这次进行buttons的移植。
环境：Ubuntu
移植内核版本：linux-3.9.6
参考友善提供的linux-3.0.8
一、主要代码
在drivers/char目录下新建smdkv210_buttons.c
代码：
/*
* linux/drivers/char/smdkv210_buttons.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
#include <mach/map.h>
#include <mach/gpio.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>
#define DEVICE_NAME "buttons"
struct button_desc {
int gpio;
int number;
char *name;
struct timer_list timer;
};
static struct button_desc buttons[] = {
{ S5PV210_GPH2(0), 0, "KEY0" },
{ S5PV210_GPH2(1), 1, "KEY1" },
{ S5PV210_GPH2(2), 2, "KEY2" },
{ S5PV210_GPH2(3), 3, "KEY3" },
{ S5PV210_GPH3(0), 4, "KEY4" },
{ S5PV210_GPH3(1), 5, "KEY5" },
{ S5PV210_GPH3(2), 6, "KEY6" },
{ S5PV210_GPH3(3), 7, "KEY7" },
};
static volatile char key_values[] = {
'0', '0', '0', '0', '0', '0', '0', '0'
};
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
static volatile int ev_press = 0;
static void smdkv210_buttons_timer(unsigned long _data)
{
struct button_desc *bdata = (struct button_desc *)_data;
int down;
int number;
unsigned tmp;
tmp = gpio_get_value(bdata->gpio);
/* active low */
down = !tmp;
printk("KEY %d: %08x\n", bdata->number, down);
number = bdata->number;
if (down != (key_values[number] & 1)) {
key_values[number] = '0' + down;
ev_press = 1;
wake_up_interruptible(&button_waitq);
}
}
static irqreturn_t button_interrupt(int irq, void *dev_id)
{
struct button_desc *bdata = (struct button_desc *)dev_id;
mod_timer(&bdata->timer, jiffies + msecs_to_jiffies(40));
return IRQ_HANDLED;
}
static int smdkv210_buttons_open(struct inode *inode, struct file *file)
{
int irq;
int i;
int err = 0;
for (i = 0; i < ARRAY_SIZE(buttons); i++) {
if (!buttons[i].gpio)
continue;
setup_timer(&buttons[i].timer, smdkv210_buttons_timer,
(unsigned long)&buttons[i]);
irq = gpio_to_irq(buttons[i].gpio);
err = request_irq(irq, button_interrupt, IRQ_TYPE_EDGE_BOTH,
buttons[i].name, (void *)&buttons[i]);
if (err)
break;
}
if (err) {
i--;
for (; i >= 0; i--) {
if (!buttons[i].gpio)
continue;
irq = gpio_to_irq(buttons[i].gpio);
disable_irq(irq);
free_irq(irq, (void *)&buttons[i]);
del_timer_sync(&buttons[i].timer);
}
return -EBUSY;
}
ev_press = 1;
return 0;
}
static int smdkv210_buttons_close(struct inode *inode, struct file *file)
{
int irq, i;
for (i = 0; i < ARRAY_SIZE(buttons); i++) {
if (!buttons[i].gpio)
continue;
irq = gpio_to_irq(buttons[i].gpio);
free_irq(irq, (void *)&buttons[i]);
del_timer_sync(&buttons[i].timer);
}
return 0;
}
static int smdkv210_buttons_read(struct file *filp, char __user *buff,
size_t count, loff_t *offp)
{
unsigned long err;
if (!ev_press) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
else
wait_event_interruptible(button_waitq, ev_press);
}
ev_press = 0;
err = copy_to_user((void *)buff, (const void *)(&key_values),
min(sizeof(key_values), count));
return err ? -EFAULT : min(sizeof(key_values), count);
}
static unsigned int smdkv210_buttons_poll( struct file *file,
struct poll_table_struct *wait)
{
unsigned int mask = 0;
poll_wait(file, &button_waitq, wait);
if (ev_press)
mask |= POLLIN | POLLRDNORM;
return mask;
}
static struct file_operations dev_fops = {
.owner = THIS_MODULE,
.open = smdkv210_buttons_open,
.release = smdkv210_buttons_close,
.read = smdkv210_buttons_read,
.poll = smdkv210_buttons_poll,
};
static struct miscdevice misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DEVICE_NAME,
.fops = &dev_fops,
};
static int __init button_dev_init(void)
{
int ret;
ret = misc_register(&misc);
printk(DEVICE_NAME"\tinitialized\n");
return ret;
}
static void __exit button_dev_exit(void)
{
misc_deregister(&misc);
}
module_init(button_dev_init);
module_exit(button_dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");
修改该目录下的Kconfig
添加：
config SMDKV210_BUTTONS
tristate"Buttons driver for FriendlyARM Mini210 development boards"
depends onCPU_S5PV210 && !KEYBOARD_GPIO
default y if!KEYBOARD_GPIO
help
this is buttons driver for FriendlyARM TINY210development boards
Makefile添加：
obj-$(CONFIG_SMDKV210_BUTTONS) += smdkv210_buttons.o
测试程序：
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/ioctl.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<sys/select.h>
#include<sys/time.h>
#include<errno.h>
int main(void)
{
int buttons_fd;
char buttons[6]= {'0','0', '0', '0','0', '0'};
buttons_fd= open("/dev/buttons",0);
if(buttons_fd< 0) {
perror("opendevice buttons");
exit(1);
}
for (;;){
charcurrent_buttons[6];
intcount_of_changed_key;
inti;
if(read(buttons_fd,current_buttons,sizeofcurrent_buttons)！=sizeof current_buttons){
perror("readbuttons:");
exit(1);
}
for(i= 0,count_of_changed_key = 0; i< sizeofbuttons / sizeofbuttons[0];i++) {
if (buttons[i]!= current_buttons[i]){
buttons[i]=current_buttons[i];
printf("%skey%d is %s",count_of_changed_key?", ": "", i+1,buttons[i] =='0'? "up" : "down");
count_of_changed_key++;
}
}
if(count_of_changed_key){
printf("\n");
}
}
close(buttons_fd);
return0;
}