LED驱动(轮询方式)在FL2440的开发(2.6.33.7内核)

一、开发环境     主   机：fedora 14 (2.6.33.7)     开发板：FL2440(nandflash:K9F1G08 128m)     编译器：arm-linux-gcc 4.3.2   二、原理分析     1.  硬件原理图分析。由原理图得知LED电路是共阳极的，LED0、LED1、LED2、LED3分别由2440的GPB5、GPB6、GPB8、GPB10口控制的，当GPB5、GPB6、GPB8、GPB10输出低电平时，相应的LED便发亮，反之，LED则熄灭。   三、实现步骤     1. 去掉内核已有的LED驱动设置，因为IO口与mini2440开发板的不一致，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. 编写适合fl2440开发板的LED驱动，代码如下，文件名称：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要用到的头文件 #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) //硬件设备资源结构体 struct led_desc { int pin; //对应的IO引脚 int pin_setting; //引脚配置 }; 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驱动代码部署到内核中去 #cp -f fl2440_leds.c /linux-2.6.33.7/drivers/char //把驱动源码复制到内核驱动的字符设备下 #vim /linux-2.6.33.7/drivers/char/Kconfig //添加LED设备配置 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设备配置 obj-$(CONFIG_FL2440_LEDS) += fl2440_leds.o     4. 配置内核，选择LED设备选项 #make menuconfig Device Drivers ---> Character devices ---> <*> FL2440 Leds Device (NEW)     5. 编译内核并下载到开发板上，查看已加载的设备：#cat /proc/devices，可以看到fl2440_leds的主设备号为231 [root@yyq2440 /]# cat /proc/devices 90 mtd 99 ppdev 116 alsa 128 ptm 136 pts 180 usb 188 ttyUSB 189 usb_device 204 s3c2410_serial 231 fl2440_leds 232 fl2440_buttons 254 rtc Block devices: 1 ramdisk 259 blkext 四、测试驱动     1. 编写应用程序测试LED驱动，文件名：leds_test.c #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <sys/ioctl.h> int main(int argc, char **argv) { int turn, index, fd; //检测输入的参数合法性 if(argc != 3 || sscanf(argv[2], "%d", &index) != 1 || index < 1 || index > 4) { printf("Usage: leds_test on|off 1|2|3|4\n"); exit(1); } if(strcmp(argv[1], "on") == 0) { turn = 1; } else if(strcmp(argv[1], "off") == 0) { turn = 0; } else { printf("Usage: leds_test on|off 1|2|3|4\n"); exit(1); } //打开LED设备 fd = open("/dev/fl2440_leds", 0); if(fd < 0) { printf("Open Led Device Faild!\n"); exit(1); } //IO控制 ioctl(fd, turn, index - 1); //关闭LED设备 close(fd); return 0; }     2. 在开发主机上交叉编译测试应用程序，并复制到文件系统的/usr/sbin目录下，然后重新编译文件系统下载到开发板上 #arm-linux-gcc -o leds_test leds_test.c     3. 在开发板上的文件系统中创建一个LED设备的节点，然后运行测试程序，效果图如下，观测开发板上的LED灯，可以看到每一步的操作对应的LED会点亮或者熄灭 [root@yyq2440 /]# mknod /dev/fl2440_leds c 231 0 [root@yyq2440 /]# leds_test --help Usage: leds_test on|off 1|2|3|4 [root@yyq2440 /]# leds_test on 1 [root@yyq2440 /]# leds_test on 2 [root@yyq2440 /]# leds_test on 3 [root@yyq2440 /]# leds_test on 4 [root@yyq2440 /]# leds_test on 4 [root@yyq2440 /]# leds_test on 3 [root@yyq2440 /]# leds_test on 2 [root@yyq2440 /]# leds_test on 1 五、存在问题。     当执行#leds_test off *(*表示LED的序号1~4)的时候，序号比*大的Led也会一起灭掉。原因暂时还没找到。   2011-02-17