mirror of https://github.com/tLDP/LDP
95 lines
2.6 KiB
C
95 lines
2.6 KiB
C
/*
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* kbleds.c - Blink keyboard leds until the module is unloaded.
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*/
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#include <linux/module.h>
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/tty.h> /* For fg_console, MAX_NR_CONSOLES */
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#include <linux/kd.h> /* For KDSETLED */
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#include <linux/console_struct.h> /* For vc_cons */
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MODULE_DESCRIPTION("Example module illustrating the use of Keyboard LEDs.");
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MODULE_AUTHOR("Daniele Paolo Scarpazza");
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MODULE_LICENSE("GPL");
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struct timer_list my_timer;
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struct tty_driver *my_driver;
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char kbledstatus = 0;
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#define BLINK_DELAY HZ/5
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#define ALL_LEDS_ON 0x07
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#define RESTORE_LEDS 0xFF
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/*
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* Function my_timer_func blinks the keyboard LEDs periodically by invoking
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* command KDSETLED of ioctl() on the keyboard driver. To learn more on virtual
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* terminal ioctl operations, please see file:
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* /usr/src/linux/drivers/char/vt_ioctl.c, function vt_ioctl().
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*
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* The argument to KDSETLED is alternatively set to 7 (thus causing the led
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* mode to be set to LED_SHOW_IOCTL, and all the leds are lit) and to 0xFF
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* (any value above 7 switches back the led mode to LED_SHOW_FLAGS, thus
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* the LEDs reflect the actual keyboard status). To learn more on this,
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* please see file:
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* /usr/src/linux/drivers/char/keyboard.c, function setledstate().
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*
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*/
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static void my_timer_func(unsigned long ptr)
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{
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int *pstatus = (int *)ptr;
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if (*pstatus == ALL_LEDS_ON)
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*pstatus = RESTORE_LEDS;
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else
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*pstatus = ALL_LEDS_ON;
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(my_driver->ioctl) (vc_cons[fg_console].d->vc_tty, NULL, KDSETLED,
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*pstatus);
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my_timer.expires = jiffies + BLINK_DELAY;
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add_timer(&my_timer);
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}
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static int __init kbleds_init(void)
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{
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int i;
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printk(KERN_INFO "kbleds: loading\n");
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printk(KERN_INFO "kbleds: fgconsole is %x\n", fg_console);
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for (i = 0; i < MAX_NR_CONSOLES; i++) {
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if (!vc_cons[i].d)
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break;
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printk(KERN_INFO "poet_atkm: console[%i/%i] #%i, tty %lx\n", i,
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MAX_NR_CONSOLES, vc_cons[i].d->vc_num,
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(unsigned long)vc_cons[i].d->vc_tty);
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}
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printk(KERN_INFO "kbleds: finished scanning consoles\n");
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my_driver = vc_cons[fg_console].d->vc_tty->driver;
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printk(KERN_INFO "kbleds: tty driver magic %x\n", my_driver->magic);
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/*
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* Set up the LED blink timer the first time
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*/
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init_timer(&my_timer);
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my_timer.function = my_timer_func;
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my_timer.data = (unsigned long)&kbledstatus;
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my_timer.expires = jiffies + BLINK_DELAY;
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add_timer(&my_timer);
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return 0;
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}
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static void __exit kbleds_cleanup(void)
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{
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printk(KERN_INFO "kbleds: unloading...\n");
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del_timer(&my_timer);
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(my_driver->ioctl) (vc_cons[fg_console].d->vc_tty, NULL, KDSETLED,
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RESTORE_LEDS);
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}
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module_init(kbleds_init);
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module_exit(kbleds_cleanup);
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