/*
   * Windfarm PowerMac thermal control. LM75 sensor
   *
   * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
   *                    <benh@kernel.crashing.org>
   *
   * Released under the term of the GNU GPL v2.
   */
  
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/wait.h>
  #include <linux/i2c.h>

  #include <asm/prom.h>
  #include <asm/machdep.h>
  #include <asm/io.h>
  #include <asm/system.h>
  #include <asm/sections.h>

  #include <asm/pmac_low_i2c.h>

  
  #include "windfarm.h"

  #define VERSION "0.2"

  
  #undef DEBUG
  
  #ifdef DEBUG
  #define DBG(args...)	printk(args)
  #else
  #define DBG(args...)	do { } while(0)
  #endif
  
  struct wf_lm75_sensor {
  	int			ds1775 : 1;
  	int			inited : 1;

  	struct 	i2c_client	*i2c;

  	struct 	wf_sensor	sens;
  };
  #define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)

  
  static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
  {
  	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  	s32 data;

  	if (lm->i2c == NULL)

  		return -ENODEV;
  
  	/* Init chip if necessary */
  	if (!lm->inited) {

  		u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);

  
  		DBG("wf_lm75: Initializing %s, cfg was: %02x
  ",
  		    sr->name, cfg);
  
  		/* clear shutdown bit, keep other settings as left by
  		 * the firmware for now
  		 */
  		cfg_new = cfg & ~0x01;

  		i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);

  		lm->inited = 1;
  
  		/* If we just powered it up, let's wait 200 ms */
  		msleep(200);
  	}
  
  	/* Read temperature register */

  	data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));

  	data <<= 8;
  	*value = data;
  
  	return 0;
  }
  
  static void wf_lm75_release(struct wf_sensor *sr)
  {
  	struct wf_lm75_sensor *lm = wf_to_lm75(sr);

  	kfree(lm);
  }
  
  static struct wf_sensor_ops wf_lm75_ops = {
  	.get_value	= wf_lm75_get,
  	.release	= wf_lm75_release,
  	.owner		= THIS_MODULE,
  };

  static int wf_lm75_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)

  {
  	struct wf_lm75_sensor *lm;

  	int rc;

  	lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);

  	if (lm == NULL)

  		return -ENODEV;
  
  	lm->inited = 0;
  	lm->ds1775 = id->driver_data;
  	lm->i2c = client;
  	lm->sens.name = client->dev.platform_data;
  	lm->sens.ops = &wf_lm75_ops;
  	i2c_set_clientdata(client, lm);
  
  	rc = wf_register_sensor(&lm->sens);

  	if (rc)

  		kfree(lm);

  
  	return rc;
  }

  static struct i2c_driver wf_lm75_driver;

  static struct i2c_client *wf_lm75_create(struct i2c_adapter *adapter,
  					     u8 addr, int ds1775,
  					     const char *loc)
  {
  	struct i2c_board_info info;
  	struct i2c_client *client;
  	char *name;
  
  	DBG("wf_lm75: creating  %s device at address 0x%02x
  ",
  	    ds1775 ? "ds1775" : "lm75", addr);

  
  	/* Usual rant about sensor names not beeing very consistent in
  	 * the device-tree, oh well ...
  	 * Add more entries below as you deal with more setups
  	 */
  	if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))

  		name = "hd-temp";

  	else if (!strcmp(loc, "Incoming Air Temp"))

  		name = "incoming-air-temp";

  	else if (!strcmp(loc, "ODD Temp"))

  		name = "optical-drive-temp";

  	else if (!strcmp(loc, "HD Temp"))

  		name = "hard-drive-temp";

  	else
  		goto fail;

  	memset(&info, 0, sizeof(struct i2c_board_info));
  	info.addr = (addr >> 1) & 0x7f;
  	info.platform_data = name;
  	strlcpy(info.type, ds1775 ? "wf_ds1775" : "wf_lm75", I2C_NAME_SIZE);

  	client = i2c_new_device(adapter, &info);
  	if (client == NULL) {
  		printk(KERN_ERR "windfarm: failed to attach %s %s to i2c
  ",
  		       ds1775 ? "ds1775" : "lm75", name);

  		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_lm75_driver.clients);

  	return client;

   fail:

  	return NULL;
  }
  
  static int wf_lm75_attach(struct i2c_adapter *adapter)
  {

  	struct device_node *busnode, *dev;
  	struct pmac_i2c_bus *bus;

  
  	DBG("wf_lm75: adapter %s detected
  ", adapter->name);

  	bus = pmac_i2c_adapter_to_bus(adapter);
  	if (bus == NULL)
  		return -ENODEV;
  	busnode = pmac_i2c_get_bus_node(bus);

  
  	DBG("wf_lm75: bus found, looking for device...
  ");
  
  	/* Now look for lm75(s) in there */
  	for (dev = NULL;

  	     (dev = of_get_next_child(busnode, dev)) != NULL;) {

  		const char *loc =

  			of_get_property(dev, "hwsensor-location", 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;
  		addr = pmac_i2c_get_dev_addr(dev);
  		if (loc == NULL || addr == 0)

  			continue;
  		/* real lm75 */

  		if (of_device_is_compatible(dev, "lm75"))

  			wf_lm75_create(adapter, addr, 0, loc);

  		/* ds1775 (compatible, better resolution */

  		else if (of_device_is_compatible(dev, "ds1775"))

  			wf_lm75_create(adapter, addr, 1, loc);

  	}

  	return 0;
  }

  static int wf_lm75_remove(struct i2c_client *client)

  {

  	struct wf_lm75_sensor *lm = i2c_get_clientdata(client);

  
  	DBG("wf_lm75: i2c detatch called for %s
  ", lm->sens.name);
  
  	/* Mark client detached */

  	lm->i2c = NULL;

  
  	/* release sensor */
  	wf_unregister_sensor(&lm->sens);
  
  	return 0;
  }

  static const struct i2c_device_id wf_lm75_id[] = {
  	{ "wf_lm75", 0 },
  	{ "wf_ds1775", 1 },
  	{ }
  };
  
  static struct i2c_driver wf_lm75_driver = {
  	.driver = {
  		.name	= "wf_lm75",
  	},
  	.attach_adapter	= wf_lm75_attach,
  	.probe		= wf_lm75_probe,
  	.remove		= wf_lm75_remove,
  	.id_table	= wf_lm75_id,
  };

  static int __init wf_lm75_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_lm75_driver);

  }
  
  static void __exit wf_lm75_sensor_exit(void)
  {
  	i2c_del_driver(&wf_lm75_driver);
  }
  
  
  module_init(wf_lm75_sensor_init);
  module_exit(wf_lm75_sensor_exit);
  
  MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
  MODULE_LICENSE("GPL");