/*
   * TI Touch Screen / ADC MFD driver
   *
   * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
   *
   * 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 version 2.
   *
   * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   * kind, whether express or implied; without even the implied warranty
   * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/module.h>

  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/clk.h>
  #include <linux/regmap.h>
  #include <linux/mfd/core.h>
  #include <linux/pm_runtime.h>

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

  #include <linux/sched.h>

  
  #include <linux/mfd/ti_am335x_tscadc.h>
  
  static unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
  {
  	unsigned int val;
  
  	regmap_read(tsadc->regmap_tscadc, reg, &val);
  	return val;
  }
  
  static void tscadc_writel(struct ti_tscadc_dev *tsadc, unsigned int reg,
  					unsigned int val)
  {
  	regmap_write(tsadc->regmap_tscadc, reg, val);
  }
  
  static const struct regmap_config tscadc_regmap_config = {
  	.name = "ti_tscadc",
  	.reg_bits = 32,
  	.reg_stride = 4,
  	.val_bits = 32,
  };

  void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val)

  {

  	unsigned long flags;
  
  	spin_lock_irqsave(&tsadc->reg_lock, flags);

  	tsadc->reg_se_cache |= val;

  	if (tsadc->adc_waiting)
  		wake_up(&tsadc->reg_se_wait);
  	else if (!tsadc->adc_in_use)

  		tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);

  	spin_unlock_irqrestore(&tsadc->reg_lock, flags);

  }

  EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);

  static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
  {
  	DEFINE_WAIT(wait);
  	u32 reg;

  	reg = tscadc_readl(tsadc, REG_ADCFSM);
  	if (reg & SEQ_STATUS) {
  		tsadc->adc_waiting = true;
  		prepare_to_wait(&tsadc->reg_se_wait, &wait,
  				TASK_UNINTERRUPTIBLE);
  		spin_unlock_irq(&tsadc->reg_lock);
  
  		schedule();
  
  		spin_lock_irq(&tsadc->reg_lock);
  		finish_wait(&tsadc->reg_se_wait, &wait);

  		/*
  		 * Sequencer should either be idle or
  		 * busy applying the charge step.
  		 */

  		reg = tscadc_readl(tsadc, REG_ADCFSM);

  		WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));

  		tsadc->adc_waiting = false;
  	}
  	tsadc->adc_in_use = true;
  }

  void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
  {

  	spin_lock_irq(&tsadc->reg_lock);
  	am335x_tscadc_need_adc(tsadc);
  
  	tscadc_writel(tsadc, REG_SE, val);
  	spin_unlock_irq(&tsadc->reg_lock);
  }
  EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
  
  void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tsadc)
  {

  	unsigned long flags;
  
  	spin_lock_irqsave(&tsadc->reg_lock, flags);

  	tsadc->adc_in_use = false;
  	tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);

  	spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  }

  EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);

  
  void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
  {

  	unsigned long flags;
  
  	spin_lock_irqsave(&tsadc->reg_lock, flags);

  	tsadc->reg_se_cache &= ~val;

  	tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);

  	spin_unlock_irqrestore(&tsadc->reg_lock, flags);

  }
  EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);

  static void tscadc_idle_config(struct ti_tscadc_dev *config)
  {
  	unsigned int idleconfig;
  
  	idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
  			STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
  
  	tscadc_writel(config, REG_IDLECONFIG, idleconfig);
  }

  static	int ti_tscadc_probe(struct platform_device *pdev)

  {
  	struct ti_tscadc_dev	*tscadc;
  	struct resource		*res;
  	struct clk		*clk;

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

  	struct mfd_cell		*cell;

  	struct property         *prop;
  	const __be32            *cur;
  	u32			val;

  	int			err, ctrl;

  	int			clock_rate;

  	int			tsc_wires = 0, adc_channels = 0, total_channels;

  	int			readouts = 0;

  	if (!pdev->dev.of_node) {
  		dev_err(&pdev->dev, "Could not find valid DT data.
  ");

  		return -EINVAL;
  	}

  	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
  	of_property_read_u32(node, "ti,wires", &tsc_wires);

  	of_property_read_u32(node, "ti,coordiante-readouts", &readouts);

  	node = of_get_child_by_name(pdev->dev.of_node, "adc");

  	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
  		adc_channels++;
  		if (val > 7) {
  			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)
  ",
  					val);
  			return -EINVAL;
  		}
  	}

  	total_channels = tsc_wires + adc_channels;

  	if (total_channels > 8) {
  		dev_err(&pdev->dev, "Number of i/p channels more than 8
  ");
  		return -EINVAL;
  	}

  	if (total_channels == 0) {
  		dev_err(&pdev->dev, "Need atleast one channel.
  ");
  		return -EINVAL;
  	}

  	if (readouts * 2 + 2 + adc_channels > 16) {
  		dev_err(&pdev->dev, "Too many step configurations requested
  ");
  		return -EINVAL;
  	}

  	/* Allocate memory for device */
  	tscadc = devm_kzalloc(&pdev->dev,
  			sizeof(struct ti_tscadc_dev), GFP_KERNEL);
  	if (!tscadc) {
  		dev_err(&pdev->dev, "failed to allocate memory.
  ");
  		return -ENOMEM;
  	}
  	tscadc->dev = &pdev->dev;

  
  	err = platform_get_irq(pdev, 0);
  	if (err < 0) {
  		dev_err(&pdev->dev, "no irq ID is specified.
  ");
  		goto ret;
  	} else
  		tscadc->irq = err;

  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(tscadc->tscadc_base))
  		return PTR_ERR(tscadc->tscadc_base);

  
  	tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
  			tscadc->tscadc_base, &tscadc_regmap_config);
  	if (IS_ERR(tscadc->regmap_tscadc)) {
  		dev_err(&pdev->dev, "regmap init failed
  ");
  		err = PTR_ERR(tscadc->regmap_tscadc);

  		goto ret;

  	}

  	spin_lock_init(&tscadc->reg_lock);

  	init_waitqueue_head(&tscadc->reg_se_wait);

  	pm_runtime_enable(&pdev->dev);
  	pm_runtime_get_sync(&pdev->dev);
  
  	/*
  	 * The TSC_ADC_Subsystem has 2 clock domains
  	 * OCP_CLK and ADC_CLK.
  	 * The ADC clock is expected to run at target of 3MHz,
  	 * and expected to capture 12-bit data at a rate of 200 KSPS.
  	 * The TSC_ADC_SS controller design assumes the OCP clock is
  	 * at least 6x faster than the ADC clock.
  	 */
  	clk = clk_get(&pdev->dev, "adc_tsc_fck");
  	if (IS_ERR(clk)) {
  		dev_err(&pdev->dev, "failed to get TSC fck
  ");
  		err = PTR_ERR(clk);
  		goto err_disable_clk;
  	}
  	clock_rate = clk_get_rate(clk);
  	clk_put(clk);

  	tscadc->clk_div = clock_rate / ADC_CLK;

  	/* TSCADC_CLKDIV needs to be configured to the value minus 1 */

  	tscadc->clk_div--;
  	tscadc_writel(tscadc, REG_CLKDIV, tscadc->clk_div);

  
  	/* Set the control register bits */

  	ctrl = CNTRLREG_STEPCONFIGWRT |	CNTRLREG_STEPID;

  	tscadc_writel(tscadc, REG_CTRL, ctrl);
  
  	/* Set register bits for Idle Config Mode */

  	if (tsc_wires > 0) {
  		tscadc->tsc_wires = tsc_wires;
  		if (tsc_wires == 5)
  			ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
  		else
  			ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;

  		tscadc_idle_config(tscadc);

  	}

  
  	/* Enable the TSC module enable bit */

  	ctrl |= CNTRLREG_TSCSSENB;
  	tscadc_writel(tscadc, REG_CTRL, ctrl);

  	tscadc->used_cells = 0;
  	tscadc->tsc_cell = -1;
  	tscadc->adc_cell = -1;

  	/* TSC Cell */

  	if (tsc_wires > 0) {
  		tscadc->tsc_cell = tscadc->used_cells;
  		cell = &tscadc->cells[tscadc->used_cells++];

  		cell->name = "TI-am335x-tsc";

  		cell->of_compatible = "ti,am3359-tsc";
  		cell->platform_data = &tscadc;
  		cell->pdata_size = sizeof(tscadc);
  	}

  	/* ADC Cell */

  	if (adc_channels > 0) {
  		tscadc->adc_cell = tscadc->used_cells;
  		cell = &tscadc->cells[tscadc->used_cells++];

  		cell->name = "TI-am335x-adc";

  		cell->of_compatible = "ti,am3359-adc";
  		cell->platform_data = &tscadc;
  		cell->pdata_size = sizeof(tscadc);
  	}

  	err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,

  			tscadc->used_cells, NULL, 0, NULL);

  	if (err < 0)
  		goto err_disable_clk;
  
  	device_init_wakeup(&pdev->dev, true);
  	platform_set_drvdata(pdev, tscadc);

  	return 0;
  
  err_disable_clk:
  	pm_runtime_put_sync(&pdev->dev);
  	pm_runtime_disable(&pdev->dev);

  ret:

  	return err;
  }

  static int ti_tscadc_remove(struct platform_device *pdev)

  {
  	struct ti_tscadc_dev	*tscadc = platform_get_drvdata(pdev);
  
  	tscadc_writel(tscadc, REG_SE, 0x00);
  
  	pm_runtime_put_sync(&pdev->dev);
  	pm_runtime_disable(&pdev->dev);
  
  	mfd_remove_devices(tscadc->dev);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int tscadc_suspend(struct device *dev)
  {
  	struct ti_tscadc_dev	*tscadc_dev = dev_get_drvdata(dev);
  
  	tscadc_writel(tscadc_dev, REG_SE, 0x00);
  	pm_runtime_put_sync(dev);
  
  	return 0;
  }
  
  static int tscadc_resume(struct device *dev)
  {
  	struct ti_tscadc_dev	*tscadc_dev = dev_get_drvdata(dev);

  	u32 ctrl;

  
  	pm_runtime_get_sync(dev);
  
  	/* context restore */

  	ctrl = CNTRLREG_STEPCONFIGWRT |	CNTRLREG_STEPID;

  	tscadc_writel(tscadc_dev, REG_CTRL, ctrl);

  	if (tscadc_dev->tsc_cell != -1) {
  		if (tscadc_dev->tsc_wires == 5)
  			ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
  		else
  			ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;

  		tscadc_idle_config(tscadc_dev);

  	}
  	ctrl |= CNTRLREG_TSCSSENB;
  	tscadc_writel(tscadc_dev, REG_CTRL, ctrl);

  	tscadc_writel(tscadc_dev, REG_CLKDIV, tscadc_dev->clk_div);

  	return 0;
  }
  
  static const struct dev_pm_ops tscadc_pm_ops = {
  	.suspend = tscadc_suspend,
  	.resume = tscadc_resume,
  };
  #define TSCADC_PM_OPS (&tscadc_pm_ops)
  #else
  #define TSCADC_PM_OPS NULL
  #endif

  static const struct of_device_id ti_tscadc_dt_ids[] = {
  	{ .compatible = "ti,am3359-tscadc", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);

  static struct platform_driver ti_tscadc_driver = {
  	.driver = {

  		.name   = "ti_am3359-tscadc",

  		.pm	= TSCADC_PM_OPS,

  		.of_match_table = ti_tscadc_dt_ids,

  	},
  	.probe	= ti_tscadc_probe,

  	.remove	= ti_tscadc_remove,

  
  };
  
  module_platform_driver(ti_tscadc_driver);
  
  MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
  MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
  MODULE_LICENSE("GPL");