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/*

 * 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)

#define i2c_to_6690(x)  container_of((x), struct wf_6690_sensor, i2c)

static int wf_max6690_attach(struct i2c_adapter *adapter);

static int wf_max6690_detach(struct i2c_client *client);

static struct i2c_driver wf_max6690_driver = {

        .driver = {

                .name           = "wf_max6690",

        },

        .attach_adapter = wf_max6690_attach,

        .detach_client  = wf_max6690_detach,

};

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.adapter == 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);

        if (max->i2c.adapter) {

                i2c_detach_client(&max->i2c);

                max->i2c.adapter = NULL;

        }

        kfree(max);

}

static struct wf_sensor_ops wf_max6690_ops = {

        .get_value      = wf_max6690_get,

        .release        = wf_max6690_release,

        .owner          = THIS_MODULE,

};

static void wf_max6690_create(struct i2c_adapter *adapter, u8 addr)

{

        struct wf_6690_sensor *max;

        char *name = "backside-temp";

        max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);

        if (max == NULL) {

                printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor %s: "

                       "no memory\n", name);

                return;

        }

        max->sens.ops = &wf_max6690_ops;

        max->sens.name = name;

        max->i2c.addr = addr >> 1;

        max->i2c.adapter = adapter;

        max->i2c.driver = &wf_max6690_driver;

        strncpy(max->i2c.name, name, I2C_NAME_SIZE-1);

        if (i2c_attach_client(&max->i2c)) {

                printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");

                goto fail;

        }

        if (wf_register_sensor(&max->sens)) {

                i2c_detach_client(&max->i2c);

                goto fail;

        }

        return;

 fail:

        kfree(max);

}

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\n", loc, addr);

                if (strcmp(loc, "BACKSIDE"))

                        continue;

                wf_max6690_create(adapter, addr);

        }

        return 0;

}

static int wf_max6690_detach(struct i2c_client *client)

{

        struct wf_6690_sensor *max = i2c_to_6690(client);

        max->i2c.adapter = NULL;

        wf_unregister_sensor(&max->sens);

        return 0;

}

static int __init wf_max6690_sensor_init(void)

{

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

        if (machine_is_compatible("PowerMac7,2") ||

            machine_is_compatible("PowerMac7,3") ||

            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");