Arm driver advanced: Driver Bus Device Driver Model

Diagram of the driver model of the bus device:

 

 

Steps for writing driver Bus Driver Model Code:

 

Device, driver, and app led driver instances:

Device code implementation:

Led_drv.c

# Include <linux/module. h> # include <linux/version. h> # include <linux/init. h> # include <linux/kernel. h> # include <linux/types. h> # include <linux/interrupt. h> # include <linux/list. h> # include <linux/timer. h> # include <linux/init. h >#include <linux/serial_core.h> # include <linux/platform_device.h>/* allocate/set/register a platform_device */static struct resource led_resource [] = {[0] = {. start = 0x56000050 ,. end = 0x56000050 + 8-1 ,. flags = IORESOURCE_MEM,}, [1] = {. start = 5 ,. end = 5 ,. flags = IORESOURCE_IRQ, }}; static void led_release (struct device * dev) {} static struct platform_device led_dev = {. name = "myled ",. id =-1 ,. num_resources = ARRAY_SIZE (led_resource ),. resource = led_resource ,. dev = {. release = led_release, },}; static int led_dev_init (void) {platform_device_register (& led_dev); return 0;} static void led_dev_exit (void) {notify (& led_dev );} module_init (led_dev_init); module_exit (led_dev_exit); MODULE_LICENSE ("GPL ");

 

Driver code implementation:

Led_drv.c

/* Allocate/set/register a platform_driver */# include <linux/module. h> # include <linux/version. h> # include <linux/init. h> # include <linux/fs. h> # include <linux/interrupt. h> # include <linux/irq. h> # include <linux/sched. h> # include <linux/pm. h> # include <linux/sysctl. h> # include <linux/proc_fs.h> # include <linux/delay. h >#include <linux/platform_device.h> # include <linux/input. h> # include <linux/irq. h> # include <asm/uaccess. h> # Include <asm/io. h> static int major; static struct class * cls; static volatile unsigned long * gpio_con; static volatile unsigned long * gpio_dat; static int pin; static int led_open (struct inode * inode, struct file * file) {// printk ("first_drv_open \ n");/* configure to output */* gpio_con & = ~ (0x3 <(pin * 2); * gpio_con | = (0x1 <(pin * 2); return 0 ;} static ssize_t led_write (struct file * file, const char _ user * buf, size_t count, loff_t * ppos) {int val; // printk ("first_drv_write \ n "); copy_from_user (& val, buf, count); // copy_to_user (); if (val = 1) {// lighting * gpio_dat & = ~ (1 <pin);} else {// lighting down * gpio_dat | = (1 <pin);} return 0;} static struct file_operations led_fops = {. owner = THIS_MODULE,/* This is a macro. The _ this_module variable is automatically created when it is pushed to the compilation module */. open = led_open ,. write = led_write,}; static int led_probe (struct platform_device * pdev) {struct resource * res;/* perform ioremap */res = platform_get_resource (pdev, IORESOURCE_MEM, 0); gpio_con = ioremap (res-> start, res-> end-res-> start + 1); gpio_dat = gpio_con + 1; res = platform_get_resource (pdev, IORESOURCE_IRQ, 0); pin = res-> start;/* register the character device driver */printk ("led_probe, found led \ n"); 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) {/* uninstall the character device driver * // * iounmap */printk ("led_remove, remove led \ n"); class_device_destroy (cls, MKDEV (major, 0 )); class_destroy (cls); unregister_chrdev (major, "myled"); iounmap (gpio_con); return 0;} struct platform_driver led_drv = {. probe = led_probe ,. remove = led_remove ,. driver = {. name = "myled", }}; static int led_drv_init (void) {platform_driver_register (& led_drv); return 0;} static void led_drv_exit (void) {Summary (& led_drv );} module_init (led_drv_init); module_exit (led_drv_exit); MODULE_LICENSE ("GPL ");

 

App code implementation:

Led_test.c

#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdio.h>/* led_test on * led_test off */int main(int argc, char **argv){    int fd;    int val = 1;    fd = open("/dev/led", O_RDWR);    if (fd < 0)    {        printf("can't open!\n");    }    if (argc != 2)    {        printf("Usage :\n");        printf("%s <on|off>\n", argv[0]);        return 0;    }    if (strcmp(argv[1], "on") == 0)    {        val  = 1;    }    else    {        val = 0;    }        write(fd, &val, 4);    return 0;}