// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * smsc47b397.c - Part of lm_sensors, Linux kernel modules
 * for hardware monitoring
 *
 * Supports the SMSC LPC47B397-NC Super-I/O chip.
 *
 * Author/Maintainer: Mark M. Hoffman <mhoffman@lightlink.com>
 * Copyright (C) 2004 Utilitek Systems, Inc.
 *
 * derived in part from smsc47m1.c:
 * Copyright (C) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
 * Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/platform_device.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/acpi.h>
#include <linux/io.h>

static unsigned short force_id;
module_param(force_id, ushort, 0);
MODULE_PARM_DESC(force_id, "Override the detected device ID");

static struct platform_device *pdev;

#define DRVNAME "smsc47b397"

/* Super-I/0 registers and commands */

#define REG     0x2e    /* The register to read/write */
#define VAL     0x2f    /* The value to read/write */

static inline void superio_outb(int reg, int val)
{
        outb(reg, REG);
        outb(val, VAL);
}

static inline int superio_inb(int reg)
{
        outb(reg, REG);
        return inb(VAL);
}

/* select superio logical device */
static inline void superio_select(int ld)
{
        superio_outb(0x07, ld);
}

static inline int superio_enter(void)
{
        if (!request_muxed_region(REG, 2, DRVNAME))
                return -EBUSY;

        outb(0x55, REG);
        return 0;
}

static inline void superio_exit(void)
{
        outb(0xAA, REG);
        release_region(REG, 2);
}

#define SUPERIO_REG_DEVID       0x20
#define SUPERIO_REG_DEVREV      0x21
#define SUPERIO_REG_BASE_MSB    0x60
#define SUPERIO_REG_BASE_LSB    0x61
#define SUPERIO_REG_LD8         0x08

#define SMSC_EXTENT             0x02

/* 0 <= nr <= 3 */
static u8 smsc47b397_reg_temp[] = {0x25, 0x26, 0x27, 0x80};
#define SMSC47B397_REG_TEMP(nr) (smsc47b397_reg_temp[(nr)])

/* 0 <= nr <= 3 */
#define SMSC47B397_REG_FAN_LSB(nr) (0x28 + 2 * (nr))
#define SMSC47B397_REG_FAN_MSB(nr) (0x29 + 2 * (nr))

struct smsc47b397_data {
        unsigned short addr;
        struct mutex lock;

        struct mutex update_lock;
        unsigned long last_updated; /* in jiffies */
        bool valid;

        /* register values */
        u16 fan[4];
        u8 temp[4];
};

static int smsc47b397_read_value(struct smsc47b397_data *data, u8 reg)
{
        int res;

        mutex_lock(&data->lock);
        outb(reg, data->addr);
        res = inb_p(data->addr + 1);
        mutex_unlock(&data->lock);
        return res;
}

static struct smsc47b397_data *smsc47b397_update_device(struct device *dev)
{
        struct smsc47b397_data *data = dev_get_drvdata(dev);
        int i;

        mutex_lock(&data->update_lock);

        if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
                dev_dbg(dev, "starting device update...\n");

                /* 4 temperature inputs, 4 fan inputs */
                for (i = 0; i < 4; i++) {
                        data->temp[i] = smsc47b397_read_value(data,
                                        SMSC47B397_REG_TEMP(i));

                        /* must read LSB first */
                        data->fan[i]  = smsc47b397_read_value(data,
                                        SMSC47B397_REG_FAN_LSB(i));
                        data->fan[i] |= smsc47b397_read_value(data,
                                        SMSC47B397_REG_FAN_MSB(i)) << 8;
                }

                data->last_updated = jiffies;
                data->valid = true;

                dev_dbg(dev, "... device update complete\n");
        }

        mutex_unlock(&data->update_lock);

        return data;
}

/*
 * TEMP: 0.001C/bit (-128C to +127C)
 * REG: 1C/bit, two's complement
 */
static int temp_from_reg(u8 reg)
{
        return (s8)reg * 1000;
}

static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
                         char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct smsc47b397_data *data = smsc47b397_update_device(dev);
        return sprintf(buf, "%d\n", temp_from_reg(data->temp[attr->index]));
}

static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
static SENSOR_DEVICE_ATTR_RO(temp2_input, temp, 1);
static SENSOR_DEVICE_ATTR_RO(temp3_input, temp, 2);
static SENSOR_DEVICE_ATTR_RO(temp4_input, temp, 3);

/*
 * FAN: 1 RPM/bit
 * REG: count of 90kHz pulses / revolution
 */
static int fan_from_reg(u16 reg)
{
        if (reg == 0 || reg == 0xffff)
                return 0;
        return 90000 * 60 / reg;
}

static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
                        char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct smsc47b397_data *data = smsc47b397_update_device(dev);
        return sprintf(buf, "%d\n", fan_from_reg(data->fan[attr->index]));
}
static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
static SENSOR_DEVICE_ATTR_RO(fan3_input, fan, 2);
static SENSOR_DEVICE_ATTR_RO(fan4_input, fan, 3);

static struct attribute *smsc47b397_attrs[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp2_input.dev_attr.attr,
        &sensor_dev_attr_temp3_input.dev_attr.attr,
        &sensor_dev_attr_temp4_input.dev_attr.attr,
        &sensor_dev_attr_fan1_input.dev_attr.attr,
        &sensor_dev_attr_fan2_input.dev_attr.attr,
        &sensor_dev_attr_fan3_input.dev_attr.attr,
        &sensor_dev_attr_fan4_input.dev_attr.attr,

        NULL
};

ATTRIBUTE_GROUPS(smsc47b397);

static int smsc47b397_probe(struct platform_device *pdev);

static struct platform_driver smsc47b397_driver = {
        .driver = {
                .name   = DRVNAME,
        },
        .probe          = smsc47b397_probe,
};

static int smsc47b397_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct smsc47b397_data *data;
        struct device *hwmon_dev;
        struct resource *res;

        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!devm_request_region(dev, res->start, SMSC_EXTENT,
                                 smsc47b397_driver.driver.name)) {
                dev_err(dev, "Region 0x%lx-0x%lx already in use!\n",
                        (unsigned long)res->start,
                        (unsigned long)res->start + SMSC_EXTENT - 1);
                return -EBUSY;
        }

        data = devm_kzalloc(dev, sizeof(struct smsc47b397_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->addr = res->start;
        mutex_init(&data->lock);
        mutex_init(&data->update_lock);

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, "smsc47b397",
                                                           data,
                                                           smsc47b397_groups);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static int __init smsc47b397_device_add(unsigned short address)
{
        struct resource res = {
                .start  = address,
                .end    = address + SMSC_EXTENT - 1,
                .name   = DRVNAME,
                .flags  = IORESOURCE_IO,
        };
        int err;

        err = acpi_check_resource_conflict(&res);
        if (err)
                goto exit;

        pdev = platform_device_alloc(DRVNAME, address);
        if (!pdev) {
                err = -ENOMEM;
                pr_err("Device allocation failed\n");
                goto exit;
        }

        err = platform_device_add_resources(pdev, &res, 1);
        if (err) {
                pr_err("Device resource addition failed (%d)\n", err);
                goto exit_device_put;
        }

        err = platform_device_add(pdev);
        if (err) {
                pr_err("Device addition failed (%d)\n", err);
                goto exit_device_put;
        }

        return 0;

exit_device_put:
        platform_device_put(pdev);
exit:
        return err;
}

static int __init smsc47b397_find(void)
{
        u8 id, rev;
        char *name;
        unsigned short addr;
        int err;

        err = superio_enter();
        if (err)
                return err;

        id = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID);

        switch (id) {
        case 0x81:
                name = "SCH5307-NS";
                break;
        case 0x6f:
                name = "LPC47B397-NC";
                break;
        case 0x85:
        case 0x8c:
                name = "SCH5317";
                break;
        default:
                superio_exit();
                return -ENODEV;
        }

        rev = superio_inb(SUPERIO_REG_DEVREV);

        superio_select(SUPERIO_REG_LD8);
        addr = (superio_inb(SUPERIO_REG_BASE_MSB) << 8)
                 |  superio_inb(SUPERIO_REG_BASE_LSB);

        pr_info("found SMSC %s (base address 0x%04x, revision %u)\n",
                name, addr, rev);

        superio_exit();
        return addr;
}

static int __init smsc47b397_init(void)
{
        unsigned short address;
        int ret;

        ret = smsc47b397_find();
        if (ret < 0)
                return ret;
        address = ret;

        ret = platform_driver_register(&smsc47b397_driver);
        if (ret)
                goto exit;

        /* Sets global pdev as a side effect */
        ret = smsc47b397_device_add(address);
        if (ret)
                goto exit_driver;

        return 0;

exit_driver:
        platform_driver_unregister(&smsc47b397_driver);
exit:
        return ret;
}

static void __exit smsc47b397_exit(void)
{
        platform_device_unregister(pdev);
        platform_driver_unregister(&smsc47b397_driver);
}

MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
MODULE_DESCRIPTION("SMSC LPC47B397 driver");
MODULE_LICENSE("GPL");

module_init(smsc47b397_init);
module_exit(smsc47b397_exit);