#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/module.h>
  
  #include <linux/platform_device.h>
  #include <linux/err.h>
  #include <linux/leds.h>
  
  #include <linux/io.h>
  #include <linux/dmi.h>
  
  #include <linux/i8042.h>
  
  #define CLEVO_MAIL_LED_OFF		0x0084
  #define CLEVO_MAIL_LED_BLINK_1HZ	0x008A
  #define CLEVO_MAIL_LED_BLINK_0_5HZ	0x0083
  
  MODULE_AUTHOR("Márton Németh <nm127@freemail.hu>");
  MODULE_DESCRIPTION("Clevo mail LED driver");
  MODULE_LICENSE("GPL");
  
  static bool nodetect;
  module_param_named(nodetect, nodetect, bool, 0);
  MODULE_PARM_DESC(nodetect, "Skip DMI hardware detection");
  
  static struct platform_device *pdev;
  
  static int __init clevo_mail_led_dmi_callback(const struct dmi_system_id *id)
  {
  	pr_info("'%s' found
  ", id->ident);
  	return 1;
  }
  
  /*
   * struct clevo_mail_led_dmi_table - List of known good models
   *
   * Contains the known good models this driver is compatible with.
   * When adding a new model try to be as strict as possible. This
   * makes it possible to keep the false positives (the model is
   * detected as working, but in reality it is not) as low as
   * possible.
   */
  static struct dmi_system_id clevo_mail_led_dmi_table[] __initdata = {
  	{
  		.callback = clevo_mail_led_dmi_callback,
  		.ident = "Clevo D410J",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "VIA"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "K8N800"),
  			DMI_MATCH(DMI_PRODUCT_VERSION, "VT8204B")
  		}
  	},
  	{
  		.callback = clevo_mail_led_dmi_callback,
  		.ident = "Clevo M5x0N",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
  			DMI_MATCH(DMI_PRODUCT_NAME, "M5x0N")
  		}
  	},
  	{
  		.callback = clevo_mail_led_dmi_callback,
  		.ident = "Clevo M5x0V",
  		.matches = {
  			DMI_MATCH(DMI_BOARD_VENDOR, "CLEVO Co. "),
  			DMI_MATCH(DMI_BOARD_NAME, "M5X0V "),
  			DMI_MATCH(DMI_PRODUCT_VERSION, "VT6198")
  		}
  	},
  	{
  		.callback = clevo_mail_led_dmi_callback,
  		.ident = "Clevo D400P",
  		.matches = {
  			DMI_MATCH(DMI_BOARD_VENDOR, "Clevo"),
  			DMI_MATCH(DMI_BOARD_NAME, "D400P"),
  			DMI_MATCH(DMI_BOARD_VERSION, "Rev.A"),
  			DMI_MATCH(DMI_PRODUCT_VERSION, "0106")
  		}
  	},
  	{
  		.callback = clevo_mail_led_dmi_callback,
  		.ident = "Clevo D410V",
  		.matches = {
  			DMI_MATCH(DMI_BOARD_VENDOR, "Clevo, Co."),
  			DMI_MATCH(DMI_BOARD_NAME, "D400V/D470V"),
  			DMI_MATCH(DMI_BOARD_VERSION, "SS78B"),
  			DMI_MATCH(DMI_PRODUCT_VERSION, "Rev. A1")
  		}
  	},
  	{ }
  };
  MODULE_DEVICE_TABLE(dmi, clevo_mail_led_dmi_table);
  
  static void clevo_mail_led_set(struct led_classdev *led_cdev,
  				enum led_brightness value)
  {
  	i8042_lock_chip();
  
  	if (value == LED_OFF)
  		i8042_command(NULL, CLEVO_MAIL_LED_OFF);
  	else if (value <= LED_HALF)
  		i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
  	else
  		i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
  
  	i8042_unlock_chip();
  
  }
  
  static int clevo_mail_led_blink(struct led_classdev *led_cdev,
  				unsigned long *delay_on,
  				unsigned long *delay_off)
  {
  	int status = -EINVAL;
  
  	i8042_lock_chip();
  
  	if (*delay_on == 0 /* ms */ && *delay_off == 0 /* ms */) {
  		/* Special case: the leds subsystem requested us to
  		 * chose one user friendly blinking of the LED, and
  		 * start it. Let's blink the led slowly (0.5Hz).
  		 */
  		*delay_on = 1000; /* ms */
  		*delay_off = 1000; /* ms */
  		i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
  		status = 0;
  
  	} else if (*delay_on == 500 /* ms */ && *delay_off == 500 /* ms */) {
  		/* blink the led with 1Hz */
  		i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
  		status = 0;
  
  	} else if (*delay_on == 1000 /* ms */ && *delay_off == 1000 /* ms */) {
  		/* blink the led with 0.5Hz */
  		i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
  		status = 0;
  
  	} else {
  		pr_debug("clevo_mail_led_blink(..., %lu, %lu),"
  		       " returning -EINVAL (unsupported)
  ",
  		       *delay_on, *delay_off);
  	}
  
  	i8042_unlock_chip();
  
  	return status;
  }
  
  static struct led_classdev clevo_mail_led = {
  	.name			= "clevo::mail",
  	.brightness_set		= clevo_mail_led_set,
  	.blink_set		= clevo_mail_led_blink,
  	.flags			= LED_CORE_SUSPENDRESUME,
  };
  
  static int __init clevo_mail_led_probe(struct platform_device *pdev)
  {
  	return led_classdev_register(&pdev->dev, &clevo_mail_led);
  }
  
  static int clevo_mail_led_remove(struct platform_device *pdev)
  {
  	led_classdev_unregister(&clevo_mail_led);
  	return 0;
  }
  
  static struct platform_driver clevo_mail_led_driver = {
  	.remove		= clevo_mail_led_remove,
  	.driver		= {
  		.name		= KBUILD_MODNAME,
  	},
  };
  
  static int __init clevo_mail_led_init(void)
  {
  	int error = 0;
  	int count = 0;
  
  	/* Check with the help of DMI if we are running on supported hardware */
  	if (!nodetect) {
  		count = dmi_check_system(clevo_mail_led_dmi_table);
  	} else {
  		count = 1;
  		pr_err("Skipping DMI detection. "
  		       "If the driver works on your hardware please "
  		       "report model and the output of dmidecode in tracker "
  		       "at http://sourceforge.net/projects/clevo-mailled/
  ");
  	}
  
  	if (!count)
  		return -ENODEV;
  
  	pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
  	if (!IS_ERR(pdev)) {
  		error = platform_driver_probe(&clevo_mail_led_driver,
  					      clevo_mail_led_probe);
  		if (error) {
  			pr_err("Can't probe platform driver
  ");
  			platform_device_unregister(pdev);
  		}
  	} else
  		error = PTR_ERR(pdev);
  
  	return error;
  }
  
  static void __exit clevo_mail_led_exit(void)
  {
  	platform_device_unregister(pdev);
  	platform_driver_unregister(&clevo_mail_led_driver);
  
  	clevo_mail_led_set(NULL, LED_OFF);
  }
  
  module_init(clevo_mail_led_init);
  module_exit(clevo_mail_led_exit);