// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Hardware monitoring driver for Maxim MAX6620
*
* Originally from L. Grunenberg.
* (C) 2012 by L. Grunenberg <[email protected]>
*
* Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
*
* based on code written by :
* 2007 by Hans J. Koch <[email protected]>
* John Morris <[email protected]>
* Copyright (c) 2003 Spirent Communications
* and Claus Gindhart <[email protected]>
*
* This module has only been tested with the MAX6620 chip.
*
* The datasheet was last seen at:
*
* http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
*
*/
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/slab.h>
/*
* MAX 6620 registers
*/
#define MAX6620_REG_CONFIG 0x00
#define MAX6620_REG_FAULT 0x01
#define MAX6620_REG_CONF_FAN0 0x02
#define MAX6620_REG_CONF_FAN1 0x03
#define MAX6620_REG_CONF_FAN2 0x04
#define MAX6620_REG_CONF_FAN3 0x05
#define MAX6620_REG_DYN_FAN0 0x06
#define MAX6620_REG_DYN_FAN1 0x07
#define MAX6620_REG_DYN_FAN2 0x08
#define MAX6620_REG_DYN_FAN3 0x09
#define MAX6620_REG_TACH0 0x10
#define MAX6620_REG_TACH1 0x12
#define MAX6620_REG_TACH2 0x14
#define MAX6620_REG_TACH3 0x16
#define MAX6620_REG_VOLT0 0x18
#define MAX6620_REG_VOLT1 0x1A
#define MAX6620_REG_VOLT2 0x1C
#define MAX6620_REG_VOLT3 0x1E
#define MAX6620_REG_TAR0 0x20
#define MAX6620_REG_TAR1 0x22
#define MAX6620_REG_TAR2 0x24
#define MAX6620_REG_TAR3 0x26
#define MAX6620_REG_DAC0 0x28
#define MAX6620_REG_DAC1 0x2A
#define MAX6620_REG_DAC2 0x2C
#define MAX6620_REG_DAC3 0x2E
/*
* Config register bits
*/
#define MAX6620_CFG_RUN BIT(7)
#define MAX6620_CFG_POR BIT(6)
#define MAX6620_CFG_TIMEOUT BIT(5)
#define MAX6620_CFG_FULLFAN BIT(4)
#define MAX6620_CFG_OSC BIT(3)
#define MAX6620_CFG_WD_MASK (BIT(2) | BIT(1))
#define MAX6620_CFG_WD_2 BIT(1)
#define MAX6620_CFG_WD_6 BIT(2)
#define MAX6620_CFG_WD10 (BIT(2) | BIT(1))
#define MAX6620_CFG_WD BIT(0)
/*
* Failure status register bits
*/
#define MAX6620_FAIL_TACH0 BIT(4)
#define MAX6620_FAIL_TACH1 BIT(5)
#define MAX6620_FAIL_TACH2 BIT(6)
#define MAX6620_FAIL_TACH3 BIT(7)
#define MAX6620_FAIL_MASK0 BIT(0)
#define MAX6620_FAIL_MASK1 BIT(1)
#define MAX6620_FAIL_MASK2 BIT(2)
#define MAX6620_FAIL_MASK3 BIT(3)
#define MAX6620_CLOCK_FREQ 8192 /* Clock frequency in Hz */
#define MAX6620_PULSE_PER_REV 2 /* Tachometer pulses per revolution */
/* Minimum and maximum values of the FAN-RPM */
#define FAN_RPM_MIN 240
#define FAN_RPM_MAX 30000
static const u8 config_reg[] = {
MAX6620_REG_CONF_FAN0,
MAX6620_REG_CONF_FAN1,
MAX6620_REG_CONF_FAN2,
MAX6620_REG_CONF_FAN3,
};
static const u8 dyn_reg[] = {
MAX6620_REG_DYN_FAN0,
MAX6620_REG_DYN_FAN1,
MAX6620_REG_DYN_FAN2,
MAX6620_REG_DYN_FAN3,
};
static const u8 tach_reg[] = {
MAX6620_REG_TACH0,
MAX6620_REG_TACH1,
MAX6620_REG_TACH2,
MAX6620_REG_TACH3,
};
static const u8 target_reg[] = {
MAX6620_REG_TAR0,
MAX6620_REG_TAR1,
MAX6620_REG_TAR2,
MAX6620_REG_TAR3,
};
/*
* Client data (each client gets its own)
*/
struct max6620_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid; /* false until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* register values */
u8 fancfg[4];
u8 fandyn[4];
u8 fault;
u16 tach[4];
u16 target[4];
};
static u8 max6620_fan_div_from_reg(u8 val)
{
return BIT((val & 0xE0) >> 5);
}
static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
{
return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
}
static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
{
return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
}
static int max6620_update_device(struct device *dev)
{
struct max6620_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int i;
int ret = 0;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
for (i = 0; i < 4; i++) {
ret = i2c_smbus_read_byte_data(client, config_reg[i]);
if (ret < 0)
goto error;
data->fancfg[i] = ret;
ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
if (ret < 0)
goto error;
data->fandyn[i] = ret;
ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
if (ret < 0)
goto error;
data->tach[i] = (ret << 3) & 0x7f8;
ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
if (ret < 0)
goto error;
data->tach[i] |= (ret >> 5) & 0x7;
ret = i2c_smbus_read_byte_data(client, target_reg[i]);
if (ret < 0)
goto error;
data->target[i] = (ret << 3) & 0x7f8;
ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
if (ret < 0)
goto error;
data->target[i] |= (ret >> 5) & 0x7;
}
/*
* Alarms are cleared on read in case the condition that
* caused the alarm is removed. Keep the value latched here
* for providing the register through different alarm files.
*/
ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
if (ret < 0)
goto error;
data->fault |= (ret >> 4) & (ret & 0x0F);
data->last_updated = jiffies;
data->valid = true;
}
error:
mutex_unlock(&data->update_lock);
return ret;
}
static umode_t
max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
int channel)
{
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_alarm:
case hwmon_fan_input:
return 0444;
case hwmon_fan_div:
case hwmon_fan_target:
return 0644;
default:
break;
}
break;
default:
break;
}
return 0;
}
static int
max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long *val)
{
struct max6620_data *data;
struct i2c_client *client;
int ret;
u8 div;
u8 val1;
u8 val2;
ret = max6620_update_device(dev);
if (ret < 0)
return ret;
data = dev_get_drvdata(dev);
client = data->client;
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_alarm:
mutex_lock(&data->update_lock);
*val = !!(data->fault & BIT(channel));
/* Setting TACH count to re-enable fan fault detection */
if (*val == 1) {
val1 = (data->target[channel] >> 3) & 0xff;
val2 = (data->target[channel] << 5) & 0xe0;
ret = i2c_smbus_write_byte_data(client,
target_reg[channel], val1);
if (ret < 0) {
mutex_unlock(&data->update_lock);
return ret;
}
ret = i2c_smbus_write_byte_data(client,
target_reg[channel] + 1, val2);
if (ret < 0) {
mutex_unlock(&data->update_lock);
return ret;
}
data->fault &= ~BIT(channel);
}
mutex_unlock(&data->update_lock);
break;
case hwmon_fan_div:
*val = max6620_fan_div_from_reg(data->fandyn[channel]);
break;
case hwmon_fan_input:
if (data->tach[channel] == 0) {
*val = 0;
} else {
div = max6620_fan_div_from_reg(data->fandyn[channel]);
*val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
}
break;
case hwmon_fan_target:
if (data->target[channel] == 0) {
*val = 0;
} else {
div = max6620_fan_div_from_reg(data->fandyn[channel]);
*val = max6620_fan_tach_to_rpm(div, data->target[channel]);
}
break;
default:
return -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int
max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long val)
{
struct max6620_data *data;
struct i2c_client *client;
int ret;
u8 div;
u16 tach;
u8 val1;
u8 val2;
ret = max6620_update_device(dev);
if (ret < 0)
return ret;
data = dev_get_drvdata(dev);
client = data->client;
mutex_lock(&data->update_lock);
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_div:
switch (val) {
case 1:
div = 0;
break;
case 2:
div = 1;
break;
case 4:
div = 2;
break;
case 8:
div = 3;
break;
case 16:
div = 4;
break;
case 32:
div = 5;
break;
default:
ret = -EINVAL;
goto error;
}
data->fandyn[channel] &= 0x1F;
data->fandyn[channel] |= div << 5;
ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
data->fandyn[channel]);
break;
case hwmon_fan_target:
val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
div = max6620_fan_div_from_reg(data->fandyn[channel]);
tach = max6620_fan_rpm_to_tach(div, val);
val1 = (tach >> 3) & 0xff;
val2 = (tach << 5) & 0xe0;
ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
if (ret < 0)
break;
ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
if (ret < 0)
break;
/* Setting TACH count re-enables fan fault detection */
data->fault &= ~BIT(channel);
break;
default:
ret = -EOPNOTSUPP;
break;
}
break;
default:
ret = -EOPNOTSUPP;
break;
}
error:
mutex_unlock(&data->update_lock);
return ret;
}
static const struct hwmon_channel_info * const max6620_info[] = {
HWMON_CHANNEL_INFO(fan,
HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
NULL
};
static const struct hwmon_ops max6620_hwmon_ops = {
.read = max6620_read,
.write = max6620_write,
.is_visible = max6620_is_visible,
};
static const struct hwmon_chip_info max6620_chip_info = {
.ops = &max6620_hwmon_ops,
.info = max6620_info,
};
static int max6620_init_client(struct max6620_data *data)
{
struct i2c_client *client = data->client;
int config;
int err;
int i;
int reg;
config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
if (config < 0) {
dev_err(&client->dev, "Error reading config, aborting.\n");
return config;
}
/*
* Set bit 4, disable other fans from going full speed on a fail
* failure.
*/
err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
if (err < 0) {
dev_err(&client->dev, "Config write error, aborting.\n");
return err;
}
for (i = 0; i < 4; i++) {
reg = i2c_smbus_read_byte_data(client, config_reg[i]);
if (reg < 0)
return reg;
data->fancfg[i] = reg;
/* Enable RPM mode */
data->fancfg[i] |= 0xa8;
err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
if (err < 0)
return err;
/* 2 counts (001) and Rate change 100 (0.125 secs) */
data->fandyn[i] = 0x30;
err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
if (err < 0)
return err;
}
return 0;
}
static int max6620_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct max6620_data *data;
struct device *hwmon_dev;
int err;
data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
err = max6620_init_client(data);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
data,
&max6620_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id max6620_id[] = {
{ "max6620" },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6620_id);
static struct i2c_driver max6620_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "max6620",
},
.probe = max6620_probe,
.id_table = max6620_id,
};
module_i2c_driver(max6620_driver);
MODULE_AUTHOR("Lucas Grunenberg");
MODULE_DESCRIPTION("MAX6620 sensor driver");
MODULE_LICENSE("GPL");
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