LED驅(qū)動(輪詢方式)在FL2440的開發(fā)(2.6.33.7內(nèi)核)

lchjczw 2012-04-10

展開全文

一、開發(fā)環(huán)境

    主   機：fedora 14 (2.6.33.7)
    開發(fā)板：FL2440(nandflash:K9F1G08 128m)
    編譯器：arm-linux-gcc 4.3.2

二、原理分析

1. 硬件原理圖分析。由原理圖得知LED電路是共陽極的，LED0、LED1、LED2、LED3分別由2440的GPB5、GPB6、GPB8、GPB10口控制的，當GPB5、GPB6、GPB8、GPB10輸出低電平時，相應(yīng)的LED便發(fā)亮，反之，LED則熄滅。

三、實現(xiàn)步驟

1. 去掉內(nèi)核已有的LED驅(qū)動設(shè)置，因為IO口與mini2440開發(fā)板的不一致，根本就不能控制板上的LED。

#gedit arch/arm/plat-s3c24xx/common-smdk.c

/* LED devices */
/*
static struct s3c24xx_led_platdata smdk_pdata_led4 = {
.gpio = S3C2410_GPF4,
.flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
.name = "led4",
.def_trigger = "timer",
};
static struct s3c24xx_led_platdata smdk_pdata_led5 = {
.gpio = S3C2410_GPF5,
.flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
.name = "led5",
.def_trigger = "nand-disk",
};
static struct s3c24xx_led_platdata smdk_pdata_led6 = {
.gpio = S3C2410_GPF6,
.flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
.name = "led6",
};
static struct s3c24xx_led_platdata smdk_pdata_led7 = {
.gpio = S3C2410_GPF7,
.flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
.name = "led7",
};
static struct platform_device smdk_led4 = {
.name = "s3c24xx_led",
.id = 0,
.dev = {
.platform_data = &smdk_pdata_led4,
},
};
static struct platform_device smdk_led5 = {
.name = "s3c24xx_led",
.id = 1,
.dev = {
.platform_data = &smdk_pdata_led5,
},
};
static struct platform_device smdk_led6 = {
.name = "s3c24xx_led",
.id = 2,
.dev = {
.platform_data = &smdk_pdata_led6,
},
};
static struct platform_device smdk_led7 = {
.name = "s3c24xx_led",
.id = 3,
.dev = {
.platform_data = &smdk_pdata_led7,
},
};*/

static struct platform_device __initdata *smdk_devs[] = {
&s3c_device_nand,
/*&smdk_led4,
&smdk_led5,
&smdk_led6,
&smdk_led7,*/
};

void __init smdk_machine_init(void)
{
/* Configure the LEDs (even if we have no LED support)*/
/*
s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);
s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);
s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);
s3c2410_gpio_cfgpin(S3C2410_GPF7, S3C2410_GPF7_OUTP);
s3c2410_gpio_setpin(S3C2410_GPF4, 1);
s3c2410_gpio_setpin(S3C2410_GPF5, 1);
s3c2410_gpio_setpin(S3C2410_GPF6, 1);
s3c2410_gpio_setpin(S3C2410_GPF7, 1);*/
if (machine_is_smdk2443())
smdk_nand_info.twrph0 = 50;
s3c_device_nand.dev.platform_data = &smdk_nand_info;
platform_add_devices(smdk_devs, ARRAY_SIZE(smdk_devs));
s3c_pm_init();
}

2. 編寫適合fl2440開發(fā)板的LED驅(qū)動，代碼如下，文件名稱：fl2440_leds.c

/*
*==============================================
*Name : fl2440_leds.c
*Author : y.q.yang
*Date : 17/2/2011
*Copyright : GPL
*Description : fl2440 leds driver
*==============================================
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/fs.h>
//#include <linux/sched.h>
//#include <linux/poll.h> //poll要用到的頭文件
#include <mach/hardware.h>
#include <mach/regs-gpio.h>
#include <mach/gpio-fns.h>
#include <mach/gpio-nrs.h>
#define DEVICER_NAME "fl2440_leds"
#define DEVICER_MAJOR 231
#define LED_ON 0
#define LED_OFF 1
#define LED_COUNT 4
#define S3C2410_GPIONO(bank,offset) ((bank) + (offset))
#define S3C2410_GPIO_BANKB (32*1)
#define S3C2410_GPB5 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 5)
#define S3C2410_GPB6 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 6)
#define S3C2410_GPB8 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 8)
#define S3C2410_GPB10 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 10)
#define S3C2410_GPB5_OUTP (0x01 << 10)
#define S3C2410_GPB6_OUTP (0x01 << 12)
#define S3C2410_GPB8_OUTP (0x01 << 16)
#define S3C2410_GPB10_OUTP (0x01 << 20)
//硬件設(shè)備資源結(jié)構(gòu)體
struct led_desc
{
int pin; //對應(yīng)的IO引腳
int pin_setting; //引腳配置
};
static struct led_desc led_configs[] =
{
{S3C2410_GPB5,S3C2410_GPB5_OUTP},
{S3C2410_GPB6,S3C2410_GPB6_OUTP},
{S3C2410_GPB8,S3C2410_GPB8_OUTP},
{S3C2410_GPB10,S3C2410_GPB10_OUTP},
};
static int leds_open(struct inode *inode, struct file *filp)
{
return 0;
}
static int leds_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
if(arg<0 || arg>3)
{
return -EINVAL;
}
switch(cmd)
{
case LED_ON:
s3c2410_gpio_setpin(led_configs[arg].pin,~(LED_ON));
break;
case LED_OFF:
s3c2410_gpio_setpin(led_configs[arg].pin,~(LED_OFF));
break;
default:
return -EINVAL;
}
return 0;
}
struct file_operations leds_fops =
{
.owner = THIS_MODULE,
.open = leds_open,
.ioctl = leds_ioctl,
};
static int __init led_init(void)
{
int i,ret;
for(i=0; i<LED_COUNT; i++)
{
s3c2410_gpio_cfgpin(led_configs[i].pin, led_configs[i].pin_setting);
s3c2410_gpio_setpin(led_configs[i].pin,~(LED_OFF));
}
ret = register_chrdev(DEVICER_MAJOR, DEVICER_NAME, &leds_fops);
if(ret < 0)
{
printk(DEVICER_NAME "register failed\n");
return ret;
}
return ret;
}
static void __exit led_exit(void)
{
unregister_chrdev(DEVICER_MAJOR, DEVICER_NAME);
}
module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("y.q.yang");
MODULE_DESCRIPTION("FL2440 led driver");

3. 把LED驅(qū)動代碼部署到內(nèi)核中去

#cp -f fl2440_leds.c /linux-2.6.33.7/drivers/char //把驅(qū)動源碼復(fù)制到內(nèi)核驅(qū)動的字符設(shè)備下
#vim /linux-2.6.33.7/drivers/char/Kconfig //添加LED設(shè)備配置
config FL2440_LEDS
tristate "FL2440 Leds Device"
depends on ARCH_S3C2440
default y
---help---
FL2440 User Leds
#gedit /linux-2.6.33.7/drivers/char/Makefile //添加LED設(shè)備配置
obj-$(CONFIG_FL2440_LEDS) += fl2440_leds.o