// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   *  Driver for TANBAC TB0219 base board.
   *

   *  Copyright (C) 2005  Yoichi Yuasa <yuasa@linux-mips.org>

   */

  #include <linux/platform_device.h>

  #include <linux/fs.h>
  #include <linux/init.h>
  #include <linux/module.h>

  #include <linux/uaccess.h>

  
  #include <asm/io.h>
  #include <asm/reboot.h>

  #include <asm/vr41xx/giu.h>
  #include <asm/vr41xx/tb0219.h>

  MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");

  MODULE_DESCRIPTION("TANBAC TB0219 base board driver");
  MODULE_LICENSE("GPL");
  
  static int major;	/* default is dynamic major device number */
  module_param(major, int, 0);
  MODULE_PARM_DESC(major, "Major device number");
  
  static void (*old_machine_restart)(char *command);
  static void __iomem *tb0219_base;

  static DEFINE_SPINLOCK(tb0219_lock);

  
  #define tb0219_read(offset)		readw(tb0219_base + (offset))
  #define tb0219_write(offset, value)	writew((value), tb0219_base + (offset))
  
  #define TB0219_START	0x0a000000UL
  #define TB0219_SIZE	0x20UL
  
  #define TB0219_LED			0x00
  #define TB0219_GPIO_INPUT		0x02
  #define TB0219_GPIO_OUTPUT		0x04
  #define TB0219_DIP_SWITCH		0x06
  #define TB0219_MISC			0x08
  #define TB0219_RESET			0x0e
  #define TB0219_PCI_SLOT1_IRQ_STATUS	0x10
  #define TB0219_PCI_SLOT2_IRQ_STATUS	0x12
  #define TB0219_PCI_SLOT3_IRQ_STATUS	0x14
  
  typedef enum {
  	TYPE_LED,
  	TYPE_GPIO_OUTPUT,
  } tb0219_type_t;
  
  /*
   * Minor device number
   *	 0 = 7 segment LED
   *
   *	16 = GPIO IN 0
   *	17 = GPIO IN 1
   *	18 = GPIO IN 2
   *	19 = GPIO IN 3
   *	20 = GPIO IN 4
   *	21 = GPIO IN 5
   *	22 = GPIO IN 6
   *	23 = GPIO IN 7
   *
   *	32 = GPIO OUT 0
   *	33 = GPIO OUT 1
   *	34 = GPIO OUT 2
   *	35 = GPIO OUT 3
   *	36 = GPIO OUT 4
   *	37 = GPIO OUT 5
   *	38 = GPIO OUT 6
   *	39 = GPIO OUT 7
   *
   *	48 = DIP switch 1
   *	49 = DIP switch 2
   *	50 = DIP switch 3
   *	51 = DIP switch 4
   *	52 = DIP switch 5
   *	53 = DIP switch 6
   *	54 = DIP switch 7
   *	55 = DIP switch 8
   */
  
  static inline char get_led(void)
  {
  	return (char)tb0219_read(TB0219_LED);
  }
  
  static inline char get_gpio_input_pin(unsigned int pin)
  {
  	uint16_t values;
  
  	values = tb0219_read(TB0219_GPIO_INPUT);
  	if (values & (1 << pin))
  		return '1';
  
  	return '0';
  }
  
  static inline char get_gpio_output_pin(unsigned int pin)
  {
  	uint16_t values;
  
  	values = tb0219_read(TB0219_GPIO_OUTPUT);
  	if (values & (1 << pin))
  		return '1';
  
  	return '0';
  }
  
  static inline char get_dip_switch(unsigned int pin)
  {
  	uint16_t values;
  
  	values = tb0219_read(TB0219_DIP_SWITCH);
  	if (values & (1 << pin))
  		return '1';
  
  	return '0';
  }
  
  static inline int set_led(char command)
  {
  	tb0219_write(TB0219_LED, command);
  
  	return 0;
  }
  
  static inline int set_gpio_output_pin(unsigned int pin, char command)
  {
  	unsigned long flags;
  	uint16_t value;
  
  	if (command != '0' && command != '1')
  		return -EINVAL;
  
  	spin_lock_irqsave(&tb0219_lock, flags);
  	value = tb0219_read(TB0219_GPIO_OUTPUT);
  	if (command == '0')
  		value &= ~(1 << pin);
  	else
  		value |= 1 << pin;
  	tb0219_write(TB0219_GPIO_OUTPUT, value);
  	spin_unlock_irqrestore(&tb0219_lock, flags);
  
  	return 0;
  
  }
  
  static ssize_t tanbac_tb0219_read(struct file *file, char __user *buf, size_t len,
                                    loff_t *ppos)
  {
  	unsigned int minor;
  	char value;

  	minor = iminor(file_inode(file));

  	switch (minor) {
  	case 0:
  		value = get_led();
  		break;
  	case 16 ... 23:
  		value = get_gpio_input_pin(minor - 16);
  		break;
  	case 32 ... 39:
  		value = get_gpio_output_pin(minor - 32);
  		break;
  	case 48 ... 55:
  		value = get_dip_switch(minor - 48);
  		break;
  	default:
  		return -EBADF;
  	}
  
  	if (len <= 0)
  		return -EFAULT;
  
  	if (put_user(value, buf))
  		return -EFAULT;
  
  	return 1;
  }
  
  static ssize_t tanbac_tb0219_write(struct file *file, const char __user *data,
                                     size_t len, loff_t *ppos)
  {
  	unsigned int minor;
  	tb0219_type_t type;
  	size_t i;
  	int retval = 0;
  	char c;

  	minor = iminor(file_inode(file));

  	switch (minor) {
  	case 0:
  		type = TYPE_LED;
  		break;
  	case 32 ... 39:
  		type = TYPE_GPIO_OUTPUT;
  		break;
  	default:
  		return -EBADF;
  	}
  
  	for (i = 0; i < len; i++) {
  		if (get_user(c, data + i))
  			return -EFAULT;
  
  		switch (type) {
  		case TYPE_LED:
  			retval = set_led(c);
  			break;
  		case TYPE_GPIO_OUTPUT:
  			retval = set_gpio_output_pin(minor - 32, c);
  			break;
  		}
  
  		if (retval < 0)
  			break;
  	}
  
  	return i;
  }
  
  static int tanbac_tb0219_open(struct inode *inode, struct file *file)
  {
  	unsigned int minor;
  
  	minor = iminor(inode);
  	switch (minor) {
  	case 0:
  	case 16 ... 23:
  	case 32 ... 39:
  	case 48 ... 55:

  		return stream_open(inode, file);

  	default:
  		break;
  	}
  
  	return -EBADF;
  }
  
  static int tanbac_tb0219_release(struct inode *inode, struct file *file)
  {
  	return 0;
  }

  static const struct file_operations tb0219_fops = {

  	.owner		= THIS_MODULE,
  	.read		= tanbac_tb0219_read,
  	.write		= tanbac_tb0219_write,
  	.open		= tanbac_tb0219_open,
  	.release	= tanbac_tb0219_release,

  	.llseek		= no_llseek,

  };
  
  static void tb0219_restart(char *command)
  {
  	tb0219_write(TB0219_RESET, 0);
  }

  static void tb0219_pci_irq_init(void)
  {
  	/* PCI Slot 1 */
  	vr41xx_set_irq_trigger(TB0219_PCI_SLOT1_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
  	vr41xx_set_irq_level(TB0219_PCI_SLOT1_PIN, IRQ_LEVEL_LOW);
  
  	/* PCI Slot 2 */
  	vr41xx_set_irq_trigger(TB0219_PCI_SLOT2_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
  	vr41xx_set_irq_level(TB0219_PCI_SLOT2_PIN, IRQ_LEVEL_LOW);
  
  	/* PCI Slot 3 */
  	vr41xx_set_irq_trigger(TB0219_PCI_SLOT3_PIN, IRQ_TRIGGER_LEVEL, IRQ_SIGNAL_THROUGH);
  	vr41xx_set_irq_level(TB0219_PCI_SLOT3_PIN, IRQ_LEVEL_LOW);
  }

  static int tb0219_probe(struct platform_device *dev)

  {
  	int retval;
  
  	if (request_mem_region(TB0219_START, TB0219_SIZE, "TB0219") == NULL)
  		return -EBUSY;
  
  	tb0219_base = ioremap(TB0219_START, TB0219_SIZE);
  	if (tb0219_base == NULL) {
  		release_mem_region(TB0219_START, TB0219_SIZE);
  		return -ENOMEM;
  	}
  
  	retval = register_chrdev(major, "TB0219", &tb0219_fops);
  	if (retval < 0) {
  		iounmap(tb0219_base);
  		tb0219_base = NULL;
  		release_mem_region(TB0219_START, TB0219_SIZE);
  		return retval;
  	}

  	old_machine_restart = _machine_restart;
  	_machine_restart = tb0219_restart;

  	tb0219_pci_irq_init();

  	if (major == 0) {
  		major = retval;
  		printk(KERN_INFO "TB0219: major number %d
  ", major);
  	}
  
  	return 0;
  }

  static int tb0219_remove(struct platform_device *dev)

  {
  	_machine_restart = old_machine_restart;
  
  	iounmap(tb0219_base);
  	tb0219_base = NULL;
  
  	release_mem_region(TB0219_START, TB0219_SIZE);
  
  	return 0;
  }
  
  static struct platform_device *tb0219_platform_device;

  static struct platform_driver tb0219_device_driver = {

  	.probe		= tb0219_probe,

  	.remove		= tb0219_remove,

  	.driver		= {
  		.name	= "TB0219",
  	},

  };

  static int __init tanbac_tb0219_init(void)

  {
  	int retval;

  	tb0219_platform_device = platform_device_alloc("TB0219", -1);
  	if (!tb0219_platform_device)
  		return -ENOMEM;
  
  	retval = platform_device_add(tb0219_platform_device);
  	if (retval < 0) {
  		platform_device_put(tb0219_platform_device);
  		return retval;
  	}

  	retval = platform_driver_register(&tb0219_device_driver);

  	if (retval < 0)
  		platform_device_unregister(tb0219_platform_device);
  
  	return retval;
  }

  static void __exit tanbac_tb0219_exit(void)

  {

  	platform_driver_unregister(&tb0219_device_driver);

  	platform_device_unregister(tb0219_platform_device);
  }
  
  module_init(tanbac_tb0219_init);
  module_exit(tanbac_tb0219_exit);