// SPDX-License-Identifier: GPL-2.0-only

  /*

   * Xilinx gpio driver for xps/axi_gpio IP.

   *

   * Copyright 2008 - 2013 Xilinx, Inc.

   */

  #include <linux/bitops.h>

  #include <linux/init.h>
  #include <linux/errno.h>

  #include <linux/module.h>

  #include <linux/of_device.h>
  #include <linux/of_platform.h>

  #include <linux/io.h>

  #include <linux/gpio/driver.h>

  #include <linux/slab.h>

  
  /* Register Offset Definitions */
  #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */
  #define XGPIO_TRI_OFFSET    (0x4)	/* I/O direction register  */

  #define XGPIO_CHANNEL_OFFSET	0x8
  
  /* Read/Write access to the GPIO registers */

  #if defined(CONFIG_ARCH_ZYNQ) || defined(CONFIG_X86)

  # define xgpio_readreg(offset)		readl(offset)
  # define xgpio_writereg(offset, val)	writel(val, offset)
  #else
  # define xgpio_readreg(offset)		__raw_readl(offset)
  # define xgpio_writereg(offset, val)	__raw_writel(val, offset)
  #endif

  
  /**
   * struct xgpio_instance - Stores information about GPIO device

   * @gc: GPIO chip
   * @regs: register block

   * @gpio_width: GPIO width for every channel

   * @gpio_state: GPIO state shadow register
   * @gpio_dir: GPIO direction shadow register
   * @gpio_lock: Lock used for synchronization

   */

  struct xgpio_instance {

  	struct gpio_chip gc;
  	void __iomem *regs;

  	unsigned int gpio_width[2];
  	u32 gpio_state[2];
  	u32 gpio_dir[2];
  	spinlock_t gpio_lock[2];

  };

  static inline int xgpio_index(struct xgpio_instance *chip, int gpio)
  {
  	if (gpio >= chip->gpio_width[0])
  		return 1;
  
  	return 0;
  }
  
  static inline int xgpio_regoffset(struct xgpio_instance *chip, int gpio)
  {
  	if (xgpio_index(chip, gpio))
  		return XGPIO_CHANNEL_OFFSET;
  
  	return 0;
  }
  
  static inline int xgpio_offset(struct xgpio_instance *chip, int gpio)
  {
  	if (xgpio_index(chip, gpio))
  		return gpio - chip->gpio_width[0];
  
  	return gpio;
  }

  
  /**
   * xgpio_get - Read the specified signal of the GPIO device.
   * @gc:     Pointer to gpio_chip device structure.
   * @gpio:   GPIO signal number.
   *

   * This function reads the specified signal of the GPIO device.
   *
   * Return:
   * 0 if direction of GPIO signals is set as input otherwise it
   * returns negative error value.

   */
  static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
  {

  	struct xgpio_instance *chip = gpiochip_get_data(gc);

  	u32 val;

  	val = xgpio_readreg(chip->regs + XGPIO_DATA_OFFSET +

  			    xgpio_regoffset(chip, gpio));
  
  	return !!(val & BIT(xgpio_offset(chip, gpio)));

  }
  
  /**
   * xgpio_set - Write the specified signal of the GPIO device.
   * @gc:     Pointer to gpio_chip device structure.
   * @gpio:   GPIO signal number.
   * @val:    Value to be written to specified signal.
   *
   * This function writes the specified value in to the specified signal of the
   * GPIO device.
   */
  static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
  {
  	unsigned long flags;

  	struct xgpio_instance *chip = gpiochip_get_data(gc);

  	int index =  xgpio_index(chip, gpio);
  	int offset =  xgpio_offset(chip, gpio);

  	spin_lock_irqsave(&chip->gpio_lock[index], flags);

  
  	/* Write to GPIO signal and set its direction to output */
  	if (val)

  		chip->gpio_state[index] |= BIT(offset);

  	else

  		chip->gpio_state[index] &= ~BIT(offset);

  	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +

  		       xgpio_regoffset(chip, gpio), chip->gpio_state[index]);

  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);

  }
  
  /**

   * xgpio_set_multiple - Write the specified signals of the GPIO device.
   * @gc:     Pointer to gpio_chip device structure.
   * @mask:   Mask of the GPIOS to modify.
   * @bits:   Value to be wrote on each GPIO
   *
   * This function writes the specified values into the specified signals of the
   * GPIO devices.
   */
  static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
  			       unsigned long *bits)
  {
  	unsigned long flags;

  	struct xgpio_instance *chip = gpiochip_get_data(gc);
  	int index = xgpio_index(chip, 0);
  	int offset, i;
  
  	spin_lock_irqsave(&chip->gpio_lock[index], flags);
  
  	/* Write to GPIO signals */
  	for (i = 0; i < gc->ngpio; i++) {
  		if (*mask == 0)
  			break;

  		/* Once finished with an index write it out to the register */

  		if (index !=  xgpio_index(chip, i)) {

  			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +

  				       index * XGPIO_CHANNEL_OFFSET,

  				       chip->gpio_state[index]);
  			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
  			index =  xgpio_index(chip, i);
  			spin_lock_irqsave(&chip->gpio_lock[index], flags);
  		}
  		if (__test_and_clear_bit(i, mask)) {
  			offset =  xgpio_offset(chip, i);
  			if (test_bit(i, bits))
  				chip->gpio_state[index] |= BIT(offset);
  			else
  				chip->gpio_state[index] &= ~BIT(offset);
  		}
  	}

  	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +

  		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);

  
  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
  }
  
  /**

   * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
   * @gc:     Pointer to gpio_chip device structure.
   * @gpio:   GPIO signal number.
   *

   * Return:
   * 0 - if direction of GPIO signals is set as input
   * otherwise it returns negative error value.

   */
  static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
  {
  	unsigned long flags;

  	struct xgpio_instance *chip = gpiochip_get_data(gc);

  	int index =  xgpio_index(chip, gpio);
  	int offset =  xgpio_offset(chip, gpio);

  	spin_lock_irqsave(&chip->gpio_lock[index], flags);

  
  	/* Set the GPIO bit in shadow register and set direction as input */

  	chip->gpio_dir[index] |= BIT(offset);

  	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET +

  		       xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);

  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);

  
  	return 0;
  }
  
  /**
   * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
   * @gc:     Pointer to gpio_chip device structure.
   * @gpio:   GPIO signal number.
   * @val:    Value to be written to specified signal.
   *

   * This function sets the direction of specified GPIO signal as output.
   *
   * Return:
   * If all GPIO signals of GPIO chip is configured as input then it returns

   * error otherwise it returns 0.
   */
  static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  {
  	unsigned long flags;

  	struct xgpio_instance *chip = gpiochip_get_data(gc);

  	int index =  xgpio_index(chip, gpio);
  	int offset =  xgpio_offset(chip, gpio);

  	spin_lock_irqsave(&chip->gpio_lock[index], flags);

  
  	/* Write state of GPIO signal */
  	if (val)

  		chip->gpio_state[index] |= BIT(offset);

  	else

  		chip->gpio_state[index] &= ~BIT(offset);

  	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +

  			xgpio_regoffset(chip, gpio), chip->gpio_state[index]);

  
  	/* Clear the GPIO bit in shadow register and set direction as output */

  	chip->gpio_dir[index] &= ~BIT(offset);

  	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET +

  			xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);

  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);

  
  	return 0;
  }
  
  /**
   * xgpio_save_regs - Set initial values of GPIO pins

   * @chip: Pointer to GPIO instance

   */

  static void xgpio_save_regs(struct xgpio_instance *chip)

  {

  	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,	chip->gpio_state[0]);
  	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);

  
  	if (!chip->gpio_width[1])
  		return;

  	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET,

  		       chip->gpio_state[1]);

  	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET,

  		       chip->gpio_dir[1]);

  }
  
  /**
   * xgpio_of_probe - Probe method for the GPIO device.

   * @pdev: pointer to the platform device

   *

   * Return:
   * It returns 0, if the driver is bound to the GPIO device, or
   * a negative value if there is an error.

   */

  static int xgpio_probe(struct platform_device *pdev)

  {
  	struct xgpio_instance *chip;

  	int status = 0;

  	struct device_node *np = pdev->dev.of_node;

  	u32 is_dual;

  	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
  	if (!chip)

  		return -ENOMEM;

  	platform_set_drvdata(pdev, chip);

  	/* Update GPIO state shadow register with default value */

  	of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]);

  
  	/* Update GPIO direction shadow register with default value */

  	if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0]))
  		chip->gpio_dir[0] = 0xFFFFFFFF;

  	/*
  	 * Check device node and parent device node for device width
  	 * and assume default width of 32
  	 */

  	if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0]))
  		chip->gpio_width[0] = 32;
  
  	spin_lock_init(&chip->gpio_lock[0]);
  
  	if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
  		is_dual = 0;

  	if (is_dual) {
  		/* Update GPIO state shadow register with default value */
  		of_property_read_u32(np, "xlnx,dout-default-2",
  				     &chip->gpio_state[1]);
  
  		/* Update GPIO direction shadow register with default value */
  		if (of_property_read_u32(np, "xlnx,tri-default-2",
  					 &chip->gpio_dir[1]))
  			chip->gpio_dir[1] = 0xFFFFFFFF;

  		/*
  		 * Check device node and parent device node for device width
  		 * and assume default width of 32
  		 */
  		if (of_property_read_u32(np, "xlnx,gpio2-width",
  					 &chip->gpio_width[1]))
  			chip->gpio_width[1] = 32;
  
  		spin_lock_init(&chip->gpio_lock[1]);
  	}

  	chip->gc.base = -1;
  	chip->gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
  	chip->gc.parent = &pdev->dev;
  	chip->gc.direction_input = xgpio_dir_in;
  	chip->gc.direction_output = xgpio_dir_out;
  	chip->gc.get = xgpio_get;
  	chip->gc.set = xgpio_set;
  	chip->gc.set_multiple = xgpio_set_multiple;
  
  	chip->gc.label = dev_name(&pdev->dev);
  
  	chip->regs = devm_platform_ioremap_resource(pdev, 0);
  	if (IS_ERR(chip->regs)) {
  		dev_err(&pdev->dev, "failed to ioremap memory resource
  ");
  		return PTR_ERR(chip->regs);
  	}

  	xgpio_save_regs(chip);

  	status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);

  	if (status) {

  		dev_err(&pdev->dev, "failed to add GPIO chip
  ");

  		return status;
  	}

  	return 0;
  }

  static const struct of_device_id xgpio_of_match[] = {

  	{ .compatible = "xlnx,xps-gpio-1.00.a", },
  	{ /* end of list */ },
  };

  MODULE_DEVICE_TABLE(of, xgpio_of_match);

  static struct platform_driver xgpio_plat_driver = {
  	.probe		= xgpio_probe,

  	.driver		= {
  			.name = "gpio-xilinx",
  			.of_match_table	= xgpio_of_match,
  	},
  };

  static int __init xgpio_init(void)
  {
  	return platform_driver_register(&xgpio_plat_driver);

  }

  subsys_initcall(xgpio_init);

  
  static void __exit xgpio_exit(void)
  {
  	platform_driver_unregister(&xgpio_plat_driver);
  }
  module_exit(xgpio_exit);

  
  MODULE_AUTHOR("Xilinx, Inc.");
  MODULE_DESCRIPTION("Xilinx GPIO driver");
  MODULE_LICENSE("GPL");