linux/drivers/hwmon/smsc47m1.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * smsc47m1.c - Part of lm_sensors, Linux kernel modules
 *		for hardware monitoring
 *
 * Supports the SMSC LPC47B27x, LPC47M10x, LPC47M112, LPC47M13x,
 * LPC47M14x, LPC47M15x, LPC47M192, LPC47M292 and LPC47M997
 * Super-I/O chips.
 *
 * Copyright (C) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
 * Copyright (C) 2004-2007 Jean Delvare <jdelvare@suse.de>
 * Ported to Linux 2.6 by Gabriele Gorla <gorlik@yahoo.com>
 *			and Jean Delvare
 */

#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/sysfs.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 *smsc47m1_pdev;

#define DRVNAME "smsc47m1"
enum chips { smsc47m1, smsc47m2 };

/* 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);
}

/* logical device for fans is 0x0A */
#define superio_select() superio_outb(0x07, 0x0A)

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_ACT		0x30
#define SUPERIO_REG_BASE	0x60
#define SUPERIO_REG_DEVID	0x20
#define SUPERIO_REG_DEVREV	0x21

/* Logical device registers */

#define SMSC_EXTENT		0x80

/* nr is 0 or 1 in the macros below */
#define SMSC47M1_REG_ALARM		0x04
#define SMSC47M1_REG_TPIN(nr)		(0x34 - (nr))
#define SMSC47M1_REG_PPIN(nr)		(0x36 - (nr))
#define SMSC47M1_REG_FANDIV		0x58

static const u8 SMSC47M1_REG_FAN[3]		= { 0x59, 0x5a, 0x6b };
static const u8 SMSC47M1_REG_FAN_PRELOAD[3]	= { 0x5b, 0x5c, 0x6c };
static const u8 SMSC47M1_REG_PWM[3]		= { 0x56, 0x57, 0x69 };

#define SMSC47M2_REG_ALARM6		0x09
#define SMSC47M2_REG_TPIN1		0x38
#define SMSC47M2_REG_TPIN2		0x37
#define SMSC47M2_REG_TPIN3		0x2d
#define SMSC47M2_REG_PPIN3		0x2c
#define SMSC47M2_REG_FANDIV3		0x6a

#define MIN_FROM_REG(reg, div)		((reg) >= 192 ? 0 : \
					 983040 / ((192 - (reg)) * (div)))
#define FAN_FROM_REG(reg, div, preload)	((reg) <= (preload) || (reg) == 255 ? \
					 0 : \
					 983040 / (((reg) - (preload)) * (div)))
#define DIV_FROM_REG(reg)		(1 << (reg))
#define PWM_FROM_REG(reg)		(((reg) & 0x7E) << 1)
#define PWM_EN_FROM_REG(reg)		((~(reg)) & 0x01)
#define PWM_TO_REG(reg)			(((reg) >> 1) & 0x7E)

struct smsc47m1_data {
	unsigned short addr;
	const char *name;
	enum chips type;
	struct device *hwmon_dev;

	struct mutex update_lock;
	unsigned long last_updated;	/* In jiffies */

	u8 fan[3];		/* Register value */
	u8 fan_preload[3];	/* Register value */
	u8 fan_div[3];		/* Register encoding, shifted right */
	u8 alarms;		/* Register encoding */
	u8 pwm[3];		/* Register value (bit 0 is disable) */
};

struct smsc47m1_sio_data {
	enum chips type;
	u8 activate;		/* Remember initial device state */
};

static inline int smsc47m1_read_value(struct smsc47m1_data *data, u8 reg)
{
	return inb_p(data->addr + reg);
}

static inline void smsc47m1_write_value(struct smsc47m1_data *data, u8 reg,
		u8 value)
{
	outb_p(value, data->addr + reg);
}

static struct smsc47m1_data *smsc47m1_update_device(struct device *dev,
		int init)
{
	struct smsc47m1_data *data = dev_get_drvdata(dev);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2) || init) {
		int i, fan_nr;
		fan_nr = data->type == smsc47m2 ? 3 : 2;

		for (i = 0; i < fan_nr; i++) {
			data->fan[i] = smsc47m1_read_value(data,
				       SMSC47M1_REG_FAN[i]);
			data->fan_preload[i] = smsc47m1_read_value(data,
					       SMSC47M1_REG_FAN_PRELOAD[i]);
			data->pwm[i] = smsc47m1_read_value(data,
				       SMSC47M1_REG_PWM[i]);
		}

		i = smsc47m1_read_value(data, SMSC47M1_REG_FANDIV);
		data->fan_div[0] = (i >> 4) & 0x03;
		data->fan_div[1] = i >> 6;

		data->alarms = smsc47m1_read_value(data,
			       SMSC47M1_REG_ALARM) >> 6;
		/* Clear alarms if needed */
		if (data->alarms)
			smsc47m1_write_value(data, SMSC47M1_REG_ALARM, 0xC0);

		if (fan_nr >= 3) {
			data->fan_div[2] = (smsc47m1_read_value(data,
					    SMSC47M2_REG_FANDIV3) >> 4) & 0x03;
			data->alarms |= (smsc47m1_read_value(data,
					 SMSC47M2_REG_ALARM6) & 0x40) >> 4;
			/* Clear alarm if needed */
			if (data->alarms & 0x04)
				smsc47m1_write_value(data,
						     SMSC47M2_REG_ALARM6,
						     0x40);
		}

		data->last_updated = jiffies;
	}

	mutex_unlock(&data->update_lock);
	return data;
}

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 smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	int nr = attr->index;
	/*
	 * This chip (stupidly) stops monitoring fan speed if PWM is
	 * enabled and duty cycle is 0%. This is fine if the monitoring
	 * and control concern the same fan, but troublesome if they are
	 * not (which could as well happen).
	 */
	int rpm = (data->pwm[nr] & 0x7F) == 0x00 ? 0 :
		  FAN_FROM_REG(data->fan[nr],
			       DIV_FROM_REG(data->fan_div[nr]),
			       data->fan_preload[nr]);
	return sprintf(buf, "%d\n", rpm);
}

static ssize_t fan_min_show(struct device *dev,
			    struct device_attribute *devattr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	int nr = attr->index;
	int rpm = MIN_FROM_REG(data->fan_preload[nr],
			       DIV_FROM_REG(data->fan_div[nr]));
	return sprintf(buf, "%d\n", rpm);
}

static ssize_t fan_div_show(struct device *dev,
			    struct device_attribute *devattr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[attr->index]));
}

static ssize_t fan_alarm_show(struct device *dev,
			      struct device_attribute *devattr, char *buf)
{
	int bitnr = to_sensor_dev_attr(devattr)->index;
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}

static ssize_t pwm_show(struct device *dev, struct device_attribute *devattr,
			char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	return sprintf(buf, "%d\n", PWM_FROM_REG(data->pwm[attr->index]));
}

static ssize_t pwm_en_show(struct device *dev,
			   struct device_attribute *devattr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	return sprintf(buf, "%d\n", PWM_EN_FROM_REG(data->pwm[attr->index]));
}

static ssize_t alarms_show(struct device *dev,
			   struct device_attribute *devattr, char *buf)
{
	struct smsc47m1_data *data = smsc47m1_update_device(dev, 0);
	return sprintf(buf, "%d\n", data->alarms);
}

static ssize_t fan_min_store(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = dev_get_drvdata(dev);
	int nr = attr->index;
	long rpmdiv;
	long val;
	int err;

	err = kstrtol(buf, 10, &val);
	if (err)
		return err;

	mutex_lock(&data->update_lock);
	rpmdiv = val * DIV_FROM_REG(data->fan_div[nr]);

	if (983040 > 192 * rpmdiv || 2 * rpmdiv > 983040) {
		mutex_unlock(&data->update_lock);
		return -EINVAL;
	}

	data->fan_preload[nr] = 192 - ((983040 + rpmdiv / 2) / rpmdiv);
	smsc47m1_write_value(data, SMSC47M1_REG_FAN_PRELOAD[nr],
			     data->fan_preload[nr]);
	mutex_unlock(&data->update_lock);

	return count;
}

/*
 * Note: we save and restore the fan minimum here, because its value is
 * determined in part by the fan clock divider.  This follows the principle
 * of least surprise; the user doesn't expect the fan minimum to change just
 * because the divider changed.
 */
static ssize_t fan_div_store(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = dev_get_drvdata(dev);
	int nr = attr->index;
	long new_div;
	int err;
	long tmp;
	u8 old_div = DIV_FROM_REG(data->fan_div[nr]);

	err = kstrtol(buf, 10, &new_div);
	if (err)
		return err;

	if (new_div == old_div) /* No change */
		return count;

	mutex_lock(&data->update_lock);
	switch (new_div) {
	case 1:
		data->fan_div[nr] = 0;
		break;
	case 2:
		data->fan_div[nr] = 1;
		break;
	case 4:
		data->fan_div[nr] = 2;
		break;
	case 8:
		data->fan_div[nr] = 3;
		break;
	default:
		mutex_unlock(&data->update_lock);
		return -EINVAL;
	}

	switch (nr) {
	case 0:
	case 1:
		tmp = smsc47m1_read_value(data, SMSC47M1_REG_FANDIV)
		      & ~(0x03 << (4 + 2 * nr));
		tmp |= data->fan_div[nr] << (4 + 2 * nr);
		smsc47m1_write_value(data, SMSC47M1_REG_FANDIV, tmp);
		break;
	case 2:
		tmp = smsc47m1_read_value(data, SMSC47M2_REG_FANDIV3) & 0xCF;
		tmp |= data->fan_div[2] << 4;
		smsc47m1_write_value(data, SMSC47M2_REG_FANDIV3, tmp);
		break;
	default:
		BUG();
	}

	/* Preserve fan min */
	tmp = 192 - (old_div * (192 - data->fan_preload[nr])
		     + new_div / 2) / new_div;
	data->fan_preload[nr] = clamp_val(tmp, 0, 191);
	smsc47m1_write_value(data, SMSC47M1_REG_FAN_PRELOAD[nr],
			     data->fan_preload[nr]);
	mutex_unlock(&data->update_lock);

	return count;
}

static ssize_t pwm_store(struct device *dev, struct device_attribute *devattr,
			 const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = dev_get_drvdata(dev);
	int nr = attr->index;
	long val;
	int err;

	err = kstrtol(buf, 10, &val);
	if (err)
		return err;

	if (val < 0 || val > 255)
		return -EINVAL;

	mutex_lock(&data->update_lock);
	data->pwm[nr] &= 0x81; /* Preserve additional bits */
	data->pwm[nr] |= PWM_TO_REG(val);
	smsc47m1_write_value(data, SMSC47M1_REG_PWM[nr],
			     data->pwm[nr]);
	mutex_unlock(&data->update_lock);

	return count;
}

static ssize_t pwm_en_store(struct device *dev,
			    struct device_attribute *devattr, const char *buf,
			    size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct smsc47m1_data *data = dev_get_drvdata(dev);
	int nr = attr->index;
	unsigned long val;
	int err;

	err = kstrtoul(buf, 10, &val);
	if (err)
		return err;

	if (val > 1)
		return -EINVAL;

	mutex_lock(&data->update_lock);
	data->pwm[nr] &= 0xFE; /* preserve the other bits */
	data->pwm[nr] |= !val;
	smsc47m1_write_value(data, SMSC47M1_REG_PWM[nr],
			     data->pwm[nr]);
	mutex_unlock(&data->update_lock);

	return count;
}

static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, 0);
static SENSOR_DEVICE_ATTR_RW(fan1_min, fan_min, 0);
static SENSOR_DEVICE_ATTR_RW(fan1_div, fan_div, 0);
static SENSOR_DEVICE_ATTR_RO(fan1_alarm, fan_alarm, 0);
static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
static SENSOR_DEVICE_ATTR_RW(pwm1_enable, pwm_en, 0);
static SENSOR_DEVICE_ATTR_RO(fan2_input, fan, 1);
static SENSOR_DEVICE_ATTR_RW(fan2_min, fan_min, 1);
static SENSOR_DEVICE_ATTR_RW(fan2_div, fan_div, 1);
static SENSOR_DEVICE_ATTR_RO(fan2_alarm, fan_alarm, 1);
static SENSOR_DEVICE_ATTR_RW(pwm2, pwm, 1);
static SENSOR_DEVICE_ATTR_RW(pwm2_enable, pwm_en, 1);
static SENSOR_DEVICE_ATTR_RO(fan3_input, fan, 2);
static SENSOR_DEVICE_ATTR_RW(fan3_min, fan_min, 2);
static SENSOR_DEVICE_ATTR_RW(fan3_div, fan_div, 2);
static SENSOR_DEVICE_ATTR_RO(fan3_alarm, fan_alarm, 2);
static SENSOR_DEVICE_ATTR_RW(pwm3, pwm, 2);
static SENSOR_DEVICE_ATTR_RW(pwm3_enable, pwm_en, 2);

static DEVICE_ATTR_RO(alarms);

static ssize_t name_show(struct device *dev, struct device_attribute
			 *devattr, char *buf)
{
	struct smsc47m1_data *data = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", data->name);
}
static DEVICE_ATTR_RO(name);

static struct attribute *smsc47m1_attributes_fan1[] = {
	&sensor_dev_attr_fan1_input.dev_attr.attr,
	&sensor_dev_attr_fan1_min.dev_attr.attr,
	&sensor_dev_attr_fan1_div.dev_attr.attr,
	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_fan1 = {
	.attrs = smsc47m1_attributes_fan1,
};

static struct attribute *smsc47m1_attributes_fan2[] = {
	&sensor_dev_attr_fan2_input.dev_attr.attr,
	&sensor_dev_attr_fan2_min.dev_attr.attr,
	&sensor_dev_attr_fan2_div.dev_attr.attr,
	&sensor_dev_attr_fan2_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_fan2 = {
	.attrs = smsc47m1_attributes_fan2,
};

static struct attribute *smsc47m1_attributes_fan3[] = {
	&sensor_dev_attr_fan3_input.dev_attr.attr,
	&sensor_dev_attr_fan3_min.dev_attr.attr,
	&sensor_dev_attr_fan3_div.dev_attr.attr,
	&sensor_dev_attr_fan3_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_fan3 = {
	.attrs = smsc47m1_attributes_fan3,
};

static struct attribute *smsc47m1_attributes_pwm1[] = {
	&sensor_dev_attr_pwm1.dev_attr.attr,
	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_pwm1 = {
	.attrs = smsc47m1_attributes_pwm1,
};

static struct attribute *smsc47m1_attributes_pwm2[] = {
	&sensor_dev_attr_pwm2.dev_attr.attr,
	&sensor_dev_attr_pwm2_enable.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_pwm2 = {
	.attrs = smsc47m1_attributes_pwm2,
};

static struct attribute *smsc47m1_attributes_pwm3[] = {
	&sensor_dev_attr_pwm3.dev_attr.attr,
	&sensor_dev_attr_pwm3_enable.dev_attr.attr,
	NULL
};

static const struct attribute_group smsc47m1_group_pwm3 = {
	.attrs = smsc47m1_attributes_pwm3,
};

static struct attribute *smsc47m1_attributes[] = {
	&dev_attr_alarms.attr,
	&dev_attr_name.attr,
	NULL
};

static const struct attribute_group smsc47m1_group = {
	.attrs = smsc47m1_attributes,
};

static int __init smsc47m1_find(struct smsc47m1_sio_data *sio_data)
{
	u8 val;
	unsigned short addr;
	int err;

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

	val = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID);

	/*
	 * SMSC LPC47M10x/LPC47M112/LPC47M13x (device id 0x59), LPC47M14x
	 * (device id 0x5F) and LPC47B27x (device id 0x51) have fan control.
	 * The LPC47M15x and LPC47M192 chips "with hardware monitoring block"
	 * can do much more besides (device id 0x60).
	 * The LPC47M997 is undocumented, but seems to be compatible with
	 * the LPC47M192, and has the same device id.
	 * The LPC47M292 (device id 0x6B) is somewhat compatible, but it
	 * supports a 3rd fan, and the pin configuration registers are
	 * unfortunately different.
	 * The LPC47M233 has the same device id (0x6B) but is not compatible.
	 * We check the high bit of the device revision register to
	 * differentiate them.
	 */
	switch (val) {
	case 0x51:
		pr_info("Found SMSC LPC47B27x\n");
		sio_data->type = smsc47m1;
		break;
	case 0x59:
		pr_info("Found SMSC LPC47M10x/LPC47M112/LPC47M13x\n");
		sio_data->type = smsc47m1;
		break;
	case 0x5F:
		pr_info("Found SMSC LPC47M14x\n");
		sio_data->type = smsc47m1;
		break;
	case 0x60:
		pr_info("Found SMSC LPC47M15x/LPC47M192/LPC47M997\n");
		sio_data->type = smsc47m1;
		break;
	case 0x6B:
		if (superio_inb(SUPERIO_REG_DEVREV) & 0x80) {
			pr_debug("Found SMSC LPC47M233, unsupported\n");
			superio_exit();
			return -ENODEV;
		}

		pr_info("Found SMSC LPC47M292\n");
		sio_data->type = smsc47m2;
		break;
	default:
		superio_exit();
		return -ENODEV;
	}

	superio_select();
	addr = (superio_inb(SUPERIO_REG_BASE) << 8)
	      |  superio_inb(SUPERIO_REG_BASE + 1);
	if (addr == 0) {
		pr_info("Device address not set, will not use\n");
		superio_exit();
		return -ENODEV;
	}

	/*
	 * Enable only if address is set (needed at least on the
	 * Compaq Presario S4000NX)
	 */
	sio_data->activate = superio_inb(SUPERIO_REG_ACT);
	if ((sio_data->activate & 0x01) == 0) {
		pr_info("Enabling device\n");
		superio_outb(SUPERIO_REG_ACT, sio_data->activate | 0x01);
	}

	superio_exit();
	return addr;
}

/* Restore device to its initial state */
static void smsc47m1_restore(const struct smsc47m1_sio_data *sio_data)
{
	if ((sio_data->activate & 0x01) == 0) {
		if (!superio_enter()) {
			superio_select();
			pr_info("Disabling device\n");
			superio_outb(SUPERIO_REG_ACT, sio_data->activate);
			superio_exit();
		} else {
			pr_warn("Failed to disable device\n");
		}
	}
}

#define CHECK		1
#define REQUEST		2

/*
 * This function can be used to:
 *  - test for resource conflicts with ACPI
 *  - request the resources
 * We only allocate the I/O ports we really need, to minimize the risk of
 * conflicts with ACPI or with other drivers.
 */
static int __init smsc47m1_handle_resources(unsigned short address,
					    enum chips type, int action,
					    struct device *dev)
{
	static const u8 ports_m1[] = {
		/* register, region length */
		0x04, 1,
		0x33, 4,
		0x56, 7,
	};

	static const u8 ports_m2[] = {
		/* register, region length */
		0x04, 1,
		0x09, 1,
		0x2c, 2,
		0x35, 4,
		0x56, 7,
		0x69, 4,
	};

	int i, ports_size, err;
	const u8 *ports;

	switch (type) {
	case smsc47m1:
	default:
		ports = ports_m1;
		ports_size = ARRAY_SIZE(ports_m1);
		break;
	case smsc47m2:
		ports = ports_m2;
		ports_size = ARRAY_SIZE(ports_m2);
		break;
	}

	for (i = 0; i + 1 < ports_size; i += 2) {
		unsigned short start = address + ports[i];
		unsigned short len = ports[i + 1];

		switch (action) {
		case CHECK:
			/* Only check for conflicts */
			err = acpi_check_region(start, len, DRVNAME);
			if (err)
				return err;
			break;
		case REQUEST:
			/* Request the resources */
			if (!devm_request_region(dev, start, len, DRVNAME)) {
				dev_err(dev,
					"Region 0x%x-0x%x already in use!\n",
					start, start + len);
				return -EBUSY;
			}
			break;
		}
	}

	return 0;
}

static void smsc47m1_remove_files(struct device *dev)
{
	sysfs_remove_group(&dev->kobj, &smsc47m1_group);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_fan1);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_fan2);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_fan3);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_pwm1);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_pwm2);
	sysfs_remove_group(&dev->kobj, &smsc47m1_group_pwm3);
}

static int __init smsc47m1_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct smsc47m1_sio_data *sio_data = dev_get_platdata(dev);
	struct smsc47m1_data *data;
	struct resource *res;
	int err;
	int fan1, fan2, fan3, pwm1, pwm2, pwm3;

	static const char * const names[] = {
		"smsc47m1",
		"smsc47m2",
	};

	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	err = smsc47m1_handle_resources(res->start, sio_data->type,
					REQUEST, dev);
	if (err < 0)
		return err;

	data = devm_kzalloc(dev, sizeof(struct smsc47m1_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->addr = res->start;
	data->type = sio_data->type;
	data->name = names[sio_data->type];
	mutex_init(&data->update_lock);
	platform_set_drvdata(pdev, data);

	/*
	 * If no function is properly configured, there's no point in
	 * actually registering the chip.
	 */
	pwm1 = (smsc47m1_read_value(data, SMSC47M1_REG_PPIN(0)) & 0x05)
	       == 0x04;
	pwm2 = (smsc47m1_read_value(data, SMSC47M1_REG_PPIN(1)) & 0x05)
	       == 0x04;
	if (data->type == smsc47m2) {
		fan1 = (smsc47m1_read_value(data, SMSC47M2_REG_TPIN1)
			& 0x0d) == 0x09;
		fan2 = (smsc47m1_read_value(data, SMSC47M2_REG_TPIN2)
			& 0x0d) == 0x09;
		fan3 = (smsc47m1_read_value(data, SMSC47M2_REG_TPIN3)
			& 0x0d) == 0x0d;
		pwm3 = (smsc47m1_read_value(data, SMSC47M2_REG_PPIN3)
			& 0x0d) == 0x08;
	} else {
		fan1 = (smsc47m1_read_value(data, SMSC47M1_REG_TPIN(0))
			& 0x05) == 0x05;
		fan2 = (smsc47m1_read_value(data, SMSC47M1_REG_TPIN(1))
			& 0x05) == 0x05;
		fan3 = 0;
		pwm3 = 0;
	}
	if (!(fan1 || fan2 || fan3 || pwm1 || pwm2 || pwm3)) {
		dev_warn(dev, "Device not configured, will not use\n");
		return -ENODEV;
	}

	/*
	 * Some values (fan min, clock dividers, pwm registers) may be
	 * needed before any update is triggered, so we better read them
	 * at least once here. We don't usually do it that way, but in
	 * this particular case, manually reading 5 registers out of 8
	 * doesn't make much sense and we're better using the existing
	 * function.
	 */
	smsc47m1_update_device(dev, 1);

	/* Register sysfs hooks */
	if (fan1) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_fan1);
		if (err)
			goto error_remove_files;
	} else
		dev_dbg(dev, "Fan 1 not enabled by hardware, skipping\n");

	if (fan2) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_fan2);
		if (err)
			goto error_remove_files;
	} else
		dev_dbg(dev, "Fan 2 not enabled by hardware, skipping\n");

	if (fan3) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_fan3);
		if (err)
			goto error_remove_files;
	} else if (data->type == smsc47m2)
		dev_dbg(dev, "Fan 3 not enabled by hardware, skipping\n");

	if (pwm1) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_pwm1);
		if (err)
			goto error_remove_files;
	} else
		dev_dbg(dev, "PWM 1 not enabled by hardware, skipping\n");

	if (pwm2) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_pwm2);
		if (err)
			goto error_remove_files;
	} else
		dev_dbg(dev, "PWM 2 not enabled by hardware, skipping\n");

	if (pwm3) {
		err = sysfs_create_group(&dev->kobj,
					 &smsc47m1_group_pwm3);
		if (err)
			goto error_remove_files;
	} else if (data->type == smsc47m2)
		dev_dbg(dev, "PWM 3 not enabled by hardware, skipping\n");

	err = sysfs_create_group(&dev->kobj, &smsc47m1_group);
	if (err)
		goto error_remove_files;

	data->hwmon_dev = hwmon_device_register(dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto error_remove_files;
	}

	return 0;

error_remove_files:
	smsc47m1_remove_files(dev);
	return err;
}

static void __exit smsc47m1_remove(struct platform_device *pdev)
{
	struct smsc47m1_data *data = platform_get_drvdata(pdev);

	hwmon_device_unregister(data->hwmon_dev);
	smsc47m1_remove_files(&pdev->dev);
}

/*
 * smsc47m1_remove() lives in .exit.text. For drivers registered via
 * module_platform_driver_probe() this ok because they cannot get unbound at
 * runtime. The driver needs to be marked with __refdata, otherwise modpost
 * triggers a section mismatch warning.
 */
static struct platform_driver smsc47m1_driver __refdata = {
	.driver = {
		.name	= DRVNAME,
	},
	.remove		= __exit_p(smsc47m1_remove),
};

static int __init smsc47m1_device_add(unsigned short address,
				      const struct smsc47m1_sio_data *sio_data)
{
	const struct resource res = {
		.start	= address,
		.end	= address + SMSC_EXTENT - 1,
		.name	= DRVNAME,
		.flags	= IORESOURCE_IO,
	};
	const struct platform_device_info pdevinfo = {
		.name = DRVNAME,
		.id = address,
		.res = &res,
		.num_res = 1,
		.data = sio_data,
		.size_data = sizeof(struct smsc47m1_sio_data),
	};
	int err;

	err = smsc47m1_handle_resources(address, sio_data->type, CHECK, NULL);
	if (err)
		return err;

	smsc47m1_pdev = platform_device_register_full(&pdevinfo);
	if (IS_ERR(smsc47m1_pdev)) {
		pr_err("Device allocation failed\n");
		return PTR_ERR(smsc47m1_pdev);
	}

	return 0;
}

static int __init sm_smsc47m1_init(void)
{
	int err;
	unsigned short address;
	struct smsc47m1_sio_data sio_data;

	err = smsc47m1_find(&sio_data);
	if (err < 0)
		return err;
	address = err;

	/* Sets global smsc47m1_pdev as a side effect */
	err = smsc47m1_device_add(address, &sio_data);
	if (err)
		return err;

	err = platform_driver_probe(&smsc47m1_driver, smsc47m1_probe);
	if (err)
		goto exit_device;

	return 0;

exit_device:
	platform_device_unregister(smsc47m1_pdev);
	smsc47m1_restore(&sio_data);
	return err;
}

static void __exit sm_smsc47m1_exit(void)
{
	platform_driver_unregister(&smsc47m1_driver);
	smsc47m1_restore(dev_get_platdata(&smsc47m1_pdev->dev));
	platform_device_unregister(smsc47m1_pdev);
}

MODULE_AUTHOR("Mark D. Studebaker <mdsxyz123@yahoo.com>");
MODULE_DESCRIPTION("SMSC LPC47M1xx fan sensors driver");
MODULE_LICENSE("GPL");

module_init(sm_smsc47m1_init);
module_exit(sm_smsc47m1_exit);