/*
   * ST1232 Touchscreen Controller Driver
   *
   * Copyright (C) 2010 Renesas Solutions Corp.
   *	Tony SIM <chinyeow.sim.xt@renesas.com>
   *
   * Using code from:
   *  - android.git.kernel.org: projects/kernel/common.git: synaptics_i2c_rmi.c
   *	Copyright (C) 2007 Google, Inc.
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * 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/delay.h>
  #include <linux/gpio.h>
  #include <linux/i2c.h>
  #include <linux/input.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/of_gpio.h>
  #include <linux/pm_qos.h>
  #include <linux/slab.h>
  #include <linux/types.h>
  #include <linux/platform_data/st1232_pdata.h>
  
  #define ST1232_TS_NAME	"st1232-ts"
  
  #define MIN_X		0x00
  #define MIN_Y		0x00
  #define MAX_X		0x31f	/* (800 - 1) */
  #define MAX_Y		0x1df	/* (480 - 1) */
  #define MAX_AREA	0xff
  #define MAX_FINGERS	2
  
  struct st1232_ts_finger {
  	u16 x;
  	u16 y;
  	u8 t;
  	bool is_valid;
  };
  
  struct st1232_ts_data {
  	struct i2c_client *client;
  	struct input_dev *input_dev;
  	struct st1232_ts_finger finger[MAX_FINGERS];
  	struct dev_pm_qos_request low_latency_req;
  	int reset_gpio;
  };
  
  static int st1232_ts_read_data(struct st1232_ts_data *ts)
  {
  	struct st1232_ts_finger *finger = ts->finger;
  	struct i2c_client *client = ts->client;
  	struct i2c_msg msg[2];
  	int error;
  	u8 start_reg;
  	u8 buf[10];
  
  	/* read touchscreen data from ST1232 */
  	msg[0].addr = client->addr;
  	msg[0].flags = 0;
  	msg[0].len = 1;
  	msg[0].buf = &start_reg;
  	start_reg = 0x10;
  
  	msg[1].addr = ts->client->addr;
  	msg[1].flags = I2C_M_RD;
  	msg[1].len = sizeof(buf);
  	msg[1].buf = buf;
  
  	error = i2c_transfer(client->adapter, msg, 2);
  	if (error < 0)
  		return error;
  
  	/* get "valid" bits */
  	finger[0].is_valid = buf[2] >> 7;
  	finger[1].is_valid = buf[5] >> 7;
  
  	/* get xy coordinate */
  	if (finger[0].is_valid) {
  		finger[0].x = ((buf[2] & 0x0070) << 4) | buf[3];
  		finger[0].y = ((buf[2] & 0x0007) << 8) | buf[4];
  		finger[0].t = buf[8];
  	}
  
  	if (finger[1].is_valid) {
  		finger[1].x = ((buf[5] & 0x0070) << 4) | buf[6];
  		finger[1].y = ((buf[5] & 0x0007) << 8) | buf[7];
  		finger[1].t = buf[9];
  	}
  
  	return 0;
  }
  
  static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
  {
  	struct st1232_ts_data *ts = dev_id;
  	struct st1232_ts_finger *finger = ts->finger;
  	struct input_dev *input_dev = ts->input_dev;
  	int count = 0;
  	int i, ret;
  
  	ret = st1232_ts_read_data(ts);
  	if (ret < 0)
  		goto end;
  
  	/* multi touch protocol */
  	for (i = 0; i < MAX_FINGERS; i++) {
  		if (!finger[i].is_valid)
  			continue;
  
  		input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, finger[i].t);
  		input_report_abs(input_dev, ABS_MT_POSITION_X, finger[i].x);
  		input_report_abs(input_dev, ABS_MT_POSITION_Y, finger[i].y);
  		input_mt_sync(input_dev);
  		count++;
  	}
  
  	/* SYN_MT_REPORT only if no contact */
  	if (!count) {
  		input_mt_sync(input_dev);
  		if (ts->low_latency_req.dev) {
  			dev_pm_qos_remove_request(&ts->low_latency_req);
  			ts->low_latency_req.dev = NULL;
  		}
  	} else if (!ts->low_latency_req.dev) {
  		/* First contact, request 100 us latency. */
  		dev_pm_qos_add_ancestor_request(&ts->client->dev,
  						&ts->low_latency_req, 100);
  	}
  
  	/* SYN_REPORT */
  	input_sync(input_dev);
  
  end:
  	return IRQ_HANDLED;
  }
  
  static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
  {
  	if (gpio_is_valid(ts->reset_gpio))
  		gpio_direction_output(ts->reset_gpio, poweron);
  }
  
  static int st1232_ts_probe(struct i2c_client *client,
  					const struct i2c_device_id *id)
  {
  	struct st1232_ts_data *ts;
  	struct st1232_pdata *pdata = dev_get_platdata(&client->dev);
  	struct input_dev *input_dev;
  	int error;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  		dev_err(&client->dev, "need I2C_FUNC_I2C
  ");
  		return -EIO;
  	}
  
  	if (!client->irq) {
  		dev_err(&client->dev, "no IRQ?
  ");
  		return -EINVAL;
  	}
  
  	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
  	if (!ts)
  		return -ENOMEM;
  
  	input_dev = devm_input_allocate_device(&client->dev);
  	if (!input_dev)
  		return -ENOMEM;
  
  	ts->client = client;
  	ts->input_dev = input_dev;
  
  	if (pdata)
  		ts->reset_gpio = pdata->reset_gpio;
  	else if (client->dev.of_node)
  		ts->reset_gpio = of_get_gpio(client->dev.of_node, 0);
  	else
  		ts->reset_gpio = -ENODEV;
  
  	if (gpio_is_valid(ts->reset_gpio)) {
  		error = devm_gpio_request(&client->dev, ts->reset_gpio, NULL);
  		if (error) {
  			dev_err(&client->dev,
  				"Unable to request GPIO pin %d.
  ",
  				ts->reset_gpio);
  				return error;
  		}
  	}
  
  	st1232_ts_power(ts, true);
  
  	input_dev->name = "st1232-touchscreen";
  	input_dev->id.bustype = BUS_I2C;
  	input_dev->dev.parent = &client->dev;
  
  	__set_bit(EV_SYN, input_dev->evbit);
  	__set_bit(EV_KEY, input_dev->evbit);
  	__set_bit(EV_ABS, input_dev->evbit);
  
  	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, MAX_AREA, 0, 0);
  	input_set_abs_params(input_dev, ABS_MT_POSITION_X, MIN_X, MAX_X, 0, 0);
  	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, MIN_Y, MAX_Y, 0, 0);
  
  	error = devm_request_threaded_irq(&client->dev, client->irq,
  					  NULL, st1232_ts_irq_handler,
  					  IRQF_ONESHOT,
  					  client->name, ts);
  	if (error) {
  		dev_err(&client->dev, "Failed to register interrupt
  ");
  		return error;
  	}
  
  	error = input_register_device(ts->input_dev);
  	if (error) {
  		dev_err(&client->dev, "Unable to register %s input device
  ",
  			input_dev->name);
  		return error;
  	}
  
  	i2c_set_clientdata(client, ts);
  	device_init_wakeup(&client->dev, 1);
  
  	return 0;
  }
  
  static int st1232_ts_remove(struct i2c_client *client)
  {
  	struct st1232_ts_data *ts = i2c_get_clientdata(client);
  
  	device_init_wakeup(&client->dev, 0);
  	st1232_ts_power(ts, false);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int st1232_ts_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct st1232_ts_data *ts = i2c_get_clientdata(client);
  
  	if (device_may_wakeup(&client->dev)) {
  		enable_irq_wake(client->irq);
  	} else {
  		disable_irq(client->irq);
  		st1232_ts_power(ts, false);
  	}
  
  	return 0;
  }
  
  static int st1232_ts_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct st1232_ts_data *ts = i2c_get_clientdata(client);
  
  	if (device_may_wakeup(&client->dev)) {
  		disable_irq_wake(client->irq);
  	} else {
  		st1232_ts_power(ts, true);
  		enable_irq(client->irq);
  	}
  
  	return 0;
  }
  
  #endif
  
  static SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
  			 st1232_ts_suspend, st1232_ts_resume);
  
  static const struct i2c_device_id st1232_ts_id[] = {
  	{ ST1232_TS_NAME, 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, st1232_ts_id);
  
  #ifdef CONFIG_OF
  static const struct of_device_id st1232_ts_dt_ids[] = {
  	{ .compatible = "sitronix,st1232", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
  #endif
  
  static struct i2c_driver st1232_ts_driver = {
  	.probe		= st1232_ts_probe,
  	.remove		= st1232_ts_remove,
  	.id_table	= st1232_ts_id,
  	.driver = {
  		.name	= ST1232_TS_NAME,
  		.owner	= THIS_MODULE,
  		.of_match_table = of_match_ptr(st1232_ts_dt_ids),
  		.pm	= &st1232_ts_pm_ops,
  	},
  };
  
  module_i2c_driver(st1232_ts_driver);
  
  MODULE_AUTHOR("Tony SIM <chinyeow.sim.xt@renesas.com>");
  MODULE_DESCRIPTION("SITRONIX ST1232 Touchscreen Controller Driver");
  MODULE_LICENSE("GPL");