/*
   * Windfarm PowerMac thermal control.  MAX6690 sensor.
   *
   * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
   *
   * Use and redistribute under the terms of the GNU GPL v2.
   */
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/i2c.h>

  #include <asm/prom.h>
  #include <asm/pmac_low_i2c.h>
  
  #include "windfarm.h"

  #define VERSION "0.2"

  
  /* This currently only exports the external temperature sensor,
     since that's all the control loops need. */
  
  /* Some MAX6690 register numbers */
  #define MAX6690_INTERNAL_TEMP	0
  #define MAX6690_EXTERNAL_TEMP	1
  
  struct wf_6690_sensor {

  	struct i2c_client	*i2c;

  	struct wf_sensor	sens;
  };
  
  #define wf_to_6690(x)	container_of((x), struct wf_6690_sensor, sens)

  
  static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
  {
  	struct wf_6690_sensor *max = wf_to_6690(sr);
  	s32 data;

  	if (max->i2c == NULL)

  		return -ENODEV;
  
  	/* chip gets initialized by firmware */

  	data = i2c_smbus_read_byte_data(max->i2c, MAX6690_EXTERNAL_TEMP);

  	if (data < 0)
  		return data;
  	*value = data << 16;
  	return 0;
  }
  
  static void wf_max6690_release(struct wf_sensor *sr)
  {
  	struct wf_6690_sensor *max = wf_to_6690(sr);

  	kfree(max);
  }
  
  static struct wf_sensor_ops wf_max6690_ops = {
  	.get_value	= wf_max6690_get,
  	.release	= wf_max6690_release,
  	.owner		= THIS_MODULE,
  };

  static int wf_max6690_probe(struct i2c_client *client,
  			    const struct i2c_device_id *id)

  {
  	struct wf_6690_sensor *max;

  	int rc;

  
  	max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  	if (max == NULL) {

  		printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
  		       "no memory
  ");
  		return -ENOMEM;
  	}
  
  	max->i2c = client;
  	max->sens.name = client->dev.platform_data;
  	max->sens.ops = &wf_max6690_ops;
  	i2c_set_clientdata(client, max);
  
  	rc = wf_register_sensor(&max->sens);
  	if (rc) {

  		kfree(max);

  	}

  	return rc;
  }

  static struct i2c_driver wf_max6690_driver;

  static struct i2c_client *wf_max6690_create(struct i2c_adapter *adapter,
  					    u8 addr, const char *loc)
  {
  	struct i2c_board_info info;
  	struct i2c_client *client;
  	char *name;

  	if (!strcmp(loc, "BACKSIDE"))
  		name = "backside-temp";
  	else if (!strcmp(loc, "NB Ambient"))
  		name = "north-bridge-temp";
  	else if (!strcmp(loc, "GPU Ambient"))
  		name = "gpu-temp";
  	else
  		goto fail;

  	memset(&info, 0, sizeof(struct i2c_board_info));
  	info.addr = addr >> 1;
  	info.platform_data = name;
  	strlcpy(info.type, "wf_max6690", I2C_NAME_SIZE);

  	client = i2c_new_device(adapter, &info);
  	if (client == NULL) {

  		printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor
  ");
  		goto fail;
  	}

  	/*
  	 * Let i2c-core delete that device on driver removal.
  	 * This is safe because i2c-core holds the core_lock mutex for us.
  	 */

  	list_add_tail(&client->detected, &wf_max6690_driver.clients);

  	return client;

  
   fail:

  	return NULL;

  }
  
  static int wf_max6690_attach(struct i2c_adapter *adapter)
  {
  	struct device_node *busnode, *dev = NULL;
  	struct pmac_i2c_bus *bus;
  	const char *loc;

  
  	bus = pmac_i2c_adapter_to_bus(adapter);
  	if (bus == NULL)
  		return -ENODEV;
  	busnode = pmac_i2c_get_bus_node(bus);
  
  	while ((dev = of_get_next_child(busnode, dev)) != NULL) {

  		u8 addr;
  
  		/* We must re-match the adapter in order to properly check
  		 * the channel on multibus setups
  		 */
  		if (!pmac_i2c_match_adapter(dev, adapter))
  			continue;

  		if (!of_device_is_compatible(dev, "max6690"))

  			continue;

  		addr = pmac_i2c_get_dev_addr(dev);

  		loc = of_get_property(dev, "hwsensor-location", NULL);

  		if (loc == NULL || addr == 0)

  			continue;

  		printk("found max6690, loc=%s addr=0x%02x
  ", loc, addr);

  		wf_max6690_create(adapter, addr, loc);

  	}
  
  	return 0;
  }

  static int wf_max6690_remove(struct i2c_client *client)

  {

  	struct wf_6690_sensor *max = i2c_get_clientdata(client);

  	max->i2c = NULL;

  	wf_unregister_sensor(&max->sens);
  
  	return 0;
  }

  static const struct i2c_device_id wf_max6690_id[] = {
  	{ "wf_max6690", 0 },
  	{ }
  };
  
  static struct i2c_driver wf_max6690_driver = {
  	.driver = {
  		.name		= "wf_max6690",
  	},
  	.attach_adapter	= wf_max6690_attach,
  	.probe		= wf_max6690_probe,
  	.remove		= wf_max6690_remove,
  	.id_table	= wf_max6690_id,
  };

  static int __init wf_max6690_sensor_init(void)
  {

  	/* Don't register on old machines that use therm_pm72 for now */

  	if (of_machine_is_compatible("PowerMac7,2") ||
  	    of_machine_is_compatible("PowerMac7,3") ||
  	    of_machine_is_compatible("RackMac3,1"))

  		return -ENODEV;

  	return i2c_add_driver(&wf_max6690_driver);
  }
  
  static void __exit wf_max6690_sensor_exit(void)
  {
  	i2c_del_driver(&wf_max6690_driver);
  }
  
  module_init(wf_max6690_sensor_init);
  module_exit(wf_max6690_sensor_exit);
  
  MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
  MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
  MODULE_LICENSE("GPL");