嵌入式开发实例

/* butt_drv.c */ #include <linux/config.h> #include <linux/module.h> #include <linux/version.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/interrupt.h> #include <linux/time.h> #include <linux/spinlock.h> #include <asm/hardware.h> #include <asm/delay.h> #include <asm/uaccess.h> #include <asm-arm/arch-s3c2410/regs-gpio.h> #include <asm/io.h> #include <asm/uaccess.h> #include <asm-arm/arch-s3c2410/irqs.h> #include <asm-arm/irq.h> #include <linux/config.h> #include <linux/module.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/cdev.h> #include <linux/ioctl.h> #include <asm/uaccess.h> #include <asm/hardware.h> #include <asm/arch/regs-gpio.h> #include "butt_drv.h" static st_key_info_matrix key_info_matrix[MAX_COLUMN][MAX_ROW] = { {{10, IRQ_EINT0, S3C2410_GPF0, S3C2410_GPE11}, {11, IRQ_EINT0, S3C2410_GPF0, S3C2410_GPG6}, {12, IRQ_EINT0, S3C2410_GPF0, S3C2410_GPE13}, {16, IRQ_EINT0, S3C2410_GPF0, S3C2410_GPG2}}, {{7, IRQ_EINT2, S3C2410_GPF2, S3C2410_GPE11}, {8, IRQ_EINT2, S3C2410_GPF2, S3C2410_GPG6}, {9, IRQ_EINT2, S3C2410_GPF2, S3C2410_GPE13}, {15, IRQ_EINT2, S3C2410_GPF2, S3C2410_GPG2}}, {{4, IRQ_EINT11, S3C2410_GPG3, S3C2410_GPE11}, {5, IRQ_EINT11, S3C2410_GPG3, S3C2410_GPG6}, {6, IRQ_EINT11, S3C2410_GPG3, S3C2410_GPE13}, {14, IRQ_EINT11, S3C2410_GPG3, S3C2410_GPG2}}, {{1, IRQ_EINT19, S3C2410_GPG11, S3C2410_GPE11}, {2, IRQ_EINT19, S3C2410_GPG11, S3C2410_GPG6}, {3, IRQ_EINT19, S3C2410_GPG11, S3C2410_GPE13}, {13, IRQ_EINT19, S3C2410_GPG11, S3C2410_GPG2}}, }; static st_key_buffer key_buffer; /* 键盘缓冲区 */ static spinlock_t buffer_lock; /*缓冲区锁 */ static int button_major = 0; /* 获取当前的毫秒数(从系统启动开始）*/ static unsigned long get_tick_count(void) { struct timeval currTick; unsigned long ulRet; do_gettimeofday(&currTick); ulRet = currTick.tv_sec; ulRet *= 1000; ulRet += (currTick.tv_usec + 500) / 1000; return ulRet; } /* 初始化键盘缓冲区 */ static void init_keybuffer(void) { int i; spin_lock_irq(&buffer_lock); /* 获得一个自旋锁 */ key_buffer.head = 0; key_buffer.tail = 0; for(i = 0; i < MAX_KEY_COUNT; i++) { key_buffer.buf[i] = 0; key_buffer.jiffy[i] = 0; } spin_unlock_irq(&buffer_lock); /* 释放自旋锁 */ } /* 从缓冲删除过时数据(5秒前的按键值) */ static void remove_timeoutkey(void) { unsigned long tick; spin_lock_irq(&buffer_lock); /* 获得一个自旋锁 */ while(key_buffer.head != key_buffer.tail) { tick = get_tick_count() - key_buffer.jiffy[key_buffer.head]; if (tick < 5000) /* 5秒 */ break; key_buffer.buf[key_buffer.head] = 0; key_buffer.jiffy[key_buffer.head] = 0; key_buffer.head ++; key_buffer.head &= (MAX_KEY_COUNT -1); } spin_unlock_irq(&buffer_lock); /* 释放自旋锁 */ } void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function) { unsigned long base = S3C2410_GPIO_BASE(pin); unsigned long shift = 1; unsigned long mask = 0x03; unsigned long con; unsigned long flags; if (pin < S3C2410_GPIO_BANKB) { shift = 0; mask = 0x01; } mask <<= (S3C2410_GPIO_OFFSET(pin) << shift); local_irq_save(flags); con = __raw_readl(base + 0x00); con &= ~mask; con |= function; __raw_writel(con, base + 0x00); local_irq_restore(flags); } void s3c2410_gpio_setpin(unsigned int pin, unsigned int to) { unsigned long base = S3C2410_GPIO_BASE(pin); unsigned long offs = S3C2410_GPIO_OFFSET(pin); unsigned long flags; unsigned long dat; local_irq_save(flags); dat = __raw_readl(base + 0x04); dat &= ~(1 << offs); dat |= to << offs; __raw_writel(dat, base + 0x04); local_irq_restore(flags); } unsigned int s3c2410_gpio_getpin(unsigned int pin) { unsigned long base = S3C2410_GPIO_BASE(pin); unsigned long offs = S3C2410_GPIO_OFFSET(pin); unsigned long dat = 0; unsigned long flags; local_irq_save(flags); dat = __raw_readl(base + 0x04); local_irq_restore(flags); return ((dat & (1 << offs)) >> offs); } /* 初始化GPIO, 设置中断0, 2, 11, 19为下降沿中断 */ static void init_gpio(void) { s3c2410_gpio_cfgpin(S3C2410_GPE11, S3C2410_GPE11_OUTP); /* GPE11 */ s3c2410_gpio_setpin(S3C2410_GPE11, 0); s3c2410_gpio_cfgpin(S3C2410_GPE13, S3C2410_GPE13_OUTP); /* GPE13 */ s3c2410_gpio_setpin(S3C2410_GPE13, 0); s3c2410_gpio_cfgpin(S3C2410_GPG2, S3C2410_GPG2_OUTP); /* GPG2 */ s3c2410_gpio_setpin(S3C2410_GPG2, 0); s3c2410_gpio_cfgpin(S3C2410_GPG6, S3C2410_GPG6_OUTP); /* GPG6 */ s3c2410_gpio_setpin(S3C2410_GPG6, 0); s3c2410_gpio_cfgpin(S3C2410_GPF0, S3C2410_GPF0_EINT0); /* GPF0 */ s3c2410_gpio_cfgpin(S3C2410_GPF2, S3C2410_GPF2_EINT2); /* GPF2 */ s3c2410_gpio_cfgpin(S3C2410_GPG3, S3C2410_GPG3_EINT11); /* GPG3 */ s3c2410_gpio_cfgpin(S3C2410_GPG11, S3C2410_GPG11_EINT19); /* GPG11 */ set_irq_type(IRQ_EINT0, IRQT_FALLING); set_irq_type(IRQ_EINT2, IRQT_FALLING); set_irq_type(IRQ_EINT11, IRQT_FALLING); set_irq_type(IRQ_EINT19, IRQT_FALLING); } /* 激活中断 */ static __inline void enable_irqs(void) { int i; for (i = 0; i < MAX_COLUMN; i++) { enable_irq(key_info_matrix[i][0].irq_no); } } /* 屏蔽中断 */ static __inline void disable_irqs(void) { int i; for (i = 0; i < MAX_COLUMN; i++) { disable_irq(key_info_matrix[i][0].irq_no); } } /* ** 进入中断后, 扫描铵键码 ** 返回: 按键码(1-16), 0xff表示错误 */ static __inline unsigned char button_scan(int irq) { unsigned char key_id = 0xff; unsigned char column = 0xff, row = 0xff; s3c2410_gpio_cfgpin(S3C2410_GPF0, S3C2410_GPF0_INP); /* GPF0 */ s3c2410_gpio_cfgpin(S3C2410_GPF2, S3C2410_GPF2_INP); /* GPF2 */ s3c2410_gpio_cfgpin(S3C2410_GPG3, S3C2410_GPG3_INP); /* GPG3 */ s3c2410_gpio_cfgpin(S3C2410_GPG11, S3C2410_GPG11_INP); /* GPG11 */ switch (irq) { case IRQ_EINT0: column = 0; break; case IRQ_EINT2: column = 1; break; case IRQ_EINT11: column = 2; break; case IRQ_EINT19: column = 3; break; } if (column != 0xff) { s3c2410_gpio_setpin(S3C2410_GPE11, 0); s3c2410_gpio_setpin(S3C2410_GPG6, 1); s3c2410_gpio_setpin(S3C2410_GPE13, 1); s3c2410_gpio_setpin(S3C2410_GPG2, 1); if (!s3c2410_gpio_getpin(key_info_matrix[column][0].irq_gpio_port)) { key_id = key_info_matrix[column][0].key_id; return key_id; } s3c2410_gpio_setpin(S3C2410_GPE11, 1); s3c2410_gpio_setpin(S3C2410_GPG6, 0); s3c2410_gpio_setpin(S3C2410_GPE13, 1); s3c2410_gpio_setpin(S3C2410_GPG2, 1); if (!s3c2410_gpio_getpin(key_info_matrix[column][1].irq_gpio_port)) { key_id = key_info_matrix[column][1].key_id; return key_id; } s3c2410_gpio_setpin(S3C2410_GPE11, 1); s3c2410_gpio_setpin(S3C2410_GPG6, 1); s3c2410_gpio_setpin(S3C2410_GPE13, 0); s3c2410_gpio_setpin(S3C2410_GPG2, 1); if (!s3c2410_gpio_getpin(key_info_matrix[column][2].irq_gpio_port)) { key_id = key_info_matrix[column][2].key_id; return key_id; } s3c2410_gpio_setpin(S3C2410_GPE11, 1); s3c2410_gpio_setpin(S3C2410_GPG6, 1); s3c2410_gpio_setpin(S3C2410_GPE13, 1); s3c2410_gpio_setpin(S3C2410_GPG2, 0); if (!s3c2410_gpio_getpin(key_info_matrix[column][3].irq_gpio_port)) { key_id = key_info_matrix[column][3].key_id; return key_id; } } return key_id; } /* 中断处理函数,其中irq为中断号 */ static irqreturn_t button_irq(int irq, void *dev_id, struct pt_regs *regs) { unsigned char ucKey = 0; disable_irqs(); /* 延迟50毫秒, 屏蔽按键毛刺 */ udelay(50000); ucKey = button_scan(irq); if ((ucKey >= 1) && (ucKey <= 16)) { /* 如果缓冲区已满, 则不添加 */ if (((key_buffer.head + 1) & (MAX_KEY_COUNT - 1)) != key_buffer.tail) { spin_lock_irq(&buffer_lock); key_buffer.buf[key_buffer.tail] = ucKey; key_buffer.jiffy[key_buffer.tail] = get_tick_count(); key_buffer.tail ++; key_buffer.tail &= (MAX_KEY_COUNT -1); spin_unlock_irq(&buffer_lock); } } init_gpio(); enable_irqs(); return IRQ_HANDLED;/* 2.6内核返回值一般是这个宏 */ }