/*
   * powr1220.c - Driver for the Lattice POWR1220 programmable power supply
   * and monitor. Users can read all ADC inputs along with their labels
   * using the sysfs nodes.
   *
   * Copyright (c) 2014 Echo360 http://www.echo360.com
   * Scott Kanowitz <skanowitz@echo360.com> <scott.kanowitz@gmail.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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; 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/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <linux/delay.h>
  
  #define ADC_STEP_MV			2
  #define ADC_MAX_LOW_MEASUREMENT_MV	2000
  
  enum powr1220_regs {
  	VMON_STATUS0,
  	VMON_STATUS1,
  	VMON_STATUS2,
  	OUTPUT_STATUS0,
  	OUTPUT_STATUS1,
  	OUTPUT_STATUS2,
  	INPUT_STATUS,
  	ADC_VALUE_LOW,
  	ADC_VALUE_HIGH,
  	ADC_MUX,
  	UES_BYTE0,
  	UES_BYTE1,
  	UES_BYTE2,
  	UES_BYTE3,
  	GP_OUTPUT1,
  	GP_OUTPUT2,
  	GP_OUTPUT3,
  	INPUT_VALUE,
  	RESET,
  	TRIM1_TRIM,
  	TRIM2_TRIM,
  	TRIM3_TRIM,
  	TRIM4_TRIM,
  	TRIM5_TRIM,
  	TRIM6_TRIM,
  	TRIM7_TRIM,
  	TRIM8_TRIM,
  	MAX_POWR1220_REGS
  };
  
  enum powr1220_adc_values {
  	VMON1,
  	VMON2,
  	VMON3,
  	VMON4,
  	VMON5,
  	VMON6,
  	VMON7,
  	VMON8,
  	VMON9,
  	VMON10,
  	VMON11,
  	VMON12,
  	VCCA,
  	VCCINP,
  	MAX_POWR1220_ADC_VALUES
  };
  
  struct powr1220_data {
  	struct i2c_client *client;
  	struct mutex update_lock;
  	bool adc_valid[MAX_POWR1220_ADC_VALUES];
  	 /* the next value is in jiffies */
  	unsigned long adc_last_updated[MAX_POWR1220_ADC_VALUES];
  
  	/* values */
  	int adc_maxes[MAX_POWR1220_ADC_VALUES];
  	int adc_values[MAX_POWR1220_ADC_VALUES];
  };
  
  static const char * const input_names[] = {
  	[VMON1]    = "vmon1",
  	[VMON2]    = "vmon2",
  	[VMON3]    = "vmon3",
  	[VMON4]    = "vmon4",
  	[VMON5]    = "vmon5",
  	[VMON6]    = "vmon6",
  	[VMON7]    = "vmon7",
  	[VMON8]    = "vmon8",
  	[VMON9]    = "vmon9",
  	[VMON10]   = "vmon10",
  	[VMON11]   = "vmon11",
  	[VMON12]   = "vmon12",
  	[VCCA]     = "vcca",
  	[VCCINP]   = "vccinp",
  };
  
  /* Reads the specified ADC channel */
  static int powr1220_read_adc(struct device *dev, int ch_num)
  {
  	struct powr1220_data *data = dev_get_drvdata(dev);
  	int reading;
  	int result;
  	int adc_range = 0;
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->adc_last_updated[ch_num] + HZ) ||
  			!data->adc_valid[ch_num]) {
  		/*
  		 * figure out if we need to use the attenuator for
  		 * high inputs or inputs that we don't yet have a measurement
  		 * for. We dynamically set the attenuator depending on the
  		 * max reading.
  		 */
  		if (data->adc_maxes[ch_num] > ADC_MAX_LOW_MEASUREMENT_MV ||
  				data->adc_maxes[ch_num] == 0)
  			adc_range = 1 << 4;
  
  		/* set the attenuator and mux */
  		result = i2c_smbus_write_byte_data(data->client, ADC_MUX,
  				adc_range | ch_num);
  		if (result)
  			goto exit;
  
  		/*
  		 * wait at least Tconvert time (200 us) for the
  		 * conversion to complete
  		 */
  		udelay(200);
  
  		/* get the ADC reading */
  		result = i2c_smbus_read_byte_data(data->client, ADC_VALUE_LOW);
  		if (result < 0)
  			goto exit;
  
  		reading = result >> 4;
  
  		/* get the upper half of the reading */
  		result = i2c_smbus_read_byte_data(data->client, ADC_VALUE_HIGH);
  		if (result < 0)
  			goto exit;
  
  		reading |= result << 4;
  
  		/* now convert the reading to a voltage */
  		reading *= ADC_STEP_MV;
  		data->adc_values[ch_num] = reading;
  		data->adc_valid[ch_num] = true;
  		data->adc_last_updated[ch_num] = jiffies;
  		result = reading;
  
  		if (reading > data->adc_maxes[ch_num])
  			data->adc_maxes[ch_num] = reading;
  	} else {
  		result = data->adc_values[ch_num];
  	}
  
  exit:
  	mutex_unlock(&data->update_lock);
  
  	return result;
  }
  
  /* Shows the voltage associated with the specified ADC channel */
  static ssize_t powr1220_show_voltage(struct device *dev,
  	struct device_attribute *dev_attr, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
  	int adc_val = powr1220_read_adc(dev, attr->index);
  
  	if (adc_val < 0)
  		return adc_val;
  
  	return sprintf(buf, "%d
  ", adc_val);
  }
  
  /* Shows the maximum setting associated with the specified ADC channel */
  static ssize_t powr1220_show_max(struct device *dev,
  	struct device_attribute *dev_attr, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
  	struct powr1220_data *data = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%d
  ", data->adc_maxes[attr->index]);
  }
  
  /* Shows the label associated with the specified ADC channel */
  static ssize_t powr1220_show_label(struct device *dev,
  	struct device_attribute *dev_attr, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
  
  	return sprintf(buf, "%s
  ", input_names[attr->index]);
  }
  
  static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON1);
  static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON2);
  static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON3);
  static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON4);
  static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON5);
  static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON6);
  static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON7);
  static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON8);
  static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON9);
  static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON10);
  static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON11);
  static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VMON12);
  static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VCCA);
  static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, powr1220_show_voltage, NULL,
  	VCCINP);
  
  static SENSOR_DEVICE_ATTR(in0_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON1);
  static SENSOR_DEVICE_ATTR(in1_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON2);
  static SENSOR_DEVICE_ATTR(in2_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON3);
  static SENSOR_DEVICE_ATTR(in3_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON4);
  static SENSOR_DEVICE_ATTR(in4_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON5);
  static SENSOR_DEVICE_ATTR(in5_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON6);
  static SENSOR_DEVICE_ATTR(in6_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON7);
  static SENSOR_DEVICE_ATTR(in7_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON8);
  static SENSOR_DEVICE_ATTR(in8_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON9);
  static SENSOR_DEVICE_ATTR(in9_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON10);
  static SENSOR_DEVICE_ATTR(in10_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON11);
  static SENSOR_DEVICE_ATTR(in11_highest, S_IRUGO, powr1220_show_max, NULL,
  	VMON12);
  static SENSOR_DEVICE_ATTR(in12_highest, S_IRUGO, powr1220_show_max, NULL,
  	VCCA);
  static SENSOR_DEVICE_ATTR(in13_highest, S_IRUGO, powr1220_show_max, NULL,
  	VCCINP);
  
  static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON1);
  static SENSOR_DEVICE_ATTR(in1_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON2);
  static SENSOR_DEVICE_ATTR(in2_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON3);
  static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON4);
  static SENSOR_DEVICE_ATTR(in4_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON5);
  static SENSOR_DEVICE_ATTR(in5_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON6);
  static SENSOR_DEVICE_ATTR(in6_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON7);
  static SENSOR_DEVICE_ATTR(in7_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON8);
  static SENSOR_DEVICE_ATTR(in8_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON9);
  static SENSOR_DEVICE_ATTR(in9_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON10);
  static SENSOR_DEVICE_ATTR(in10_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON11);
  static SENSOR_DEVICE_ATTR(in11_label, S_IRUGO, powr1220_show_label, NULL,
  	VMON12);
  static SENSOR_DEVICE_ATTR(in12_label, S_IRUGO, powr1220_show_label, NULL,
  	VCCA);
  static SENSOR_DEVICE_ATTR(in13_label, S_IRUGO, powr1220_show_label, NULL,
  	VCCINP);
  
  static struct attribute *powr1220_attrs[] = {
  	&sensor_dev_attr_in0_input.dev_attr.attr,
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in2_input.dev_attr.attr,
  	&sensor_dev_attr_in3_input.dev_attr.attr,
  	&sensor_dev_attr_in4_input.dev_attr.attr,
  	&sensor_dev_attr_in5_input.dev_attr.attr,
  	&sensor_dev_attr_in6_input.dev_attr.attr,
  	&sensor_dev_attr_in7_input.dev_attr.attr,
  	&sensor_dev_attr_in8_input.dev_attr.attr,
  	&sensor_dev_attr_in9_input.dev_attr.attr,
  	&sensor_dev_attr_in10_input.dev_attr.attr,
  	&sensor_dev_attr_in11_input.dev_attr.attr,
  	&sensor_dev_attr_in12_input.dev_attr.attr,
  	&sensor_dev_attr_in13_input.dev_attr.attr,
  
  	&sensor_dev_attr_in0_highest.dev_attr.attr,
  	&sensor_dev_attr_in1_highest.dev_attr.attr,
  	&sensor_dev_attr_in2_highest.dev_attr.attr,
  	&sensor_dev_attr_in3_highest.dev_attr.attr,
  	&sensor_dev_attr_in4_highest.dev_attr.attr,
  	&sensor_dev_attr_in5_highest.dev_attr.attr,
  	&sensor_dev_attr_in6_highest.dev_attr.attr,
  	&sensor_dev_attr_in7_highest.dev_attr.attr,
  	&sensor_dev_attr_in8_highest.dev_attr.attr,
  	&sensor_dev_attr_in9_highest.dev_attr.attr,
  	&sensor_dev_attr_in10_highest.dev_attr.attr,
  	&sensor_dev_attr_in11_highest.dev_attr.attr,
  	&sensor_dev_attr_in12_highest.dev_attr.attr,
  	&sensor_dev_attr_in13_highest.dev_attr.attr,
  
  	&sensor_dev_attr_in0_label.dev_attr.attr,
  	&sensor_dev_attr_in1_label.dev_attr.attr,
  	&sensor_dev_attr_in2_label.dev_attr.attr,
  	&sensor_dev_attr_in3_label.dev_attr.attr,
  	&sensor_dev_attr_in4_label.dev_attr.attr,
  	&sensor_dev_attr_in5_label.dev_attr.attr,
  	&sensor_dev_attr_in6_label.dev_attr.attr,
  	&sensor_dev_attr_in7_label.dev_attr.attr,
  	&sensor_dev_attr_in8_label.dev_attr.attr,
  	&sensor_dev_attr_in9_label.dev_attr.attr,
  	&sensor_dev_attr_in10_label.dev_attr.attr,
  	&sensor_dev_attr_in11_label.dev_attr.attr,
  	&sensor_dev_attr_in12_label.dev_attr.attr,
  	&sensor_dev_attr_in13_label.dev_attr.attr,
  
  	NULL
  };
  
  ATTRIBUTE_GROUPS(powr1220);
  
  static int powr1220_probe(struct i2c_client *client,
  		const struct i2c_device_id *id)
  {
  	struct powr1220_data *data;
  	struct device *hwmon_dev;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;
  
  	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	mutex_init(&data->update_lock);
  	data->client = client;
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
  			client->name, data, powr1220_groups);
  
  	return PTR_ERR_OR_ZERO(hwmon_dev);
  }
  
  static const struct i2c_device_id powr1220_ids[] = {
  	{ "powr1220", 0, },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(i2c, powr1220_ids);
  
  static struct i2c_driver powr1220_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "powr1220",
  	},
  	.probe		= powr1220_probe,
  	.id_table	= powr1220_ids,
  };
  
  module_i2c_driver(powr1220_driver);
  
  MODULE_AUTHOR("Scott Kanowitz");
  MODULE_DESCRIPTION("POWR1220 driver");
  MODULE_LICENSE("GPL");