144 lines
3.2 KiB
C
144 lines
3.2 KiB
C
/*
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* blinker device driver
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*
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* Author: Carlos Camargo
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* Created: Abril 29 2010
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/module.h> /* Needed by all modules */
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#include <linux/kernel.h> /* Needed for KERN_INFO */
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#include <linux/ioport.h>
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#include <linux/device.h>
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#include <linux/interrupt.h> /* We want an interrupt */
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#include <linux/irq.h> /* We want an interrupt */
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#include <linux/platform_device.h>
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#include <linux/fs.h>
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#include <asm/delay.h>
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#include <linux/delay.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <linux/gpio.h>
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#include <asm/mach-jz4740/gpio.h>
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#define LED_PORT JZ_GPIO_BASE_C
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#define LED_PIN JZ_GPIO_PORTC(17)
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#define SUCCESS 0
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#define DEVICE_NAME "blink" /* Dev name as it appears in /proc/devices */
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#define BUF_LEN 80 /* Max length of the message from the device */
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static int is_device_open = 0; /* Used to prevent multiple access to device */
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static int Major;
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static int device_open(struct inode *inode, struct file *file)
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{
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unsigned int i;
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printk( KERN_INFO "Open BLINKER\n" );
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if (is_device_open)
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return -EBUSY;
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is_device_open = 1;
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for( i=0; i<5; i++ ){
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gpio_set_value(LED_PIN, 1);
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mdelay(0x0040);
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gpio_set_value(LED_PIN, 0);
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mdelay(0x0040);
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}
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try_module_get(THIS_MODULE);
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return SUCCESS;
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}
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static ssize_t
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device_write(struct file *filp, const char *buff, size_t count, loff_t * off)
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{
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const char cmd = buff[0];
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if(cmd=='Q')
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{
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printk(KERN_INFO "Q...\n");
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gpio_set_value(LED_PIN, 1);
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}
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else
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if(cmd=='S'){
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printk(KERN_INFO "S...\n");
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gpio_set_value(LED_PIN, 0);
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}
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return 1;
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}
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static int device_release(struct inode *inode, struct file *file)
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{
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is_device_open = 0;
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module_put(THIS_MODULE);
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printk( KERN_INFO "Close BLINKER\n" );
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return 0;
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}
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struct file_operations fops = {
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.open = device_open,
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.write = device_write,
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.release = device_release,
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};
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static int __init blink_init(void)
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{
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printk(KERN_INFO "BLINK module is Up.\n");
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Major = register_chrdev(0, DEVICE_NAME, &fops);
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if (Major < 0) {
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printk(KERN_ALERT "Registering char device failed with %d\n", Major);
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return Major;
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}
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printk(KERN_ALERT "I was assigned major number %d. To talk to\n", Major);
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printk(KERN_ALERT "the driver, create a dev file with\n");
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printk(KERN_ALERT "'mknod /dev/%s c %d 0'.\n", DEVICE_NAME, Major);
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jz_gpio_set_function(LED_PIN, JZ_GPIO_FUNC_NONE);
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gpio_direction_output(LED_PIN,0);
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gpio_set_value(LED_PIN, 1);
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return 0;
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}
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static void __exit blink_exit(void)
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{
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gpio_set_value(LED_PIN, 0);
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unregister_chrdev(Major, DEVICE_NAME);
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printk( KERN_INFO "BLINK driver is down...\n" );
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}
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module_init(blink_init);
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module_exit(blink_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Carlos Camargo <cicamargoba@gmail.com>");
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MODULE_DESCRIPTION("BLINKER LED driver");
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MODULE_VERSION("1:0.1");
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