/*
   * Driver for the ADC on Freescale Semiconductor MC13783 and MC13892 PMICs.
   *
   * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   * Copyright (C) 2009 Sascha Hauer, Pengutronix
   *
   * 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.
   *
   * 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., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include <linux/mfd/mc13xxx.h>
  #include <linux/platform_device.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/hwmon.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/err.h>
  
  #define DRIVER_NAME	"mc13783-adc"
  
  /* platform device id driver data */
  #define MC13783_ADC_16CHANS	1
  #define MC13783_ADC_BPDIV2	2
  
  struct mc13783_adc_priv {
  	struct mc13xxx *mc13xxx;
  	struct device *hwmon_dev;
  	char name[PLATFORM_NAME_SIZE];
  };
  
  static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
  			      *devattr, char *buf)
  {
  	struct mc13783_adc_priv *priv = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%s
  ", priv->name);
  }
  
  static int mc13783_adc_read(struct device *dev,
  		struct device_attribute *devattr, unsigned int *val)
  {
  	struct mc13783_adc_priv *priv = dev_get_drvdata(dev);
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	unsigned int channel = attr->index;
  	unsigned int sample[4];
  	int ret;
  
  	ret = mc13xxx_adc_do_conversion(priv->mc13xxx,
  			MC13XXX_ADC_MODE_MULT_CHAN,
  			channel, 0, 0, sample);
  	if (ret)
  		return ret;
  
  	channel &= 0x7;
  
  	*val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
  
  	return 0;
  }
  
  static ssize_t mc13783_adc_read_bp(struct device *dev,
  		struct device_attribute *devattr, char *buf)
  {
  	unsigned val;
  	struct platform_device *pdev = to_platform_device(dev);
  	kernel_ulong_t driver_data = platform_get_device_id(pdev)->driver_data;
  	int ret = mc13783_adc_read(dev, devattr, &val);
  
  	if (ret)
  		return ret;
  
  	if (driver_data & MC13783_ADC_BPDIV2)
  		val = DIV_ROUND_CLOSEST(val * 9, 2);
  	else
  		/*
  		 * BP (channel 2) reports with offset 2.4V to the actual value
  		 * to fit the input range of the ADC.  unit = 2.25mV = 9/4 mV.
  		 */
  		val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;
  
  	return sprintf(buf, "%u
  ", val);
  }
  
  static ssize_t mc13783_adc_read_gp(struct device *dev,
  		struct device_attribute *devattr, char *buf)
  {
  	unsigned val;
  	int ret = mc13783_adc_read(dev, devattr, &val);
  
  	if (ret)
  		return ret;
  
  	/*
  	 * input range is [0, 2.3V], val has 10 bits, so each bit
  	 * is worth 9/4 mV.
  	 */
  	val = DIV_ROUND_CLOSEST(val * 9, 4);
  
  	return sprintf(buf, "%u
  ", val);
  }
  
  static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
  static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, mc13783_adc_read_bp, NULL, 2);
  static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, mc13783_adc_read_gp, NULL, 5);
  static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, mc13783_adc_read_gp, NULL, 6);
  static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, mc13783_adc_read_gp, NULL, 7);
  static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, mc13783_adc_read_gp, NULL, 8);
  static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, mc13783_adc_read_gp, NULL, 9);
  static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, mc13783_adc_read_gp, NULL, 10);
  static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, mc13783_adc_read_gp, NULL, 11);
  static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, mc13783_adc_read_gp, NULL, 12);
  static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, mc13783_adc_read_gp, NULL, 13);
  static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, mc13783_adc_read_gp, NULL, 14);
  static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, mc13783_adc_read_gp, NULL, 15);
  
  static struct attribute *mc13783_attr_base[] = {
  	&dev_attr_name.attr,
  	&sensor_dev_attr_in2_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,
  	NULL
  };
  
  static const struct attribute_group mc13783_group_base = {
  	.attrs = mc13783_attr_base,
  };
  
  /* these are only used if MC13783_ADC_16CHANS is provided in driver data */
  static struct attribute *mc13783_attr_16chans[] = {
  	&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,
  	NULL
  };
  
  static const struct attribute_group mc13783_group_16chans = {
  	.attrs = mc13783_attr_16chans,
  };
  
  /* last four channels may be occupied by the touchscreen */
  static struct attribute *mc13783_attr_ts[] = {
  	&sensor_dev_attr_in12_input.dev_attr.attr,
  	&sensor_dev_attr_in13_input.dev_attr.attr,
  	&sensor_dev_attr_in14_input.dev_attr.attr,
  	&sensor_dev_attr_in15_input.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group mc13783_group_ts = {
  	.attrs = mc13783_attr_ts,
  };
  
  static int mc13783_adc_use_touchscreen(struct platform_device *pdev)
  {
  	struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
  	unsigned flags = mc13xxx_get_flags(priv->mc13xxx);
  
  	return flags & MC13XXX_USE_TOUCHSCREEN;
  }
  
  static int __init mc13783_adc_probe(struct platform_device *pdev)
  {
  	struct mc13783_adc_priv *priv;
  	int ret;
  	const struct platform_device_id *id = platform_get_device_id(pdev);
  	char *dash;
  
  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
  	snprintf(priv->name, ARRAY_SIZE(priv->name), "%s", id->name);
  	dash = strchr(priv->name, '-');
  	if (dash)
  		*dash = '\0';
  
  	platform_set_drvdata(pdev, priv);
  
  	/* Register sysfs hooks */
  	ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_base);
  	if (ret)
  		return ret;
  
  	if (id->driver_data & MC13783_ADC_16CHANS) {
  		ret = sysfs_create_group(&pdev->dev.kobj,
  				&mc13783_group_16chans);
  		if (ret)
  			goto out_err_create_16chans;
  	}
  
  	if (!mc13783_adc_use_touchscreen(pdev)) {
  		ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_ts);
  		if (ret)
  			goto out_err_create_ts;
  	}
  
  	priv->hwmon_dev = hwmon_device_register(&pdev->dev);
  	if (IS_ERR(priv->hwmon_dev)) {
  		ret = PTR_ERR(priv->hwmon_dev);
  		dev_err(&pdev->dev,
  				"hwmon_device_register failed with %d.
  ", ret);
  		goto out_err_register;
  	}
  
  	return 0;
  
  out_err_register:
  
  	if (!mc13783_adc_use_touchscreen(pdev))
  		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
  out_err_create_ts:
  
  	if (id->driver_data & MC13783_ADC_16CHANS)
  		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_16chans);
  out_err_create_16chans:
  
  	sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_base);
  	return ret;
  }
  
  static int mc13783_adc_remove(struct platform_device *pdev)
  {
  	struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
  	kernel_ulong_t driver_data = platform_get_device_id(pdev)->driver_data;
  
  	hwmon_device_unregister(priv->hwmon_dev);
  
  	if (!mc13783_adc_use_touchscreen(pdev))
  		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
  
  	if (driver_data & MC13783_ADC_16CHANS)
  		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_16chans);
  
  	sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_base);
  
  	return 0;
  }
  
  static const struct platform_device_id mc13783_adc_idtable[] = {
  	{
  		.name = "mc13783-adc",
  		.driver_data = MC13783_ADC_16CHANS,
  	}, {
  		.name = "mc13892-adc",
  		.driver_data = MC13783_ADC_BPDIV2,
  	}, {
  		/* sentinel */
  	}
  };
  MODULE_DEVICE_TABLE(platform, mc13783_adc_idtable);
  
  static struct platform_driver mc13783_adc_driver = {
  	.remove		= mc13783_adc_remove,
  	.driver		= {
  		.owner	= THIS_MODULE,
  		.name	= DRIVER_NAME,
  	},
  	.id_table	= mc13783_adc_idtable,
  };
  
  module_platform_driver_probe(mc13783_adc_driver, mc13783_adc_probe);
  
  MODULE_DESCRIPTION("MC13783 ADC driver");
  MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
  MODULE_LICENSE("GPL");