/*
   * MFD core driver for Ricoh RN5T618 PMIC
   *
   * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>

   * Copyright (C) 2016 Toradex AG

   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program. If not, see <http://www.gnu.org/licenses/>.
   */

  #include <linux/delay.h>

  #include <linux/i2c.h>
  #include <linux/mfd/core.h>
  #include <linux/mfd/rn5t618.h>
  #include <linux/module.h>

  #include <linux/of_device.h>

  #include <linux/reboot.h>

  #include <linux/regmap.h>
  
  static const struct mfd_cell rn5t618_cells[] = {
  	{ .name = "rn5t618-regulator" },
  	{ .name = "rn5t618-wdt" },
  };
  
  static bool rn5t618_volatile_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case RN5T618_WATCHDOGCNT:
  	case RN5T618_DCIRQ:
  	case RN5T618_ILIMDATAH ... RN5T618_AIN0DATAL:
  	case RN5T618_IR_ADC1 ... RN5T618_IR_ADC3:
  	case RN5T618_IR_GPR:
  	case RN5T618_IR_GPF:
  	case RN5T618_MON_IOIN:
  	case RN5T618_INTMON:
  		return true;
  	default:
  		return false;
  	}
  }
  
  static const struct regmap_config rn5t618_regmap_config = {
  	.reg_bits	= 8,
  	.val_bits	= 8,
  	.volatile_reg	= rn5t618_volatile_reg,
  	.max_register	= RN5T618_MAX_REG,
  	.cache_type	= REGCACHE_RBTREE,
  };
  
  static struct rn5t618 *rn5t618_pm_power_off;

  static struct notifier_block rn5t618_restart_handler;

  static void rn5t618_trigger_poweroff_sequence(bool repower)

  {
  	/* disable automatic repower-on */
  	regmap_update_bits(rn5t618_pm_power_off->regmap, RN5T618_REPCNT,

  			   RN5T618_REPCNT_REPWRON,
  			   repower ? RN5T618_REPCNT_REPWRON : 0);

  	/* start power-off sequence */
  	regmap_update_bits(rn5t618_pm_power_off->regmap, RN5T618_SLPCNT,
  			   RN5T618_SLPCNT_SWPWROFF, RN5T618_SLPCNT_SWPWROFF);
  }

  static void rn5t618_power_off(void)
  {
  	rn5t618_trigger_poweroff_sequence(false);
  }
  
  static int rn5t618_restart(struct notifier_block *this,
  			    unsigned long mode, void *cmd)
  {
  	rn5t618_trigger_poweroff_sequence(true);
  
  	/*
  	 * Re-power factor detection on PMIC side is not instant. 1ms
  	 * proved to be enough time until reset takes effect.
  	 */
  	mdelay(1);
  
  	return NOTIFY_DONE;
  }

  static const struct of_device_id rn5t618_of_match[] = {
  	{ .compatible = "ricoh,rn5t567", .data = (void *)RN5T567 },
  	{ .compatible = "ricoh,rn5t618", .data = (void *)RN5T618 },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, rn5t618_of_match);

  static int rn5t618_i2c_probe(struct i2c_client *i2c,
  			     const struct i2c_device_id *id)
  {

  	const struct of_device_id *of_id;

  	struct rn5t618 *priv;
  	int ret;

  	of_id = of_match_device(rn5t618_of_match, &i2c->dev);
  	if (!of_id) {
  		dev_err(&i2c->dev, "Failed to find matching DT ID
  ");
  		return -EINVAL;
  	}

  	priv = devm_kzalloc(&i2c->dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	i2c_set_clientdata(i2c, priv);

  	priv->variant = (long)of_id->data;

  
  	priv->regmap = devm_regmap_init_i2c(i2c, &rn5t618_regmap_config);
  	if (IS_ERR(priv->regmap)) {
  		ret = PTR_ERR(priv->regmap);
  		dev_err(&i2c->dev, "regmap init failed: %d
  ", ret);
  		return ret;
  	}

  	ret = devm_mfd_add_devices(&i2c->dev, -1, rn5t618_cells,
  				   ARRAY_SIZE(rn5t618_cells), NULL, 0, NULL);

  	if (ret) {
  		dev_err(&i2c->dev, "failed to add sub-devices: %d
  ", ret);
  		return ret;
  	}

  	rn5t618_pm_power_off = priv;

  	if (of_device_is_system_power_controller(i2c->dev.of_node)) {

  		if (!pm_power_off)

  			pm_power_off = rn5t618_power_off;

  		else

  			dev_warn(&i2c->dev, "Poweroff callback already assigned
  ");

  	}
  
  	rn5t618_restart_handler.notifier_call = rn5t618_restart;
  	rn5t618_restart_handler.priority = 192;
  
  	ret = register_restart_handler(&rn5t618_restart_handler);
  	if (ret) {
  		dev_err(&i2c->dev, "cannot register restart handler, %d
  ", ret);
  		return ret;

  	}
  
  	return 0;
  }
  
  static int rn5t618_i2c_remove(struct i2c_client *i2c)
  {
  	struct rn5t618 *priv = i2c_get_clientdata(i2c);
  
  	if (priv == rn5t618_pm_power_off) {
  		rn5t618_pm_power_off = NULL;
  		pm_power_off = NULL;
  	}

  	return 0;
  }

  static const struct i2c_device_id rn5t618_i2c_id[] = {
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, rn5t618_i2c_id);
  
  static struct i2c_driver rn5t618_i2c_driver = {
  	.driver = {
  		.name = "rn5t618",
  		.of_match_table = of_match_ptr(rn5t618_of_match),
  	},
  	.probe = rn5t618_i2c_probe,
  	.remove = rn5t618_i2c_remove,
  	.id_table = rn5t618_i2c_id,
  };
  
  module_i2c_driver(rn5t618_i2c_driver);
  
  MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");

  MODULE_DESCRIPTION("Ricoh RN5T567/618 MFD driver");

  MODULE_LICENSE("GPL v2");