20130801 linux添加驱动 在dev下可以看到
友善之臂的Tiny210 linux3.0.8 for android
实现：在linux内核下添加LED的驱动 LED@LZM@FJICC并且可以在# /dev/下看到。
#ls /dev/? 看到驱动LED@LZM@FJICC
1.进入linux/drivers/char/新建一个文件lzm_fjicc.c
编写内容：
//lzm_fjicc.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/delay.h>
#include <mach/gpio.h>
#include <mach/regs-gpio.h>
#include <plat/gpio-cfg.h>
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#define DEVICE_NAME "LED@LZM@FJICC"
static int led_gpios[] = {
?????? S5PV210_GPJ2(0),
?????? S5PV210_GPJ2(1),
?????? S5PV210_GPJ2(2),
?????? S5PV210_GPJ2(3),
};
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#define LED_NUMARRAY_SIZE(led_gpios)
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static long fjicc_leds_ioctl(struct file *filp, unsigned int cmd,
????????????? unsigned long arg)
{
?????? switch(cmd) {
????????????? case 0:
????????????? case 1:
???????????????????? if (arg > LED_NUM) {
??????????????????????????? return -EINVAL;
???????????????????? }
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???????????????????? gpio_set_value(led_gpios[arg], !cmd);
???????????????????? //printk(DEVICE_NAME": %d %d\n", arg, cmd);
???????????????????? break;
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????????????? default:
???????????????????? return -EINVAL;
?????? }
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?????? return 0;
}
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static struct file_operations fjicc_led_dev_fops = {
?????? .owner????????????????? = THIS_MODULE,
?????? .unlocked_ioctl?????? = fjicc_leds_ioctl,
};
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static struct miscdevice fjicc_led_dev = {
?????? .minor?????????????????? = MISC_DYNAMIC_MINOR,
?????? .name??????????????????? = DEVICE_NAME,
?????? .fops???????????????????? = &fjicc_led_dev_fops,
};
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static int __init fjicc_led_dev_init(void) {
?????? int ret;
?????? int i;
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?????? for (i = 0; i < LED_NUM; i++) {
????????????? ret = gpio_request(led_gpios[i], "LED");
????????????? if (ret) {
???????????????????? printk("%s: request GPIO %d for LED failed, ret = %d\n", DEVICE_NAME,
?????????????????????????????????? led_gpios[i], ret);
???????????????????? return ret;
????????????? }
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????????????? s3c_gpio_cfgpin(led_gpios[i], S3C_GPIO_OUTPUT);
????????????? gpio_set_value(led_gpios[i], 1);
?????? }
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?????? ret = misc_register(&fjicc_led_dev);
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?????? printk(DEVICE_NAME"\tinitialized\n");
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?????? return ret;
}
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static void __exit fjicc_led_dev_exit(void) {
?????? int i;
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?????? for (i = 0; i < LED_NUM; i++) {
????????????? gpio_free(led_gpios[i]);
?????? }
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?????? misc_deregister(&fjicc_led_dev);
}
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module_init(fjicc_led_dev_init);
module_exit(fjicc_led_dev_exit);
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MODULE_LICENSE("GPL");
MODULE_AUTHOR("LZM@FJICC");
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2.然后修改char目录下的Kconfig和Makefile文件：
Kconfig:
config LEDS_LZM_FJICC
?????? tristate "LEDS_LZM_FJICC"
?????? depends on MACH_MINI210
?????? default y
?????? help
?????? ? This option enables support for LEDs connected to GPIO lines
?????? ? on Mini210 boards.
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Makefile:
obj-$(CONFIG_LEDS_LZM_FJICC)?? += lzm_fjicc.o
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3.进到linux根目录，然后#make menuconfig
就可以在配置菜单中看到LEDS_LZM_FJICC,具体在devices driversàchracter devicesà就可以看到了。
4.配置好了，make zImage就可以了。
5.烧写了系统后，就可以查看驱动了。#ls /dev/
6.提升驱动权限：#chmod 777 /dev/LED@LZM@FJICC
