/*
   * HWMON Driver for Dialog DA9055
   *
   * Copyright(c) 2012 Dialog Semiconductor Ltd.
   *
   * Author: David Dajun Chen <dchen@diasemi.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;  either version 2 of the  License, or (at your
   *  option) any later version.
   *
   */
  
  #include <linux/delay.h>
  #include <linux/err.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/completion.h>
  
  #include <linux/mfd/da9055/core.h>
  #include <linux/mfd/da9055/reg.h>
  
  #define DA9055_ADCIN_DIV	102
  #define DA9055_VSYS_DIV	85
  
  #define DA9055_ADC_VSYS	0
  #define DA9055_ADC_ADCIN1	1
  #define DA9055_ADC_ADCIN2	2
  #define DA9055_ADC_ADCIN3	3
  #define DA9055_ADC_TJUNC	4
  
  struct da9055_hwmon {
  	struct da9055	*da9055;
  	struct device	*class_device;
  	struct mutex	hwmon_lock;
  	struct mutex	irq_lock;
  	struct completion done;
  };
  
  static const char * const input_names[] = {
  	[DA9055_ADC_VSYS]	= "VSYS",
  	[DA9055_ADC_ADCIN1]	= "ADC IN1",
  	[DA9055_ADC_ADCIN2]	= "ADC IN2",
  	[DA9055_ADC_ADCIN3]	= "ADC IN3",
  	[DA9055_ADC_TJUNC]	= "CHIP TEMP",
  };
  
  static const u8 chan_mux[DA9055_ADC_TJUNC + 1] = {
  	[DA9055_ADC_VSYS]	= DA9055_ADC_MUX_VSYS,
  	[DA9055_ADC_ADCIN1]	= DA9055_ADC_MUX_ADCIN1,
  	[DA9055_ADC_ADCIN2]	= DA9055_ADC_MUX_ADCIN2,
  	[DA9055_ADC_ADCIN3]	= DA9055_ADC_MUX_ADCIN3,
  	[DA9055_ADC_TJUNC]	= DA9055_ADC_MUX_T_SENSE,
  };
  
  static int da9055_adc_manual_read(struct da9055_hwmon *hwmon,
  					unsigned char channel)
  {
  	int ret;
  	unsigned short calc_data;
  	unsigned short data;
  	unsigned char mux_sel;
  	struct da9055 *da9055 = hwmon->da9055;
  
  	if (channel > DA9055_ADC_TJUNC)
  		return -EINVAL;
  
  	mutex_lock(&hwmon->irq_lock);
  
  	/* Selects desired MUX for manual conversion */
  	mux_sel = chan_mux[channel] | DA9055_ADC_MAN_CONV;
  
  	ret = da9055_reg_write(da9055, DA9055_REG_ADC_MAN, mux_sel);
  	if (ret < 0)
  		goto err;
  
  	/* Wait for an interrupt */
  	if (!wait_for_completion_timeout(&hwmon->done,
  					msecs_to_jiffies(500))) {
  		dev_err(da9055->dev,
  			"timeout waiting for ADC conversion interrupt
  ");
  		ret = -ETIMEDOUT;
  		goto err;
  	}
  
  	ret = da9055_reg_read(da9055, DA9055_REG_ADC_RES_H);
  	if (ret < 0)
  		goto err;
  
  	calc_data = (unsigned short)ret;
  	data = calc_data << 2;
  
  	ret = da9055_reg_read(da9055, DA9055_REG_ADC_RES_L);
  	if (ret < 0)
  		goto err;
  
  	calc_data = (unsigned short)(ret & DA9055_ADC_LSB_MASK);
  	data |= calc_data;
  
  	ret = data;
  
  err:
  	mutex_unlock(&hwmon->irq_lock);
  	return ret;
  }
  
  static irqreturn_t da9055_auxadc_irq(int irq, void *irq_data)
  {
  	struct da9055_hwmon *hwmon = irq_data;
  
  	complete(&hwmon->done);
  
  	return IRQ_HANDLED;
  }
  
  /* Conversion function for VSYS and ADCINx */
  static inline int volt_reg_to_mv(int value, int channel)
  {
  	if (channel == DA9055_ADC_VSYS)
  		return DIV_ROUND_CLOSEST(value * 1000, DA9055_VSYS_DIV) + 2500;
  	else
  		return DIV_ROUND_CLOSEST(value * 1000, DA9055_ADCIN_DIV);
  }
  
  static int da9055_enable_auto_mode(struct da9055 *da9055, int channel)
  {
  
  	return da9055_reg_update(da9055, DA9055_REG_ADC_CONT, 1 << channel,
  				1 << channel);
  
  }
  
  static int da9055_disable_auto_mode(struct da9055 *da9055, int channel)
  {
  
  	return da9055_reg_update(da9055, DA9055_REG_ADC_CONT, 1 << channel, 0);
  }
  
  static ssize_t da9055_read_auto_ch(struct device *dev,
  				struct device_attribute *devattr, char *buf)
  {
  	struct da9055_hwmon *hwmon = dev_get_drvdata(dev);
  	int ret, adc;
  	int channel = to_sensor_dev_attr(devattr)->index;
  
  	mutex_lock(&hwmon->hwmon_lock);
  
  	ret = da9055_enable_auto_mode(hwmon->da9055, channel);
  	if (ret < 0)
  		goto hwmon_err;
  
  	usleep_range(10000, 10500);
  
  	adc = da9055_reg_read(hwmon->da9055, DA9055_REG_VSYS_RES + channel);
  	if (adc < 0) {
  		ret = adc;
  		goto hwmon_err_release;
  	}
  
  	ret = da9055_disable_auto_mode(hwmon->da9055, channel);
  	if (ret < 0)
  		goto hwmon_err;
  
  	mutex_unlock(&hwmon->hwmon_lock);
  
  	return sprintf(buf, "%d
  ", volt_reg_to_mv(adc, channel));
  
  hwmon_err_release:
  	da9055_disable_auto_mode(hwmon->da9055, channel);
  hwmon_err:
  	mutex_unlock(&hwmon->hwmon_lock);
  	return ret;
  }
  
  static ssize_t da9055_read_tjunc(struct device *dev,
  				 struct device_attribute *devattr, char *buf)
  {
  	struct da9055_hwmon *hwmon = dev_get_drvdata(dev);
  	int tjunc;
  	int toffset;
  
  	tjunc = da9055_adc_manual_read(hwmon, DA9055_ADC_TJUNC);
  	if (tjunc < 0)
  		return tjunc;
  
  	toffset = da9055_reg_read(hwmon->da9055, DA9055_REG_T_OFFSET);
  	if (toffset < 0)
  		return toffset;
  
  	/*
  	 * Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332
  	 * T_OFFSET is a trim value used to improve accuracy of the result
  	 */
  	return sprintf(buf, "%d
  ", DIV_ROUND_CLOSEST(-4084 * (tjunc - toffset)
  							+ 3076332, 10000));
  }
  
  static ssize_t da9055_hwmon_show_name(struct device *dev,
  				      struct device_attribute *devattr,
  				      char *buf)
  {
  	return sprintf(buf, "da9055
  ");
  }
  
  static ssize_t show_label(struct device *dev,
  			  struct device_attribute *devattr, char *buf)
  {
  	return sprintf(buf, "%s
  ",
  		       input_names[to_sensor_dev_attr(devattr)->index]);
  }
  
  static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, da9055_read_auto_ch, NULL,
  			  DA9055_ADC_VSYS);
  static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL,
  			  DA9055_ADC_VSYS);
  static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, da9055_read_auto_ch, NULL,
  			  DA9055_ADC_ADCIN1);
  static SENSOR_DEVICE_ATTR(in1_label, S_IRUGO, show_label, NULL,
  			  DA9055_ADC_ADCIN1);
  static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, da9055_read_auto_ch, NULL,
  			  DA9055_ADC_ADCIN2);
  static SENSOR_DEVICE_ATTR(in2_label, S_IRUGO, show_label, NULL,
  			  DA9055_ADC_ADCIN2);
  static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, da9055_read_auto_ch, NULL,
  			  DA9055_ADC_ADCIN3);
  static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, show_label, NULL,
  			  DA9055_ADC_ADCIN3);
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, da9055_read_tjunc, NULL,
  			  DA9055_ADC_TJUNC);
  static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL,
  			  DA9055_ADC_TJUNC);
  
  static DEVICE_ATTR(name, S_IRUGO, da9055_hwmon_show_name, NULL);
  
  static struct attribute *da9055_attr[] = {
  	&dev_attr_name.attr,
  	&sensor_dev_attr_in0_input.dev_attr.attr,
  	&sensor_dev_attr_in0_label.dev_attr.attr,
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in1_label.dev_attr.attr,
  	&sensor_dev_attr_in2_input.dev_attr.attr,
  	&sensor_dev_attr_in2_label.dev_attr.attr,
  	&sensor_dev_attr_in3_input.dev_attr.attr,
  	&sensor_dev_attr_in3_label.dev_attr.attr,
  
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_label.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group da9055_attr_group = {.attrs = da9055_attr};
  
  static int da9055_hwmon_probe(struct platform_device *pdev)
  {
  	struct da9055_hwmon *hwmon;
  	int hwmon_irq, ret;
  
  	hwmon = devm_kzalloc(&pdev->dev, sizeof(struct da9055_hwmon),
  			     GFP_KERNEL);
  	if (!hwmon)
  		return -ENOMEM;
  
  	mutex_init(&hwmon->hwmon_lock);
  	mutex_init(&hwmon->irq_lock);
  
  	init_completion(&hwmon->done);
  	hwmon->da9055 = dev_get_drvdata(pdev->dev.parent);
  
  	platform_set_drvdata(pdev, hwmon);
  
  	hwmon_irq = platform_get_irq_byname(pdev, "HWMON");
  	if (hwmon_irq < 0)
  		return hwmon_irq;
  
  	ret = devm_request_threaded_irq(&pdev->dev, hwmon_irq,
  					NULL, da9055_auxadc_irq,
  					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
  					"adc-irq", hwmon);
  	if (ret != 0) {
  		dev_err(hwmon->da9055->dev, "DA9055 ADC IRQ failed ret=%d
  ",
  			ret);
  		return ret;
  	}
  
  	ret = sysfs_create_group(&pdev->dev.kobj, &da9055_attr_group);
  	if (ret)
  		return ret;
  
  	hwmon->class_device = hwmon_device_register(&pdev->dev);
  	if (IS_ERR(hwmon->class_device)) {
  		ret = PTR_ERR(hwmon->class_device);
  		goto err;
  	}
  
  	return 0;
  
  err:
  	sysfs_remove_group(&pdev->dev.kobj, &da9055_attr_group);
  	return ret;
  }
  
  static int da9055_hwmon_remove(struct platform_device *pdev)
  {
  	struct da9055_hwmon *hwmon = platform_get_drvdata(pdev);
  
  	sysfs_remove_group(&pdev->dev.kobj, &da9055_attr_group);
  	hwmon_device_unregister(hwmon->class_device);
  
  	return 0;
  }
  
  static struct platform_driver da9055_hwmon_driver = {
  	.probe = da9055_hwmon_probe,
  	.remove = da9055_hwmon_remove,
  	.driver = {
  		.name = "da9055-hwmon",
  		.owner = THIS_MODULE,
  	},
  };
  
  module_platform_driver(da9055_hwmon_driver);
  
  MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
  MODULE_DESCRIPTION("DA9055 HWMON driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:da9055-hwmon");