __exit led_exit(void) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); class_destroy(led_class); unregister_chrdev(major, "100ask_led"); } /* 7. 其他完善：提供设备信息，自动创建设备节点 */ module_init(led_init); module_exit(led_exit); MODULE_LICENSE("GPL");
chip_demo_gpio.c
#include <linux/module.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/stat.h> #include <linux/init.h> #include <linux/device.h> #include <linux/tty.h> #include <linux/kmod.h> #include <linux/gfp.h> #include <linux/platform_device.h> #include "led_opr.h" #include "leddrv.h" #include "led_resource.h" static int g_ledpins[100]; static int g_ledcnt = 0; static int board_demo_led_init (int which) /* 初始化LED, which-哪个LED */ { //printk("%s %s line %d, led %d\n", __FILE__, __FUNCTION__, __LINE__, which); printk("init gpio: group %d, pin %d\n", GROUP(g_ledpins[which]), PIN(g_ledpins[which])); switch(GROUP(g_ledpins[which])) { case 0: { printk("init pin of group 0 ...\n"); break; } case 1: { printk("init pin of group 1 ...\n"); break; } case 2: { printk("init pin of group 2 ...\n"); break; } case 3: { printk("init pin of group 3 ...\n"); break; } } return 0; } static int board_demo_led_ctl (int which, char status) /* 控制LED, which-哪个LED, status:1-亮,0-灭 */ { //printk("%s %s line %d, led %d, %s\n", __FILE__, __FUNCTION__, __LINE__, which, status ? "on" : "off"); printk("set led %s: group %d, pin %d\n", status ? "on" : "off", GROUP(g_ledpins[which]), PIN(g_ledpins[which])); switch(GROUP(g_ledpins[which])) { case 0: { printk("set pin of group 0 ...\n"); break; } case 1: { printk("set pin of group 1 ...\n"); break; } case 2: { printk("set pin of group 2 ...\n"); break; } case 3: { printk("set pin of group 3 ...\n"); break; } } return 0; } static struct led_operations board_demo_led_opr = { .init = board_demo_led_init, .ctl = board_demo_led_ctl, }; struct led_operations *get_board_led_opr(void) { return &board_demo_led_opr; } static int chip_demo_gpio_probe(struct platform_device *pdev) { struct resource *res; int i = 0; while (1) { res = platform_get_resource(pdev, IORESOURCE_IRQ, i++); if (!res) break; g_ledpins[g_ledcnt] = res->start; led_class_create_device(g_ledcnt); g_ledcnt++; } return 0; } static int chip_demo_gpio_remove(struct platform_device *pdev) { struct resource *res; int i = 0; while (1) { res = platform_get_resource(pdev, IORESOURCE_IRQ, i); if (!res) break; led_class_destroy_device(i); i++; g_ledcnt--; } return 0; } static struct platform_driver chip_demo_gpio_driver = { .probe = chip_demo_gpio_probe, .remove = chip_demo_gpio_remove, .driver = { .name = "100ask_led", }, }; static int __init chip_demo_gpio_drv_init(void) { int err; err = platform_driver_register(&chip_demo_gpio_driver); register_led_operations(&board_demo_led_opr); return 0; } static void __exit lchip_demo_gpio_drv_exit(void) { platform_driver_unregister(&chip_demo_gpio_driver); } module_init(chip_demo_gpio_drv_init); module_exit(lchip_demo_gpio_drv_exit); MODULE_LICENSE("GPL");
board_A_led.c
#include <linux/module.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/kernel.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/stat.h> #include <linux/init.h> #include <linux/device.h> #include <linux/tty.h> #include <linux/kmod.h> #include <linux/gfp.h> #include <linux/platform_device.h> #include "led_resource.h" static void led_dev_release(struct device *dev) { } static struct resource resources[] = { { .start = GROUP_PIN(3,1), .flags = IORESOURCE_IRQ, .name = "100ask_led_pin", }, { .start = GROUP_PIN(5,8), .flags = IORESOURCE_IRQ, .name = "100ask_led_pin", }, }; static struct platform_device board_A_led_dev = { .name = "100ask_led", .num_resources = ARRAY_SIZE(resources), .resource = resources, .dev = { .release = led_dev_release, }, }; static int __init led_dev_init(void) { int err; err = platform_device_register(&board_A_led_dev); return 0; } static void __exit led_dev_exit(void) { platform_device_unregister(&board_A_led_dev); } module_init(led_dev_init); module_exit(led_dev_exit); MODULE_LICENSE("GPL");
2.总结