// SPDX-License-Identifier: GPL-2.0-only
/*
 * Device driver for the i2c thermostat found on the iBook G4, Albook G4
 *
 * Copyright (C) 2003, 2004 Colin Leroy, Rasmus Rohde, Benjamin Herrenschmidt
 *
 * Documentation from 115254175ADT7467_pra.pdf and 3686221171167ADT7460_b.pdf
 * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7467
 * https://www.onsemi.com/PowerSolutions/product.do?id=ADT7460
 *
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/suspend.h>
#include <linux/kthread.h>
#include <linux/moduleparam.h>
#include <linux/freezer.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

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

#undef DEBUG

#define CONFIG_REG   0x40
#define MANUAL_MASK  0xe0
#define AUTO_MASK    0x20
#define INVERT_MASK  0x10

static u8 TEMP_REG[3]    = {0x26, 0x25, 0x27}; /* local, sensor1, sensor2 */
static u8 LIMIT_REG[3]   = {0x6b, 0x6a, 0x6c}; /* local, sensor1, sensor2 */
static u8 MANUAL_MODE[2] = {0x5c, 0x5d};       
static u8 REM_CONTROL[2] = {0x00, 0x40};
static u8 FAN_SPEED[2]   = {0x28, 0x2a};
static u8 FAN_SPD_SET[2] = {0x30, 0x31};

static u8 default_limits_local[3] = {70, 50, 70};    /* local, sensor1, sensor2 */
static u8 default_limits_chip[3] = {80, 65, 80};    /* local, sensor1, sensor2 */
static const char *sensor_location[3] = { "?", "?", "?" };

static int limit_adjust;
static int fan_speed = -1;
static bool verbose;

MODULE_AUTHOR("Colin Leroy <colin@colino.net>");
MODULE_DESCRIPTION("Driver for ADT746x thermostat in iBook G4 and "
                   "Powerbook G4 Alu");
MODULE_LICENSE("GPL");

module_param(limit_adjust, int, 0644);
MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 sensor1, 70 sensor2) "
                 "by N degrees.");

module_param(fan_speed, int, 0644);
MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
                 "(default 64)");

module_param(verbose, bool, 0);
MODULE_PARM_DESC(verbose,"Verbose log operations "
                 "(default 0)");

struct thermostat {
        struct i2c_client       *clt;
        u8                      temps[3];
        u8                      cached_temp[3];
        u8                      initial_limits[3];
        u8                      limits[3];
        int                     last_speed[2];
        int                     last_var[2];
        int                     pwm_inv[2];
        struct task_struct      *thread;
        struct platform_device  *pdev;
        enum {
                ADT7460,
                ADT7467
        }                       type;
};

static void write_both_fan_speed(struct thermostat *th, int speed);
static void write_fan_speed(struct thermostat *th, int speed, int fan);

static int
write_reg(struct thermostat* th, int reg, u8 data)
{
        u8 tmp[2];
        int rc;
        
        tmp[0] = reg;
        tmp[1] = data;
        rc = i2c_master_send(th->clt, (const char *)tmp, 2);
        if (rc < 0)
                return rc;
        if (rc != 2)
                return -ENODEV;
        return 0;
}

static int
read_reg(struct thermostat* th, int reg)
{
        u8 reg_addr, data;
        int rc;

        reg_addr = (u8)reg;
        rc = i2c_master_send(th->clt, &reg_addr, 1);
        if (rc < 0)
                return rc;
        if (rc != 1)
                return -ENODEV;
        rc = i2c_master_recv(th->clt, (char *)&data, 1);
        if (rc < 0)
                return rc;
        return data;
}

static int read_fan_speed(struct thermostat *th, u8 addr)
{
        u8 tmp[2];
        u16 res;
        
        /* should start with low byte */
        tmp[1] = read_reg(th, addr);
        tmp[0] = read_reg(th, addr + 1);
        
        res = tmp[1] + (tmp[0] << 8);
        /* "a value of 0xffff means that the fan has stopped" */
        return (res == 0xffff ? 0 : (90000*60)/res);
}

static void write_both_fan_speed(struct thermostat *th, int speed)
{
        write_fan_speed(th, speed, 0);
        if (th->type == ADT7460)
                write_fan_speed(th, speed, 1);
}

static void write_fan_speed(struct thermostat *th, int speed, int fan)
{
        u8 manual;
        
        if (speed > 0xff) 
                speed = 0xff;
        else if (speed < -1) 
                speed = 0;
        
        if (th->type == ADT7467 && fan == 1)
                return;
        
        if (th->last_speed[fan] != speed) {
                if (verbose) {
                        if (speed == -1)
                                printk(KERN_DEBUG "adt746x: Setting speed to automatic "
                                        "for %s fan.\n", sensor_location[fan+1]);
                        else
                                printk(KERN_DEBUG "adt746x: Setting speed to %d "
                                        "for %s fan.\n", speed, sensor_location[fan+1]);
                }
        } else
                return;
        
        if (speed >= 0) {
                manual = read_reg(th, MANUAL_MODE[fan]);
                manual &= ~INVERT_MASK;
                write_reg(th, MANUAL_MODE[fan],
                        manual | MANUAL_MASK | th->pwm_inv[fan]);
                write_reg(th, FAN_SPD_SET[fan], speed);
        } else {
                /* back to automatic */
                if(th->type == ADT7460) {
                        manual = read_reg(th,
                                MANUAL_MODE[fan]) & (~MANUAL_MASK);
                        manual &= ~INVERT_MASK;
                        manual |= th->pwm_inv[fan];
                        write_reg(th,
                                MANUAL_MODE[fan], manual|REM_CONTROL[fan]);
                } else {
                        manual = read_reg(th, MANUAL_MODE[fan]);
                        manual &= ~INVERT_MASK;
                        manual |= th->pwm_inv[fan];
                        write_reg(th, MANUAL_MODE[fan], manual&(~AUTO_MASK));
                }
        }
        
        th->last_speed[fan] = speed;                    
}

static void read_sensors(struct thermostat *th)
{
        int i = 0;

        for (i = 0; i < 3; i++)
                th->temps[i]  = read_reg(th, TEMP_REG[i]);
}

#ifdef DEBUG
static void display_stats(struct thermostat *th)
{
        if (th->temps[0] != th->cached_temp[0]
        ||  th->temps[1] != th->cached_temp[1]
        ||  th->temps[2] != th->cached_temp[2]) {
                printk(KERN_INFO "adt746x: Temperature infos:"
                                 " thermostats: %d,%d,%d;"
                                 " limits: %d,%d,%d;"
                                 " fan speed: %d RPM\n",
                                 th->temps[0], th->temps[1], th->temps[2],
                                 th->limits[0],  th->limits[1],  th->limits[2],
                                 read_fan_speed(th, FAN_SPEED[0]));
        }
        th->cached_temp[0] = th->temps[0];
        th->cached_temp[1] = th->temps[1];
        th->cached_temp[2] = th->temps[2];
}
#endif

static void update_fans_speed (struct thermostat *th)
{
        int lastvar = 0; /* last variation, for iBook */
        int i = 0;

        /* we don't care about local sensor, so we start at sensor 1 */
        for (i = 1; i < 3; i++) {
                bool started = false;
                int fan_number = (th->type == ADT7460 && i == 2);
                int var = th->temps[i] - th->limits[i];

                if (var > -1) {
                        int step = (255 - fan_speed) / 7;
                        int new_speed = 0;

                        /* hysteresis : change fan speed only if variation is
                         * more than two degrees */
                        if (abs(var - th->last_var[fan_number]) < 2)
                                continue;

                        started = true;
                        new_speed = fan_speed + ((var-1)*step);

                        if (new_speed < fan_speed)
                                new_speed = fan_speed;
                        if (new_speed > 255)
                                new_speed = 255;

                        if (verbose)
                                printk(KERN_DEBUG "adt746x: Setting fans speed to %d "
                                                 "(limit exceeded by %d on %s)\n",
                                                new_speed, var,
                                                sensor_location[fan_number+1]);
                        write_both_fan_speed(th, new_speed);
                        th->last_var[fan_number] = var;
                } else if (var < -2) {
                        /* don't stop fan if sensor2 is cold and sensor1 is not
                         * so cold (lastvar >= -1) */
                        if (i == 2 && lastvar < -1) {
                                if (th->last_speed[fan_number] != 0)
                                        if (verbose)
                                                printk(KERN_DEBUG "adt746x: Stopping "
                                                        "fans.\n");
                                write_both_fan_speed(th, 0);
                        }
                }

                lastvar = var;

                if (started)
                        return; /* we don't want to re-stop the fan
                                * if sensor1 is heating and sensor2 is not */
        }
}

static int monitor_task(void *arg)
{
        struct thermostat* th = arg;

        set_freezable();
        while(!kthread_should_stop()) {
                try_to_freeze();
                msleep_interruptible(2000);

#ifndef DEBUG
                if (fan_speed != -1)
                        read_sensors(th);
#else
                read_sensors(th);
#endif          

                if (fan_speed != -1)
                        update_fans_speed(th);

#ifdef DEBUG
                display_stats(th);
#endif

        }

        return 0;
}

static void set_limit(struct thermostat *th, int i)
{
        /* Set sensor1 limit higher to avoid powerdowns */
        th->limits[i] = default_limits_chip[i] + limit_adjust;
        write_reg(th, LIMIT_REG[i], th->limits[i]);
                
        /* set our limits to normal */
        th->limits[i] = default_limits_local[i] + limit_adjust;
}

#define BUILD_SHOW_FUNC_INT(name, data)                         \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
{                                                               \
        struct thermostat *th = dev_get_drvdata(dev);           \
        return sprintf(buf, "%d\n", data);                      \
}

#define BUILD_SHOW_FUNC_INT_LITE(name, data)                            \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
{                                                               \
        return sprintf(buf, "%d\n", data);                      \
}

#define BUILD_SHOW_FUNC_STR(name, data)                         \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
{                                                               \
        return sprintf(buf, "%s\n", data);                      \
}

#define BUILD_SHOW_FUNC_FAN(name, data)                         \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
{                                                               \
        struct thermostat *th = dev_get_drvdata(dev);           \
        return sprintf(buf, "%d (%d rpm)\n",                    \
                th->last_speed[data],                           \
                read_fan_speed(th, FAN_SPEED[data])             \
                );                                              \
}

#define BUILD_STORE_FUNC_DEG(name, data)                        \
static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
{                                                               \
        struct thermostat *th = dev_get_drvdata(dev);           \
        int val;                                                \
        int i;                                                  \
        val = simple_strtol(buf, NULL, 10);                     \
        printk(KERN_INFO "Adjusting limits by %d degrees\n", val);      \
        limit_adjust = val;                                     \
        for (i=0; i < 3; i++)                                   \
                set_limit(th, i);                               \
        return n;                                               \
}

#define BUILD_STORE_FUNC_INT(name, data)                        \
static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
{                                                               \
        int val;                                                \
        val = simple_strtol(buf, NULL, 10);                     \
        if (val < 0 || val > 255)                               \
                return -EINVAL;                                 \
        printk(KERN_INFO "Setting specified fan speed to %d\n", val);   \
        data = val;                                             \
        return n;                                               \
}

BUILD_SHOW_FUNC_INT(sensor1_temperature,         (read_reg(th, TEMP_REG[1])))
BUILD_SHOW_FUNC_INT(sensor2_temperature,         (read_reg(th, TEMP_REG[2])))
BUILD_SHOW_FUNC_INT(sensor1_limit,               th->limits[1])
BUILD_SHOW_FUNC_INT(sensor2_limit,               th->limits[2])
BUILD_SHOW_FUNC_STR(sensor1_location,            sensor_location[1])
BUILD_SHOW_FUNC_STR(sensor2_location,            sensor_location[2])

BUILD_SHOW_FUNC_INT_LITE(specified_fan_speed, fan_speed)
BUILD_STORE_FUNC_INT(specified_fan_speed,fan_speed)

BUILD_SHOW_FUNC_FAN(sensor1_fan_speed,   0)
BUILD_SHOW_FUNC_FAN(sensor2_fan_speed,   1)

BUILD_SHOW_FUNC_INT_LITE(limit_adjust,   limit_adjust)
BUILD_STORE_FUNC_DEG(limit_adjust,       th)
                
static DEVICE_ATTR(sensor1_temperature, S_IRUGO,
                   show_sensor1_temperature,NULL);
static DEVICE_ATTR(sensor2_temperature, S_IRUGO,
                   show_sensor2_temperature,NULL);
static DEVICE_ATTR(sensor1_limit, S_IRUGO,
                   show_sensor1_limit,  NULL);
static DEVICE_ATTR(sensor2_limit, S_IRUGO,
                   show_sensor2_limit,  NULL);
static DEVICE_ATTR(sensor1_location, S_IRUGO,
                   show_sensor1_location, NULL);
static DEVICE_ATTR(sensor2_location, S_IRUGO,
                   show_sensor2_location, NULL);

static DEVICE_ATTR(specified_fan_speed, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
                   show_specified_fan_speed,store_specified_fan_speed);

static DEVICE_ATTR(sensor1_fan_speed,   S_IRUGO,
                   show_sensor1_fan_speed,      NULL);
static DEVICE_ATTR(sensor2_fan_speed,   S_IRUGO,
                   show_sensor2_fan_speed,      NULL);

static DEVICE_ATTR(limit_adjust,        S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
                   show_limit_adjust,   store_limit_adjust);

static void thermostat_create_files(struct thermostat *th)
{
        struct device_node *np = th->clt->dev.of_node;
        struct device *dev;
        int err;

        /* To maintain ABI compatibility with userspace, create
         * the old style platform driver and attach the attributes
         * to it here
         */
        th->pdev = of_platform_device_create(np, "temperatures", NULL);
        if (!th->pdev)
                return;
        dev = &th->pdev->dev;
        dev_set_drvdata(dev, th);
        err = device_create_file(dev, &dev_attr_sensor1_temperature);
        err |= device_create_file(dev, &dev_attr_sensor2_temperature);
        err |= device_create_file(dev, &dev_attr_sensor1_limit);
        err |= device_create_file(dev, &dev_attr_sensor2_limit);
        err |= device_create_file(dev, &dev_attr_sensor1_location);
        err |= device_create_file(dev, &dev_attr_sensor2_location);
        err |= device_create_file(dev, &dev_attr_limit_adjust);
        err |= device_create_file(dev, &dev_attr_specified_fan_speed);
        err |= device_create_file(dev, &dev_attr_sensor1_fan_speed);
        if(th->type == ADT7460)
                err |= device_create_file(dev, &dev_attr_sensor2_fan_speed);
        if (err)
                printk(KERN_WARNING
                        "Failed to create temperature attribute file(s).\n");
}

static void thermostat_remove_files(struct thermostat *th)
{
        struct device *dev;

        if (!th->pdev)
                return;
        dev = &th->pdev->dev;
        device_remove_file(dev, &dev_attr_sensor1_temperature);
        device_remove_file(dev, &dev_attr_sensor2_temperature);
        device_remove_file(dev, &dev_attr_sensor1_limit);
        device_remove_file(dev, &dev_attr_sensor2_limit);
        device_remove_file(dev, &dev_attr_sensor1_location);
        device_remove_file(dev, &dev_attr_sensor2_location);
        device_remove_file(dev, &dev_attr_limit_adjust);
        device_remove_file(dev, &dev_attr_specified_fan_speed);
        device_remove_file(dev, &dev_attr_sensor1_fan_speed);   
        if (th->type == ADT7460)
                device_remove_file(dev, &dev_attr_sensor2_fan_speed);
        of_device_unregister(th->pdev);

}

static int probe_thermostat(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct device_node *np = client->dev.of_node;
        struct thermostat* th;
        const __be32 *prop;
        int i, rc, vers, offset = 0;

        if (!np)
                return -ENXIO;
        prop = of_get_property(np, "hwsensor-params-version", NULL);
        if (!prop)
                return -ENXIO;
        vers = be32_to_cpup(prop);
        printk(KERN_INFO "adt746x: version %d (%ssupported)\n",
               vers, vers == 1 ? "" : "un");
        if (vers != 1)
                return -ENXIO;

        if (of_property_present(np, "hwsensor-location")) {
                for (i = 0; i < 3; i++) {
                        sensor_location[i] = of_get_property(np,
                                        "hwsensor-location", NULL) + offset;

                        if (sensor_location[i] == NULL)
                                sensor_location[i] = "";

                        printk(KERN_INFO "sensor %d: %s\n", i, sensor_location[i]);
                        offset += strlen(sensor_location[i]) + 1;
                }
        }

        th = kzalloc_obj(struct thermostat);
        if (!th)
                return -ENOMEM;

        i2c_set_clientdata(client, th);
        th->clt = client;
        th->type = id->driver_data;

        rc = read_reg(th, CONFIG_REG);
        if (rc < 0) {
                dev_err(&client->dev, "Thermostat failed to read config!\n");
                kfree(th);
                return -ENODEV;
        }

        /* force manual control to start the fan quieter */
        if (fan_speed == -1)
                fan_speed = 64;
        
        if (th->type == ADT7460) {
                printk(KERN_INFO "adt746x: ADT7460 initializing\n");
                /* The 7460 needs to be started explicitly */
                write_reg(th, CONFIG_REG, 1);
        } else
                printk(KERN_INFO "adt746x: ADT7467 initializing\n");

        for (i = 0; i < 3; i++) {
                th->initial_limits[i] = read_reg(th, LIMIT_REG[i]);
                set_limit(th, i);
        }

        printk(KERN_INFO "adt746x: Lowering max temperatures from %d, %d, %d"
                         " to %d, %d, %d\n",
                         th->initial_limits[0], th->initial_limits[1],
                         th->initial_limits[2], th->limits[0], th->limits[1],
                         th->limits[2]);

        /* record invert bit status because fw can corrupt it after suspend */
        th->pwm_inv[0] = read_reg(th, MANUAL_MODE[0]) & INVERT_MASK;
        th->pwm_inv[1] = read_reg(th, MANUAL_MODE[1]) & INVERT_MASK;

        /* be sure to really write fan speed the first time */
        th->last_speed[0] = -2;
        th->last_speed[1] = -2;
        th->last_var[0] = -80;
        th->last_var[1] = -80;

        if (fan_speed != -1) {
                /* manual mode, stop fans */
                write_both_fan_speed(th, 0);
        } else {
                /* automatic mode */
                write_both_fan_speed(th, -1);
        }
        
        th->thread = kthread_run(monitor_task, th, "kfand");
        if (th->thread == ERR_PTR(-ENOMEM)) {
                printk(KERN_INFO "adt746x: Kthread creation failed\n");
                th->thread = NULL;
                return -ENOMEM;
        }

        thermostat_create_files(th);

        return 0;
}

static void remove_thermostat(struct i2c_client *client)
{
        struct thermostat *th = i2c_get_clientdata(client);
        int i;
        
        thermostat_remove_files(th);

        if (th->thread != NULL)
                kthread_stop(th->thread);

        printk(KERN_INFO "adt746x: Putting max temperatures back from "
                         "%d, %d, %d to %d, %d, %d\n",
                th->limits[0], th->limits[1], th->limits[2],
                th->initial_limits[0], th->initial_limits[1],
                th->initial_limits[2]);

        for (i = 0; i < 3; i++)
                write_reg(th, LIMIT_REG[i], th->initial_limits[i]);

        write_both_fan_speed(th, -1);

        kfree(th);
}

static const struct i2c_device_id therm_adt746x_id[] = {
        { "MAC,adt7460", ADT7460 },
        { "MAC,adt7467", ADT7467 },
        { }
};
MODULE_DEVICE_TABLE(i2c, therm_adt746x_id);

static struct i2c_driver thermostat_driver = {
        .driver = {
                .name   = "therm_adt746x",
        },
        .probe = probe_thermostat,
        .remove = remove_thermostat,
        .id_table = therm_adt746x_id,
};

static int __init thermostat_init(void)
{
#ifndef CONFIG_I2C_POWERMAC
        request_module("i2c-powermac");
#endif

        return i2c_add_driver(&thermostat_driver);
}

static void __exit thermostat_exit(void)
{
        i2c_del_driver(&thermostat_driver);
}

module_init(thermostat_init);
module_exit(thermostat_exit);