【驱动篇】龙芯LS2K0300之红外驱动

实验目标

编写HX1838红外接收器驱动，根据接收的波形脉冲解码红外按键键值

模块连接

模块连接：VCC接Pin 2，GND接Pin1，DATA接Pin16

在这里插入图片描述

驱动代码

HX1838 GPIO初始化，申请中断，注意：GPIO48默认是给i2c0使用的，使用前记得注释掉i2c0设备树节点

#define CODE_SIZE 4
#define HX1838_IO 48
#define TIME_UNIT 140
#define GPIO_VALUE gpio_get_value(HX1838_IO)static int __init hx1838_init(void)
{int ret;int irq = gpio_to_irq(HX1838_IO);printk("irq : %d\n", irq);gpio_request(HX1838_IO, "hx1838-gpio");gpio_direction_input(HX1838_IO);ret = request_irq(irq, irq_callback, IRQF_TRIGGER_FALLING, "hx1838-irq", NULL);if (ret < 0)goto LABEL;return 0;LABEL:gpio_free(HX1838_IO);return ret;
}

中断处理函数，解码格式：地址码 + 地址码反码 + 数据码 + 数据码反码，13.5ms为前导波形信号，第56行需要注意数据取反默认是32位的（需要强制转换）

typedef unsigned char uchar;static uchar array[CODE_SIZE];irqreturn_t irq_callback(int irqno, void *arg)
{unsigned char j,k,N=0;udelay(15 * TIME_UNIT);if (GPIO_VALUE == 1){// printk("111\n");return IRQ_HANDLED;}while (!GPIO_VALUE)  {udelay(TIME_UNIT);}                                       for (j=0; j < 4; j++)                                          {for (k = 0; k < 8; k++)                                {while (GPIO_VALUE)                                  {udelay(TIME_UNIT);}while (!GPIO_VALUE)                                {udelay(TIME_UNIT);}while (GPIO_VALUE)                                  {udelay(TIME_UNIT);N++;           if (N >= 30){// printk("222\n");return IRQ_HANDLED;}                                              } array[j] = array[j] >> 1;                            if(N >= 8){array[j] = array[j] | 0x80;                     }  N = 0;}}      if(array[2] != (unsigned char)(~array[3])){// printk("333\n");return IRQ_HANDLED;}printk("%d,%d,%d,%d\n", array[0], array[1], array[2], array[3]);return IRQ_HANDLED;
}

完整驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/gpio.h>#define CODE_SIZE 4
#define HX1838_IO 48
#define TIME_UNIT 140
#define GPIO_VALUE gpio_get_value(HX1838_IO)typedef unsigned char uchar;static uchar array[CODE_SIZE];irqreturn_t irq_callback(int irqno, void *arg)
{unsigned char j,k,N=0;udelay(15 * TIME_UNIT);if (GPIO_VALUE == 1){// printk("111\n");return IRQ_HANDLED;}while (!GPIO_VALUE)  {udelay(TIME_UNIT);}                                       for (j=0; j < 4; j++)                                          {for (k = 0; k < 8; k++)                                {while (GPIO_VALUE)                                  {udelay(TIME_UNIT);}while (!GPIO_VALUE)                                {udelay(TIME_UNIT);}while (GPIO_VALUE)                                  {udelay(TIME_UNIT);N++;           if (N >= 30){// printk("222\n");return IRQ_HANDLED;}                                              } array[j] = array[j] >> 1;                            if(N >= 8){array[j] = array[j] | 0x80;                     }  N = 0;}}      if(array[2] != (unsigned char)(~array[3])){// printk("333\n");return IRQ_HANDLED;}printk("%d,%d,%d,%d\n", array[0], array[1], array[2], array[3]);return IRQ_HANDLED;
}static int __init hx1838_init(void)
{int ret;int irq = gpio_to_irq(HX1838_IO);printk("irq : %d\n", irq);gpio_request(HX1838_IO, "hx1838-gpio");gpio_direction_input(HX1838_IO);ret = request_irq(irq, irq_callback, IRQF_TRIGGER_FALLING, "hx1838-irq", NULL);if (ret < 0)goto LABEL;return 0;LABEL:gpio_free(HX1838_IO);return ret;
}static void __exit hx1838_exit(void)
{free_irq(gpio_to_irq(HX1838_IO), NULL);gpio_free(HX1838_IO);
}module_init(hx1838_init);
module_exit(hx1838_exit);MODULE_LICENSE("GPL");

Makefile文件

obj-m += irda.o 
KDIR:=/home/asensing/loongson/linux-4.19
ARCH=loongarch 
CROSS_COMPILE=loongarch64-linux-gnu-
PWD?=$(shell pwd) 
all:make -C $(KDIR) M=$(PWD) modules

构建脚本

export PATH=$PATH:/home/asensing/loongson/loongson-gnu-toolchain-8.3-x86_64-loongarch64-linux-gnu-rc1.3-1/bin
make -j8
# loongarch64-linux-gnu-gcc test.c -o test
FILE=$PWD/$(basename $PWD).ko
scp $FILE root@192.168.137.232:/home/root