/*
   * Copyright (c) 2015 Intel Corporation
   *
   * Driver for TXC PA12203001 Proximity and Ambient Light Sensor.
   *
   * 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.
   * To do: Interrupt support.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/acpi.h>
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  #include <linux/mutex.h>
  #include <linux/pm.h>
  #include <linux/pm_runtime.h>
  #include <linux/regmap.h>
  
  #define PA12203001_DRIVER_NAME	"pa12203001"
  
  #define PA12203001_REG_CFG0		0x00
  #define PA12203001_REG_CFG1		0x01
  #define PA12203001_REG_CFG2		0x02
  #define PA12203001_REG_CFG3		0x03
  
  #define PA12203001_REG_ADL		0x0b
  #define PA12203001_REG_PDH		0x0e
  
  #define PA12203001_REG_POFS		0x10
  #define PA12203001_REG_PSET		0x11
  
  #define PA12203001_ALS_EN_MASK		BIT(0)
  #define PA12203001_PX_EN_MASK		BIT(1)
  #define PA12203001_PX_NORMAL_MODE_MASK		GENMASK(7, 6)
  #define PA12203001_AFSR_MASK		GENMASK(5, 4)
  #define PA12203001_AFSR_SHIFT		4
  
  #define PA12203001_PSCAN			0x03
  
  /* als range 31000, ps, als disabled */
  #define PA12203001_REG_CFG0_DEFAULT		0x30
  
  /* led current: 100 mA */
  #define PA12203001_REG_CFG1_DEFAULT		0x20
  
  /* ps mode: normal, interrupts not active */
  #define PA12203001_REG_CFG2_DEFAULT		0xcc
  
  #define PA12203001_REG_CFG3_DEFAULT		0x00
  
  #define PA12203001_SLEEP_DELAY_MS		3000
  
  #define PA12203001_CHIP_ENABLE		0xff
  #define PA12203001_CHIP_DISABLE		0x00
  
  /* available scales: corresponding to [500, 4000, 7000, 31000]  lux */
  static const int pa12203001_scales[] = { 7629, 61036, 106813, 473029};
  
  struct pa12203001_data {
  	struct i2c_client *client;
  
  	/* protect device states */
  	struct mutex lock;
  
  	bool als_enabled;
  	bool px_enabled;
  	bool als_needs_enable;
  	bool px_needs_enable;
  
  	struct regmap *map;
  };
  
  static const struct {
  	u8 reg;
  	u8 val;
  } regvals[] = {
  	{PA12203001_REG_CFG0, PA12203001_REG_CFG0_DEFAULT},
  	{PA12203001_REG_CFG1, PA12203001_REG_CFG1_DEFAULT},
  	{PA12203001_REG_CFG2, PA12203001_REG_CFG2_DEFAULT},
  	{PA12203001_REG_CFG3, PA12203001_REG_CFG3_DEFAULT},
  	{PA12203001_REG_PSET, PA12203001_PSCAN},
  };
  
  static IIO_CONST_ATTR(in_illuminance_scale_available,
  		      "0.007629 0.061036 0.106813 0.473029");
  
  static struct attribute *pa12203001_attrs[] = {
  	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group pa12203001_attr_group = {
  	.attrs = pa12203001_attrs,
  };
  
  static const struct iio_chan_spec pa12203001_channels[] = {
  	{
  		.type = IIO_LIGHT,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  				      BIT(IIO_CHAN_INFO_SCALE),
  	},
  	{
  		.type = IIO_PROXIMITY,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  	}
  };
  
  static const struct regmap_range pa12203001_volatile_regs_ranges[] = {
  	regmap_reg_range(PA12203001_REG_ADL, PA12203001_REG_ADL + 1),
  	regmap_reg_range(PA12203001_REG_PDH, PA12203001_REG_PDH),
  };
  
  static const struct regmap_access_table pa12203001_volatile_regs = {
  	.yes_ranges = pa12203001_volatile_regs_ranges,
  	.n_yes_ranges = ARRAY_SIZE(pa12203001_volatile_regs_ranges),
  };
  
  static const struct regmap_config pa12203001_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  	.max_register = PA12203001_REG_PSET,
  	.cache_type = REGCACHE_RBTREE,
  	.volatile_table = &pa12203001_volatile_regs,
  };
  
  static inline int pa12203001_als_enable(struct pa12203001_data *data, u8 enable)
  {
  	int ret;
  
  	ret = regmap_update_bits(data->map, PA12203001_REG_CFG0,
  				 PA12203001_ALS_EN_MASK, enable);
  	if (ret < 0)
  		return ret;
  
  	data->als_enabled = !!enable;
  
  	return 0;
  }
  
  static inline int pa12203001_px_enable(struct pa12203001_data *data, u8 enable)
  {
  	int ret;
  
  	ret = regmap_update_bits(data->map, PA12203001_REG_CFG0,
  				 PA12203001_PX_EN_MASK, enable);
  	if (ret < 0)
  		return ret;
  
  	data->px_enabled = !!enable;
  
  	return 0;
  }
  
  static int pa12203001_set_power_state(struct pa12203001_data *data, bool on,
  				      u8 mask)
  {
  #ifdef CONFIG_PM
  	int ret;
  
  	if (on && (mask & PA12203001_ALS_EN_MASK)) {
  		mutex_lock(&data->lock);
  		if (data->px_enabled) {
  			ret = pa12203001_als_enable(data,
  						    PA12203001_ALS_EN_MASK);
  			if (ret < 0)
  				goto err;
  		} else {
  			data->als_needs_enable = true;
  		}
  		mutex_unlock(&data->lock);
  	}
  
  	if (on && (mask & PA12203001_PX_EN_MASK)) {
  		mutex_lock(&data->lock);
  		if (data->als_enabled) {
  			ret = pa12203001_px_enable(data, PA12203001_PX_EN_MASK);
  			if (ret < 0)
  				goto err;
  		} else {
  			data->px_needs_enable = true;
  		}
  		mutex_unlock(&data->lock);
  	}
  
  	if (on) {
  		ret = pm_runtime_get_sync(&data->client->dev);
  		if (ret < 0)
  			pm_runtime_put_noidle(&data->client->dev);
  
  	} else {
  		pm_runtime_mark_last_busy(&data->client->dev);
  		ret = pm_runtime_put_autosuspend(&data->client->dev);
  	}
  
  	return ret;
  
  err:
  	mutex_unlock(&data->lock);
  	return ret;
  
  #endif
  	return 0;
  }
  
  static int pa12203001_read_raw(struct iio_dev *indio_dev,
  			       struct iio_chan_spec const *chan, int *val,
  			       int *val2, long mask)
  {
  	struct pa12203001_data *data = iio_priv(indio_dev);
  	int ret;
  	u8 dev_mask;
  	unsigned int reg_byte;
  	__le16 reg_word;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		switch (chan->type) {
  		case IIO_LIGHT:
  			dev_mask = PA12203001_ALS_EN_MASK;
  			ret = pa12203001_set_power_state(data, true, dev_mask);
  			if (ret < 0)
  				return ret;
  			/*
  			 * ALS ADC value is stored in registers
  			 * PA12203001_REG_ADL and in PA12203001_REG_ADL + 1.
  			 */
  			ret = regmap_bulk_read(data->map, PA12203001_REG_ADL,
  					       &reg_word, 2);
  			if (ret < 0)
  				goto reg_err;
  
  			*val = le16_to_cpu(reg_word);
  			ret = pa12203001_set_power_state(data, false, dev_mask);
  			if (ret < 0)
  				return ret;
  			break;
  		case IIO_PROXIMITY:
  			dev_mask = PA12203001_PX_EN_MASK;
  			ret = pa12203001_set_power_state(data, true, dev_mask);
  			if (ret < 0)
  				return ret;
  			ret = regmap_read(data->map, PA12203001_REG_PDH,
  					  &reg_byte);
  			if (ret < 0)
  				goto reg_err;
  
  			*val = reg_byte;
  			ret = pa12203001_set_power_state(data, false, dev_mask);
  			if (ret < 0)
  				return ret;
  			break;
  		default:
  			return -EINVAL;
  		}
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_SCALE:
  		ret = regmap_read(data->map, PA12203001_REG_CFG0, &reg_byte);
  		if (ret < 0)
  			return ret;
  		*val = 0;
  		reg_byte = (reg_byte & PA12203001_AFSR_MASK);
  		*val2 = pa12203001_scales[reg_byte >> 4];
  		return IIO_VAL_INT_PLUS_MICRO;
  	default:
  		return -EINVAL;
  	}
  
  reg_err:
  	pa12203001_set_power_state(data, false, dev_mask);
  	return ret;
  }
  
  static int pa12203001_write_raw(struct iio_dev *indio_dev,
  				struct iio_chan_spec const *chan, int val,
  				int val2, long mask)
  {
  	struct pa12203001_data *data = iio_priv(indio_dev);
  	int i, ret, new_val;
  	unsigned int reg_byte;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_SCALE:
  		ret = regmap_read(data->map, PA12203001_REG_CFG0, &reg_byte);
  		if (val != 0 || ret < 0)
  			return -EINVAL;
  		for (i = 0; i < ARRAY_SIZE(pa12203001_scales); i++) {
  			if (val2 == pa12203001_scales[i]) {
  				new_val = i << PA12203001_AFSR_SHIFT;
  				return regmap_update_bits(data->map,
  							  PA12203001_REG_CFG0,
  							  PA12203001_AFSR_MASK,
  							  new_val);
  			}
  		}
  		break;
  	default:
  		break;
  	}
  
  	return -EINVAL;
  }
  
  static const struct iio_info pa12203001_info = {
  	.driver_module	= THIS_MODULE,
  	.read_raw = pa12203001_read_raw,
  	.write_raw = pa12203001_write_raw,
  	.attrs = &pa12203001_attr_group,
  };
  
  static int pa12203001_init(struct iio_dev *indio_dev)
  {
  	struct pa12203001_data *data = iio_priv(indio_dev);
  	int i, ret;
  
  	for (i = 0; i < ARRAY_SIZE(regvals); i++) {
  		ret = regmap_write(data->map, regvals[i].reg, regvals[i].val);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  
  static int pa12203001_power_chip(struct iio_dev *indio_dev, u8 state)
  {
  	struct pa12203001_data *data = iio_priv(indio_dev);
  	int ret;
  
  	mutex_lock(&data->lock);
  	ret = pa12203001_als_enable(data, state);
  	if (ret < 0)
  		goto out;
  
  	ret = pa12203001_px_enable(data, state);
  
  out:
  	mutex_unlock(&data->lock);
  	return ret;
  }
  
  static int pa12203001_probe(struct i2c_client *client,
  			    const struct i2c_device_id *id)
  {
  	struct pa12203001_data *data;
  	struct iio_dev *indio_dev;
  	int ret;
  
  	indio_dev = devm_iio_device_alloc(&client->dev,
  					  sizeof(struct pa12203001_data));
  	if (!indio_dev)
  		return -ENOMEM;
  
  	data = iio_priv(indio_dev);
  	i2c_set_clientdata(client, indio_dev);
  	data->client = client;
  
  	data->map = devm_regmap_init_i2c(client, &pa12203001_regmap_config);
  	if (IS_ERR(data->map))
  		return PTR_ERR(data->map);
  
  	mutex_init(&data->lock);
  
  	indio_dev->dev.parent = &client->dev;
  	indio_dev->info = &pa12203001_info;
  	indio_dev->name = PA12203001_DRIVER_NAME;
  	indio_dev->channels = pa12203001_channels;
  	indio_dev->num_channels = ARRAY_SIZE(pa12203001_channels);
  	indio_dev->modes = INDIO_DIRECT_MODE;
  
  	ret = pa12203001_init(indio_dev);
  	if (ret < 0)
  		return ret;
  
  	ret = pa12203001_power_chip(indio_dev, PA12203001_CHIP_ENABLE);
  	if (ret < 0)
  		return ret;
  
  	ret = pm_runtime_set_active(&client->dev);
  	if (ret < 0) {
  		pa12203001_power_chip(indio_dev, PA12203001_CHIP_DISABLE);
  		return ret;
  	}
  
  	pm_runtime_enable(&client->dev);
  	pm_runtime_set_autosuspend_delay(&client->dev,
  					 PA12203001_SLEEP_DELAY_MS);
  	pm_runtime_use_autosuspend(&client->dev);
  
  	return iio_device_register(indio_dev);
  }
  
  static int pa12203001_remove(struct i2c_client *client)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
  
  	iio_device_unregister(indio_dev);
  
  	pm_runtime_disable(&client->dev);
  	pm_runtime_set_suspended(&client->dev);
  
  	return pa12203001_power_chip(indio_dev, PA12203001_CHIP_DISABLE);
  }
  
  #if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM)
  static int pa12203001_suspend(struct device *dev)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
  
  	return pa12203001_power_chip(indio_dev, PA12203001_CHIP_DISABLE);
  }
  #endif
  
  #ifdef CONFIG_PM_SLEEP
  static int pa12203001_resume(struct device *dev)
  {
  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
  
  	return pa12203001_power_chip(indio_dev, PA12203001_CHIP_ENABLE);
  }
  #endif
  
  #ifdef CONFIG_PM
  static int pa12203001_runtime_resume(struct device *dev)
  {
  	struct pa12203001_data *data;
  
  	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
  
  	mutex_lock(&data->lock);
  	if (data->als_needs_enable) {
  		pa12203001_als_enable(data, PA12203001_ALS_EN_MASK);
  		data->als_needs_enable = false;
  	}
  	if (data->px_needs_enable) {
  		pa12203001_px_enable(data, PA12203001_PX_EN_MASK);
  		data->px_needs_enable = false;
  	}
  	mutex_unlock(&data->lock);
  
  	return 0;
  }
  #endif
  
  static const struct dev_pm_ops pa12203001_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(pa12203001_suspend, pa12203001_resume)
  	SET_RUNTIME_PM_OPS(pa12203001_suspend, pa12203001_runtime_resume, NULL)
  };
  
  static const struct acpi_device_id pa12203001_acpi_match[] = {
  	{ "TXCPA122", 0},
  	{}
  };
  
  MODULE_DEVICE_TABLE(acpi, pa12203001_acpi_match);
  
  static const struct i2c_device_id pa12203001_id[] = {
  		{"txcpa122", 0},
  		{}
  };
  
  MODULE_DEVICE_TABLE(i2c, pa12203001_id);
  
  static struct i2c_driver pa12203001_driver = {
  	.driver = {
  		.name = PA12203001_DRIVER_NAME,
  		.pm = &pa12203001_pm_ops,
  		.acpi_match_table = ACPI_PTR(pa12203001_acpi_match),
  	},
  	.probe = pa12203001_probe,
  	.remove = pa12203001_remove,
  	.id_table = pa12203001_id,
  
  };
  module_i2c_driver(pa12203001_driver);
  
  MODULE_AUTHOR("Adriana Reus <adriana.reus@intel.com>");
  MODULE_DESCRIPTION("Driver for TXC PA12203001 Proximity and Light Sensor");
  MODULE_LICENSE("GPL v2");