// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control. LM87 sensor
 *
 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
 */

#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/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)
{       
        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
         */
        for_each_child_of_node(client->dev.of_node, np) {
                if (!of_node_name_eq(np, "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_warn("wf_lm87: Unsupported sensor %pOF\n",
                        client->dev.of_node);
                return -ENODEV;
        }

        lm = kzalloc_obj(struct wf_lm87_sensor);
        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 void wf_lm87_remove(struct i2c_client *client)
{
        struct wf_lm87_sensor *lm = i2c_get_clientdata(client);

        /* Mark client detached */
        lm->i2c = NULL;

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

static const struct i2c_device_id wf_lm87_id[] = {
        { "MAC,lm87cimt" },
        { }
};
MODULE_DEVICE_TABLE(i2c, wf_lm87_id);

static const struct of_device_id wf_lm87_of_id[] = {
        { .compatible = "lm87cimt", },
        { }
};
MODULE_DEVICE_TABLE(of, wf_lm87_of_id);

static struct i2c_driver wf_lm87_driver = {
        .driver = {
                .name   = "wf_lm87",
                .of_match_table = wf_lm87_of_id,
        },
        .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");