/*
   * Copyright (c) 2010, 2011 Fabien Marteau <fabien.marteau@armadeus.com>
   * Sponsored by ARMadeus Systems
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   *
   * Driver for Austria Microsystems joysticks AS5011
   *
   * TODO:
   *	- Power on the chip when open() and power down when close()
   *	- Manage power mode
   */
  
  #include <linux/i2c.h>
  #include <linux/interrupt.h>
  #include <linux/input.h>
  #include <linux/gpio.h>
  #include <linux/delay.h>
  #include <linux/input/as5011.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  
  #define DRIVER_DESC "Driver for Austria Microsystems AS5011 joystick"
  #define MODULE_DEVICE_ALIAS "as5011"
  
  MODULE_AUTHOR("Fabien Marteau <fabien.marteau@armadeus.com>");
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  
  /* registers */
  #define AS5011_CTRL1		0x76
  #define AS5011_CTRL2		0x75
  #define AS5011_XP		0x43
  #define AS5011_XN		0x44
  #define AS5011_YP		0x53
  #define AS5011_YN		0x54
  #define AS5011_X_REG		0x41
  #define AS5011_Y_REG		0x42
  #define AS5011_X_RES_INT	0x51
  #define AS5011_Y_RES_INT	0x52
  
  /* CTRL1 bits */
  #define AS5011_CTRL1_LP_PULSED		0x80
  #define AS5011_CTRL1_LP_ACTIVE		0x40
  #define AS5011_CTRL1_LP_CONTINUE	0x20
  #define AS5011_CTRL1_INT_WUP_EN		0x10
  #define AS5011_CTRL1_INT_ACT_EN		0x08
  #define AS5011_CTRL1_EXT_CLK_EN		0x04
  #define AS5011_CTRL1_SOFT_RST		0x02
  #define AS5011_CTRL1_DATA_VALID		0x01
  
  /* CTRL2 bits */
  #define AS5011_CTRL2_EXT_SAMPLE_EN	0x08
  #define AS5011_CTRL2_RC_BIAS_ON		0x04
  #define AS5011_CTRL2_INV_SPINNING	0x02
  
  #define AS5011_MAX_AXIS	80
  #define AS5011_MIN_AXIS	(-80)
  #define AS5011_FUZZ	8
  #define AS5011_FLAT	40
  
  struct as5011_device {
  	struct input_dev *input_dev;
  	struct i2c_client *i2c_client;
  	unsigned int button_gpio;
  	unsigned int button_irq;
  	unsigned int axis_irq;
  };
  
  static int as5011_i2c_write(struct i2c_client *client,
  			    uint8_t aregaddr,
  			    uint8_t avalue)
  {
  	uint8_t data[2] = { aregaddr, avalue };
  	struct i2c_msg msg = {
  		.addr = client->addr,
  		.flags = I2C_M_IGNORE_NAK,
  		.len = 2,
  		.buf = (uint8_t *)data
  	};
  	int error;
  
  	error = i2c_transfer(client->adapter, &msg, 1);
  	return error < 0 ? error : 0;
  }
  
  static int as5011_i2c_read(struct i2c_client *client,
  			   uint8_t aregaddr, signed char *value)
  {
  	uint8_t data[2] = { aregaddr };
  	struct i2c_msg msg_set[2] = {
  		{
  			.addr = client->addr,
  			.flags = I2C_M_REV_DIR_ADDR,
  			.len = 1,
  			.buf = (uint8_t *)data
  		},
  		{
  			.addr = client->addr,
  			.flags = I2C_M_RD | I2C_M_NOSTART,
  			.len = 1,
  			.buf = (uint8_t *)data
  		}
  	};
  	int error;
  
  	error = i2c_transfer(client->adapter, msg_set, 2);
  	if (error < 0)
  		return error;
  
  	*value = data[0] & 0x80 ? -1 * (1 + ~data[0]) : data[0];
  	return 0;
  }
  
  static irqreturn_t as5011_button_interrupt(int irq, void *dev_id)
  {
  	struct as5011_device *as5011 = dev_id;
  	int val = gpio_get_value_cansleep(as5011->button_gpio);
  
  	input_report_key(as5011->input_dev, BTN_JOYSTICK, !val);
  	input_sync(as5011->input_dev);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t as5011_axis_interrupt(int irq, void *dev_id)
  {
  	struct as5011_device *as5011 = dev_id;
  	int error;
  	signed char x, y;
  
  	error = as5011_i2c_read(as5011->i2c_client, AS5011_X_RES_INT, &x);
  	if (error < 0)
  		goto out;
  
  	error = as5011_i2c_read(as5011->i2c_client, AS5011_Y_RES_INT, &y);
  	if (error < 0)
  		goto out;
  
  	input_report_abs(as5011->input_dev, ABS_X, x);
  	input_report_abs(as5011->input_dev, ABS_Y, y);
  	input_sync(as5011->input_dev);
  
  out:
  	return IRQ_HANDLED;
  }
  
  static int as5011_configure_chip(struct as5011_device *as5011,
  				const struct as5011_platform_data *plat_dat)
  {
  	struct i2c_client *client = as5011->i2c_client;
  	int error;
  	signed char value;
  
  	/* chip soft reset */
  	error = as5011_i2c_write(client, AS5011_CTRL1,
  				 AS5011_CTRL1_SOFT_RST);
  	if (error < 0) {
  		dev_err(&client->dev, "Soft reset failed
  ");
  		return error;
  	}
  
  	mdelay(10);
  
  	error = as5011_i2c_write(client, AS5011_CTRL1,
  				 AS5011_CTRL1_LP_PULSED |
  				 AS5011_CTRL1_LP_ACTIVE |
  				 AS5011_CTRL1_INT_ACT_EN);
  	if (error < 0) {
  		dev_err(&client->dev, "Power config failed
  ");
  		return error;
  	}
  
  	error = as5011_i2c_write(client, AS5011_CTRL2,
  				 AS5011_CTRL2_INV_SPINNING);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't invert spinning
  ");
  		return error;
  	}
  
  	/* write threshold */
  	error = as5011_i2c_write(client, AS5011_XP, plat_dat->xp);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't write threshold
  ");
  		return error;
  	}
  
  	error = as5011_i2c_write(client, AS5011_XN, plat_dat->xn);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't write threshold
  ");
  		return error;
  	}
  
  	error = as5011_i2c_write(client, AS5011_YP, plat_dat->yp);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't write threshold
  ");
  		return error;
  	}
  
  	error = as5011_i2c_write(client, AS5011_YN, plat_dat->yn);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't write threshold
  ");
  		return error;
  	}
  
  	/* to free irq gpio in chip */
  	error = as5011_i2c_read(client, AS5011_X_RES_INT, &value);
  	if (error < 0) {
  		dev_err(&client->dev, "Can't read i2c X resolution value
  ");
  		return error;
  	}
  
  	return 0;
  }
  
  static int as5011_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	const struct as5011_platform_data *plat_data;
  	struct as5011_device *as5011;
  	struct input_dev *input_dev;
  	int irq;
  	int error;
  
  	plat_data = dev_get_platdata(&client->dev);
  	if (!plat_data)
  		return -EINVAL;
  
  	if (!plat_data->axis_irq) {
  		dev_err(&client->dev, "No axis IRQ?
  ");
  		return -EINVAL;
  	}
  
  	if (!i2c_check_functionality(client->adapter,
  				     I2C_FUNC_NOSTART |
  				     I2C_FUNC_PROTOCOL_MANGLING)) {
  		dev_err(&client->dev,
  			"need i2c bus that supports protocol mangling
  ");
  		return -ENODEV;
  	}
  
  	as5011 = kmalloc(sizeof(struct as5011_device), GFP_KERNEL);
  	input_dev = input_allocate_device();
  	if (!as5011 || !input_dev) {
  		dev_err(&client->dev,
  			"Can't allocate memory for device structure
  ");
  		error = -ENOMEM;
  		goto err_free_mem;
  	}
  
  	as5011->i2c_client = client;
  	as5011->input_dev = input_dev;
  	as5011->button_gpio = plat_data->button_gpio;
  	as5011->axis_irq = plat_data->axis_irq;
  
  	input_dev->name = "Austria Microsystem as5011 joystick";
  	input_dev->id.bustype = BUS_I2C;
  	input_dev->dev.parent = &client->dev;
  
  	__set_bit(EV_KEY, input_dev->evbit);
  	__set_bit(EV_ABS, input_dev->evbit);
  	__set_bit(BTN_JOYSTICK, input_dev->keybit);
  
  	input_set_abs_params(input_dev, ABS_X,
  		AS5011_MIN_AXIS, AS5011_MAX_AXIS, AS5011_FUZZ, AS5011_FLAT);
  	input_set_abs_params(as5011->input_dev, ABS_Y,
  		AS5011_MIN_AXIS, AS5011_MAX_AXIS, AS5011_FUZZ, AS5011_FLAT);
  
  	error = gpio_request(as5011->button_gpio, "AS5011 button");
  	if (error < 0) {
  		dev_err(&client->dev, "Failed to request button gpio
  ");
  		goto err_free_mem;
  	}
  
  	irq = gpio_to_irq(as5011->button_gpio);
  	if (irq < 0) {
  		dev_err(&client->dev,
  			"Failed to get irq number for button gpio
  ");
  		error = irq;
  		goto err_free_button_gpio;
  	}
  
  	as5011->button_irq = irq;
  
  	error = request_threaded_irq(as5011->button_irq,
  				     NULL, as5011_button_interrupt,
  				     IRQF_TRIGGER_RISING |
  					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				     "as5011_button", as5011);
  	if (error < 0) {
  		dev_err(&client->dev,
  			"Can't allocate button irq %d
  ", as5011->button_irq);
  		goto err_free_button_gpio;
  	}
  
  	error = as5011_configure_chip(as5011, plat_data);
  	if (error)
  		goto err_free_button_irq;
  
  	error = request_threaded_irq(as5011->axis_irq, NULL,
  				     as5011_axis_interrupt,
  				     plat_data->axis_irqflags | IRQF_ONESHOT,
  				     "as5011_joystick", as5011);
  	if (error) {
  		dev_err(&client->dev,
  			"Can't allocate axis irq %d
  ", plat_data->axis_irq);
  		goto err_free_button_irq;
  	}
  
  	error = input_register_device(as5011->input_dev);
  	if (error) {
  		dev_err(&client->dev, "Failed to register input device
  ");
  		goto err_free_axis_irq;
  	}
  
  	i2c_set_clientdata(client, as5011);
  
  	return 0;
  
  err_free_axis_irq:
  	free_irq(as5011->axis_irq, as5011);
  err_free_button_irq:
  	free_irq(as5011->button_irq, as5011);
  err_free_button_gpio:
  	gpio_free(as5011->button_gpio);
  err_free_mem:
  	input_free_device(input_dev);
  	kfree(as5011);
  
  	return error;
  }
  
  static int as5011_remove(struct i2c_client *client)
  {
  	struct as5011_device *as5011 = i2c_get_clientdata(client);
  
  	free_irq(as5011->axis_irq, as5011);
  	free_irq(as5011->button_irq, as5011);
  	gpio_free(as5011->button_gpio);
  
  	input_unregister_device(as5011->input_dev);
  	kfree(as5011);
  
  	return 0;
  }
  
  static const struct i2c_device_id as5011_id[] = {
  	{ MODULE_DEVICE_ALIAS, 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, as5011_id);
  
  static struct i2c_driver as5011_driver = {
  	.driver = {
  		.name = "as5011",
  	},
  	.probe		= as5011_probe,
  	.remove		= as5011_remove,
  	.id_table	= as5011_id,
  };
  
  module_i2c_driver(as5011_driver);