text: /*
   * Windfarm PowerMac thermal control. LM87 sensor
   *
   * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
   *
   * 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/sections.h>
  #include <asm/pmac_low_i2c.h>
  
  #include "windfarm.h"
  
  #define VERSION "1.0"
  
  #undef DEBUG
  
  #ifdef DEBUG
  #define DBG(args...)	printk(args)
  #else
  #define DBG(args...)	do { } while(0)
  #endif
  
  struct wf_lm87_sensor {
  	struct i2c_client	*i2c;
  	struct wf_sensor	sens;
  };
  #define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)
  
  
  static int wf_lm87_read_reg(struct i2c_client *chip, int reg)
  {
  	int rc, tries = 0;
  	u8 buf;
  
  	for (;;) {
  		/* Set address */
  		buf = (u8)reg;
  		rc = i2c_master_send(chip, &buf, 1);
  		if (rc <= 0)
  			goto error;
  		rc = i2c_master_recv(chip, &buf, 1);
  		if (rc <= 0)
  			goto error;
  		return (int)buf;
  	error:
  		DBG("wf_lm87: Error reading LM87, retrying...\n");
  		if (++tries > 10) {
  			printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");
  			return -EIO;
  		}
  		msleep(10);
  	}
  }
  
  static int wf_lm87_get(struct wf_sensor *sr, s32 *value)
  {
  	struct wf_lm87_sensor *lm = sr->priv;
  	s32 temp;
  
  	if (lm->i2c == NULL)
  		return -ENODEV;
  
  #define LM87_INT_TEMP		0x27
  
  	/* Read temperature register */
  	temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);
  	if (temp < 0)
  		return temp;
  	*value = temp << 16;
  
  	return 0;
  }
  
  static void wf_lm87_release(struct wf_sensor *sr)
  {
  	struct wf_lm87_sensor *lm = wf_to_lm87(sr);
  
  	kfree(lm);
  }
  
  static const struct wf_sensor_ops wf_lm87_ops = {
  	.get_value	= wf_lm87_get,
  	.release	= wf_lm87_release,
  	.owner		= THIS_MODULE,
  };
  
  static int wf_lm87_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {	
  	struct wf_lm87_sensor *lm;
  	const char *name = NULL, *loc;
  	struct device_node *np = NULL;
  	int rc;
  
  	/*
  	 * The lm87 contains a whole pile of sensors, additionally,
  	 * the Xserve G5 has several lm87's. However, for now we only
  	 * care about the internal temperature sensor
  	 */
  	while ((np = of_get_next_child(client->dev.of_node, np)) != NULL) {
  		if (strcmp(np->name, "int-temp"))
  			continue;
  		loc = of_get_property(np, "location", NULL);
  		if (!loc)
  			continue;
  		if (strstr(loc, "DIMM"))
  			name = "dimms-temp";
  		else if (strstr(loc, "Processors"))
  			name = "between-cpus-temp";
  		if (name) {
  			of_node_put(np);
  			break;
  		}
  	}
  	if (!name) {
  		pr_warning("wf_lm87: Unsupported sensor %pOF\n",
  			   client->dev.of_node);
  		return -ENODEV;
  	}
  
  	lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
  	if (lm == NULL)
  		return -ENODEV;
  
  	lm->i2c = client;
  	lm->sens.name = name;
  	lm->sens.ops = &wf_lm87_ops;
  	lm->sens.priv = lm;
  	i2c_set_clientdata(client, lm);
  
  	rc = wf_register_sensor(&lm->sens);
  	if (rc)
  		kfree(lm);
  	return rc;
  }
  
  static int wf_lm87_remove(struct i2c_client *client)
  {
  	struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
  
  	DBG("wf_lm87: i2c detatch called for %s\n", 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_lm87_id[] = {
  	{ "MAC,lm87cimt", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
  
  static struct i2c_driver wf_lm87_driver = {
  	.driver = {
  		.name	= "wf_lm87",
  	},
  	.probe		= wf_lm87_probe,
  	.remove		= wf_lm87_remove,
  	.id_table	= wf_lm87_id,
  };
  
  static int __init wf_lm87_sensor_init(void)
  {
  	/* We only support this on the Xserve */
  	if (!of_machine_is_compatible("RackMac3,1"))
  		return -ENODEV;
  
  	return i2c_add_driver(&wf_lm87_driver);
  }
  
  static void __exit wf_lm87_sensor_exit(void)
  {
  	i2c_del_driver(&wf_lm87_driver);
  }
  
  
  module_init(wf_lm87_sensor_init);
  module_exit(wf_lm87_sensor_exit);
  
  MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
  MODULE_LICENSE("GPL");
  
  