/*
   * Touchscreen driver for the tps6507x chip.
   *
   * Copyright (c) 2009 RidgeRun (todd.fischer@ridgerun.com)
   *
   * Credits:
   *
   *    Using code from tsc2007, MtekVision Co., Ltd.
   *
   * For licencing details see kernel-base/COPYING
   *
   * TPS65070, TPS65073, TPS650731, and TPS650732 support
   * 10 bit touch screen interface.
   */
  
  #include <linux/module.h>
  #include <linux/workqueue.h>
  #include <linux/slab.h>
  #include <linux/input.h>
  #include <linux/input-polldev.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/tps6507x.h>
  #include <linux/input/tps6507x-ts.h>
  #include <linux/delay.h>
  
  #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
  #define TPS_DEFAULT_MIN_PRESSURE 0x30
  #define MAX_10BIT ((1 << 10) - 1)
  
  #define	TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
  					 TPS6507X_ADCONFIG_START_CONVERSION | \
  					 TPS6507X_ADCONFIG_INPUT_REAL_TSC)
  #define	TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
  
  struct ts_event {
  	u16	x;
  	u16	y;
  	u16	pressure;
  };
  
  struct tps6507x_ts {
  	struct device		*dev;
  	struct input_polled_dev	*poll_dev;
  	struct tps6507x_dev	*mfd;
  	char			phys[32];
  	struct ts_event		tc;
  	u16			min_pressure;
  	bool			pendown;
  };
  
  static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
  {
  	int err;
  
  	err = tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
  
  	if (err)
  		return err;
  
  	return 0;
  }
  
  static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
  {
  	return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
  }
  
  static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
  				   u8 tsc_mode, u16 *value)
  {
  	s32 ret;
  	u8 adc_status;
  	u8 result;
  
  	/* Route input signal to A/D converter */
  
  	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
  	if (ret) {
  		dev_err(tsc->dev, "TSC mode read failed
  ");
  		goto err;
  	}
  
  	/* Start A/D conversion */
  
  	ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
  				TPS6507X_ADCONFIG_CONVERT_TS);
  	if (ret) {
  		dev_err(tsc->dev, "ADC config write failed
  ");
  		return ret;
  	}
  
  	do {
  		ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
  				       &adc_status);
  		if (ret) {
  			dev_err(tsc->dev, "ADC config read failed
  ");
  			goto err;
  		}
  	} while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
  
  	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
  	if (ret) {
  		dev_err(tsc->dev, "ADC result 2 read failed
  ");
  		goto err;
  	}
  
  	*value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
  
  	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
  	if (ret) {
  		dev_err(tsc->dev, "ADC result 1 read failed
  ");
  		goto err;
  	}
  
  	*value |= result;
  
  	dev_dbg(tsc->dev, "TSC channel %d = 0x%X
  ", tsc_mode, *value);
  
  err:
  	return ret;
  }
  
  /* Need to call tps6507x_adc_standby() after using A/D converter for the
   * touch screen interrupt to work properly.
   */
  
  static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
  {
  	s32 ret;
  	s32 loops = 0;
  	u8 val;
  
  	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
  				TPS6507X_ADCONFIG_INPUT_TSC);
  	if (ret)
  		return ret;
  
  	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
  				TPS6507X_TSCMODE_STANDBY);
  	if (ret)
  		return ret;
  
  	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
  	if (ret)
  		return ret;
  
  	while (val & TPS6507X_REG_TSC_INT) {
  		mdelay(10);
  		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
  		if (ret)
  			return ret;
  		loops++;
  	}
  
  	return ret;
  }
  
  static void tps6507x_ts_poll(struct input_polled_dev *poll_dev)
  {
  	struct tps6507x_ts *tsc = poll_dev->private;
  	struct input_dev *input_dev = poll_dev->input;
  	bool pendown;
  	s32 ret;
  
  	ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
  				      &tsc->tc.pressure);
  	if (ret)
  		goto done;
  
  	pendown = tsc->tc.pressure > tsc->min_pressure;
  
  	if (unlikely(!pendown && tsc->pendown)) {
  		dev_dbg(tsc->dev, "UP
  ");
  		input_report_key(input_dev, BTN_TOUCH, 0);
  		input_report_abs(input_dev, ABS_PRESSURE, 0);
  		input_sync(input_dev);
  		tsc->pendown = false;
  	}
  
  	if (pendown) {
  
  		if (!tsc->pendown) {
  			dev_dbg(tsc->dev, "DOWN
  ");
  			input_report_key(input_dev, BTN_TOUCH, 1);
  		} else
  			dev_dbg(tsc->dev, "still down
  ");
  
  		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
  					       &tsc->tc.x);
  		if (ret)
  			goto done;
  
  		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
  					       &tsc->tc.y);
  		if (ret)
  			goto done;
  
  		input_report_abs(input_dev, ABS_X, tsc->tc.x);
  		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
  		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
  		input_sync(input_dev);
  		tsc->pendown = true;
  	}
  
  done:
  	tps6507x_adc_standby(tsc);
  }
  
  static int tps6507x_ts_probe(struct platform_device *pdev)
  {
  	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
  	const struct tps6507x_board *tps_board;
  	const struct touchscreen_init_data *init_data;
  	struct tps6507x_ts *tsc;
  	struct input_polled_dev *poll_dev;
  	struct input_dev *input_dev;
  	int error;
  
  	/*
  	 * tps_board points to pmic related constants
  	 * coming from the board-evm file.
  	 */
  	tps_board = dev_get_platdata(tps6507x_dev->dev);
  	if (!tps_board) {
  		dev_err(tps6507x_dev->dev,
  			"Could not find tps6507x platform data
  ");
  		return -ENODEV;
  	}
  
  	/*
  	 * init_data points to array of regulator_init structures
  	 * coming from the board-evm file.
  	 */
  	init_data = tps_board->tps6507x_ts_init_data;
  
  	tsc = kzalloc(sizeof(struct tps6507x_ts), GFP_KERNEL);
  	if (!tsc) {
  		dev_err(tps6507x_dev->dev, "failed to allocate driver data
  ");
  		return -ENOMEM;
  	}
  
  	tsc->mfd = tps6507x_dev;
  	tsc->dev = tps6507x_dev->dev;
  	tsc->min_pressure = init_data ?
  			init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
  
  	snprintf(tsc->phys, sizeof(tsc->phys),
  		 "%s/input0", dev_name(tsc->dev));
  
  	poll_dev = input_allocate_polled_device();
  	if (!poll_dev) {
  		dev_err(tsc->dev, "Failed to allocate polled input device.
  ");
  		error = -ENOMEM;
  		goto err_free_mem;
  	}
  
  	tsc->poll_dev = poll_dev;
  
  	poll_dev->private = tsc;
  	poll_dev->poll = tps6507x_ts_poll;
  	poll_dev->poll_interval = init_data ?
  			init_data->poll_period : TSC_DEFAULT_POLL_PERIOD;
  
  	input_dev = poll_dev->input;
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
  
  	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
  	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
  	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
  
  	input_dev->name = "TPS6507x Touchscreen";
  	input_dev->phys = tsc->phys;
  	input_dev->dev.parent = tsc->dev;
  	input_dev->id.bustype = BUS_I2C;
  	if (init_data) {
  		input_dev->id.vendor = init_data->vendor;
  		input_dev->id.product = init_data->product;
  		input_dev->id.version = init_data->version;
  	}
  
  	error = tps6507x_adc_standby(tsc);
  	if (error)
  		goto err_free_polled_dev;
  
  	error = input_register_polled_device(poll_dev);
  	if (error)
  		goto err_free_polled_dev;
  
  	platform_set_drvdata(pdev, tsc);
  
  	return 0;
  
  err_free_polled_dev:
  	input_free_polled_device(poll_dev);
  err_free_mem:
  	kfree(tsc);
  	return error;
  }
  
  static int tps6507x_ts_remove(struct platform_device *pdev)
  {
  	struct tps6507x_ts *tsc = platform_get_drvdata(pdev);
  	struct input_polled_dev *poll_dev = tsc->poll_dev;
  
  	input_unregister_polled_device(poll_dev);
  	input_free_polled_device(poll_dev);
  
  	kfree(tsc);
  
  	return 0;
  }
  
  static struct platform_driver tps6507x_ts_driver = {
  	.driver = {
  		.name = "tps6507x-ts",
  		.owner = THIS_MODULE,
  	},
  	.probe = tps6507x_ts_probe,
  	.remove = tps6507x_ts_remove,
  };
  module_platform_driver(tps6507x_ts_driver);
  
  MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
  MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("platform:tps6507x-ts");