/*
   * DRV2665 haptics driver family
   *
   * Author: Dan Murphy <dmurphy@ti.com>
   *
   * Copyright: (C) 2015 Texas Instruments, Inc.
   *
   * 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/input.h>
  #include <linux/module.h>
  #include <linux/regmap.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <linux/regulator/consumer.h>
  
  /* Contol registers */
  #define DRV2665_STATUS	0x00
  #define DRV2665_CTRL_1	0x01
  #define DRV2665_CTRL_2	0x02
  #define DRV2665_FIFO	0x0b
  
  /* Status Register */
  #define DRV2665_FIFO_FULL		BIT(0)
  #define DRV2665_FIFO_EMPTY		BIT(1)
  
  /* Control 1 Register */
  #define DRV2665_25_VPP_GAIN		0x00
  #define DRV2665_50_VPP_GAIN		0x01
  #define DRV2665_75_VPP_GAIN		0x02
  #define DRV2665_100_VPP_GAIN		0x03
  #define DRV2665_DIGITAL_IN		0xfc
  #define DRV2665_ANALOG_IN		BIT(2)
  
  /* Control 2 Register */
  #define DRV2665_BOOST_EN		BIT(1)
  #define DRV2665_STANDBY			BIT(6)
  #define DRV2665_DEV_RST			BIT(7)
  #define DRV2665_5_MS_IDLE_TOUT		0x00
  #define DRV2665_10_MS_IDLE_TOUT		0x04
  #define DRV2665_15_MS_IDLE_TOUT		0x08
  #define DRV2665_20_MS_IDLE_TOUT		0x0c
  
  /**
   * struct drv2665_data -
   * @input_dev - Pointer to the input device
   * @client - Pointer to the I2C client
   * @regmap - Register map of the device
   * @work - Work item used to off load the enable/disable of the vibration
   * @regulator - Pointer to the regulator for the IC
   */
  struct drv2665_data {
  	struct input_dev *input_dev;
  	struct i2c_client *client;
  	struct regmap *regmap;
  	struct work_struct work;
  	struct regulator *regulator;
  };
  
  /* 8kHz Sine wave to stream to the FIFO */
  static const u8 drv2665_sine_wave_form[] = {
  	0x00, 0x10, 0x20, 0x2e, 0x3c, 0x48, 0x53, 0x5b, 0x61, 0x65, 0x66,
  	0x65, 0x61, 0x5b, 0x53, 0x48, 0x3c, 0x2e, 0x20, 0x10,
  	0x00, 0xf0, 0xe0, 0xd2, 0xc4, 0xb8, 0xad, 0xa5, 0x9f, 0x9b, 0x9a,
  	0x9b, 0x9f, 0xa5, 0xad, 0xb8, 0xc4, 0xd2, 0xe0, 0xf0, 0x00,
  };
  
  static const struct reg_default drv2665_reg_defs[] = {
  	{ DRV2665_STATUS, 0x02 },
  	{ DRV2665_CTRL_1, 0x28 },
  	{ DRV2665_CTRL_2, 0x40 },
  	{ DRV2665_FIFO, 0x00 },
  };
  
  static void drv2665_worker(struct work_struct *work)
  {
  	struct drv2665_data *haptics =
  				container_of(work, struct drv2665_data, work);
  	unsigned int read_buf;
  	int error;
  
  	error = regmap_read(haptics->regmap, DRV2665_STATUS, &read_buf);
  	if (error) {
  		dev_err(&haptics->client->dev,
  			"Failed to read status: %d
  ", error);
  		return;
  	}
  
  	if (read_buf & DRV2665_FIFO_EMPTY) {
  		error = regmap_bulk_write(haptics->regmap,
  					  DRV2665_FIFO,
  					  drv2665_sine_wave_form,
  					  ARRAY_SIZE(drv2665_sine_wave_form));
  		if (error) {
  			dev_err(&haptics->client->dev,
  				"Failed to write FIFO: %d
  ", error);
  			return;
  		}
  	}
  }
  
  static int drv2665_haptics_play(struct input_dev *input, void *data,
  				struct ff_effect *effect)
  {
  	struct drv2665_data *haptics = input_get_drvdata(input);
  
  	schedule_work(&haptics->work);
  
  	return 0;
  }
  
  static void drv2665_close(struct input_dev *input)
  {
  	struct drv2665_data *haptics = input_get_drvdata(input);
  	int error;
  
  	cancel_work_sync(&haptics->work);
  
  	error = regmap_update_bits(haptics->regmap,
  				   DRV2665_CTRL_2, DRV2665_STANDBY, 1);
  	if (error)
  		dev_err(&haptics->client->dev,
  			"Failed to enter standby mode: %d
  ", error);
  }
  
  static const struct reg_sequence drv2665_init_regs[] = {
  	{ DRV2665_CTRL_2, 0 | DRV2665_10_MS_IDLE_TOUT },
  	{ DRV2665_CTRL_1, DRV2665_25_VPP_GAIN },
  };
  
  static int drv2665_init(struct drv2665_data *haptics)
  {
  	int error;
  
  	error = regmap_register_patch(haptics->regmap,
  				      drv2665_init_regs,
  				      ARRAY_SIZE(drv2665_init_regs));
  	if (error) {
  		dev_err(&haptics->client->dev,
  			"Failed to write init registers: %d
  ",
  			error);
  		return error;
  	}
  
  	return 0;
  }
  
  static const struct regmap_config drv2665_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  
  	.max_register = DRV2665_FIFO,
  	.reg_defaults = drv2665_reg_defs,
  	.num_reg_defaults = ARRAY_SIZE(drv2665_reg_defs),
  	.cache_type = REGCACHE_NONE,
  };
  
  static int drv2665_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct drv2665_data *haptics;
  	int error;
  
  	haptics = devm_kzalloc(&client->dev, sizeof(*haptics), GFP_KERNEL);
  	if (!haptics)
  		return -ENOMEM;
  
  	haptics->regulator = devm_regulator_get(&client->dev, "vbat");
  	if (IS_ERR(haptics->regulator)) {
  		error = PTR_ERR(haptics->regulator);
  		dev_err(&client->dev,
  			"unable to get regulator, error: %d
  ", error);
  		return error;
  	}
  
  	haptics->input_dev = devm_input_allocate_device(&client->dev);
  	if (!haptics->input_dev) {
  		dev_err(&client->dev, "Failed to allocate input device
  ");
  		return -ENOMEM;
  	}
  
  	haptics->input_dev->name = "drv2665:haptics";
  	haptics->input_dev->dev.parent = client->dev.parent;
  	haptics->input_dev->close = drv2665_close;
  	input_set_drvdata(haptics->input_dev, haptics);
  	input_set_capability(haptics->input_dev, EV_FF, FF_RUMBLE);
  
  	error = input_ff_create_memless(haptics->input_dev, NULL,
  					drv2665_haptics_play);
  	if (error) {
  		dev_err(&client->dev, "input_ff_create() failed: %d
  ",
  			error);
  		return error;
  	}
  
  	INIT_WORK(&haptics->work, drv2665_worker);
  
  	haptics->client = client;
  	i2c_set_clientdata(client, haptics);
  
  	haptics->regmap = devm_regmap_init_i2c(client, &drv2665_regmap_config);
  	if (IS_ERR(haptics->regmap)) {
  		error = PTR_ERR(haptics->regmap);
  		dev_err(&client->dev, "Failed to allocate register map: %d
  ",
  			error);
  		return error;
  	}
  
  	error = drv2665_init(haptics);
  	if (error) {
  		dev_err(&client->dev, "Device init failed: %d
  ", error);
  		return error;
  	}
  
  	error = input_register_device(haptics->input_dev);
  	if (error) {
  		dev_err(&client->dev, "couldn't register input device: %d
  ",
  			error);
  		return error;
  	}
  
  	return 0;
  }
  
  static int __maybe_unused drv2665_suspend(struct device *dev)
  {
  	struct drv2665_data *haptics = dev_get_drvdata(dev);
  	int ret = 0;
  
  	mutex_lock(&haptics->input_dev->mutex);
  
  	if (haptics->input_dev->users) {
  		ret = regmap_update_bits(haptics->regmap, DRV2665_CTRL_2,
  				DRV2665_STANDBY, 1);
  		if (ret) {
  			dev_err(dev, "Failed to set standby mode
  ");
  			regulator_disable(haptics->regulator);
  			goto out;
  		}
  
  		ret = regulator_disable(haptics->regulator);
  		if (ret) {
  			dev_err(dev, "Failed to disable regulator
  ");
  			regmap_update_bits(haptics->regmap,
  					   DRV2665_CTRL_2,
  					   DRV2665_STANDBY, 0);
  		}
  	}
  out:
  	mutex_unlock(&haptics->input_dev->mutex);
  	return ret;
  }
  
  static int __maybe_unused drv2665_resume(struct device *dev)
  {
  	struct drv2665_data *haptics = dev_get_drvdata(dev);
  	int ret = 0;
  
  	mutex_lock(&haptics->input_dev->mutex);
  
  	if (haptics->input_dev->users) {
  		ret = regulator_enable(haptics->regulator);
  		if (ret) {
  			dev_err(dev, "Failed to enable regulator
  ");
  			goto out;
  		}
  
  		ret = regmap_update_bits(haptics->regmap, DRV2665_CTRL_2,
  					 DRV2665_STANDBY, 0);
  		if (ret) {
  			dev_err(dev, "Failed to unset standby mode
  ");
  			regulator_disable(haptics->regulator);
  			goto out;
  		}
  
  	}
  
  out:
  	mutex_unlock(&haptics->input_dev->mutex);
  	return ret;
  }
  
  static SIMPLE_DEV_PM_OPS(drv2665_pm_ops, drv2665_suspend, drv2665_resume);
  
  static const struct i2c_device_id drv2665_id[] = {
  	{ "drv2665", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, drv2665_id);
  
  #ifdef CONFIG_OF
  static const struct of_device_id drv2665_of_match[] = {
  	{ .compatible = "ti,drv2665", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, drv2665_of_match);
  #endif
  
  static struct i2c_driver drv2665_driver = {
  	.probe		= drv2665_probe,
  	.driver		= {
  		.name	= "drv2665-haptics",
  		.of_match_table = of_match_ptr(drv2665_of_match),
  		.pm	= &drv2665_pm_ops,
  	},
  	.id_table = drv2665_id,
  };
  module_i2c_driver(drv2665_driver);
  
  MODULE_DESCRIPTION("TI DRV2665 haptics driver");
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");