/*
   * Battery driver for One Laptop Per Child board.
   *

   *	Copyright © 2006-2010  David Woodhouse <dwmw2@infradead.org>

   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */

  #include <linux/kernel.h>

  #include <linux/module.h>

  #include <linux/types.h>

  #include <linux/err.h>

  #include <linux/device.h>

  #include <linux/platform_device.h>
  #include <linux/power_supply.h>
  #include <linux/jiffies.h>
  #include <linux/sched.h>
  #include <asm/olpc.h>
  
  
  #define EC_BAT_VOLTAGE	0x10	/* uint16_t,	*9.76/32,    mV   */
  #define EC_BAT_CURRENT	0x11	/* int16_t,	*15.625/120, mA   */

  #define EC_BAT_ACR	0x12	/* int16_t,	*6250/15,    µAh  */

  #define EC_BAT_TEMP	0x13	/* uint16_t,	*100/256,   °C  */
  #define EC_AMB_TEMP	0x14	/* uint16_t,	*100/256,   °C  */
  #define EC_BAT_STATUS	0x15	/* uint8_t,	bitmask */
  #define EC_BAT_SOC	0x16	/* uint8_t,	percentage */
  #define EC_BAT_SERIAL	0x17	/* uint8_t[6] */
  #define EC_BAT_EEPROM	0x18	/* uint8_t adr as input, uint8_t output */
  #define EC_BAT_ERRCODE	0x1f	/* uint8_t,	bitmask */
  
  #define BAT_STAT_PRESENT	0x01
  #define BAT_STAT_FULL		0x02
  #define BAT_STAT_LOW		0x04
  #define BAT_STAT_DESTROY	0x08
  #define BAT_STAT_AC		0x10
  #define BAT_STAT_CHARGING	0x20
  #define BAT_STAT_DISCHARGING	0x40

  #define BAT_STAT_TRICKLE	0x80

  
  #define BAT_ERR_INFOFAIL	0x02
  #define BAT_ERR_OVERVOLTAGE	0x04
  #define BAT_ERR_OVERTEMP	0x05
  #define BAT_ERR_GAUGESTOP	0x06
  #define BAT_ERR_OUT_OF_CONTROL	0x07
  #define BAT_ERR_ID_FAIL		0x09
  #define BAT_ERR_ACR_FAIL	0x10
  
  #define BAT_ADDR_MFR_TYPE	0x5F
  
  /*********************************************************************
   *		Power
   *********************************************************************/
  
  static int olpc_ac_get_prop(struct power_supply *psy,
  			    enum power_supply_property psp,
  			    union power_supply_propval *val)
  {
  	int ret = 0;
  	uint8_t status;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
  		if (ret)
  			return ret;
  
  		val->intval = !!(status & BAT_STAT_AC);
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  	return ret;
  }
  
  static enum power_supply_property olpc_ac_props[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static struct power_supply olpc_ac = {
  	.name = "olpc-ac",
  	.type = POWER_SUPPLY_TYPE_MAINS,
  	.properties = olpc_ac_props,
  	.num_properties = ARRAY_SIZE(olpc_ac_props),
  	.get_property = olpc_ac_get_prop,
  };

  static char bat_serial[17]; /* Ick */

  static int olpc_bat_get_status(union power_supply_propval *val, uint8_t ec_byte)
  {
  	if (olpc_platform_info.ecver > 0x44) {

  		if (ec_byte & (BAT_STAT_CHARGING | BAT_STAT_TRICKLE))

  			val->intval = POWER_SUPPLY_STATUS_CHARGING;
  		else if (ec_byte & BAT_STAT_DISCHARGING)
  			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  		else if (ec_byte & BAT_STAT_FULL)
  			val->intval = POWER_SUPPLY_STATUS_FULL;
  		else /* er,... */
  			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  	} else {
  		/* Older EC didn't report charge/discharge bits */
  		if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
  			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  		else if (ec_byte & BAT_STAT_FULL)
  			val->intval = POWER_SUPPLY_STATUS_FULL;
  		else /* Not _necessarily_ true but EC doesn't tell all yet */
  			val->intval = POWER_SUPPLY_STATUS_CHARGING;
  	}
  
  	return 0;
  }
  
  static int olpc_bat_get_health(union power_supply_propval *val)
  {
  	uint8_t ec_byte;
  	int ret;
  
  	ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
  	if (ret)
  		return ret;
  
  	switch (ec_byte) {
  	case 0:
  		val->intval = POWER_SUPPLY_HEALTH_GOOD;
  		break;
  
  	case BAT_ERR_OVERTEMP:
  		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  		break;
  
  	case BAT_ERR_OVERVOLTAGE:
  		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
  		break;
  
  	case BAT_ERR_INFOFAIL:
  	case BAT_ERR_OUT_OF_CONTROL:
  	case BAT_ERR_ID_FAIL:
  	case BAT_ERR_ACR_FAIL:
  		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
  		break;
  
  	default:
  		/* Eep. We don't know this failure code */
  		ret = -EIO;
  	}
  
  	return ret;
  }
  
  static int olpc_bat_get_mfr(union power_supply_propval *val)
  {
  	uint8_t ec_byte;
  	int ret;
  
  	ec_byte = BAT_ADDR_MFR_TYPE;
  	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
  	if (ret)
  		return ret;
  
  	switch (ec_byte >> 4) {
  	case 1:
  		val->strval = "Gold Peak";
  		break;
  	case 2:
  		val->strval = "BYD";
  		break;
  	default:
  		val->strval = "Unknown";
  		break;
  	}
  
  	return ret;
  }
  
  static int olpc_bat_get_tech(union power_supply_propval *val)
  {
  	uint8_t ec_byte;
  	int ret;
  
  	ec_byte = BAT_ADDR_MFR_TYPE;
  	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
  	if (ret)
  		return ret;
  
  	switch (ec_byte & 0xf) {
  	case 1:
  		val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
  		break;
  	case 2:
  		val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
  		break;
  	default:
  		val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
  		break;
  	}
  
  	return ret;
  }

  static int olpc_bat_get_charge_full_design(union power_supply_propval *val)
  {
  	uint8_t ec_byte;
  	union power_supply_propval tech;
  	int ret, mfr;
  
  	ret = olpc_bat_get_tech(&tech);
  	if (ret)
  		return ret;
  
  	ec_byte = BAT_ADDR_MFR_TYPE;
  	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
  	if (ret)
  		return ret;
  
  	mfr = ec_byte >> 4;
  
  	switch (tech.intval) {
  	case POWER_SUPPLY_TECHNOLOGY_NiMH:
  		switch (mfr) {
  		case 1: /* Gold Peak */
  			val->intval = 3000000*.8;
  			break;
  		default:
  			return -EIO;
  		}
  		break;
  
  	case POWER_SUPPLY_TECHNOLOGY_LiFe:
  		switch (mfr) {
  		case 1: /* Gold Peak */
  			val->intval = 2800000;
  			break;
  		case 2: /* BYD */
  			val->intval = 3100000;
  			break;
  		default:
  			return -EIO;
  		}
  		break;
  
  	default:
  		return -EIO;
  	}
  
  	return ret;
  }

  static int olpc_bat_get_charge_now(union power_supply_propval *val)
  {
  	uint8_t soc;
  	union power_supply_propval full;
  	int ret;
  
  	ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &soc, 1);
  	if (ret)
  		return ret;
  
  	ret = olpc_bat_get_charge_full_design(&full);
  	if (ret)
  		return ret;
  
  	val->intval = soc * (full.intval / 100);
  	return 0;
  }

  /*********************************************************************
   *		Battery properties
   *********************************************************************/
  static int olpc_bat_get_property(struct power_supply *psy,
  				 enum power_supply_property psp,
  				 union power_supply_propval *val)
  {
  	int ret = 0;

  	__be16 ec_word;

  	uint8_t ec_byte;

  	__be64 ser_buf;

  
  	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
  	if (ret)
  		return ret;
  
  	/* Theoretically there's a race here -- the battery could be
  	   removed immediately after we check whether it's present, and
  	   then we query for some other property of the now-absent battery.
  	   It doesn't matter though -- the EC will return the last-known
  	   information, and it's as if we just ran that _little_ bit faster
  	   and managed to read it out before the battery went away. */

  	if (!(ec_byte & (BAT_STAT_PRESENT | BAT_STAT_TRICKLE)) &&
  			psp != POWER_SUPPLY_PROP_PRESENT)

  		return -ENODEV;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:

  		ret = olpc_bat_get_status(val, ec_byte);
  		if (ret)
  			return ret;
  		break;

  	case POWER_SUPPLY_PROP_CHARGE_TYPE:
  		if (ec_byte & BAT_STAT_TRICKLE)
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
  		else if (ec_byte & BAT_STAT_CHARGING)
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
  		else
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
  		break;

  	case POWER_SUPPLY_PROP_PRESENT:

  		val->intval = !!(ec_byte & (BAT_STAT_PRESENT |
  					    BAT_STAT_TRICKLE));

  		break;
  
  	case POWER_SUPPLY_PROP_HEALTH:
  		if (ec_byte & BAT_STAT_DESTROY)
  			val->intval = POWER_SUPPLY_HEALTH_DEAD;
  		else {

  			ret = olpc_bat_get_health(val);

  			if (ret)
  				return ret;

  		}
  		break;
  
  	case POWER_SUPPLY_PROP_MANUFACTURER:

  		ret = olpc_bat_get_mfr(val);

  		if (ret)
  			return ret;

  		break;
  	case POWER_SUPPLY_PROP_TECHNOLOGY:

  		ret = olpc_bat_get_tech(val);

  		if (ret)
  			return ret;

  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_AVG:

  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:

  		ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
  		if (ret)
  			return ret;

  		val->intval = (s16)be16_to_cpu(ec_word) * 9760L / 32;

  		break;
  	case POWER_SUPPLY_PROP_CURRENT_AVG:

  	case POWER_SUPPLY_PROP_CURRENT_NOW:

  		ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
  		if (ret)
  			return ret;

  		val->intval = (s16)be16_to_cpu(ec_word) * 15625L / 120;

  		break;
  	case POWER_SUPPLY_PROP_CAPACITY:
  		ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
  		if (ret)
  			return ret;
  		val->intval = ec_byte;
  		break;

  	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
  		if (ec_byte & BAT_STAT_FULL)
  			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
  		else if (ec_byte & BAT_STAT_LOW)
  			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
  		else
  			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
  		break;

  	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
  		ret = olpc_bat_get_charge_full_design(val);
  		if (ret)
  			return ret;
  		break;

  	case POWER_SUPPLY_PROP_CHARGE_NOW:
  		ret = olpc_bat_get_charge_now(val);
  		if (ret)
  			return ret;
  		break;

  	case POWER_SUPPLY_PROP_TEMP:
  		ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
  		if (ret)
  			return ret;

  		val->intval = (s16)be16_to_cpu(ec_word) * 100 / 256;

  		break;
  	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
  		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
  		if (ret)
  			return ret;

  		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;

  		break;

  	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
  		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
  		if (ret)
  			return ret;

  		val->intval = (s16)be16_to_cpu(ec_word) * 6250 / 15;

  		break;

  	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
  		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
  		if (ret)
  			return ret;
  
  		sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
  		val->strval = bat_serial;
  		break;

  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	return ret;
  }

  static enum power_supply_property olpc_xo1_bat_props[] = {

  	POWER_SUPPLY_PROP_STATUS,

  	POWER_SUPPLY_PROP_CHARGE_TYPE,

  	POWER_SUPPLY_PROP_PRESENT,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_VOLTAGE_AVG,

  	POWER_SUPPLY_PROP_VOLTAGE_NOW,

  	POWER_SUPPLY_PROP_CURRENT_AVG,

  	POWER_SUPPLY_PROP_CURRENT_NOW,

  	POWER_SUPPLY_PROP_CAPACITY,

  	POWER_SUPPLY_PROP_CAPACITY_LEVEL,

  	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,

  	POWER_SUPPLY_PROP_CHARGE_NOW,

  	POWER_SUPPLY_PROP_TEMP,
  	POWER_SUPPLY_PROP_TEMP_AMBIENT,
  	POWER_SUPPLY_PROP_MANUFACTURER,

  	POWER_SUPPLY_PROP_SERIAL_NUMBER,

  	POWER_SUPPLY_PROP_CHARGE_COUNTER,

  };

  /* XO-1.5 does not have ambient temperature property */
  static enum power_supply_property olpc_xo15_bat_props[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_CHARGE_TYPE,
  	POWER_SUPPLY_PROP_PRESENT,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_VOLTAGE_AVG,

  	POWER_SUPPLY_PROP_VOLTAGE_NOW,

  	POWER_SUPPLY_PROP_CURRENT_AVG,

  	POWER_SUPPLY_PROP_CURRENT_NOW,

  	POWER_SUPPLY_PROP_CAPACITY,
  	POWER_SUPPLY_PROP_CAPACITY_LEVEL,

  	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
  	POWER_SUPPLY_PROP_CHARGE_NOW,

  	POWER_SUPPLY_PROP_TEMP,
  	POWER_SUPPLY_PROP_MANUFACTURER,
  	POWER_SUPPLY_PROP_SERIAL_NUMBER,
  	POWER_SUPPLY_PROP_CHARGE_COUNTER,
  };

  /* EEPROM reading goes completely around the power_supply API, sadly */
  
  #define EEPROM_START	0x20
  #define EEPROM_END	0x80
  #define EEPROM_SIZE	(EEPROM_END - EEPROM_START)

  static ssize_t olpc_bat_eeprom_read(struct file *filp, struct kobject *kobj,

  		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
  {
  	uint8_t ec_byte;

  	int ret;
  	int i;

  
  	if (off >= EEPROM_SIZE)
  		return 0;
  	if (off + count > EEPROM_SIZE)
  		count = EEPROM_SIZE - off;

  	for (i = 0; i < count; i++) {
  		ec_byte = EEPROM_START + off + i;
  		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &buf[i], 1);

  		if (ret) {

  			pr_err("olpc-battery: "
  			       "EC_BAT_EEPROM cmd @ 0x%x failed - %d!
  ",
  			       ec_byte, ret);

  			return -EIO;
  		}
  	}
  
  	return count;
  }
  
  static struct bin_attribute olpc_bat_eeprom = {
  	.attr = {
  		.name = "eeprom",
  		.mode = S_IRUGO,

  	},
  	.size = 0,
  	.read = olpc_bat_eeprom_read,
  };

  /* Allow userspace to see the specific error value pulled from the EC */
  
  static ssize_t olpc_bat_error_read(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	uint8_t ec_byte;
  	ssize_t ret;
  
  	ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
  	if (ret < 0)
  		return ret;
  
  	return sprintf(buf, "%d
  ", ec_byte);
  }
  
  static struct device_attribute olpc_bat_error = {
  	.attr = {
  		.name = "error",
  		.mode = S_IRUGO,
  	},
  	.show = olpc_bat_error_read,
  };

  /*********************************************************************
   *		Initialisation
   *********************************************************************/

  static struct power_supply olpc_bat = {

  	.name = "olpc-battery",

  	.get_property = olpc_bat_get_property,
  	.use_for_apm = 1,
  };

  static int olpc_battery_suspend(struct platform_device *pdev,
  				pm_message_t state)
  {
  	if (device_may_wakeup(olpc_ac.dev))
  		olpc_ec_wakeup_set(EC_SCI_SRC_ACPWR);
  	else
  		olpc_ec_wakeup_clear(EC_SCI_SRC_ACPWR);
  
  	if (device_may_wakeup(olpc_bat.dev))
  		olpc_ec_wakeup_set(EC_SCI_SRC_BATTERY | EC_SCI_SRC_BATSOC
  				   | EC_SCI_SRC_BATERR);
  	else
  		olpc_ec_wakeup_clear(EC_SCI_SRC_BATTERY | EC_SCI_SRC_BATSOC
  				     | EC_SCI_SRC_BATERR);
  
  	return 0;
  }

  static int __devinit olpc_battery_probe(struct platform_device *pdev)

  {

  	int ret;

  	uint8_t status;

  	/*
  	 * We've seen a number of EC protocol changes; this driver requires
  	 * the latest EC protocol, supported by 0x44 and above.
  	 */
  	if (olpc_platform_info.ecver < 0x44) {
  		printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
  			"battery driver.
  ", olpc_platform_info.ecver);

  		return -ENXIO;
  	}
  
  	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
  	if (ret)
  		return ret;
  
  	/* Ignore the status. It doesn't actually matter */

  	ret = power_supply_register(&pdev->dev, &olpc_ac);

  	if (ret)

  		return ret;

  	if (olpc_board_at_least(olpc_board_pre(0xd0))) { /* XO-1.5 */
  		olpc_bat.properties = olpc_xo15_bat_props;
  		olpc_bat.num_properties = ARRAY_SIZE(olpc_xo15_bat_props);
  	} else { /* XO-1 */
  		olpc_bat.properties = olpc_xo1_bat_props;
  		olpc_bat.num_properties = ARRAY_SIZE(olpc_xo1_bat_props);
  	}

  	ret = power_supply_register(&pdev->dev, &olpc_bat);

  	if (ret)
  		goto battery_failed;

  	ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
  	if (ret)
  		goto eeprom_failed;

  	ret = device_create_file(olpc_bat.dev, &olpc_bat_error);
  	if (ret)
  		goto error_failed;

  	if (olpc_ec_wakeup_available()) {
  		device_set_wakeup_capable(olpc_ac.dev, true);
  		device_set_wakeup_capable(olpc_bat.dev, true);
  	}

  	return 0;

  error_failed:
  	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);

  eeprom_failed:
  	power_supply_unregister(&olpc_bat);

  battery_failed:
  	power_supply_unregister(&olpc_ac);

  	return ret;
  }

  static int __devexit olpc_battery_remove(struct platform_device *pdev)

  {

  	device_remove_file(olpc_bat.dev, &olpc_bat_error);

  	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);

  	power_supply_unregister(&olpc_bat);
  	power_supply_unregister(&olpc_ac);

  	return 0;

  }

  static const struct of_device_id olpc_battery_ids[] __devinitconst = {
  	{ .compatible = "olpc,xo1-battery" },
  	{}
  };
  MODULE_DEVICE_TABLE(of, olpc_battery_ids);

  static struct platform_driver olpc_battery_driver = {

  	.driver = {
  		.name = "olpc-battery",
  		.owner = THIS_MODULE,
  		.of_match_table = olpc_battery_ids,
  	},
  	.probe = olpc_battery_probe,
  	.remove = __devexit_p(olpc_battery_remove),

  	.suspend = olpc_battery_suspend,

  };

  module_platform_driver(olpc_battery_driver);

  
  MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");