/*
   * max7359_keypad.c - MAX7359 Key Switch Controller Driver
   *
   * Copyright (C) 2009 Samsung Electronics
   * Kim Kyuwon <q1.kim@samsung.com>
   *
   * Based on pxa27x_keypad.c
   *
   * 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.
   *
   * Datasheet: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5456
   */
  
  #include <linux/module.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <linux/interrupt.h>
  #include <linux/pm.h>
  #include <linux/input.h>
  #include <linux/input/matrix_keypad.h>
  
  #define MAX7359_MAX_KEY_ROWS	8
  #define MAX7359_MAX_KEY_COLS	8
  #define MAX7359_MAX_KEY_NUM	(MAX7359_MAX_KEY_ROWS * MAX7359_MAX_KEY_COLS)
  #define MAX7359_ROW_SHIFT	3
  
  /*
   * MAX7359 registers
   */
  #define MAX7359_REG_KEYFIFO	0x00
  #define MAX7359_REG_CONFIG	0x01
  #define MAX7359_REG_DEBOUNCE	0x02
  #define MAX7359_REG_INTERRUPT	0x03
  #define MAX7359_REG_PORTS	0x04
  #define MAX7359_REG_KEYREP	0x05
  #define MAX7359_REG_SLEEP	0x06
  
  /*
   * Configuration register bits
   */
  #define MAX7359_CFG_SLEEP	(1 << 7)
  #define MAX7359_CFG_INTERRUPT	(1 << 5)
  #define MAX7359_CFG_KEY_RELEASE	(1 << 3)
  #define MAX7359_CFG_WAKEUP	(1 << 1)
  #define MAX7359_CFG_TIMEOUT	(1 << 0)
  
  /*
   * Autosleep register values (ms)
   */
  #define MAX7359_AUTOSLEEP_8192	0x01
  #define MAX7359_AUTOSLEEP_4096	0x02
  #define MAX7359_AUTOSLEEP_2048	0x03
  #define MAX7359_AUTOSLEEP_1024	0x04
  #define MAX7359_AUTOSLEEP_512	0x05
  #define MAX7359_AUTOSLEEP_256	0x06
  
  struct max7359_keypad {
  	/* matrix key code map */
  	unsigned short keycodes[MAX7359_MAX_KEY_NUM];
  
  	struct input_dev *input_dev;
  	struct i2c_client *client;
  };
  
  static int max7359_write_reg(struct i2c_client *client, u8 reg, u8 val)
  {
  	int ret = i2c_smbus_write_byte_data(client, reg, val);
  
  	if (ret < 0)
  		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d
  ",
  			__func__, reg, val, ret);
  	return ret;
  }
  
  static int max7359_read_reg(struct i2c_client *client, int reg)
  {
  	int ret = i2c_smbus_read_byte_data(client, reg);
  
  	if (ret < 0)
  		dev_err(&client->dev, "%s: reg 0x%x, err %d
  ",
  			__func__, reg, ret);
  	return ret;
  }
  
  /* runs in an IRQ thread -- can (and will!) sleep */
  static irqreturn_t max7359_interrupt(int irq, void *dev_id)
  {
  	struct max7359_keypad *keypad = dev_id;
  	struct input_dev *input_dev = keypad->input_dev;
  	int val, row, col, release, code;
  
  	val = max7359_read_reg(keypad->client, MAX7359_REG_KEYFIFO);
  	row = val & 0x7;
  	col = (val >> 3) & 0x7;
  	release = val & 0x40;
  
  	code = MATRIX_SCAN_CODE(row, col, MAX7359_ROW_SHIFT);
  
  	dev_dbg(&keypad->client->dev,
  		"key[%d:%d] %s
  ", row, col, release ? "release" : "press");
  
  	input_event(input_dev, EV_MSC, MSC_SCAN, code);
  	input_report_key(input_dev, keypad->keycodes[code], !release);
  	input_sync(input_dev);
  
  	return IRQ_HANDLED;
  }
  
  /*
   * Let MAX7359 fall into a deep sleep:
   * If no keys are pressed, enter sleep mode for 8192 ms. And if any
   * key is pressed, the MAX7359 returns to normal operating mode.
   */
  static inline void max7359_fall_deepsleep(struct i2c_client *client)
  {
  	max7359_write_reg(client, MAX7359_REG_SLEEP, MAX7359_AUTOSLEEP_8192);
  }
  
  /*
   * Let MAX7359 take a catnap:
   * Autosleep just for 256 ms.
   */
  static inline void max7359_take_catnap(struct i2c_client *client)
  {
  	max7359_write_reg(client, MAX7359_REG_SLEEP, MAX7359_AUTOSLEEP_256);
  }
  
  static int max7359_open(struct input_dev *dev)
  {
  	struct max7359_keypad *keypad = input_get_drvdata(dev);
  
  	max7359_take_catnap(keypad->client);
  
  	return 0;
  }
  
  static void max7359_close(struct input_dev *dev)
  {
  	struct max7359_keypad *keypad = input_get_drvdata(dev);
  
  	max7359_fall_deepsleep(keypad->client);
  }
  
  static void max7359_initialize(struct i2c_client *client)
  {
  	max7359_write_reg(client, MAX7359_REG_CONFIG,
  		MAX7359_CFG_KEY_RELEASE | /* Key release enable */
  		MAX7359_CFG_WAKEUP); /* Key press wakeup enable */
  
  	/* Full key-scan functionality */
  	max7359_write_reg(client, MAX7359_REG_DEBOUNCE, 0x1F);
  
  	/* nINT asserts every debounce cycles */
  	max7359_write_reg(client, MAX7359_REG_INTERRUPT, 0x01);
  
  	max7359_fall_deepsleep(client);
  }
  
  static int max7359_probe(struct i2c_client *client,
  					const struct i2c_device_id *id)
  {
  	const struct matrix_keymap_data *keymap_data =
  			dev_get_platdata(&client->dev);
  	struct max7359_keypad *keypad;
  	struct input_dev *input_dev;
  	int ret;
  	int error;
  
  	if (!client->irq) {
  		dev_err(&client->dev, "The irq number should not be zero
  ");
  		return -EINVAL;
  	}
  
  	/* Detect MAX7359: The initial Keys FIFO value is '0x3F' */
  	ret = max7359_read_reg(client, MAX7359_REG_KEYFIFO);
  	if (ret < 0) {
  		dev_err(&client->dev, "failed to detect device
  ");
  		return -ENODEV;
  	}
  
  	dev_dbg(&client->dev, "keys FIFO is 0x%02x
  ", ret);
  
  	keypad = devm_kzalloc(&client->dev, sizeof(struct max7359_keypad),
  			      GFP_KERNEL);
  	if (!keypad) {
  		dev_err(&client->dev, "failed to allocate memory
  ");
  		return -ENOMEM;
  	}
  
  	input_dev = devm_input_allocate_device(&client->dev);
  	if (!input_dev) {
  		dev_err(&client->dev, "failed to allocate input device
  ");
  		return -ENOMEM;
  	}
  
  	keypad->client = client;
  	keypad->input_dev = input_dev;
  
  	input_dev->name = client->name;
  	input_dev->id.bustype = BUS_I2C;
  	input_dev->open = max7359_open;
  	input_dev->close = max7359_close;
  	input_dev->dev.parent = &client->dev;
  
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
  	input_dev->keycodesize = sizeof(keypad->keycodes[0]);
  	input_dev->keycodemax = ARRAY_SIZE(keypad->keycodes);
  	input_dev->keycode = keypad->keycodes;
  
  	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
  	input_set_drvdata(input_dev, keypad);
  
  	error = matrix_keypad_build_keymap(keymap_data, NULL,
  					   MAX7359_MAX_KEY_ROWS,
  					   MAX7359_MAX_KEY_COLS,
  					   keypad->keycodes,
  					   input_dev);
  	if (error) {
  		dev_err(&client->dev, "failed to build keymap
  ");
  		return error;
  	}
  
  	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
  					  max7359_interrupt,
  					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
  					  client->name, keypad);
  	if (error) {
  		dev_err(&client->dev, "failed to register interrupt
  ");
  		return error;
  	}
  
  	/* Register the input device */
  	error = input_register_device(input_dev);
  	if (error) {
  		dev_err(&client->dev, "failed to register input device
  ");
  		return error;
  	}
  
  	/* Initialize MAX7359 */
  	max7359_initialize(client);
  
  	i2c_set_clientdata(client, keypad);
  	device_init_wakeup(&client->dev, 1);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int max7359_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	max7359_fall_deepsleep(client);
  
  	if (device_may_wakeup(&client->dev))
  		enable_irq_wake(client->irq);
  
  	return 0;
  }
  
  static int max7359_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	if (device_may_wakeup(&client->dev))
  		disable_irq_wake(client->irq);
  
  	/* Restore the default setting */
  	max7359_take_catnap(client);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(max7359_pm, max7359_suspend, max7359_resume);
  
  static const struct i2c_device_id max7359_ids[] = {
  	{ "max7359", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, max7359_ids);
  
  static struct i2c_driver max7359_i2c_driver = {
  	.driver = {
  		.name = "max7359",
  		.pm   = &max7359_pm,
  	},
  	.probe		= max7359_probe,
  	.id_table	= max7359_ids,
  };
  
  module_i2c_driver(max7359_i2c_driver);
  
  MODULE_AUTHOR("Kim Kyuwon <q1.kim@samsung.com>");
  MODULE_DESCRIPTION("MAX7359 Key Switch Controller Driver");
  MODULE_LICENSE("GPL v2");