/*
 *  linux/drivers/i2c/chips/tsc2003.c
 *
 *  Copyright (C) 2005 Bill Gatliff <bgat at billgatliff.com>
 *  Changes for 2.6.20 kernel by Nicholas Chen <nchen at cs.umd.edu>
 *
 *  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.
 *
 *  Driver for TI's TSC2003 I2C Touch Screen Controller
 */

//#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/bcd.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <asm-arm/arch-pxa/irqs.h>

static unsigned short normal_i2c[]
= {0x48, I2C_CLIENT_END };

I2C_CLIENT_INSMOD_1(tsc2003);

#define DRIVER_NAME "tsc2003"

enum tsc2003_pd {
  PD_POWERDOWN = 0, /* penirq */
  PD_IREFOFF_ADCON = 1, /* no penirq */
  PD_IREFON_ADCOFF = 2, /* penirq */
  PD_IREFON_ADCON = 3, /* no penirq */
  PD_PENIRQ_ARM = PD_IREFON_ADCOFF,
  PD_PENIRQ_DISARM = PD_IREFON_ADCON,
};

enum tsc2003_m {
  M_12BIT = 0,
  M_8BIT = 1
};

enum tsc2003_cmd {
  MEAS_TEMP0 = 0,
  MEAS_VBAT1 = 1,
  MEAS_IN1 = 2,
  MEAS_TEMP1 = 4,
  MEAS_VBAT2 = 5,
  MEAS_IN2 = 6,
  ACTIVATE_NX_DRIVERS = 8,
  ACTIVATE_NY_DRIVERS = 9,
  ACTIVATE_YNX_DRIVERS = 10,
  MEAS_XPOS = 12,
  MEAS_YPOS = 13,
  MEAS_Z1POS = 14,
  MEAS_Z2POS = 15
};

#define TSC2003_CMD(cn,pdn,m) (((cn) << 4) | ((pdn) << 2) | ((m) << 1))

#define ADC_MAX ((1 << 12) - 1)

struct tsc2003_data {
  struct i2c_client client;
  struct device_driver driver;
  struct input_dev *idev;
  struct timer_list penirq_timer;
  struct semaphore sem;
  struct task_struct *tstask;
  struct completion tstask_completion;
  struct completion penirq_completion;
  enum tsc2003_pd pd;
  enum tsc2003_m m;
  int penirq;

  int vbat1;
  int vbat2;
  int temp0;
  int temp1;
  int in1;
  int in2;
};

static int tsc2003_i2c_detect (struct i2c_adapter *adapter, int address, 
int kind);

static inline int tsc2003_command (struct tsc2003_data *data,
                                   enum tsc2003_cmd cmd,
                                   enum tsc2003_pd pd)
{
  char c;
  int ret;
  down(&data->sem);
  c = TSC2003_CMD(cmd, pd, data->m);
  ret = i2c_master_send(&data->client, &c, 1);
  up(&data->sem);
  return ret;
}

static int tsc2003_read (struct tsc2003_data *data,
                         enum tsc2003_cmd cmd,
                         enum tsc2003_pd pd,
                         int *val)
{
  char c;
  char d[2];
  int ret;

  c = TSC2003_CMD(cmd, pd, data->m);
  ret = i2c_master_send(&data->client, &c, 1);
  if (ret <= 0) goto err;

  udelay(20);
  ret = i2c_master_recv(&data->client, d, data->m == M_12BIT ? 2 : 1);
  if (ret <= 0) goto err;

  if (val)
    {
      *val = d[0];
      *val <<= 4;
      if (data->m == M_12BIT)
        *val += (d[1] >> 4);
    }

#if defined(CONFIG_I2C_DEBUG_CHIP)
  printk(KERN_ERR "%s: val[%x] = %d\n",
         __FUNCTION__, cmd, (((int)d[0]) << 8) + d[1]);
#endif

  return 0;
 err:
  if (!ret) ret = -ENODEV;
  return ret;
}

static inline int tsc2003_read_temp0 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_TEMP0, pd, t);
}

static inline int tsc2003_read_temp1 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_TEMP1, pd, t);
}

static inline int tsc2003_read_xpos (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *x)
{
  return tsc2003_read(d, MEAS_XPOS, pd, x);
}

static inline int tsc2003_read_ypos (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *y)
{
  return tsc2003_read(d, MEAS_YPOS, pd, y);
}

static inline int tsc2003_read_pressure (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *p)
{
  return tsc2003_read(d, MEAS_Z1POS, pd, p);
}

static inline int tsc2003_read_in1 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_IN1, pd, t);
}

static inline int tsc2003_read_in2 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_IN2, pd, t);
}

static inline int tsc2003_read_vbat1 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_VBAT1, pd, t);
}

static inline int tsc2003_read_vbat2 (struct tsc2003_data *d, enum 
tsc2003_pd pd, int *t)
{
  return tsc2003_read(d, MEAS_VBAT2, pd, t);
}

static inline int tsc2003_powerdown (struct tsc2003_data *d)
{
  /* we don't have a distinct powerdown command,
     so do a benign read with the PD bits cleared */
  return tsc2003_read(d, MEAS_IN1, PD_POWERDOWN, 0);
}

void tsc2003_init_client (struct i2c_client *client)
{
  struct tsc2003_data *data = i2c_get_clientdata(client);

  data->pd = PD_PENIRQ_DISARM;
  data->m = M_8BIT;
  return;
}

#define PENUP_TIMEOUT 50 /* msec */

static irqreturn_t tsc2003_penirq (int irq, void *v)
{
  struct tsc2003_data *d = v;
  complete(&d->penirq_completion);
  return IRQ_HANDLED;
}

/*
static int tsc2003_remove (struct device *dev)
{
  struct tsc2003_data *d = container_of(dev->driver, struct tsc2003_data, driver);
  free_irq(d->penirq,d);
  input_unregister_device(d->idev);
  return 0;
}
*/

static void tsc2003_pen_up (unsigned long v)
{
  struct tsc2003_data *d = (struct tsc2003_data *)v;
  input_report_abs(d->idev, ABS_PRESSURE, 0);
  input_sync(d->idev);
  return;
}

static inline void tsc2003_restart_pen_up_timer (struct tsc2003_data *d)
{
  mod_timer(&d->penirq_timer, jiffies + (PENUP_TIMEOUT * HZ) / 1000);
}

static int tsc2003ts_thread (void *v)
{
  struct tsc2003_data *d = v;
  struct task_struct *tsk = current;
  int ret;
  
  d->tstask = tsk;

  daemonize(DRIVER_NAME "tsd");
  allow_signal(SIGKILL);

  complete(&d->tstask_completion);

#if defined(CONFIG_I2C_DEBUG_CHIP)
  printk(KERN_INFO "%s: address 0x%x\n",
         __FUNCTION__, d->client.addr);
#endif

  while (!signal_pending(tsk))
    {
      unsigned int x, y, p;
     
      if (!down_interruptible(&d->sem))
        {
          d->pd = PD_PENIRQ_DISARM;
          disable_irq(d->penirq);
          tsc2003_read_xpos(d, PD_PENIRQ_DISARM, &x);
          tsc2003_read_ypos(d, PD_PENIRQ_DISARM, &y);
          tsc2003_read_pressure(d, PD_PENIRQ_DISARM, &p);
         
          /* non-X-Y driver read to avoid glitch in penirq (errata?) */
          tsc2003_read_vbat1(d, PD_PENIRQ_DISARM, 0);
          enable_irq(d->penirq);
         
	  
          input_report_abs(d->idev, ABS_X, 4096 - x);
          input_report_abs(d->idev, ABS_Y, 4096 - y);
          input_report_abs(d->idev, ABS_PRESSURE, p);
         input_sync(d->idev);
  
         
          do
            {
              ret = wait_for_completion_interruptible_timeout(&d->penirq_completion, HZ / 100);
              if (ret)
                {
                  if (d->pd == PD_PENIRQ_DISARM)
                    {
                      /* fake penirq, avoid glitch and then start watching for real now */
                      d->pd = PD_PENIRQ_ARM;
                      tsc2003_read_vbat1(d, PD_PENIRQ_ARM, 0);
                      up(&d->sem);
                    }
                  else
                    {
                      /* pen down event, (re)start the pen up timer */
                      tsc2003_restart_pen_up_timer(d);
                    }
                }
              else
                {
                  if (d->pd != PD_PENIRQ_ARM)
                    {
                      /* fake penirq never arrived, which would be the case
                         for a level-triggered irq line */
                      tsc2003_read_vbat1(d, PD_PENIRQ_ARM, 0);
                      d->pd = PD_PENIRQ_ARM;
                      up(&d->sem);
                    }
                  if (timer_pending(&d->penirq_timer))
                    {
                      /* pen is down, time to send (another) sample */
                      break;
                    }
                  else
                    {
                      /* pen is up, nothing to do but wait for it to 
			come down */			
			wait_for_completion_interruptible(&d->penirq_completion);
                      /* pen is down, (re)start the pen up timer */
                      tsc2003_restart_pen_up_timer(d);
                      break;
                    }
                }
            }
          while (!signal_pending(tsk));
        }
    }
     
  d->tstask = NULL;
  complete_and_exit(&d->tstask_completion, 0);
}

static int tsc2003_idev_open (struct input_dev *idev)
{
  struct tsc2003_data *d = idev->private;
  int ret = 0;

  if (down_interruptible(&d->sem))
    return -EINTR;

  if (d->tstask)
    panic(DRIVER_NAME "tsd already running (!). abort.");
  
  d->penirq_timer.data = (unsigned long)d;
  d->penirq_timer.function = tsc2003_pen_up;

  ret = kernel_thread(tsc2003ts_thread, d, CLONE_KERNEL);
  if (ret >= 0)
  {
      wait_for_completion(&d->tstask_completion);
      ret = 0;
   }

   

  up(&d->sem);
  return ret;
}

static void tsc2003_idev_close (struct input_dev *idev)
{
  struct tsc2003_data *d = idev->private;
  down_interruptible(&d->sem);
  if (d->tstask)
    {
      send_sig(SIGKILL, d->tstask, 1);
      wait_for_completion(&d->tstask_completion);
    }

  if (timer_pending(&d->penirq_timer))
    del_timer(&d->penirq_timer);
  up(&d->sem);
  return;
}

#if defined(CONFIG_SYSFS) && defined(CONFIG_SENSORS_TSC2003_SYSFS)
static ssize_t show_addr (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->client.addr);
}
static DEVICE_ATTR(addr, S_IRUGO, show_addr, NULL);

static ssize_t show_vbat1 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->vbat1);
}
static DEVICE_ATTR(vbat1, S_IRUGO, show_vbat1, NULL);

static ssize_t show_vbat2 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->vbat2);
}
static DEVICE_ATTR(vbat2, S_IRUGO, show_vbat2, NULL);

static ssize_t show_in1 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->in1);
}
static DEVICE_ATTR(in1, S_IRUGO, show_in1, NULL);

static ssize_t show_in2 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->in2);
}
static DEVICE_ATTR(in2, S_IRUGO, show_in2, NULL);

static ssize_t show_temp0 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->temp0);
}
static DEVICE_ATTR(temp0, S_IRUGO, show_temp0, NULL);

static ssize_t show_temp1 (struct device *dev, char *buf)
{
  struct tsc2003_data *d = container_of(dev->driver, struct 
tsc2003_data, driver);
  return sprintf(buf, "%d\n", d->temp1);
}
static DEVICE_ATTR(temp1, S_IRUGO, show_temp1, NULL);

#warning "TODO: this daemon sometimes hangs the touchscreen daemon"
#warning "TODO: under periods of heavy touch screen activity."
#warning "TODO: Use with caution until the bug is squashed."
static int tsc2003s_thread (void *v)
{
  struct tsc2003_data *d = v;

  daemonize(DRIVER_NAME "sd");
  allow_signal(SIGKILL);

  printk(KERN_INFO "%s: address 0x%x\n",
         __FUNCTION__, d->client.addr);

  while (!signal_pending(current))
    {
      if (!down_interruptible(&d->sem))
        {
          if (!timer_pending(&d->penirq_timer))
            {
              tsc2003_read_vbat1(d, d->pd, &d->vbat1);
              tsc2003_read_vbat2(d, d->pd, &d->vbat2);
              tsc2003_read_in1(d, d->pd, &d->in1);
              tsc2003_read_in2(d, d->pd, &d->in2);
              tsc2003_read_temp0(d, d->pd, &d->temp0);
              tsc2003_read_temp1(d, d->pd, &d->temp1);
            }
          up(&d->sem);
        }
      set_task_state(current, TASK_INTERRUPTIBLE);
      schedule_timeout(5 * HZ);
    }
  do_exit(0);
}
#endif

static int tsc2003_detect_irq (struct tsc2003_data *d)
{
	d->penirq = IRQ_GPIO(16);	//PWM0 GPIO
	return 0;
}

/*
static int tsc2003_probe (struct device *dev)
{
  //struct platform_device *p = to_platform_device(dev);  
  struct tsc2003_data *d = container_of(dev->driver, struct tsc2003_data, driver);
  int ret = 0;  
  int error;
 
  printk(KERN_ERR "TSC2003: tsc2003_probe probing...\n"); 

  error = tsc2003_detect_irq(d);
   if(error)
   {
	printk(KERN_ERR "TSC2003: IRQ probe failed\n");
   }

   if (d->penirq)
   {
      ret = request_irq(d->penirq, tsc2003_penirq, IRQF_TRIGGER_FALLING, DRIVER_NAME, d);
      if (!ret)
        {
          printk(KERN_INFO "%s: irq %d\n", __FUNCTION__, d->penirq);
        }
       else
        {
	  printk(KERN_INFO "%s: cannot grab irq %d\n", __FUNCTION__, d->penirq);
        }
    }

#if defined(CONFIG_SYSFS) && defined(CONFIG_SENSORS_TSC2003_SYSFS)
  ret = kernel_thread(tsc2003s_thread, d, CLONE_KERNEL);
  if (ret >= 0)
    ret = 0;

  device_create_file(dev, &dev_attr_addr);
  device_create_file(dev, &dev_attr_vbat1);
  device_create_file(dev, &dev_attr_vbat2);
  device_create_file(dev, &dev_attr_in1);
  device_create_file(dev, &dev_attr_in2);
  device_create_file(dev, &dev_attr_temp0);
  device_create_file(dev, &dev_attr_temp1);
#endif


  return ret;
}
*/

static int tsc2003_driver_register (struct tsc2003_data *data)
{
  struct input_dev *idev;
  int ret = 0;
  int error;  

  init_MUTEX(&data->sem);

  init_timer(&data->penirq_timer);
  data->penirq_timer.data = (unsigned long)data;
  data->penirq_timer.function = tsc2003_pen_up;  

  error = tsc2003_detect_irq(data);
   if(error)
   {
	printk(KERN_ERR "TSC2003: IRQ probe failed\n");
   }

   if (data->penirq)
   {
      ret = request_irq(data->penirq, tsc2003_penirq, IRQF_TRIGGER_FALLING, DRIVER_NAME, data);
      if (!ret)
        {
          printk(KERN_INFO "%s: irq %d\n", __FUNCTION__, data->penirq);
	  init_completion(&data->tstask_completion);
	  init_completion(&data->penirq_completion);
        }
       else
        {
	  printk(KERN_ERR "%s: cannot grab irq %d\n", __FUNCTION__, data->penirq);
        }
    }
  
  idev = input_allocate_device();
  data->idev = idev;

  idev->private = data;
  idev->name = DRIVER_NAME;
  idev->evbit[0] = BIT(EV_ABS);
  idev->open = tsc2003_idev_open;
  idev->close = tsc2003_idev_close;
  idev->absbit[LONG(ABS_X)] = BIT(ABS_X);
  idev->absbit[LONG(ABS_Y)] = BIT(ABS_Y);
  idev->absbit[LONG(ABS_PRESSURE)] = BIT(ABS_PRESSURE);
  input_set_abs_params(idev, ABS_X, 0, ADC_MAX, 0, 0);
  input_set_abs_params(idev, ABS_Y, 0, ADC_MAX, 0, 0);
  input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);

  if (!ret)
  {
    input_register_device(idev);
        printk(KERN_INFO "tsc2003 - registering input device\n");
  }

  return ret;
}

static int tsc2003_i2c_attach_adapter(struct i2c_adapter *adapter)
{
  printk(KERN_INFO "tsc2003 i2c touch screen controller\n");
  printk(KERN_INFO "Bill Gatliff <bgat at billgatliff.com\n");
  printk(KERN_INFO "Nicholas Chen <nchen at cs.umd.edu>\n");
 
  return i2c_probe(adapter, &addr_data, tsc2003_i2c_detect);
}

static int tsc2003_i2c_detach_client(struct i2c_client *client)
{
  int err;  
  struct tsc2003_data *d = i2c_get_clientdata(client);

  free_irq(d->penirq,d);
  input_unregister_device(d->idev);

  if ((err = i2c_detach_client(client))) {
    dev_err(&client->dev, "Client deregistration failed, "
            "client not detached.\n");
    return err;
  }

  return 0;
}

static struct i2c_driver tsc2003_driver = {
  .driver = {
	  .owner        = THIS_MODULE,
	  .name         = DRIVER_NAME,
   },
  .attach_adapter    = tsc2003_i2c_attach_adapter,
  .detach_client    = tsc2003_i2c_detach_client,
  //  .command              = tsc2003_command,
};

static int tsc2003_i2c_detect (struct i2c_adapter *adapter, int address, 
int kind)
{
  struct i2c_client *new_client;
  struct tsc2003_data *data;

  int err = 0;
  const char *name = "";

  if (!i2c_check_functionality(adapter,
                               I2C_FUNC_SMBUS_BYTE_DATA
                               | I2C_FUNC_I2C
                               | I2C_FUNC_SMBUS_WORD_DATA))
    goto exit;

  data = kcalloc(1, sizeof(*data), GFP_KERNEL);
  if (!data) {
    err = -ENOMEM;
    goto exit;
  }

  new_client = &data->client;
  i2c_set_clientdata(new_client, data);
  new_client->addr = address;
  new_client->adapter = adapter;
  new_client->driver = &tsc2003_driver;
  new_client->flags = 0;

  /* TODO: I'm pretty sure I'm not dealing with kind correctly */
  if (kind == 0 /* identification */ || kind < 0 /* detection */)
      kind = tsc2003;

  if (kind == tsc2003)
    name = DRIVER_NAME;

  /* try a command, see if we get an ack;
     if we do, assume it's our device */
  printk(KERN_INFO "%s: probing address 0x%x\n",
         __FUNCTION__, address);
  err = tsc2003_powerdown(data);
  if (err >= 0)
    {
      strlcpy(new_client->name, name, I2C_NAME_SIZE);
      err = i2c_attach_client(new_client);
      if (err) goto exit_free;

      tsc2003_init_client(new_client);

      err = tsc2003_driver_register(data);
      if (err < 0) goto exit_free;
     
      printk(KERN_INFO "%s: device address 0x%x attached.\n",
             __FUNCTION__, address);
      return 0;
    }
  /* failure to detect when everything else is ok isn't an error */
  else err = 0;

 exit_free:
  kfree(new_client);
 exit:
  return err;
}

static int __init tsc2003_init(void)
{
  return i2c_add_driver(&tsc2003_driver);
}

static void __exit tsc2003_exit(void)
{
  i2c_del_driver(&tsc2003_driver);
}

MODULE_AUTHOR("Bill Gatliff <bgat at billgatliff.com>");
MODULE_DESCRIPTION("TSC2003 Touch Screen Controller driver");
MODULE_LICENSE("GPL");

module_init(tsc2003_init);
module_exit(tsc2003_exit);