/*
   * dell_led.c - Dell LED Driver
   *
   * Copyright (C) 2010 Dell Inc.
   * Louis Davis <louis_davis@dell.com>
   * Jim Dailey <jim_dailey@dell.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/acpi.h>
  #include <linux/leds.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/dmi.h>
  #include <linux/dell-led.h>
  
  MODULE_AUTHOR("Louis Davis/Jim Dailey");
  MODULE_DESCRIPTION("Dell LED Control Driver");
  MODULE_LICENSE("GPL");
  
  #define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396"
  #define DELL_APP_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"
  MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID);
  
  /* Error Result Codes: */
  #define INVALID_DEVICE_ID	250
  #define INVALID_PARAMETER	251
  #define INVALID_BUFFER		252
  #define INTERFACE_ERROR		253
  #define UNSUPPORTED_COMMAND	254
  #define UNSPECIFIED_ERROR	255
  
  /* Device ID */
  #define DEVICE_ID_PANEL_BACK	1
  
  /* LED Commands */
  #define CMD_LED_ON	16
  #define CMD_LED_OFF	17
  #define CMD_LED_BLINK	18
  
  struct app_wmi_args {
  	u16 class;
  	u16 selector;
  	u32 arg1;
  	u32 arg2;
  	u32 arg3;
  	u32 arg4;
  	u32 res1;
  	u32 res2;
  	u32 res3;
  	u32 res4;
  	char dummy[92];
  };
  
  #define GLOBAL_MIC_MUTE_ENABLE	0x364
  #define GLOBAL_MIC_MUTE_DISABLE	0x365
  
  struct dell_bios_data_token {
  	u16 tokenid;
  	u16 location;
  	u16 value;
  };
  
  struct __attribute__ ((__packed__)) dell_bios_calling_interface {
  	struct	dmi_header header;
  	u16	cmd_io_addr;
  	u8	cmd_io_code;
  	u32	supported_cmds;
  	struct	dell_bios_data_token damap[];
  };
  
  static struct dell_bios_data_token dell_mic_tokens[2];
  
  static int dell_wmi_perform_query(struct app_wmi_args *args)
  {
  	struct app_wmi_args *bios_return;
  	union acpi_object *obj;
  	struct acpi_buffer input;
  	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  	acpi_status status;
  	u32 rc = -EINVAL;
  
  	input.length = 128;
  	input.pointer = args;
  
  	status = wmi_evaluate_method(DELL_APP_GUID, 0, 1, &input, &output);
  	if (!ACPI_SUCCESS(status))
  		goto err_out0;
  
  	obj = output.pointer;
  	if (!obj)
  		goto err_out0;
  
  	if (obj->type != ACPI_TYPE_BUFFER)
  		goto err_out1;
  
  	bios_return = (struct app_wmi_args *)obj->buffer.pointer;
  	rc = bios_return->res1;
  	if (rc)
  		goto err_out1;
  
  	memcpy(args, bios_return, sizeof(struct app_wmi_args));
  	rc = 0;
  
   err_out1:
  	kfree(obj);
   err_out0:
  	return rc;
  }
  
  static void __init find_micmute_tokens(const struct dmi_header *dm, void *dummy)
  {
  	struct dell_bios_calling_interface *calling_interface;
  	struct dell_bios_data_token *token;
  	int token_size = sizeof(struct dell_bios_data_token);
  	int i = 0;
  
  	if (dm->type == 0xda && dm->length > 17) {
  		calling_interface = container_of(dm,
  				struct dell_bios_calling_interface, header);
  
  		token = &calling_interface->damap[i];
  		while (token->tokenid != 0xffff) {
  			if (token->tokenid == GLOBAL_MIC_MUTE_DISABLE)
  				memcpy(&dell_mic_tokens[0], token, token_size);
  			else if (token->tokenid == GLOBAL_MIC_MUTE_ENABLE)
  				memcpy(&dell_mic_tokens[1], token, token_size);
  
  			i++;
  			token = &calling_interface->damap[i];
  		}
  	}
  }
  
  static int dell_micmute_led_set(int state)
  {
  	struct app_wmi_args args;
  	struct dell_bios_data_token *token;
  
  	if (!wmi_has_guid(DELL_APP_GUID))
  		return -ENODEV;
  
  	if (state == 0 || state == 1)
  		token = &dell_mic_tokens[state];
  	else
  		return -EINVAL;
  
  	memset(&args, 0, sizeof(struct app_wmi_args));
  
  	args.class = 1;
  	args.arg1 = token->location;
  	args.arg2 = token->value;
  
  	dell_wmi_perform_query(&args);
  
  	return state;
  }
  
  int dell_app_wmi_led_set(int whichled, int on)
  {
  	int state = 0;
  
  	switch (whichled) {
  	case DELL_LED_MICMUTE:
  		state = dell_micmute_led_set(on);
  		break;
  	default:
  		pr_warn("led type %x is not supported
  ", whichled);
  		break;
  	}
  
  	return state;
  }
  EXPORT_SYMBOL_GPL(dell_app_wmi_led_set);
  
  static int __init dell_micmute_led_init(void)
  {
  	memset(dell_mic_tokens, 0, sizeof(struct dell_bios_data_token) * 2);
  	dmi_walk(find_micmute_tokens, NULL);
  
  	return 0;
  }
  
  struct bios_args {
  	unsigned char length;
  	unsigned char result_code;
  	unsigned char device_id;
  	unsigned char command;
  	unsigned char on_time;
  	unsigned char off_time;
  };
  
  static int dell_led_perform_fn(u8 length,
  		u8 result_code,
  		u8 device_id,
  		u8 command,
  		u8 on_time,
  		u8 off_time)
  {
  	struct bios_args *bios_return;
  	u8 return_code;
  	union acpi_object *obj;
  	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  	struct acpi_buffer input;
  	acpi_status status;
  
  	struct bios_args args;
  	args.length = length;
  	args.result_code = result_code;
  	args.device_id = device_id;
  	args.command = command;
  	args.on_time = on_time;
  	args.off_time = off_time;
  
  	input.length = sizeof(struct bios_args);
  	input.pointer = &args;
  
  	status = wmi_evaluate_method(DELL_LED_BIOS_GUID,
  		1,
  		1,
  		&input,
  		&output);
  
  	if (ACPI_FAILURE(status))
  		return status;
  
  	obj = output.pointer;
  
  	if (!obj)
  		return -EINVAL;
  	else if (obj->type != ACPI_TYPE_BUFFER) {
  		kfree(obj);
  		return -EINVAL;
  	}
  
  	bios_return = ((struct bios_args *)obj->buffer.pointer);
  	return_code = bios_return->result_code;
  
  	kfree(obj);
  
  	return return_code;
  }
  
  static int led_on(void)
  {
  	return dell_led_perform_fn(3,	/* Length of command */
  		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
  		DEVICE_ID_PANEL_BACK,	/* Device ID */
  		CMD_LED_ON,		/* Command */
  		0,			/* not used */
  		0);			/* not used */
  }
  
  static int led_off(void)
  {
  	return dell_led_perform_fn(3,	/* Length of command */
  		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
  		DEVICE_ID_PANEL_BACK,	/* Device ID */
  		CMD_LED_OFF,		/* Command */
  		0,			/* not used */
  		0);			/* not used */
  }
  
  static int led_blink(unsigned char on_eighths,
  		unsigned char off_eighths)
  {
  	return dell_led_perform_fn(5,	/* Length of command */
  		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
  		DEVICE_ID_PANEL_BACK,	/* Device ID */
  		CMD_LED_BLINK,		/* Command */
  		on_eighths,		/* blink on in eigths of a second */
  		off_eighths);		/* blink off in eights of a second */
  }
  
  static void dell_led_set(struct led_classdev *led_cdev,
  		enum led_brightness value)
  {
  	if (value == LED_OFF)
  		led_off();
  	else
  		led_on();
  }
  
  static int dell_led_blink(struct led_classdev *led_cdev,
  		unsigned long *delay_on,
  		unsigned long *delay_off)
  {
  	unsigned long on_eighths;
  	unsigned long off_eighths;
  
  	/* The Dell LED delay is based on 125ms intervals.
  	   Need to round up to next interval. */
  
  	on_eighths = (*delay_on + 124) / 125;
  	if (0 == on_eighths)
  		on_eighths = 1;
  	if (on_eighths > 255)
  		on_eighths = 255;
  	*delay_on = on_eighths * 125;
  
  	off_eighths = (*delay_off + 124) / 125;
  	if (0 == off_eighths)
  		off_eighths = 1;
  	if (off_eighths > 255)
  		off_eighths = 255;
  	*delay_off = off_eighths * 125;
  
  	led_blink(on_eighths, off_eighths);
  
  	return 0;
  }
  
  static struct led_classdev dell_led = {
  	.name		= "dell::lid",
  	.brightness	= LED_OFF,
  	.max_brightness = 1,
  	.brightness_set = dell_led_set,
  	.blink_set	= dell_led_blink,
  	.flags		= LED_CORE_SUSPENDRESUME,
  };
  
  static int __init dell_led_init(void)
  {
  	int error = 0;
  
  	if (!wmi_has_guid(DELL_LED_BIOS_GUID) && !wmi_has_guid(DELL_APP_GUID))
  		return -ENODEV;
  
  	if (wmi_has_guid(DELL_APP_GUID))
  		error = dell_micmute_led_init();
  
  	if (wmi_has_guid(DELL_LED_BIOS_GUID)) {
  		error = led_off();
  		if (error != 0)
  			return -ENODEV;
  
  		error = led_classdev_register(NULL, &dell_led);
  	}
  
  	return error;
  }
  
  static void __exit dell_led_exit(void)
  {
  	int error = 0;
  
  	if (wmi_has_guid(DELL_LED_BIOS_GUID)) {
  		error = led_off();
  		if (error == 0)
  			led_classdev_unregister(&dell_led);
  	}
  }
  
  module_init(dell_led_init);
  module_exit(dell_led_exit);