/*
   * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
   * JZ4740 SoC ADC driver
   *
   * 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;  either version 2 of the License, or (at your
   * option) any later version.
   *
   * You should have received a copy of the GNU General Public License along
   * with this program; if not, write to the Free Software Foundation, Inc.,
   * 675 Mass Ave, Cambridge, MA 02139, USA.
   *
   * This driver synchronizes access to the JZ4740 ADC core between the
   * JZ4740 battery and hwmon drivers.
   */
  
  #include <linux/err.h>

  #include <linux/io.h>

  #include <linux/irq.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  
  #include <linux/clk.h>
  #include <linux/mfd/core.h>
  
  #include <linux/jz4740-adc.h>
  
  
  #define JZ_REG_ADC_ENABLE	0x00
  #define JZ_REG_ADC_CFG		0x04
  #define JZ_REG_ADC_CTRL		0x08
  #define JZ_REG_ADC_STATUS	0x0c
  
  #define JZ_REG_ADC_TOUCHSCREEN_BASE	0x10
  #define JZ_REG_ADC_BATTERY_BASE	0x1c
  #define JZ_REG_ADC_HWMON_BASE	0x20
  
  #define JZ_ADC_ENABLE_TOUCH	BIT(2)
  #define JZ_ADC_ENABLE_BATTERY	BIT(1)
  #define JZ_ADC_ENABLE_ADCIN	BIT(0)
  
  enum {
  	JZ_ADC_IRQ_ADCIN = 0,
  	JZ_ADC_IRQ_BATTERY,
  	JZ_ADC_IRQ_TOUCH,
  	JZ_ADC_IRQ_PENUP,
  	JZ_ADC_IRQ_PENDOWN,
  };
  
  struct jz4740_adc {
  	struct resource *mem;
  	void __iomem *base;
  
  	int irq;

  	struct irq_chip_generic *gc;

  
  	struct clk *clk;
  	atomic_t clk_ref;
  
  	spinlock_t lock;
  };

  static void jz4740_adc_irq_demux(struct irq_desc *desc)

  {

  	struct irq_chip_generic *gc = irq_desc_get_handler_data(desc);

  	uint8_t status;
  	unsigned int i;

  	status = readb(gc->reg_base + JZ_REG_ADC_STATUS);

  
  	for (i = 0; i < 5; ++i) {
  		if (status & BIT(i))

  			generic_handle_irq(gc->irq_base + i);

  	}
  }
  
  
  /* Refcounting for the ADC clock is done in here instead of in the clock
   * framework, because it is the only clock which is shared between multiple
   * devices and thus is the only clock which needs refcounting */
  static inline void jz4740_adc_clk_enable(struct jz4740_adc *adc)
  {
  	if (atomic_inc_return(&adc->clk_ref) == 1)

  		clk_prepare_enable(adc->clk);

  }
  
  static inline void jz4740_adc_clk_disable(struct jz4740_adc *adc)
  {
  	if (atomic_dec_return(&adc->clk_ref) == 0)

  		clk_disable_unprepare(adc->clk);

  }
  
  static inline void jz4740_adc_set_enabled(struct jz4740_adc *adc, int engine,
  	bool enabled)
  {
  	unsigned long flags;
  	uint8_t val;
  
  	spin_lock_irqsave(&adc->lock, flags);
  
  	val = readb(adc->base + JZ_REG_ADC_ENABLE);
  	if (enabled)
  		val |= BIT(engine);
  	else

  		val &= ~BIT(engine);

  	writeb(val, adc->base + JZ_REG_ADC_ENABLE);
  
  	spin_unlock_irqrestore(&adc->lock, flags);
  }
  
  static int jz4740_adc_cell_enable(struct platform_device *pdev)
  {
  	struct jz4740_adc *adc = dev_get_drvdata(pdev->dev.parent);
  
  	jz4740_adc_clk_enable(adc);
  	jz4740_adc_set_enabled(adc, pdev->id, true);
  
  	return 0;
  }
  
  static int jz4740_adc_cell_disable(struct platform_device *pdev)
  {
  	struct jz4740_adc *adc = dev_get_drvdata(pdev->dev.parent);
  
  	jz4740_adc_set_enabled(adc, pdev->id, false);
  	jz4740_adc_clk_disable(adc);
  
  	return 0;
  }
  
  int jz4740_adc_set_config(struct device *dev, uint32_t mask, uint32_t val)
  {
  	struct jz4740_adc *adc = dev_get_drvdata(dev);
  	unsigned long flags;
  	uint32_t cfg;
  
  	if (!adc)
  		return -ENODEV;
  
  	spin_lock_irqsave(&adc->lock, flags);
  
  	cfg = readl(adc->base + JZ_REG_ADC_CFG);
  
  	cfg &= ~mask;
  	cfg |= val;
  
  	writel(cfg, adc->base + JZ_REG_ADC_CFG);
  
  	spin_unlock_irqrestore(&adc->lock, flags);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(jz4740_adc_set_config);
  
  static struct resource jz4740_hwmon_resources[] = {
  	{
  		.start = JZ_ADC_IRQ_ADCIN,
  		.flags = IORESOURCE_IRQ,
  	},
  	{
  		.start	= JZ_REG_ADC_HWMON_BASE,
  		.end	= JZ_REG_ADC_HWMON_BASE + 3,
  		.flags	= IORESOURCE_MEM,
  	},
  };
  
  static struct resource jz4740_battery_resources[] = {
  	{
  		.start = JZ_ADC_IRQ_BATTERY,
  		.flags = IORESOURCE_IRQ,
  	},
  	{
  		.start	= JZ_REG_ADC_BATTERY_BASE,
  		.end	= JZ_REG_ADC_BATTERY_BASE + 3,
  		.flags	= IORESOURCE_MEM,
  	},
  };

  static const struct mfd_cell jz4740_adc_cells[] = {

  	{
  		.id = 0,
  		.name = "jz4740-hwmon",
  		.num_resources = ARRAY_SIZE(jz4740_hwmon_resources),
  		.resources = jz4740_hwmon_resources,

  
  		.enable = jz4740_adc_cell_enable,
  		.disable = jz4740_adc_cell_disable,
  	},
  	{
  		.id = 1,
  		.name = "jz4740-battery",
  		.num_resources = ARRAY_SIZE(jz4740_battery_resources),
  		.resources = jz4740_battery_resources,

  
  		.enable = jz4740_adc_cell_enable,
  		.disable = jz4740_adc_cell_disable,
  	},
  };

  static int jz4740_adc_probe(struct platform_device *pdev)

  {

  	struct irq_chip_generic *gc;
  	struct irq_chip_type *ct;

  	struct jz4740_adc *adc;
  	struct resource *mem_base;

  	int ret;
  	int irq_base;

  	adc = devm_kzalloc(&pdev->dev, sizeof(*adc), GFP_KERNEL);

  	if (!adc) {
  		dev_err(&pdev->dev, "Failed to allocate driver structure
  ");
  		return -ENOMEM;
  	}

  
  	adc->irq = platform_get_irq(pdev, 0);
  	if (adc->irq < 0) {
  		ret = adc->irq;
  		dev_err(&pdev->dev, "Failed to get platform irq: %d
  ", ret);

  		return ret;

  	}

  	irq_base = platform_get_irq(pdev, 1);
  	if (irq_base < 0) {

  		dev_err(&pdev->dev, "Failed to get irq base: %d
  ", irq_base);
  		return irq_base;

  	}
  
  	mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!mem_base) {

  		dev_err(&pdev->dev, "Failed to get platform mmio resource
  ");

  		return -ENOENT;

  	}
  
  	/* Only request the shared registers for the MFD driver */
  	adc->mem = request_mem_region(mem_base->start, JZ_REG_ADC_STATUS,
  					pdev->name);
  	if (!adc->mem) {

  		dev_err(&pdev->dev, "Failed to request mmio memory region
  ");

  		return -EBUSY;

  	}
  
  	adc->base = ioremap_nocache(adc->mem->start, resource_size(adc->mem));
  	if (!adc->base) {
  		ret = -EBUSY;
  		dev_err(&pdev->dev, "Failed to ioremap mmio memory
  ");
  		goto err_release_mem_region;
  	}
  
  	adc->clk = clk_get(&pdev->dev, "adc");
  	if (IS_ERR(adc->clk)) {
  		ret = PTR_ERR(adc->clk);
  		dev_err(&pdev->dev, "Failed to get clock: %d
  ", ret);
  		goto err_iounmap;
  	}
  
  	spin_lock_init(&adc->lock);
  	atomic_set(&adc->clk_ref, 0);
  
  	platform_set_drvdata(pdev, adc);

  	gc = irq_alloc_generic_chip("INTC", 1, irq_base, adc->base,
  		handle_level_irq);
  
  	ct = gc->chip_types;
  	ct->regs.mask = JZ_REG_ADC_CTRL;
  	ct->regs.ack = JZ_REG_ADC_STATUS;
  	ct->chip.irq_mask = irq_gc_mask_set_bit;
  	ct->chip.irq_unmask = irq_gc_mask_clr_bit;

  	ct->chip.irq_ack = irq_gc_ack_set_bit;

  	irq_setup_generic_chip(gc, IRQ_MSK(5), IRQ_GC_INIT_MASK_CACHE, 0,
  				IRQ_NOPROBE | IRQ_LEVEL);

  
  	adc->gc = gc;

  	irq_set_chained_handler_and_data(adc->irq, jz4740_adc_irq_demux, gc);

  
  	writeb(0x00, adc->base + JZ_REG_ADC_ENABLE);
  	writeb(0xff, adc->base + JZ_REG_ADC_CTRL);

  	ret = mfd_add_devices(&pdev->dev, 0, jz4740_adc_cells,

  			      ARRAY_SIZE(jz4740_adc_cells), mem_base,
  			      irq_base, NULL);

  	if (ret < 0)
  		goto err_clk_put;

  	return 0;
  
  err_clk_put:
  	clk_put(adc->clk);

  err_iounmap:

  	iounmap(adc->base);
  err_release_mem_region:
  	release_mem_region(adc->mem->start, resource_size(adc->mem));

  	return ret;
  }

  static int jz4740_adc_remove(struct platform_device *pdev)

  {
  	struct jz4740_adc *adc = platform_get_drvdata(pdev);
  
  	mfd_remove_devices(&pdev->dev);

  	irq_remove_generic_chip(adc->gc, IRQ_MSK(5), IRQ_NOPROBE | IRQ_LEVEL, 0);
  	kfree(adc->gc);

  	irq_set_chained_handler_and_data(adc->irq, NULL, NULL);

  
  	iounmap(adc->base);
  	release_mem_region(adc->mem->start, resource_size(adc->mem));
  
  	clk_put(adc->clk);

  	return 0;
  }

  static struct platform_driver jz4740_adc_driver = {

  	.probe	= jz4740_adc_probe,

  	.remove = jz4740_adc_remove,

  	.driver = {
  		.name = "jz4740-adc",

  	},
  };

  module_platform_driver(jz4740_adc_driver);

  
  MODULE_DESCRIPTION("JZ4740 SoC ADC driver");
  MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:jz4740-adc");