// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control.  MAX6690 sensor.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
 */
#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/pmac_low_i2c.h>

#include "windfarm.h"

#define VERSION "1.0"

/* 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 const 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 char *name, *loc;
        struct wf_6690_sensor *max;
        int rc;

        loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
        if (!loc) {
                dev_warn(&client->dev, "Missing hwsensor-location property!\n");
                return -ENXIO;
        }

        /*
         * We only expose the external temperature register for
         * now as this is all we need for our control loops
         */
        if (!strcmp(loc, "BACKSIDE") || !strcmp(loc, "SYS CTRLR AMBIENT"))
                name = "backside-temp";
        else if (!strcmp(loc, "NB Ambient"))
                name = "north-bridge-temp";
        else if (!strcmp(loc, "GPU Ambient"))
                name = "gpu-temp";
        else
                return -ENXIO;

        max = kzalloc_obj(struct wf_6690_sensor);
        if (max == NULL) {
                printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
                       "no memory\n");
                return -ENOMEM;
        }

        max->i2c = client;
        max->sens.name = name;
        max->sens.ops = &wf_max6690_ops;
        i2c_set_clientdata(client, max);

        rc = wf_register_sensor(&max->sens);
        if (rc)
                kfree(max);
        return rc;
}

static void wf_max6690_remove(struct i2c_client *client)
{
        struct wf_6690_sensor *max = i2c_get_clientdata(client);

        max->i2c = NULL;
        wf_unregister_sensor(&max->sens);
}

static const struct i2c_device_id wf_max6690_id[] = {
        { "MAC,max6690" },
        { }
};
MODULE_DEVICE_TABLE(i2c, wf_max6690_id);

static const struct of_device_id wf_max6690_of_id[] = {
        { .compatible = "max6690", },
        { }
};
MODULE_DEVICE_TABLE(of, wf_max6690_of_id);

static struct i2c_driver wf_max6690_driver = {
        .driver = {
                .name           = "wf_max6690",
                .of_match_table = wf_max6690_of_id,
        },
        .probe          = wf_max6690_probe,
        .remove         = wf_max6690_remove,
        .id_table       = wf_max6690_id,
};

module_i2c_driver(wf_max6690_driver);

MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
MODULE_LICENSE("GPL");