/*
   * Linear Technology LTC3589,LTC3589-1 regulator support
   *
   * Copyright (c) 2014 Philipp Zabel <p.zabel@pengutronix.de>, Pengutronix
   *
   * See file CREDITS for list of people who contributed to this
   * project.
   *
   * 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.
   *
   * 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/i2c.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/of.h>
  #include <linux/regmap.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/of_regulator.h>
  
  #define DRIVER_NAME		"ltc3589"
  
  #define LTC3589_IRQSTAT		0x02
  #define LTC3589_SCR1		0x07
  #define LTC3589_OVEN		0x10
  #define LTC3589_SCR2		0x12
  #define LTC3589_PGSTAT		0x13
  #define LTC3589_VCCR		0x20
  #define LTC3589_CLIRQ		0x21
  #define LTC3589_B1DTV1		0x23
  #define LTC3589_B1DTV2		0x24
  #define LTC3589_VRRCR		0x25
  #define LTC3589_B2DTV1		0x26
  #define LTC3589_B2DTV2		0x27
  #define LTC3589_B3DTV1		0x29
  #define LTC3589_B3DTV2		0x2a
  #define LTC3589_L2DTV1		0x32
  #define LTC3589_L2DTV2		0x33
  
  #define LTC3589_IRQSTAT_PGOOD_TIMEOUT	BIT(3)
  #define LTC3589_IRQSTAT_UNDERVOLT_WARN	BIT(4)
  #define LTC3589_IRQSTAT_UNDERVOLT_FAULT	BIT(5)
  #define LTC3589_IRQSTAT_THERMAL_WARN	BIT(6)
  #define LTC3589_IRQSTAT_THERMAL_FAULT	BIT(7)
  
  #define LTC3589_OVEN_SW1		BIT(0)
  #define LTC3589_OVEN_SW2		BIT(1)
  #define LTC3589_OVEN_SW3		BIT(2)
  #define LTC3589_OVEN_BB_OUT		BIT(3)
  #define LTC3589_OVEN_LDO2		BIT(4)
  #define LTC3589_OVEN_LDO3		BIT(5)
  #define LTC3589_OVEN_LDO4		BIT(6)
  #define LTC3589_OVEN_SW_CTRL		BIT(7)
  
  #define LTC3589_VCCR_SW1_GO		BIT(0)
  #define LTC3589_VCCR_SW2_GO		BIT(2)
  #define LTC3589_VCCR_SW3_GO		BIT(4)
  #define LTC3589_VCCR_LDO2_GO		BIT(6)
  
  enum ltc3589_variant {
  	LTC3589,
  	LTC3589_1,
  	LTC3589_2,
  };
  
  enum ltc3589_reg {
  	LTC3589_SW1,
  	LTC3589_SW2,
  	LTC3589_SW3,
  	LTC3589_BB_OUT,
  	LTC3589_LDO1,
  	LTC3589_LDO2,
  	LTC3589_LDO3,
  	LTC3589_LDO4,
  	LTC3589_NUM_REGULATORS,
  };
  
  struct ltc3589_regulator {
  	struct regulator_desc desc;
  
  	/* External feedback voltage divider */
  	unsigned int r1;
  	unsigned int r2;
  };
  
  struct ltc3589 {
  	struct regmap *regmap;
  	struct device *dev;
  	enum ltc3589_variant variant;
  	struct ltc3589_regulator regulator_descs[LTC3589_NUM_REGULATORS];
  	struct regulator_dev *regulators[LTC3589_NUM_REGULATORS];
  };
  
  static const int ltc3589_ldo4[] = {
  	2800000, 2500000, 1800000, 3300000,
  };
  
  static const int ltc3589_12_ldo4[] = {
  	1200000, 1800000, 2500000, 3200000,
  };
  
  static int ltc3589_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
  {
  	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
  	int sel, shift;
  
  	if (unlikely(ramp_delay <= 0))
  		return -EINVAL;
  
  	/* VRRCR slew rate offsets are the same as VCCR go bit offsets */
  	shift = ffs(rdev->desc->apply_bit) - 1;
  
  	/* The slew rate can be set to 0.88, 1.75, 3.5, or 7 mV/uS */
  	for (sel = 0; sel < 4; sel++) {
  		if ((880 << sel) >= ramp_delay) {
  			return regmap_update_bits(ltc3589->regmap,
  						  LTC3589_VRRCR,
  						  0x3 << shift, sel << shift);
  		}
  	}
  	return -EINVAL;
  }
  
  static int ltc3589_set_suspend_voltage(struct regulator_dev *rdev, int uV)
  {
  	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
  	int sel;
  
  	sel = regulator_map_voltage_linear(rdev, uV, uV);
  	if (sel < 0)
  		return sel;
  
  	/* DTV2 register follows right after the corresponding DTV1 register */
  	return regmap_update_bits(ltc3589->regmap, rdev->desc->vsel_reg + 1,
  				  rdev->desc->vsel_mask, sel);
  }
  
  static int ltc3589_set_suspend_mode(struct regulator_dev *rdev,
  				    unsigned int mode)
  {
  	struct ltc3589 *ltc3589 = rdev_get_drvdata(rdev);
  	int mask, bit = 0;
  
  	/* VCCR reference selects are right next to the VCCR go bits */
  	mask = rdev->desc->apply_bit << 1;
  
  	if (mode == REGULATOR_MODE_STANDBY)
  		bit = mask;	/* Select DTV2 */
  
  	mask |= rdev->desc->apply_bit;
  	bit |= rdev->desc->apply_bit;
  	return regmap_update_bits(ltc3589->regmap, LTC3589_VCCR, mask, bit);
  }
  
  /* SW1, SW2, SW3, LDO2 */
  static struct regulator_ops ltc3589_linear_regulator_ops = {
  	.enable = regulator_enable_regmap,
  	.disable = regulator_disable_regmap,
  	.is_enabled = regulator_is_enabled_regmap,
  	.list_voltage = regulator_list_voltage_linear,
  	.set_voltage_sel = regulator_set_voltage_sel_regmap,
  	.get_voltage_sel = regulator_get_voltage_sel_regmap,
  	.set_ramp_delay = ltc3589_set_ramp_delay,
  	.set_voltage_time_sel = regulator_set_voltage_time_sel,
  	.set_suspend_voltage = ltc3589_set_suspend_voltage,
  	.set_suspend_mode = ltc3589_set_suspend_mode,
  };
  
  /* BB_OUT, LDO3 */
  static struct regulator_ops ltc3589_fixed_regulator_ops = {
  	.enable = regulator_enable_regmap,
  	.disable = regulator_disable_regmap,
  	.is_enabled = regulator_is_enabled_regmap,
  };
  
  /* LDO1 */
  static struct regulator_ops ltc3589_fixed_standby_regulator_ops = {
  };
  
  /* LDO4 */
  static struct regulator_ops ltc3589_table_regulator_ops = {
  	.enable = regulator_enable_regmap,
  	.disable = regulator_disable_regmap,
  	.is_enabled = regulator_is_enabled_regmap,
  	.list_voltage = regulator_list_voltage_table,
  	.set_voltage_sel = regulator_set_voltage_sel_regmap,
  	.get_voltage_sel = regulator_get_voltage_sel_regmap,
  };
  
  
  #define LTC3589_REG(_name, _ops, en_bit, dtv1_reg, dtv_mask, go_bit)	\
  	[LTC3589_ ## _name] = {						\
  		.desc = {						\
  			.name = #_name,					\
  			.n_voltages = (dtv_mask) + 1,			\
  			.min_uV = (go_bit) ? 362500 : 0,		\
  			.uV_step = (go_bit) ? 12500 : 0,		\
  			.ramp_delay = (go_bit) ? 1750 : 0,		\
  			.fixed_uV = (dtv_mask) ? 0 : 800000,		\
  			.ops = &ltc3589_ ## _ops ## _regulator_ops,	\
  			.type = REGULATOR_VOLTAGE,			\
  			.id = LTC3589_ ## _name,			\
  			.owner = THIS_MODULE,				\
  			.vsel_reg = (dtv1_reg),			\
  			.vsel_mask = (dtv_mask),			\
  			.apply_reg = (go_bit) ? LTC3589_VCCR : 0,	\
  			.apply_bit = (go_bit),				\
  			.enable_reg = (en_bit) ? LTC3589_OVEN : 0,	\
  			.enable_mask = (en_bit),			\
  		},							\
  	}
  
  #define LTC3589_LINEAR_REG(_name, _dtv1)				\
  	LTC3589_REG(_name, linear, LTC3589_OVEN_ ## _name,		\
  		    LTC3589_ ## _dtv1, 0x1f,				\
  		    LTC3589_VCCR_ ## _name ## _GO)
  
  #define LTC3589_FIXED_REG(_name) \
  	LTC3589_REG(_name, fixed, LTC3589_OVEN_ ## _name, 0, 0, 0)
  
  static struct ltc3589_regulator ltc3589_regulators[LTC3589_NUM_REGULATORS] = {
  	LTC3589_LINEAR_REG(SW1, B1DTV1),
  	LTC3589_LINEAR_REG(SW2, B2DTV1),
  	LTC3589_LINEAR_REG(SW3, B3DTV1),
  	LTC3589_FIXED_REG(BB_OUT),
  	LTC3589_REG(LDO1, fixed_standby, 0, 0, 0, 0),
  	LTC3589_LINEAR_REG(LDO2, L2DTV1),
  	LTC3589_FIXED_REG(LDO3),
  	LTC3589_REG(LDO4, table, LTC3589_OVEN_LDO4, LTC3589_L2DTV2, 0x60, 0),
  };
  
  #ifdef CONFIG_OF
  static struct of_regulator_match ltc3589_matches[LTC3589_NUM_REGULATORS] = {
  	{ .name = "sw1",    },
  	{ .name = "sw2",    },
  	{ .name = "sw3",    },
  	{ .name = "bb-out", },
  	{ .name = "ldo1",   }, /* standby */
  	{ .name = "ldo2",   },
  	{ .name = "ldo3",   },
  	{ .name = "ldo4",   },
  };
  
  static int ltc3589_parse_regulators_dt(struct ltc3589 *ltc3589)
  {
  	struct device *dev = ltc3589->dev;
  	struct device_node *node;
  	int i, ret;
  
  	node = of_get_child_by_name(dev->of_node, "regulators");
  	if (!node) {
  		dev_err(dev, "regulators node not found
  ");
  		return -EINVAL;
  	}
  
  	ret = of_regulator_match(dev, node, ltc3589_matches,
  				 ARRAY_SIZE(ltc3589_matches));
  	of_node_put(node);
  	if (ret < 0) {
  		dev_err(dev, "Error parsing regulator init data: %d
  ", ret);
  		return ret;
  	}
  	if (ret != LTC3589_NUM_REGULATORS) {
  		dev_err(dev, "Only %d regulators described in device tree
  ",
  			ret);
  		return -EINVAL;
  	}
  
  	/* Parse feedback voltage dividers. LDO3 and LDO4 don't have them */
  	for (i = 0; i < LTC3589_LDO3; i++) {
  		struct ltc3589_regulator *desc = &ltc3589->regulator_descs[i];
  		struct device_node *np = ltc3589_matches[i].of_node;
  		u32 vdiv[2];
  
  		ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider",
  						 vdiv, 2);
  		if (ret) {
  			dev_err(dev, "Failed to parse voltage divider: %d
  ",
  				ret);
  			return ret;
  		}
  
  		desc->r1 = vdiv[0];
  		desc->r2 = vdiv[1];
  	}
  
  	return 0;
  }
  
  static inline struct regulator_init_data *match_init_data(int index)
  {
  	return ltc3589_matches[index].init_data;
  }
  
  static inline struct device_node *match_of_node(int index)
  {
  	return ltc3589_matches[index].of_node;
  }
  #else
  static inline int ltc3589_parse_regulators_dt(struct ltc3589 *ltc3589)
  {
  	return 0;
  }
  
  static inline struct regulator_init_data *match_init_data(int index)
  {
  	return NULL;
  }
  
  static inline struct device_node *match_of_node(int index)
  {
  	return NULL;
  }
  #endif
  
  static bool ltc3589_writeable_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case LTC3589_IRQSTAT:
  	case LTC3589_SCR1:
  	case LTC3589_OVEN:
  	case LTC3589_SCR2:
  	case LTC3589_VCCR:
  	case LTC3589_CLIRQ:
  	case LTC3589_B1DTV1:
  	case LTC3589_B1DTV2:
  	case LTC3589_VRRCR:
  	case LTC3589_B2DTV1:
  	case LTC3589_B2DTV2:
  	case LTC3589_B3DTV1:
  	case LTC3589_B3DTV2:
  	case LTC3589_L2DTV1:
  	case LTC3589_L2DTV2:
  		return true;
  	}
  	return false;
  }
  
  static bool ltc3589_readable_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case LTC3589_IRQSTAT:
  	case LTC3589_SCR1:
  	case LTC3589_OVEN:
  	case LTC3589_SCR2:
  	case LTC3589_PGSTAT:
  	case LTC3589_VCCR:
  	case LTC3589_B1DTV1:
  	case LTC3589_B1DTV2:
  	case LTC3589_VRRCR:
  	case LTC3589_B2DTV1:
  	case LTC3589_B2DTV2:
  	case LTC3589_B3DTV1:
  	case LTC3589_B3DTV2:
  	case LTC3589_L2DTV1:
  	case LTC3589_L2DTV2:
  		return true;
  	}
  	return false;
  }
  
  static bool ltc3589_volatile_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case LTC3589_IRQSTAT:
  	case LTC3589_PGSTAT:
  	case LTC3589_VCCR:
  		return true;
  	}
  	return false;
  }
  
  static const struct reg_default ltc3589_reg_defaults[] = {
  	{ LTC3589_SCR1,   0x00 },
  	{ LTC3589_OVEN,   0x00 },
  	{ LTC3589_SCR2,   0x00 },
  	{ LTC3589_VCCR,   0x00 },
  	{ LTC3589_B1DTV1, 0x19 },
  	{ LTC3589_B1DTV2, 0x19 },
  	{ LTC3589_VRRCR,  0xff },
  	{ LTC3589_B2DTV1, 0x19 },
  	{ LTC3589_B2DTV2, 0x19 },
  	{ LTC3589_B3DTV1, 0x19 },
  	{ LTC3589_B3DTV2, 0x19 },
  	{ LTC3589_L2DTV1, 0x19 },
  	{ LTC3589_L2DTV2, 0x19 },
  };
  
  static const struct regmap_config ltc3589_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  	.writeable_reg = ltc3589_writeable_reg,
  	.readable_reg = ltc3589_readable_reg,
  	.volatile_reg = ltc3589_volatile_reg,
  	.max_register = LTC3589_L2DTV2,
  	.reg_defaults = ltc3589_reg_defaults,
  	.num_reg_defaults = ARRAY_SIZE(ltc3589_reg_defaults),
  	.use_single_rw = true,
  	.cache_type = REGCACHE_RBTREE,
  };
  
  
  static irqreturn_t ltc3589_isr(int irq, void *dev_id)
  {
  	struct ltc3589 *ltc3589 = dev_id;
  	unsigned int i, irqstat, event;
  
  	regmap_read(ltc3589->regmap, LTC3589_IRQSTAT, &irqstat);
  
  	if (irqstat & LTC3589_IRQSTAT_THERMAL_WARN) {
  		event = REGULATOR_EVENT_OVER_TEMP;
  		for (i = 0; i < LTC3589_NUM_REGULATORS; i++)
  			regulator_notifier_call_chain(ltc3589->regulators[i],
  						      event, NULL);
  	}
  
  	if (irqstat & LTC3589_IRQSTAT_UNDERVOLT_WARN) {
  		event = REGULATOR_EVENT_UNDER_VOLTAGE;
  		for (i = 0; i < LTC3589_NUM_REGULATORS; i++)
  			regulator_notifier_call_chain(ltc3589->regulators[i],
  						      event, NULL);
  	}
  
  	/* Clear warning condition */
  	regmap_write(ltc3589->regmap, LTC3589_CLIRQ, 0);
  
  	return IRQ_HANDLED;
  }
  
  static inline unsigned int ltc3589_scale(unsigned int uV, u32 r1, u32 r2)
  {
  	uint64_t tmp;
  	if (uV == 0)
  		return 0;
  	tmp = (uint64_t)uV * r1;
  	do_div(tmp, r2);
  	return uV + (unsigned int)tmp;
  }
  
  static void ltc3589_apply_fb_voltage_divider(struct ltc3589_regulator *rdesc)
  {
  	struct regulator_desc *desc = &rdesc->desc;
  
  	if (!rdesc->r1 || !rdesc->r2)
  		return;
  
  	desc->min_uV = ltc3589_scale(desc->min_uV, rdesc->r1, rdesc->r2);
  	desc->uV_step = ltc3589_scale(desc->uV_step, rdesc->r1, rdesc->r2);
  	desc->fixed_uV = ltc3589_scale(desc->fixed_uV, rdesc->r1, rdesc->r2);
  }
  
  static int ltc3589_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct device *dev = &client->dev;
  	struct ltc3589_regulator *descs;
  	struct ltc3589 *ltc3589;
  	int i, ret;
  
  	ltc3589 = devm_kzalloc(dev, sizeof(*ltc3589), GFP_KERNEL);
  	if (!ltc3589)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, ltc3589);
  	ltc3589->variant = id->driver_data;
  	ltc3589->dev = dev;
  
  	descs = ltc3589->regulator_descs;
  	memcpy(descs, ltc3589_regulators, sizeof(ltc3589_regulators));
  	if (ltc3589->variant == LTC3589) {
  		descs[LTC3589_LDO3].desc.fixed_uV = 1800000;
  		descs[LTC3589_LDO4].desc.volt_table = ltc3589_ldo4;
  	} else {
  		descs[LTC3589_LDO3].desc.fixed_uV = 2800000;
  		descs[LTC3589_LDO4].desc.volt_table = ltc3589_12_ldo4;
  	}
  
  	ltc3589->regmap = devm_regmap_init_i2c(client, &ltc3589_regmap_config);
  	if (IS_ERR(ltc3589->regmap)) {
  		ret = PTR_ERR(ltc3589->regmap);
  		dev_err(dev, "failed to initialize regmap: %d
  ", ret);
  		return ret;
  	}
  
  	ret = ltc3589_parse_regulators_dt(ltc3589);
  	if (ret)
  		return ret;
  
  	for (i = 0; i < LTC3589_NUM_REGULATORS; i++) {
  		struct ltc3589_regulator *rdesc = &ltc3589->regulator_descs[i];
  		struct regulator_desc *desc = &rdesc->desc;
  		struct regulator_init_data *init_data;
  		struct regulator_config config = { };
  
  		init_data = match_init_data(i);
  
  		if (i < LTC3589_LDO3)
  			ltc3589_apply_fb_voltage_divider(rdesc);
  
  		config.dev = dev;
  		config.init_data = init_data;
  		config.driver_data = ltc3589;
  		config.of_node = match_of_node(i);
  
  		ltc3589->regulators[i] = devm_regulator_register(dev, desc,
  								 &config);
  		if (IS_ERR(ltc3589->regulators[i])) {
  			ret = PTR_ERR(ltc3589->regulators[i]);
  			dev_err(dev, "failed to register regulator %s: %d
  ",
  				desc->name, ret);
  			return ret;
  		}
  	}
  
  	ret = devm_request_threaded_irq(dev, client->irq, NULL, ltc3589_isr,
  					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
  					client->name, ltc3589);
  	if (ret) {
  		dev_err(dev, "Failed to request IRQ: %d
  ", ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  static struct i2c_device_id ltc3589_i2c_id[] = {
  	{ "ltc3589",   LTC3589   },
  	{ "ltc3589-1", LTC3589_1 },
  	{ "ltc3589-2", LTC3589_2 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, ltc3589_i2c_id);
  
  static struct i2c_driver ltc3589_driver = {
  	.driver = {
  		.name = DRIVER_NAME,
  	},
  	.probe = ltc3589_probe,
  	.id_table = ltc3589_i2c_id,
  };
  module_i2c_driver(ltc3589_driver);
  
  MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
  MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3589(-1,2)");
  MODULE_LICENSE("GPL v2");