/*
   * LEDs driver for PCEngines ALIX.2 and ALIX.3
   *
   * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
   */
  
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/leds.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/string.h>

  #include <linux/pci.h>

  
  static int force = 0;
  module_param(force, bool, 0444);

  MODULE_PARM_DESC(force, "Assume system has ALIX.2/ALIX.3 style LEDs");

  #define MSR_LBAR_GPIO		0x5140000C
  #define CS5535_GPIO_SIZE	256
  
  static u32 gpio_base;
  
  static struct pci_device_id divil_pci[] = {
  	{ PCI_DEVICE(PCI_VENDOR_ID_NS,  PCI_DEVICE_ID_NS_CS5535_ISA) },
  	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
  	{ } /* NULL entry */
  };
  MODULE_DEVICE_TABLE(pci, divil_pci);

  struct alix_led {
  	struct led_classdev cdev;
  	unsigned short port;
  	unsigned int on_value;
  	unsigned int off_value;
  };
  
  static void alix_led_set(struct led_classdev *led_cdev,
  			 enum led_brightness brightness)
  {
  	struct alix_led *led_dev =
  		container_of(led_cdev, struct alix_led, cdev);
  
  	if (brightness)

  		outl(led_dev->on_value, gpio_base + led_dev->port);

  	else

  		outl(led_dev->off_value, gpio_base + led_dev->port);

  }
  
  static struct alix_led alix_leds[] = {
  	{
  		.cdev = {
  			.name = "alix:1",
  			.brightness_set = alix_led_set,
  		},

  		.port = 0x00,

  		.on_value = 1 << 22,
  		.off_value = 1 << 6,
  	},
  	{
  		.cdev = {
  			.name = "alix:2",
  			.brightness_set = alix_led_set,
  		},

  		.port = 0x80,

  		.on_value = 1 << 25,
  		.off_value = 1 << 9,
  	},
  	{
  		.cdev = {
  			.name = "alix:3",
  			.brightness_set = alix_led_set,
  		},

  		.port = 0x80,

  		.on_value = 1 << 27,
  		.off_value = 1 << 11,
  	},
  };

  static int __init alix_led_probe(struct platform_device *pdev)
  {
  	int i;
  	int ret;
  
  	for (i = 0; i < ARRAY_SIZE(alix_leds); i++) {

  		alix_leds[i].cdev.flags |= LED_CORE_SUSPENDRESUME;

  		ret = led_classdev_register(&pdev->dev, &alix_leds[i].cdev);
  		if (ret < 0)
  			goto fail;
  	}
  	return 0;
  
  fail:
  	while (--i >= 0)
  		led_classdev_unregister(&alix_leds[i].cdev);
  	return ret;
  }
  
  static int alix_led_remove(struct platform_device *pdev)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
  		led_classdev_unregister(&alix_leds[i].cdev);
  	return 0;
  }
  
  static struct platform_driver alix_led_driver = {
  	.remove = alix_led_remove,

  	.driver = {
  		.name = KBUILD_MODNAME,
  		.owner = THIS_MODULE,
  	},
  };

  static int __init alix_present(unsigned long bios_phys,
  				const char *alix_sig,
  				size_t alix_sig_len)

  {

  	const size_t bios_len = 0x00010000;

  	const char *bios_virt;
  	const char *scan_end;
  	const char *p;

  	char name[64];

  
  	if (force) {
  		printk(KERN_NOTICE "%s: forced to skip BIOS test, "
  		       "assume system has ALIX.2 style LEDs
  ",
  		       KBUILD_MODNAME);

  		return 1;

  	}
  
  	bios_virt = phys_to_virt(bios_phys);
  	scan_end = bios_virt + bios_len - (alix_sig_len + 2);
  	for (p = bios_virt; p < scan_end; p++) {
  		const char *tail;

  		char *a;

  		if (memcmp(p, alix_sig, alix_sig_len) != 0)

  			continue;

  
  		memcpy(name, p, sizeof(name));
  
  		/* remove the first \0 character from string */
  		a = strchr(name, '\0');
  		if (a)
  			*a = ' ';
  
  		/* cut the string at a newline */
  		a = strchr(name, '\r');
  		if (a)
  			*a = '\0';

  
  		tail = p + alix_sig_len;

  		if ((tail[0] == '2' || tail[0] == '3')) {

  			printk(KERN_INFO
  			       "%s: system is recognized as \"%s\"
  ",

  			       KBUILD_MODNAME, name);
  			return 1;

  		}
  	}

  	return 0;

  }
  
  static struct platform_device *pdev;

  static int __init alix_pci_led_init(void)

  {

  	u32 low, hi;

  	if (pci_dev_present(divil_pci) == 0) {
  		printk(KERN_WARNING KBUILD_MODNAME": DIVIL not found
  ");
  		return -ENODEV;

  	}

  	/* Grab the GPIO I/O range */
  	rdmsr(MSR_LBAR_GPIO, low, hi);
  
  	/* Check the mask and whether GPIO is enabled (sanity check) */
  	if (hi != 0x0000f001) {
  		printk(KERN_WARNING KBUILD_MODNAME": GPIO not enabled
  ");
  		return -ENODEV;
  	}
  
  	/* Mask off the IO base address */
  	gpio_base = low & 0x0000ff00;
  
  	if (!request_region(gpio_base, CS5535_GPIO_SIZE, KBUILD_MODNAME)) {
  		printk(KERN_ERR KBUILD_MODNAME": can't allocate I/O for GPIO
  ");
  		return -ENODEV;
  	}
  
  	/* Set GPIO function to output */
  	outl(1 << 6, gpio_base + 0x04);
  	outl(1 << 9, gpio_base + 0x84);
  	outl(1 << 11, gpio_base + 0x84);
  
  	return 0;
  }
  
  static int __init alix_led_init(void)
  {
  	int ret = -ENODEV;
  	const char tinybios_sig[] = "PC Engines ALIX.";
  	const char coreboot_sig[] = "PC Engines\0ALIX.";
  
  	if (alix_present(0xf0000, tinybios_sig, sizeof(tinybios_sig) - 1) ||
  	    alix_present(0x500, coreboot_sig, sizeof(coreboot_sig) - 1))
  		ret = alix_pci_led_init();
  
  	if (ret < 0)
  		return ret;

  	pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
  	if (!IS_ERR(pdev)) {
  		ret = platform_driver_probe(&alix_led_driver, alix_led_probe);
  		if (ret)
  			platform_device_unregister(pdev);
  	} else
  		ret = PTR_ERR(pdev);

  	return ret;
  }
  
  static void __exit alix_led_exit(void)
  {
  	platform_device_unregister(pdev);
  	platform_driver_unregister(&alix_led_driver);

  	release_region(gpio_base, CS5535_GPIO_SIZE);

  }
  
  module_init(alix_led_init);
  module_exit(alix_led_exit);
  
  MODULE_AUTHOR("Constantin Baranov <const@mimas.ru>");
  MODULE_DESCRIPTION("PCEngines ALIX.2 and ALIX.3 LED driver");
  MODULE_LICENSE("GPL");