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original_kernel/drivers/hwmon/max6650.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* max6650.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring.
*
* (C) 2007 by Hans J. Koch <hjk@hansjkoch.de>
*
* based on code written by John Morris <john.morris@spirentcom.com>
* Copyright (c) 2003 Spirent Communications
* and Claus Gindhart <claus.gindhart@kontron.com>
*
* This module has only been tested with the MAX6650 chip. It should
* also work with the MAX6651. It does not distinguish max6650 and max6651
* chips.
*
* The datasheet was last seen at:
*
* http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/thermal.h>
/*
* Insmod parameters
*/
/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */
static int fan_voltage;
/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */
static int prescaler;
/* clock: The clock frequency of the chip (max6651 can be clocked externally) */
static int clock = 254000;
module_param(fan_voltage, int, 0444);
module_param(prescaler, int, 0444);
module_param(clock, int, 0444);
/*
* MAX 6650/6651 registers
*/
#define MAX6650_REG_SPEED 0x00
#define MAX6650_REG_CONFIG 0x02
#define MAX6650_REG_GPIO_DEF 0x04
#define MAX6650_REG_DAC 0x06
#define MAX6650_REG_ALARM_EN 0x08
#define MAX6650_REG_ALARM 0x0A
#define MAX6650_REG_TACH0 0x0C
#define MAX6650_REG_TACH1 0x0E
#define MAX6650_REG_TACH2 0x10
#define MAX6650_REG_TACH3 0x12
#define MAX6650_REG_GPIO_STAT 0x14
#define MAX6650_REG_COUNT 0x16
/*
* Config register bits
*/
#define MAX6650_CFG_V12 0x08
#define MAX6650_CFG_PRESCALER_MASK 0x07
#define MAX6650_CFG_PRESCALER_2 0x01
#define MAX6650_CFG_PRESCALER_4 0x02
#define MAX6650_CFG_PRESCALER_8 0x03
#define MAX6650_CFG_PRESCALER_16 0x04
#define MAX6650_CFG_MODE_MASK 0x30
#define MAX6650_CFG_MODE_ON 0x00
#define MAX6650_CFG_MODE_OFF 0x10
#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20
#define MAX6650_CFG_MODE_OPEN_LOOP 0x30
#define MAX6650_COUNT_MASK 0x03
/*
* Alarm status register bits
*/
#define MAX6650_ALRM_MAX 0x01
#define MAX6650_ALRM_MIN 0x02
#define MAX6650_ALRM_TACH 0x04
#define MAX6650_ALRM_GPIO1 0x08
#define MAX6650_ALRM_GPIO2 0x10
/* Minimum and maximum values of the FAN-RPM */
#define FAN_RPM_MIN 240
#define FAN_RPM_MAX 30000
#define DIV_FROM_REG(reg) (1 << ((reg) & 7))
#define DAC_LIMIT(v12) ((v12) ? 180 : 76)
/*
* Client data (each client gets its own)
*/
struct max6650_data {
struct i2c_client *client;
struct mutex update_lock; /* protect alarm register updates */
int nr_fans;
bool valid; /* false until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* register values */
u8 speed;
u8 config;
u8 tach[4];
u8 count;
u8 dac;
u8 alarm;
u8 alarm_en;
unsigned long cooling_dev_state;
};
static const u8 tach_reg[] = {
MAX6650_REG_TACH0,
MAX6650_REG_TACH1,
MAX6650_REG_TACH2,
MAX6650_REG_TACH3,
};
static const struct of_device_id __maybe_unused max6650_dt_match[] = {
{
.compatible = "maxim,max6650",
.data = (void *)1
},
{
.compatible = "maxim,max6651",
.data = (void *)4
},
{ },
};
MODULE_DEVICE_TABLE(of, max6650_dt_match);
static int dac_to_pwm(int dac, bool v12)
{
/*
* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
* Lower DAC values mean higher speeds.
*/
return clamp_val(255 - (255 * dac) / DAC_LIMIT(v12), 0, 255);
}
static u8 pwm_to_dac(unsigned int pwm, bool v12)
{
int limit = DAC_LIMIT(v12);
return limit - (limit * pwm) / 255;
}
static struct max6650_data *max6650_update_device(struct device *dev)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int reg, err = 0;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
for (i = 0; i < data->nr_fans; i++) {
reg = i2c_smbus_read_byte_data(client, tach_reg[i]);
if (reg < 0) {
err = reg;
goto error;
}
data->tach[i] = reg;
}
/*
* 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.
*/
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM);
if (reg < 0) {
err = reg;
goto error;
}
data->alarm |= reg;
data->last_updated = jiffies;
data->valid = true;
}
error:
mutex_unlock(&data->update_lock);
if (err)
data = ERR_PTR(err);
return data;
}
/*
* Change the operating mode of the chip (if needed).
* mode is one of the MAX6650_CFG_MODE_* values.
*/
static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
{
int result;
u8 config = data->config;
if (mode == (config & MAX6650_CFG_MODE_MASK))
return 0;
config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
config);
if (result < 0)
return result;
data->config = config;
return 0;
}
/*
* Set the fan speed to the specified RPM (or read back the RPM setting).
* This works in closed loop mode only. Use pwm1 for open loop speed setting.
*
* The MAX6650/1 will automatically control fan speed when in closed loop
* mode.
*
* Assumptions:
*
* 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use
* the clock module parameter if you need to fine tune this.
*
* 2) The prescaler (low three bits of the config register) has already
* been set to an appropriate value. Use the prescaler module parameter
* if your BIOS doesn't initialize the chip properly.
*
* The relevant equations are given on pages 21 and 22 of the datasheet.
*
* From the datasheet, the relevant equation when in regulation is:
*
* [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE
*
* where:
*
* fCLK is the oscillator frequency (either the 254kHz internal
* oscillator or the externally applied clock)
*
* KTACH is the value in the speed register
*
* FanSpeed is the speed of the fan in rps
*
* KSCALE is the prescaler value (1, 2, 4, 8, or 16)
*
* When reading, we need to solve for FanSpeed. When writing, we need to
* solve for KTACH.
*
* Note: this tachometer is completely separate from the tachometers
* used to measure the fan speeds. Only one fan's speed (fan1) is
* controlled.
*/
static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
{
int kscale, ktach;
if (rpm == 0)
return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
/*
* Divide the required speed by 60 to get from rpm to rps, then
* use the datasheet equation:
*
* KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
*/
kscale = DIV_FROM_REG(data->config);
ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
if (ktach < 0)
ktach = 0;
if (ktach > 255)
ktach = 255;
data->speed = ktach;
return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
data->speed);
}
/*
* Get gpio alarm status:
* Possible values:
* 0 = no alarm
* 1 = alarm
*/
static ssize_t alarm_show(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct max6650_data *data = max6650_update_device(dev);
bool alarm;
if (IS_ERR(data))
return PTR_ERR(data);
alarm = data->alarm & attr->index;
if (alarm) {
mutex_lock(&data->update_lock);
data->alarm &= ~attr->index;
data->valid = false;
mutex_unlock(&data->update_lock);
}
return sprintf(buf, "%d\n", alarm);
}
static SENSOR_DEVICE_ATTR_RO(gpio1_alarm, alarm, MAX6650_ALRM_GPIO1);
static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2);
static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
int n)
{
struct device *dev = kobj_to_dev(kobj);
struct max6650_data *data = dev_get_drvdata(dev);
struct device_attribute *devattr;
/*
* Hide the alarms that have not been enabled by the firmware
*/
devattr = container_of(a, struct device_attribute, attr);
if (devattr == &sensor_dev_attr_gpio1_alarm.dev_attr ||
devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) {
if (!(data->alarm_en & to_sensor_dev_attr(devattr)->index))
return 0;
}
return a->mode;
}
static struct attribute *max6650_attrs[] = {
&sensor_dev_attr_gpio1_alarm.dev_attr.attr,
&sensor_dev_attr_gpio2_alarm.dev_attr.attr,
NULL
};
static const struct attribute_group max6650_group = {
.attrs = max6650_attrs,
.is_visible = max6650_attrs_visible,
};
static const struct attribute_group *max6650_groups[] = {
&max6650_group,
NULL
};
static int max6650_init_client(struct max6650_data *data,
struct i2c_client *client)
{
struct device *dev = &client->dev;
int reg;
int err;
u32 voltage;
u32 prescale;
u32 target_rpm;
if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
&voltage))
voltage = fan_voltage;
else
voltage /= 1000000; /* Microvolts to volts */
if (of_property_read_u32(dev->of_node, "maxim,fan-prescale",
&prescale))
prescale = prescaler;
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
if (reg < 0) {
dev_err(dev, "Error reading config register, aborting.\n");
return reg;
}
switch (voltage) {
case 0:
break;
case 5:
reg &= ~MAX6650_CFG_V12;
break;
case 12:
reg |= MAX6650_CFG_V12;
break;
default:
dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage);
}
switch (prescale) {
case 0:
break;
case 1:
reg &= ~MAX6650_CFG_PRESCALER_MASK;
break;
case 2:
reg = (reg & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_2;
break;
case 4:
reg = (reg & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_4;
break;
case 8:
reg = (reg & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_8;
break;
case 16:
reg = (reg & ~MAX6650_CFG_PRESCALER_MASK)
| MAX6650_CFG_PRESCALER_16;
break;
default:
dev_err(dev, "illegal value for prescaler (%d)\n", prescale);
}
dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n",
(reg & MAX6650_CFG_V12) ? 12 : 5,
1 << (reg & MAX6650_CFG_PRESCALER_MASK));
err = i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, reg);
if (err) {
dev_err(dev, "Config write error, aborting.\n");
return err;
}
data->config = reg;
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_SPEED);
if (reg < 0) {
dev_err(dev, "Failed to read speed register, aborting.\n");
return reg;
}
data->speed = reg;
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC);
if (reg < 0) {
dev_err(dev, "Failed to read DAC register, aborting.\n");
return reg;
}
data->dac = reg;
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
if (reg < 0) {
dev_err(dev, "Failed to read count register, aborting.\n");
return reg;
}
data->count = reg;
reg = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN);
if (reg < 0) {
dev_err(dev, "Failed to read alarm configuration, aborting.\n");
return reg;
}
data->alarm_en = reg;
if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
&target_rpm)) {
max6650_set_target(data, target_rpm);
max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
}
return 0;
}
static int max6650_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
*state = 255;
return 0;
}
static int max6650_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct max6650_data *data = cdev->devdata;
*state = data->cooling_dev_state;
return 0;
}
static int max6650_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct max6650_data *data = cdev->devdata;
struct i2c_client *client = data->client;
int err;
state = clamp_val(state, 0, 255);
mutex_lock(&data->update_lock);
data->dac = pwm_to_dac(state, data->config & MAX6650_CFG_V12);
err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
if (!err) {
max6650_set_operating_mode(data, state ?
MAX6650_CFG_MODE_OPEN_LOOP :
MAX6650_CFG_MODE_OFF);
data->cooling_dev_state = state;
}
mutex_unlock(&data->update_lock);
return err;
}
static const struct thermal_cooling_device_ops max6650_cooling_ops = {
.get_max_state = max6650_get_max_state,
.get_cur_state = max6650_get_cur_state,
.set_cur_state = max6650_set_cur_state,
};
static int max6650_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct max6650_data *data = max6650_update_device(dev);
int mode;
if (IS_ERR(data))
return PTR_ERR(data);
switch (type) {
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
*val = dac_to_pwm(data->dac,
data->config & MAX6650_CFG_V12);
break;
case hwmon_pwm_enable:
/*
* Possible values:
* 0 = Fan always on
* 1 = Open loop, Voltage is set according to speed,
* not regulated.
* 2 = Closed loop, RPM for all fans regulated by fan1
* tachometer
* 3 = Fan off
*/
mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
*val = (4 - mode) & 3; /* {0 1 2 3} -> {0 3 2 1} */
break;
default:
return -EOPNOTSUPP;
}
break;
case hwmon_fan:
switch (attr) {
case hwmon_fan_input:
/*
* Calculation details:
*
* Each tachometer counts over an interval given by the
* "count" register (0.25, 0.5, 1 or 2 seconds).
* The driver assumes that the fans produce two pulses
* per revolution (this seems to be the most common).
*/
*val = DIV_ROUND_CLOSEST(data->tach[channel] * 120,
DIV_FROM_REG(data->count));
break;
case hwmon_fan_div:
*val = DIV_FROM_REG(data->count);
break;
case hwmon_fan_target:
/*
* Use the datasheet equation:
* FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
* then multiply by 60 to give rpm.
*/
*val = 60 * DIV_FROM_REG(data->config) * clock /
(256 * (data->speed + 1));
break;
case hwmon_fan_min_alarm:
*val = !!(data->alarm & MAX6650_ALRM_MIN);
data->alarm &= ~MAX6650_ALRM_MIN;
data->valid = false;
break;
case hwmon_fan_max_alarm:
*val = !!(data->alarm & MAX6650_ALRM_MAX);
data->alarm &= ~MAX6650_ALRM_MAX;
data->valid = false;
break;
case hwmon_fan_fault:
*val = !!(data->alarm & MAX6650_ALRM_TACH);
data->alarm &= ~MAX6650_ALRM_TACH;
data->valid = false;
break;
default:
return -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static const u8 max6650_pwm_modes[] = {
MAX6650_CFG_MODE_ON,
MAX6650_CFG_MODE_OPEN_LOOP,
MAX6650_CFG_MODE_CLOSED_LOOP,
MAX6650_CFG_MODE_OFF,
};
static int max6650_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct max6650_data *data = dev_get_drvdata(dev);
int ret = 0;
u8 reg;
mutex_lock(&data->update_lock);
switch (type) {
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
reg = pwm_to_dac(clamp_val(val, 0, 255),
data->config & MAX6650_CFG_V12);
ret = i2c_smbus_write_byte_data(data->client,
MAX6650_REG_DAC, reg);
if (ret)
break;
data->dac = reg;
break;
case hwmon_pwm_enable:
if (val < 0 || val >= ARRAY_SIZE(max6650_pwm_modes)) {
ret = -EINVAL;
break;
}
ret = max6650_set_operating_mode(data,
max6650_pwm_modes[val]);
break;
default:
ret = -EOPNOTSUPP;
break;
}
break;
case hwmon_fan:
switch (attr) {
case hwmon_fan_div:
switch (val) {
case 1:
reg = 0;
break;
case 2:
reg = 1;
break;
case 4:
reg = 2;
break;
case 8:
reg = 3;
break;
default:
ret = -EINVAL;
goto error;
}
ret = i2c_smbus_write_byte_data(data->client,
MAX6650_REG_COUNT, reg);
if (ret)
break;
data->count = reg;
break;
case hwmon_fan_target:
if (val < 0) {
ret = -EINVAL;
break;
}
ret = max6650_set_target(data, val);
break;
default:
ret = -EOPNOTSUPP;
break;
}
break;
default:
ret = -EOPNOTSUPP;
break;
}
error:
mutex_unlock(&data->update_lock);
return ret;
}
static umode_t max6650_is_visible(const void *_data,
enum hwmon_sensor_types type, u32 attr,
int channel)
{
const struct max6650_data *data = _data;
if (channel && (channel >= data->nr_fans || type != hwmon_fan))
return 0;
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_input:
return 0444;
case hwmon_fan_target:
case hwmon_fan_div:
return 0644;
case hwmon_fan_min_alarm:
if (data->alarm_en & MAX6650_ALRM_MIN)
return 0444;
break;
case hwmon_fan_max_alarm:
if (data->alarm_en & MAX6650_ALRM_MAX)
return 0444;
break;
case hwmon_fan_fault:
if (data->alarm_en & MAX6650_ALRM_TACH)
return 0444;
break;
default:
break;
}
break;
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
case hwmon_pwm_enable:
return 0644;
default:
break;
}
break;
default:
break;
}
return 0;
}
static const struct hwmon_channel_info * const max6650_info[] = {
HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_DIV |
HWMON_F_MIN_ALARM | HWMON_F_MAX_ALARM |
HWMON_F_FAULT,
HWMON_F_INPUT, HWMON_F_INPUT, HWMON_F_INPUT),
HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
NULL
};
static const struct hwmon_ops max6650_hwmon_ops = {
.read = max6650_read,
.write = max6650_write,
.is_visible = max6650_is_visible,
};
static const struct hwmon_chip_info max6650_chip_info = {
.ops = &max6650_hwmon_ops,
.info = max6650_info,
};
static const struct i2c_device_id max6650_id[];
static int max6650_probe(struct i2c_client *client)
{
struct thermal_cooling_device *cooling_dev;
struct device *dev = &client->dev;
struct max6650_data *data;
struct device *hwmon_dev;
int err;
data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
data->nr_fans = (uintptr_t)i2c_get_match_data(client);
/*
* Initialize the max6650 chip
*/
err = max6650_init_client(data, client);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev,
client->name, data,
&max6650_chip_info,
max6650_groups);
err = PTR_ERR_OR_ZERO(hwmon_dev);
if (err)
return err;
if (IS_ENABLED(CONFIG_THERMAL)) {
cooling_dev = devm_thermal_of_cooling_device_register(dev,
dev->of_node, client->name,
data, &max6650_cooling_ops);
if (IS_ERR(cooling_dev)) {
dev_warn(dev, "thermal cooling device register failed: %ld\n",
PTR_ERR(cooling_dev));
}
}
return 0;
}
static const struct i2c_device_id max6650_id[] = {
{ "max6650", 1 },
{ "max6651", 4 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6650_id);
static struct i2c_driver max6650_driver = {
.driver = {
.name = "max6650",
.of_match_table = of_match_ptr(max6650_dt_match),
},
.probe = max6650_probe,
.id_table = max6650_id,
};
module_i2c_driver(max6650_driver);
MODULE_AUTHOR("Hans J. Koch");
MODULE_DESCRIPTION("MAX6650 sensor driver");
MODULE_LICENSE("GPL");
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