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

  #include <linux/clk.h>
  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/ioport.h>
  #include <linux/kernel.h>
  #include <linux/platform_device.h>

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/export.h>

  #include <linux/of.h>

  #include <soc/at91/atmel_tcb.h>

  /*
   * This is a thin library to solve the problem of how to portably allocate
   * one of the TC blocks.  For simplicity, it doesn't currently expect to
   * share individual timers between different drivers.
   */
  
  #if defined(CONFIG_AVR32)
  /* AVR32 has these divide PBB */
  const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
  EXPORT_SYMBOL(atmel_tc_divisors);
  
  #elif defined(CONFIG_ARCH_AT91)
  /* AT91 has these divide MCK */
  const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
  EXPORT_SYMBOL(atmel_tc_divisors);
  
  #endif
  
  static DEFINE_SPINLOCK(tc_list_lock);
  static LIST_HEAD(tc_list);
  
  /**
   * atmel_tc_alloc - allocate a specified TC block
   * @block: which block to allocate

   *
   * Caller allocates a block.  If it is available, a pointer to a
   * pre-initialized struct atmel_tc is returned. The caller can access
   * the registers directly through the "regs" field.
   */

  struct atmel_tc *atmel_tc_alloc(unsigned block)

  {
  	struct atmel_tc		*tc;
  	struct platform_device	*pdev = NULL;

  
  	spin_lock(&tc_list_lock);
  	list_for_each_entry(tc, &tc_list, node) {

  		if (tc->allocated)
  			continue;
  
  		if ((tc->pdev->dev.of_node && tc->id == block) ||
  		    (tc->pdev->id == block)) {

  			pdev = tc->pdev;

  			tc->allocated = true;

  			break;
  		}
  	}

  	spin_unlock(&tc_list_lock);

  	return pdev ? tc : NULL;

  }
  EXPORT_SYMBOL_GPL(atmel_tc_alloc);
  
  /**
   * atmel_tc_free - release a specified TC block
   * @tc: Timer/counter block that was returned by atmel_tc_alloc()
   *

   * This reverses the effect of atmel_tc_alloc(), invalidating the resource
   * returned by that routine and making the TC available to other drivers.

   */
  void atmel_tc_free(struct atmel_tc *tc)
  {
  	spin_lock(&tc_list_lock);

  	if (tc->allocated)
  		tc->allocated = false;

  	spin_unlock(&tc_list_lock);
  }
  EXPORT_SYMBOL_GPL(atmel_tc_free);

  #if defined(CONFIG_OF)

  static struct atmel_tcb_config tcb_rm9200_config = {
  	.counter_width = 16,
  };
  
  static struct atmel_tcb_config tcb_sam9x5_config = {
  	.counter_width = 32,
  };

  static const struct of_device_id atmel_tcb_dt_ids[] = {
  	{
  		.compatible = "atmel,at91rm9200-tcb",

  		.data = &tcb_rm9200_config,
  	}, {
  		.compatible = "atmel,at91sam9x5-tcb",
  		.data = &tcb_sam9x5_config,

  	}, {
  		/* sentinel */
  	}
  };
  
  MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
  #endif

  static int __init tc_probe(struct platform_device *pdev)
  {
  	struct atmel_tc *tc;
  	struct clk	*clk;
  	int		irq;

  	struct resource	*r;

  	unsigned int	i;

  	if (of_get_child_count(pdev->dev.of_node))
  		return -EBUSY;

  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0)
  		return -EINVAL;

  	tc = devm_kzalloc(&pdev->dev, sizeof(struct atmel_tc), GFP_KERNEL);

  	if (!tc)
  		return -ENOMEM;
  
  	tc->pdev = pdev;

  	clk = devm_clk_get(&pdev->dev, "t0_clk");
  	if (IS_ERR(clk))
  		return PTR_ERR(clk);

  	tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk");
  	if (IS_ERR(tc->slow_clk))
  		return PTR_ERR(tc->slow_clk);

  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	tc->regs = devm_ioremap_resource(&pdev->dev, r);
  	if (IS_ERR(tc->regs))
  		return PTR_ERR(tc->regs);

  	/* Now take SoC information if available */
  	if (pdev->dev.of_node) {
  		const struct of_device_id *match;
  		match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node);
  		if (match)
  			tc->tcb_config = match->data;

  
  		tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb");
  	} else {
  		tc->id = pdev->id;

  	}

  	tc->clk[0] = clk;

  	tc->clk[1] = devm_clk_get(&pdev->dev, "t1_clk");

  	if (IS_ERR(tc->clk[1]))
  		tc->clk[1] = clk;

  	tc->clk[2] = devm_clk_get(&pdev->dev, "t2_clk");

  	if (IS_ERR(tc->clk[2]))
  		tc->clk[2] = clk;
  
  	tc->irq[0] = irq;
  	tc->irq[1] = platform_get_irq(pdev, 1);
  	if (tc->irq[1] < 0)
  		tc->irq[1] = irq;
  	tc->irq[2] = platform_get_irq(pdev, 2);
  	if (tc->irq[2] < 0)
  		tc->irq[2] = irq;

  	for (i = 0; i < 3; i++)
  		writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));

  	spin_lock(&tc_list_lock);
  	list_add_tail(&tc->node, &tc_list);
  	spin_unlock(&tc_list_lock);

  	platform_set_drvdata(pdev, tc);

  	return 0;
  }

  static void tc_shutdown(struct platform_device *pdev)
  {
  	int i;
  	struct atmel_tc *tc = platform_get_drvdata(pdev);
  
  	for (i = 0; i < 3; i++)
  		writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
  }

  static struct platform_driver tc_driver = {

  	.driver = {
  		.name	= "atmel_tcb",
  		.of_match_table	= of_match_ptr(atmel_tcb_dt_ids),
  	},

  	.shutdown = tc_shutdown,

  };
  
  static int __init tc_init(void)
  {
  	return platform_driver_probe(&tc_driver, tc_probe);
  }
  arch_initcall(tc_init);