text: /*
   * Regulator driver for tps65090 power management chip.
   *
   * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
  
   * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>
   */
  
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/init.h>
  #include <linux/of.h>
  #include <linux/gpio/consumer.h>
  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/machine.h>
  #include <linux/regulator/of_regulator.h>
  #include <linux/mfd/tps65090.h>
  
  #define MAX_CTRL_READ_TRIES	5
  #define MAX_FET_ENABLE_TRIES	1000
  
  #define CTRL_EN_BIT		0 /* Regulator enable bit, active high */
  #define CTRL_WT_BIT		2 /* Regulator wait time 0 bit */
  #define CTRL_PG_BIT		4 /* Regulator power good bit, 1=good */
  #define CTRL_TO_BIT		7 /* Regulator timeout bit, 1=wait */
  
  #define MAX_OVERCURRENT_WAIT	3 /* Overcurrent wait must be <= this */
  
  /**
   * struct tps65090_regulator - Per-regulator data for a tps65090 regulator
   *
   * @dev: Pointer to our device.
   * @desc: The struct regulator_desc for the regulator.
   * @rdev: The struct regulator_dev for the regulator.
   * @overcurrent_wait_valid: True if overcurrent_wait is valid.
   * @overcurrent_wait: For FETs, the value to put in the WTFET bitfield.
   */
  
  struct tps65090_regulator {
  	struct device		*dev;
  	struct regulator_desc	*desc;
  	struct regulator_dev	*rdev;
  	bool			overcurrent_wait_valid;
  	int			overcurrent_wait;
  };
  
  static struct regulator_ops tps65090_ext_control_ops = {
  };
  
  /**
   * tps65090_reg_set_overcurrent_wait - Setup overcurrent wait
   *
   * This will set the overcurrent wait time based on what's in the regulator
   * info.
   *
   * @ri:		Overall regulator data
   * @rdev:	Regulator device
   *
   * Return: 0 if no error, non-zero if there was an error writing the register.
   */
  static int tps65090_reg_set_overcurrent_wait(struct tps65090_regulator *ri,
  					     struct regulator_dev *rdev)
  {
  	int ret;
  
  	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
  				 MAX_OVERCURRENT_WAIT << CTRL_WT_BIT,
  				 ri->overcurrent_wait << CTRL_WT_BIT);
  	if (ret) {
  		dev_err(&rdev->dev, "Error updating overcurrent wait %#x\n",
  			rdev->desc->enable_reg);
  	}
  
  	return ret;
  }
  
  /**
   * tps65090_try_enable_fet - Try to enable a FET
   *
   * @rdev:	Regulator device
   *
   * Return: 0 if ok, -ENOTRECOVERABLE if the FET power good bit did not get
   * set, or some other -ve value if another error occurred (e.g. i2c error)
   */
  static int tps65090_try_enable_fet(struct regulator_dev *rdev)
  {
  	unsigned int control;
  	int ret, i;
  
  	ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
  				 rdev->desc->enable_mask,
  				 rdev->desc->enable_mask);
  	if (ret < 0) {
  		dev_err(&rdev->dev, "Error in updating reg %#x\n",
  			rdev->desc->enable_reg);
  		return ret;
  	}
  
  	for (i = 0; i < MAX_CTRL_READ_TRIES; i++) {
  		ret = regmap_read(rdev->regmap, rdev->desc->enable_reg,
  				  &control);
  		if (ret < 0)
  			return ret;
  
  		if (!(control & BIT(CTRL_TO_BIT)))
  			break;
  
  		usleep_range(1000, 1500);
  	}
  	if (!(control & BIT(CTRL_PG_BIT)))
  		return -ENOTRECOVERABLE;
  
  	return 0;
  }
  
  /**
   * tps65090_fet_enable - Enable a FET, trying a few times if it fails
   *
   * Some versions of the tps65090 have issues when turning on the FETs.
   * This function goes through several steps to ensure the best chance of the
   * FET going on.  Specifically:
   * - We'll make sure that we bump the "overcurrent wait" to the maximum, which
   *   increases the chances that we'll turn on properly.
   * - We'll retry turning the FET on multiple times (turning off in between).
   *
   * @rdev:	Regulator device
   *
   * Return: 0 if ok, non-zero if it fails.
   */
  static int tps65090_fet_enable(struct regulator_dev *rdev)
  {
  	int ret, tries;
  
  	/*
  	 * Try enabling multiple times until we succeed since sometimes the
  	 * first try times out.
  	 */
  	tries = 0;
  	while (true) {
  		ret = tps65090_try_enable_fet(rdev);
  		if (!ret)
  			break;
  		if (ret != -ENOTRECOVERABLE || tries == MAX_FET_ENABLE_TRIES)
  			goto err;
  
  		/* Try turning the FET off (and then on again) */
  		ret = regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
  					 rdev->desc->enable_mask, 0);
  		if (ret)
  			goto err;
  
  		tries++;
  	}
  
  	if (tries)
  		dev_warn(&rdev->dev, "reg %#x enable ok after %d tries\n",
  			 rdev->desc->enable_reg, tries);
  
  	return 0;
  err:
  	dev_warn(&rdev->dev, "reg %#x enable failed\n", rdev->desc->enable_reg);
  	WARN_ON(1);
  
  	return ret;
  }
  
  static struct regulator_ops tps65090_reg_control_ops = {
  	.enable		= regulator_enable_regmap,
  	.disable	= regulator_disable_regmap,
  	.is_enabled	= regulator_is_enabled_regmap,
  };
  
  static struct regulator_ops tps65090_fet_control_ops = {
  	.enable		= tps65090_fet_enable,
  	.disable	= regulator_disable_regmap,
  	.is_enabled	= regulator_is_enabled_regmap,
  };
  
  static struct regulator_ops tps65090_ldo_ops = {
  };
  
  #define tps65090_REG_DESC(_id, _sname, _en_reg, _en_bits, _nvolt, _volt, _ops) \
  {							\
  	.name = "TPS65090_RAILS"#_id,			\
  	.supply_name = _sname,				\
  	.id = TPS65090_REGULATOR_##_id,			\
  	.n_voltages = _nvolt,				\
  	.ops = &_ops,					\
  	.fixed_uV = _volt,				\
  	.enable_reg = _en_reg,				\
  	.enable_val = _en_bits,				\
  	.enable_mask = _en_bits,			\
  	.type = REGULATOR_VOLTAGE,			\
  	.owner = THIS_MODULE,				\
  }
  
  #define tps65090_REG_FIXEDV(_id, _sname, en_reg, _en_bits, _volt, _ops) \
  	tps65090_REG_DESC(_id, _sname, en_reg, _en_bits, 1, _volt, _ops)
  
  #define tps65090_REG_SWITCH(_id, _sname, en_reg, _en_bits, _ops) \
  	tps65090_REG_DESC(_id, _sname, en_reg, _en_bits, 0, 0, _ops)
  
  static struct regulator_desc tps65090_regulator_desc[] = {
  	tps65090_REG_FIXEDV(DCDC1, "vsys1",   0x0C, BIT(CTRL_EN_BIT), 5000000,
  			    tps65090_reg_control_ops),
  	tps65090_REG_FIXEDV(DCDC2, "vsys2",   0x0D, BIT(CTRL_EN_BIT), 3300000,
  			    tps65090_reg_control_ops),
  	tps65090_REG_SWITCH(DCDC3, "vsys3",   0x0E, BIT(CTRL_EN_BIT),
  			    tps65090_reg_control_ops),
  
  	tps65090_REG_SWITCH(FET1,  "infet1",  0x0F,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET2,  "infet2",  0x10,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET3,  "infet3",  0x11,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET4,  "infet4",  0x12,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET5,  "infet5",  0x13,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET6,  "infet6",  0x14,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  	tps65090_REG_SWITCH(FET7,  "infet7",  0x15,
  			    BIT(CTRL_EN_BIT) | BIT(CTRL_PG_BIT),
  			    tps65090_fet_control_ops),
  
  	tps65090_REG_FIXEDV(LDO1,  "vsys-l1", 0, 0, 5000000,
  			    tps65090_ldo_ops),
  	tps65090_REG_FIXEDV(LDO2,  "vsys-l2", 0, 0, 3300000,
  			    tps65090_ldo_ops),
  };
  
  static inline bool is_dcdc(int id)
  {
  	switch (id) {
  	case TPS65090_REGULATOR_DCDC1:
  	case TPS65090_REGULATOR_DCDC2:
  	case TPS65090_REGULATOR_DCDC3:
  		return true;
  	default:
  		return false;
  	}
  }
  
  static int tps65090_config_ext_control(
  	struct tps65090_regulator *ri, bool enable)
  {
  	int ret;
  	struct device *parent = ri->dev->parent;
  	unsigned int reg_en_reg = ri->desc->enable_reg;
  
  	if (enable)
  		ret = tps65090_set_bits(parent, reg_en_reg, 1);
  	else
  		ret =  tps65090_clr_bits(parent, reg_en_reg, 1);
  	if (ret < 0)
  		dev_err(ri->dev, "Error in updating reg 0x%x\n", reg_en_reg);
  	return ret;
  }
  
  static int tps65090_regulator_disable_ext_control(
  		struct tps65090_regulator *ri,
  		struct tps65090_regulator_plat_data *tps_pdata)
  {
  	int ret = 0;
  	struct device *parent = ri->dev->parent;
  	unsigned int reg_en_reg = ri->desc->enable_reg;
  
  	/*
  	 * First enable output for internal control if require.
  	 * And then disable external control.
  	 */
  	if (tps_pdata->reg_init_data->constraints.always_on ||
  			tps_pdata->reg_init_data->constraints.boot_on) {
  		ret =  tps65090_set_bits(parent, reg_en_reg, 0);
  		if (ret < 0) {
  			dev_err(ri->dev, "Error in set reg 0x%x\n", reg_en_reg);
  			return ret;
  		}
  	}
  	return tps65090_config_ext_control(ri, false);
  }
  
  #ifdef CONFIG_OF
  static struct of_regulator_match tps65090_matches[] = {
  	{ .name = "dcdc1", },
  	{ .name = "dcdc2", },
  	{ .name = "dcdc3", },
  	{ .name = "fet1",  },
  	{ .name = "fet2",  },
  	{ .name = "fet3",  },
  	{ .name = "fet4",  },
  	{ .name = "fet5",  },
  	{ .name = "fet6",  },
  	{ .name = "fet7",  },
  	{ .name = "ldo1",  },
  	{ .name = "ldo2",  },
  };
  
  static struct tps65090_platform_data *tps65090_parse_dt_reg_data(
  		struct platform_device *pdev,
  		struct of_regulator_match **tps65090_reg_matches)
  {
  	struct tps65090_platform_data *tps65090_pdata;
  	struct device_node *np = pdev->dev.parent->of_node;
  	struct device_node *regulators;
  	int idx = 0, ret;
  	struct tps65090_regulator_plat_data *reg_pdata;
  
  	tps65090_pdata = devm_kzalloc(&pdev->dev, sizeof(*tps65090_pdata),
  				GFP_KERNEL);
  	if (!tps65090_pdata)
  		return ERR_PTR(-ENOMEM);
  
  	reg_pdata = devm_kcalloc(&pdev->dev,
  				 TPS65090_REGULATOR_MAX, sizeof(*reg_pdata),
  				 GFP_KERNEL);
  	if (!reg_pdata)
  		return ERR_PTR(-ENOMEM);
  
  	regulators = of_get_child_by_name(np, "regulators");
  	if (!regulators) {
  		dev_err(&pdev->dev, "regulator node not found\n");
  		return ERR_PTR(-ENODEV);
  	}
  
  	ret = of_regulator_match(&pdev->dev, regulators, tps65090_matches,
  			ARRAY_SIZE(tps65090_matches));
  	of_node_put(regulators);
  	if (ret < 0) {
  		dev_err(&pdev->dev,
  			"Error parsing regulator init data: %d\n", ret);
  		return ERR_PTR(ret);
  	}
  
  	*tps65090_reg_matches = tps65090_matches;
  	for (idx = 0; idx < ARRAY_SIZE(tps65090_matches); idx++) {
  		struct regulator_init_data *ri_data;
  		struct tps65090_regulator_plat_data *rpdata;
  
  		rpdata = &reg_pdata[idx];
  		ri_data = tps65090_matches[idx].init_data;
  		if (!ri_data || !tps65090_matches[idx].of_node)
  			continue;
  
  		rpdata->reg_init_data = ri_data;
  		rpdata->enable_ext_control = of_property_read_bool(
  					tps65090_matches[idx].of_node,
  					"ti,enable-ext-control");
  		if (rpdata->enable_ext_control) {
  			enum gpiod_flags gflags;
  
  			if (ri_data->constraints.always_on ||
  			    ri_data->constraints.boot_on)
  				gflags = GPIOD_OUT_HIGH;
  			else
  				gflags = GPIOD_OUT_LOW;
  			gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
  
  			rpdata->gpiod = devm_gpiod_get_from_of_node(&pdev->dev,
  								    tps65090_matches[idx].of_node,
  								    "dcdc-ext-control-gpios", 0,
  								    gflags,
  								    "tps65090");
  			if (IS_ERR(rpdata->gpiod))
  				return ERR_CAST(rpdata->gpiod);
  			if (!rpdata->gpiod)
  				dev_err(&pdev->dev,
  					"could not find DCDC external control GPIO\n");
  		}
  
  		if (of_property_read_u32(tps65090_matches[idx].of_node,
  					 "ti,overcurrent-wait",
  					 &rpdata->overcurrent_wait) == 0)
  			rpdata->overcurrent_wait_valid = true;
  
  		tps65090_pdata->reg_pdata[idx] = rpdata;
  	}
  	return tps65090_pdata;
  }
  #else
  static inline struct tps65090_platform_data *tps65090_parse_dt_reg_data(
  			struct platform_device *pdev,
  			struct of_regulator_match **tps65090_reg_matches)
  {
  	*tps65090_reg_matches = NULL;
  	return NULL;
  }
  #endif
  
  static int tps65090_regulator_probe(struct platform_device *pdev)
  {
  	struct tps65090 *tps65090_mfd = dev_get_drvdata(pdev->dev.parent);
  	struct tps65090_regulator *ri = NULL;
  	struct regulator_config config = { };
  	struct regulator_dev *rdev;
  	struct tps65090_regulator_plat_data *tps_pdata;
  	struct tps65090_regulator *pmic;
  	struct tps65090_platform_data *tps65090_pdata;
  	struct of_regulator_match *tps65090_reg_matches = NULL;
  	int num;
  	int ret;
  
  	dev_dbg(&pdev->dev, "Probing regulator\n");
  
  	tps65090_pdata = dev_get_platdata(pdev->dev.parent);
  	if (!tps65090_pdata && tps65090_mfd->dev->of_node)
  		tps65090_pdata = tps65090_parse_dt_reg_data(pdev,
  					&tps65090_reg_matches);
  	if (IS_ERR_OR_NULL(tps65090_pdata)) {
  		dev_err(&pdev->dev, "Platform data missing\n");
  		return tps65090_pdata ? PTR_ERR(tps65090_pdata) : -EINVAL;
  	}
  
  	pmic = devm_kcalloc(&pdev->dev,
  			    TPS65090_REGULATOR_MAX, sizeof(*pmic),
  			    GFP_KERNEL);
  	if (!pmic)
  		return -ENOMEM;
  
  	for (num = 0; num < TPS65090_REGULATOR_MAX; num++) {
  		tps_pdata = tps65090_pdata->reg_pdata[num];
  
  		ri = &pmic[num];
  		ri->dev = &pdev->dev;
  		ri->desc = &tps65090_regulator_desc[num];
  		if (tps_pdata) {
  			ri->overcurrent_wait_valid =
  				tps_pdata->overcurrent_wait_valid;
  			ri->overcurrent_wait = tps_pdata->overcurrent_wait;
  		}
  
  		/*
  		 * TPS5090 DCDC support the control from external digital input.
  		 * Configure it as per platform data.
  		 */
  		if (tps_pdata && is_dcdc(num) && tps_pdata->reg_init_data) {
  			if (tps_pdata->enable_ext_control) {
  				config.ena_gpiod = tps_pdata->gpiod;
  				ri->desc->ops = &tps65090_ext_control_ops;
  			} else {
  				ret = tps65090_regulator_disable_ext_control(
  						ri, tps_pdata);
  				if (ret < 0) {
  					dev_err(&pdev->dev,
  						"failed disable ext control\n");
  					return ret;
  				}
  			}
  		}
  
  		config.dev = pdev->dev.parent;
  		config.driver_data = ri;
  		config.regmap = tps65090_mfd->rmap;
  		if (tps_pdata)
  			config.init_data = tps_pdata->reg_init_data;
  		else
  			config.init_data = NULL;
  		if (tps65090_reg_matches)
  			config.of_node = tps65090_reg_matches[num].of_node;
  		else
  			config.of_node = NULL;
  
  		/*
  		 * Hand the GPIO descriptor management over to the regulator
  		 * core, remove it from devres management.
  		 */
  		if (config.ena_gpiod)
  			devm_gpiod_unhinge(&pdev->dev, config.ena_gpiod);
  		rdev = devm_regulator_register(&pdev->dev, ri->desc, &config);
  		if (IS_ERR(rdev)) {
  			dev_err(&pdev->dev, "failed to register regulator %s\n",
  				ri->desc->name);
  			return PTR_ERR(rdev);
  		}
  		ri->rdev = rdev;
  
  		if (ri->overcurrent_wait_valid) {
  			ret = tps65090_reg_set_overcurrent_wait(ri, rdev);
  			if (ret < 0)
  				return ret;
  		}
  
  		/* Enable external control if it is require */
  		if (tps_pdata && is_dcdc(num) && tps_pdata->reg_init_data &&
  				tps_pdata->enable_ext_control) {
  			ret = tps65090_config_ext_control(ri, true);
  			if (ret < 0)
  				return ret;
  		}
  	}
  
  	platform_set_drvdata(pdev, pmic);
  	return 0;
  }
  
  static struct platform_driver tps65090_regulator_driver = {
  	.driver	= {
  		.name	= "tps65090-pmic",
  	},
  	.probe		= tps65090_regulator_probe,
  };
  
  static int __init tps65090_regulator_init(void)
  {
  	return platform_driver_register(&tps65090_regulator_driver);
  }
  subsys_initcall(tps65090_regulator_init);
  
  static void __exit tps65090_regulator_exit(void)
  {
  	platform_driver_unregister(&tps65090_regulator_driver);
  }
  module_exit(tps65090_regulator_exit);
  
  MODULE_DESCRIPTION("tps65090 regulator driver");
  MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("platform:tps65090-pmic");
  