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

 lchjczw 2012-04-10
一、開(kāi)發(fā)環(huán)境
    主   機(jī)：fedora 14 (2.6.33.7)
    開(kāi)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(yáng)極的，LED0、LED1、LED2、LED3分別由2440的GPB5、GPB6、GPB8、GPB10口控制的，當(dāng)GPB5、GPB6、GPB8、GPB10輸出低電平時(shí)，相應(yīng)的LED便發(fā)亮，反之，LED則熄滅。
 
三、實(shí)現(xiàn)步驟
    1. 去掉內(nèi)核已有的LED驅(qū)動(dòng)設(shè)置，因?yàn)镮O口與mini2440開(kāi)發(fā)板的不一致，根本就不能控制板上的LED。
  1. #gedit arch/arm/plat-s3c24xx/common-smdk.c
  1. /* LED devices */
  2. /*
  3. static struct s3c24xx_led_platdata smdk_pdata_led4 = {
  4.     .gpio = S3C2410_GPF4,
  5.     .flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
  6.     .name = "led4",
  7.     .def_trigger = "timer",
  8. };

  10. static struct s3c24xx_led_platdata smdk_pdata_led5 = {
  11.     .gpio = S3C2410_GPF5,
  12.     .flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
  13.     .name = "led5",
  14.     .def_trigger = "nand-disk",
  15. };

  17. static struct s3c24xx_led_platdata smdk_pdata_led6 = {
  18.     .gpio = S3C2410_GPF6,
  19.     .flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
  20.     .name = "led6",
  21. };

  23. static struct s3c24xx_led_platdata smdk_pdata_led7 = {
  24.     .gpio = S3C2410_GPF7,
  25.     .flags = S3C24XX_LEDF_ACTLOW | S3C24XX_LEDF_TRISTATE,
  26.     .name = "led7",
  27. };

  29. static struct platform_device smdk_led4 = {
  30.     .name = "s3c24xx_led",
  31.     .id = 0,
  32.     .dev = {
  33.         .platform_data = &smdk_pdata_led4,
  34.     },
  35. };

  37. static struct platform_device smdk_led5 = {
  38.     .name = "s3c24xx_led",
  39.     .id = 1,
  40.     .dev = {
  41.         .platform_data = &smdk_pdata_led5,
  42.     },
  43. };

  45. static struct platform_device smdk_led6 = {
  46.     .name = "s3c24xx_led",
  47.     .id = 2,
  48.     .dev = {
  49.         .platform_data = &smdk_pdata_led6,
  50.     },
  51. };

  53. static struct platform_device smdk_led7 = {
  54.     .name = "s3c24xx_led",
  55.     .id = 3,
  56.     .dev = {
  57.         .platform_data = &smdk_pdata_led7,
  58.     },
  59. };*/
  1. static struct platform_device __initdata *smdk_devs[] = {
  2.     &s3c_device_nand,
  3.     /*&smdk_led4,
  4.     &smdk_led5,
  5.     &smdk_led6,
  6.     &smdk_led7,*/
  7. };
  1. void __init smdk_machine_init(void)
  2. {
  3.     /* Configure the LEDs (even if we have no LED support)*/
  4.     /*
  5.     s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);
  6.     s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);
  7.     s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);
  8.     s3c2410_gpio_cfgpin(S3C2410_GPF7, S3C2410_GPF7_OUTP);

  10.     s3c2410_gpio_setpin(S3C2410_GPF4, 1);
  11.     s3c2410_gpio_setpin(S3C2410_GPF5, 1);
  12.     s3c2410_gpio_setpin(S3C2410_GPF6, 1);
  13.     s3c2410_gpio_setpin(S3C2410_GPF7, 1);*/

  15.     if (machine_is_smdk2443())
  16.         smdk_nand_info.twrph0 = 50;

  18.     s3c_device_nand.dev.platform_data = &smdk_nand_info;

  20.     platform_add_devices(smdk_devs, ARRAY_SIZE(smdk_devs));

  22.     s3c_pm_init();
  23. }

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

  1. /*
  2.  *==============================================
  3.  *Name : fl2440_leds.c
  4.  *Author : y.q.yang
  5.  *Date : 17/2/2011
  6.  *Copyright : GPL
  7.  *Description : fl2440 leds driver
  8.  *==============================================
  9.  */

  11. #include <linux/kernel.h>
  12. #include <linux/module.h>
  13. #include <linux/init.h>
  14. #include <linux/errno.h>
  15. #include <linux/fs.h>
  16. //#include <linux/sched.h>
  17. //#include <linux/poll.h>    //poll要用到的頭文件

  19. #include <mach/hardware.h>
  20. #include <mach/regs-gpio.h>
  21. #include <mach/gpio-fns.h>
  22. #include <mach/gpio-nrs.h>

  24. #define DEVICER_NAME    "fl2440_leds"
  25. #define DEVICER_MAJOR    231
  26. #define LED_ON            0
  27. #define LED_OFF            1
  28. #define LED_COUNT        4

  30. #define S3C2410_GPIONO(bank,offset) ((bank) + (offset))
  31. #define S3C2410_GPIO_BANKB (32*1)
  32. #define S3C2410_GPB5 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 5)
  33. #define S3C2410_GPB6 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 6)
  34. #define S3C2410_GPB8 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 8)
  35. #define S3C2410_GPB10 S3C2410_GPIONO(S3C2410_GPIO_BANKB, 10)

  37. #define S3C2410_GPB5_OUTP    (0x01 << 10)
  38. #define S3C2410_GPB6_OUTP    (0x01 << 12)
  39. #define S3C2410_GPB8_OUTP    (0x01 << 16)
  40. #define S3C2410_GPB10_OUTP    (0x01 << 20)


  43. //硬件設(shè)備資源結(jié)構(gòu)體
  44. struct led_desc
  45. {
  46.     int pin;            //對(duì)應(yīng)的IO引腳
  47.     int pin_setting;    //引腳配置
  48. };

  50. static struct led_desc led_configs[] =
  51. {
  52.     {S3C2410_GPB5,S3C2410_GPB5_OUTP},
  53.     {S3C2410_GPB6,S3C2410_GPB6_OUTP},
  54.     {S3C2410_GPB8,S3C2410_GPB8_OUTP},
  55.     {S3C2410_GPB10,S3C2410_GPB10_OUTP},
  56. };

  58. static int leds_open(struct inode *inode, struct file *filp)
  59. {
  60.     return 0;
  61. }

  63. static int leds_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
  64. {
  65.     if(arg<0 || arg>3)
  66.     {
  67.         return -EINVAL;
  68.     }
  69.     
  70.     switch(cmd)
  71.     {
  72.         case LED_ON:
  73.             s3c2410_gpio_setpin(led_configs[arg].pin,~(LED_ON));
  74.             break;
  75.             
  76.         case LED_OFF:
  77.             s3c2410_gpio_setpin(led_configs[arg].pin,~(LED_OFF));
  78.             break;
  79.             
  80.         default:
  81.             return -EINVAL;
  82.     }
  83.     return 0;
  84. }

  86. struct file_operations leds_fops =
  87. {
  88.     .owner = THIS_MODULE,
  89.     .open = leds_open,
  90.     .ioctl = leds_ioctl,
  91. };

  93. static int __init led_init(void)
  94. {
  95.     int i,ret;
  96.     
  97.     for(i=0; i<LED_COUNT; i++)
  98.     {
  99.         s3c2410_gpio_cfgpin(led_configs[i].pin, led_configs[i].pin_setting);
  100.         s3c2410_gpio_setpin(led_configs[i].pin,~(LED_OFF));
  101.     }
  102.     
  103.     ret = register_chrdev(DEVICER_MAJOR, DEVICER_NAME, &leds_fops);
  104.     
  105.     if(ret < 0)
  106.     {
  107.         printk(DEVICER_NAME "register failed\n");
  108.         return ret;
  109.     }
  110.     
  111.     return ret;
  112. }

  114. static void __exit led_exit(void)
  115. {
  116.     unregister_chrdev(DEVICER_MAJOR, DEVICER_NAME);
  117. }

  119. module_init(led_init);
  120. module_exit(led_exit);

  122. MODULE_LICENSE("GPL");
  123. MODULE_AUTHOR("y.q.yang");
  124. MODULE_DESCRIPTION("FL2440 led driver");

    3. 把LED驅(qū)動(dòng)代碼部署到內(nèi)核中去

  1. #cp -f fl2440_leds.c /linux-2.6.33.7/drivers/char //把驅(qū)動(dòng)源碼復(fù)制到內(nèi)核驅(qū)動(dòng)的字符設(shè)備下
  3. #vim /linux-2.6.33.7/drivers/char/Kconfig //添加LED設(shè)備配置
  4. config FL2440_LEDS
  5.     tristate "FL2440 Leds Device"
  6.     depends on ARCH_S3C2440
  7.     default y
  8.     ---help---
  9.       FL2440 User Leds

  11. #gedit /linux-2.6.33.7/drivers/char/Makefile //添加LED設(shè)備配置
  12. obj-$(CONFIG_FL2440_LEDS) += fl2440_leds.o

    4. 配置內(nèi)核，選擇LED設(shè)備選項(xiàng)

  1. #make menuconfig
  2. Device Drivers --->
  3.     Character devices --->
  4.         <*> FL2440 Leds Device (NEW)

    5. 編譯內(nèi)核并下載到開(kāi)發(fā)板上，查看已加載的設(shè)備：#cat /proc/devices，可以看到fl2440_leds的主設(shè)備號(hào)為231

  1. [root@yyq2440 /]# cat /proc/devices
  1. 90 mtd
  2.  99 ppdev
  3. 116 alsa
  4. 128 ptm
  5. 136 pts
  6. 180 usb
  7. 188 ttyUSB
  8. 189 usb_device
  9. 204 s3c2410_serial
  10. 231 fl2440_leds
  11. 232 fl2440_buttons
  12. 254 rtc

  14. Block devices:
  15.   1 ramdisk
  16. 259 blkext

四、測(cè)試驅(qū)動(dòng)

    1. 編寫應(yīng)用程序測(cè)試LED驅(qū)動(dòng)，文件名：leds_test.c

  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <fcntl.h>
  4. #include <sys/ioctl.h>

  6. int main(int argc, char **argv)
  7. {
  8.     int turn, index, fd;

  10.     //檢測(cè)輸入的參數(shù)合法性
  11.     if(argc != 3 || sscanf(argv[2], "%d", &index) != 1 || index < 1 || index > 4)
  12.     {
  13.         printf("Usage: leds_test on|off 1|2|3|4\n");
  14.         exit(1);
  15.     }

  17.     if(strcmp(argv[1], "on") == 0)
  18.     {
  19.         turn = 1;
  20.     }
  21.     else if(strcmp(argv[1], "off") == 0)
  22.     {
  23.         turn = 0;
  24.     }
  25.     else
  26.     {
  27.         printf("Usage: leds_test on|off 1|2|3|4\n");
  28.         exit(1);
  29.     }

  31.     //打開(kāi)LED設(shè)備
  32.     fd = open("/dev/fl2440_leds", 0);

  34.     if(fd < 0)
  35.     {
  36.         printf("Open Led Device Faild!\n");
  37.         exit(1);
  38.     }

  40.     //IO控制
  41.     ioctl(fd, turn, index - 1);

  43.     //關(guān)閉LED設(shè)備
  44.     close(fd);

  46.     return 0;
  47. }

    2. 在開(kāi)發(fā)主機(jī)上交叉編譯測(cè)試應(yīng)用程序，并復(fù)制到文件系統(tǒng)的/usr/sbin目錄下，然后重新編譯文件系統(tǒng)下載到開(kāi)發(fā)板上

  1. #arm-linux-gcc -o leds_test leds_test.c

    3. 在開(kāi)發(fā)板上的文件系統(tǒng)中創(chuàng)建一個(gè)LED設(shè)備的節(jié)點(diǎn)，然后運(yùn)行測(cè)試程序，效果圖如下，觀測(cè)開(kāi)發(fā)板上的LED燈，可以看到每一步的操作對(duì)應(yīng)的LED會(huì)點(diǎn)亮或者熄滅

  1. [root@yyq2440 /]# mknod /dev/fl2440_leds c 231 0
  2. [root@yyq2440 /]# leds_test --help
  3. Usage: leds_test on|off 1|2|3|4

  5. [root@yyq2440 /]# leds_test on 1
  6. [root@yyq2440 /]# leds_test on 2
  7. [root@yyq2440 /]# leds_test on 3
  8. [root@yyq2440 /]# leds_test on 4
  9. [root@yyq2440 /]# leds_test on 4
  10. [root@yyq2440 /]# leds_test on 3
  11. [root@yyq2440 /]# leds_test on 2
  12. [root@yyq2440 /]# leds_test on 1

五、存在問(wèn)題。

    當(dāng)執(zhí)行#leds_test off *(*表示LED的序號(hào)1~4)的時(shí)候，序號(hào)比*大的Led也會(huì)一起滅掉。原因暫時(shí)還沒(méi)找到。

 

2011-02-17

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