// SPDX-License-Identifier: GPL-2.0+
/*
* Hardware monitoring driver for EMC2305 fan controller
*
* Copyright (C) 2022 Nvidia Technologies Ltd.
*/
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/platform_data/emc2305.h>
#include <linux/thermal.h>
#define EMC2305_REG_DRIVE_FAIL_STATUS 0x27
#define EMC2305_REG_VENDOR 0xfe
#define EMC2305_FAN_MAX 0xff
#define EMC2305_FAN_MIN 0x00
#define EMC2305_FAN_MAX_STATE 10
#define EMC2305_DEVICE 0x34
#define EMC2305_VENDOR 0x5d
#define EMC2305_REG_PRODUCT_ID 0xfd
#define EMC2305_TACH_REGS_UNUSE_BITS 3
#define EMC2305_TACH_CNT_MULTIPLIER 0x02
#define EMC2305_TACH_RANGE_MIN 480
#define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \
DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max))
#define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \
DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state))
/*
* Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges
* equal (poles * 2 + 1).
*/
#define EMC2305_RPM_FACTOR 3932160
#define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n))
#define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n))
#define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n))
enum emc230x_product_id {
EMC2305 = 0x34,
EMC2303 = 0x35,
EMC2302 = 0x36,
EMC2301 = 0x37,
};
static const struct i2c_device_id emc2305_ids[] = {
{ "emc2305" },
{ "emc2303" },
{ "emc2302" },
{ "emc2301" },
{ }
};
MODULE_DEVICE_TABLE(i2c, emc2305_ids);
/**
* struct emc2305_cdev_data - device-specific cooling device state
* @cdev: cooling device
* @cur_state: cooling current state
* @last_hwmon_state: last cooling state updated by hwmon subsystem
* @last_thermal_state: last cooling state updated by thermal subsystem
*
* The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit
* speed feature. The purpose of this feature is to provides ability to limit fan speed
* according to some system wise considerations, like absence of some replaceable units (PSU or
* line cards), high system ambient temperature, unreliable transceivers temperature sensing or
* some other factors which indirectly impacts system's airflow
* Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is
* used for setting low limit for fan speed in case 'thermal' subsystem is configured in
* kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal'
* subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm'
* attribute.
* From other side, fan speed is to be updated in hardware through 'pwm' only in case the
* requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan
* speed will be just stored with no PWM update.
*/
struct emc2305_cdev_data {
struct thermal_cooling_device *cdev;
unsigned int cur_state;
unsigned long last_hwmon_state;
unsigned long last_thermal_state;
};
/**
* struct emc2305_data - device-specific data
* @client: i2c client
* @hwmon_dev: hwmon device
* @max_state: maximum cooling state of the cooling device
* @pwm_num: number of PWM channels
* @pwm_separate: separate PWM settings for every channel
* @pwm_min: array of minimum PWM per channel
* @cdev_data: array of cooling devices data
*/
struct emc2305_data {
struct i2c_client *client;
struct device *hwmon_dev;
u8 max_state;
u8 pwm_num;
bool pwm_separate;
u8 pwm_min[EMC2305_PWM_MAX];
struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX];
};
static char *emc2305_fan_name[] = {
"emc2305_fan",
"emc2305_fan1",
"emc2305_fan2",
"emc2305_fan3",
"emc2305_fan4",
"emc2305_fan5",
};
static void emc2305_unset_tz(struct device *dev);
static int emc2305_get_max_channel(const struct emc2305_data *data)
{
return data->pwm_num;
}
static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev)
{
struct emc2305_data *data = cdev->devdata;
size_t len = strlen(cdev->type);
int ret;
if (len <= 0)
return -EINVAL;
/*
* Returns index of cooling device 0..4 in case of separate PWM setting.
* Zero index is used in case of one common PWM setting.
* If the mode is not set as pwm_separate, all PWMs are to be bound
* to the common thermal zone and should work at the same speed
* to perform cooling for the same thermal junction.
* Otherwise, return specific channel that will be used in bound
* related PWM to the thermal zone.
*/
if (!data->pwm_separate)
return 0;
ret = cdev->type[len - 1];
switch (ret) {
case '1' ... '5':
return ret - '1';
default:
break;
}
return -EINVAL;
}
static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state)
{
int cdev_idx;
struct emc2305_data *data = cdev->devdata;
cdev_idx = emc2305_get_cdev_idx(cdev);
if (cdev_idx < 0)
return cdev_idx;
*state = data->cdev_data[cdev_idx].cur_state;
return 0;
}
static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state)
{
struct emc2305_data *data = cdev->devdata;
*state = data->max_state;
return 0;
}
static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state)
{
int ret;
struct i2c_client *client = data->client;
u8 val, i;
state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state);
val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX);
data->cdev_data[cdev_idx].cur_state = state;
if (data->pwm_separate) {
ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val);
if (ret < 0)
return ret;
} else {
/*
* Set the same PWM value in all channels
* if common PWM channel is used.
*/
for (i = 0; i < data->pwm_num; i++) {
ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val);
if (ret < 0)
return ret;
}
}
return 0;
}
static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
{
int cdev_idx, ret;
struct emc2305_data *data = cdev->devdata;
if (state > data->max_state)
return -EINVAL;
cdev_idx = emc2305_get_cdev_idx(cdev);
if (cdev_idx < 0)
return cdev_idx;
/* Save thermal state. */
data->cdev_data[cdev_idx].last_thermal_state = state;
ret = __emc2305_set_cur_state(data, cdev_idx, state);
if (ret < 0)
return ret;
return 0;
}
static const struct thermal_cooling_device_ops emc2305_cooling_ops = {
.get_max_state = emc2305_get_max_state,
.get_cur_state = emc2305_get_cur_state,
.set_cur_state = emc2305_set_cur_state,
};
static int emc2305_show_fault(struct device *dev, int channel)
{
struct emc2305_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int status_reg;
status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS);
if (status_reg < 0)
return status_reg;
return status_reg & (1 << channel) ? 1 : 0;
}
static int emc2305_show_fan(struct device *dev, int channel)
{
struct emc2305_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int ret;
ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel));
if (ret <= 0)
return ret;
ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS;
ret = EMC2305_RPM_FACTOR / ret;
if (ret <= EMC2305_TACH_RANGE_MIN)
return 0;
return ret * EMC2305_TACH_CNT_MULTIPLIER;
}
static int emc2305_show_pwm(struct device *dev, int channel)
{
struct emc2305_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel));
}
static int emc2305_set_pwm(struct device *dev, long val, int channel)
{
struct emc2305_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int ret;
if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX)
return -EINVAL;
ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);
if (ret < 0)
return ret;
data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state,
EMC2305_FAN_MAX);
return 0;
}
static int emc2305_set_single_tz(struct device *dev, int idx)
{
struct emc2305_data *data = dev_get_drvdata(dev);
long pwm;
int i, cdev_idx, ret;
cdev_idx = (idx) ? idx - 1 : 0;
pwm = data->pwm_min[cdev_idx];
data->cdev_data[cdev_idx].cdev =
thermal_cooling_device_register(emc2305_fan_name[idx], data,
&emc2305_cooling_ops);
if (IS_ERR(data->cdev_data[cdev_idx].cdev)) {
dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]);
return PTR_ERR(data->cdev_data[cdev_idx].cdev);
}
/* Set minimal PWM speed. */
if (data->pwm_separate) {
ret = emc2305_set_pwm(dev, pwm, cdev_idx);
if (ret < 0)
return ret;
} else {
for (i = 0; i < data->pwm_num; i++) {
ret = emc2305_set_pwm(dev, pwm, i);
if (ret < 0)
return ret;
}
}
data->cdev_data[cdev_idx].cur_state =
EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
EMC2305_FAN_MAX);
data->cdev_data[cdev_idx].last_hwmon_state =
EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
EMC2305_FAN_MAX);
return 0;
}
static int emc2305_set_tz(struct device *dev)
{
struct emc2305_data *data = dev_get_drvdata(dev);
int i, ret;
if (!data->pwm_separate)
return emc2305_set_single_tz(dev, 0);
for (i = 0; i < data->pwm_num; i++) {
ret = emc2305_set_single_tz(dev, i + 1);
if (ret)
goto thermal_cooling_device_register_fail;
}
return 0;
thermal_cooling_device_register_fail:
emc2305_unset_tz(dev);
return ret;
}
static void emc2305_unset_tz(struct device *dev)
{
struct emc2305_data *data = dev_get_drvdata(dev);
int i;
/* Unregister cooling device. */
for (i = 0; i < EMC2305_PWM_MAX; i++)
if (data->cdev_data[i].cdev)
thermal_cooling_device_unregister(data->cdev_data[i].cdev);
}
static umode_t
emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)
{
int max_channel = emc2305_get_max_channel(data);
/* Don't show channels which are not physically connected. */
if (channel >= max_channel)
return 0;
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_input:
return 0444;
case hwmon_fan_fault:
return 0444;
default:
break;
}
break;
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
return 0644;
default:
break;
}
break;
default:
break;
}
return 0;
};
static int
emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val)
{
struct emc2305_data *data = dev_get_drvdata(dev);
int cdev_idx;
switch (type) {
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
/* If thermal is configured - handle PWM limit setting. */
if (IS_REACHABLE(CONFIG_THERMAL)) {
if (data->pwm_separate)
cdev_idx = channel;
else
cdev_idx = 0;
data->cdev_data[cdev_idx].last_hwmon_state =
EMC2305_PWM_DUTY2STATE(val, data->max_state,
EMC2305_FAN_MAX);
/*
* Update PWM only in case requested state is not less than the
* last thermal state.
*/
if (data->cdev_data[cdev_idx].last_hwmon_state >=
data->cdev_data[cdev_idx].last_thermal_state)
return __emc2305_set_cur_state(data, cdev_idx,
data->cdev_data[cdev_idx].last_hwmon_state);
return 0;
}
return emc2305_set_pwm(dev, val, channel);
default:
break;
}
break;
default:
break;
}
return -EOPNOTSUPP;
};
static int
emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val)
{
int ret;
switch (type) {
case hwmon_fan:
switch (attr) {
case hwmon_fan_input:
ret = emc2305_show_fan(dev, channel);
if (ret < 0)
return ret;
*val = ret;
return 0;
case hwmon_fan_fault:
ret = emc2305_show_fault(dev, channel);
if (ret < 0)
return ret;
*val = ret;
return 0;
default:
break;
}
break;
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
ret = emc2305_show_pwm(dev, channel);
if (ret < 0)
return ret;
*val = ret;
return 0;
default:
break;
}
break;
default:
break;
}
return -EOPNOTSUPP;
};
static const struct hwmon_ops emc2305_ops = {
.is_visible = emc2305_is_visible,
.read = emc2305_read,
.write = emc2305_write,
};
static const struct hwmon_channel_info * const emc2305_info[] = {
HWMON_CHANNEL_INFO(fan,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT),
HWMON_CHANNEL_INFO(pwm,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT,
HWMON_PWM_INPUT),
NULL
};
static const struct hwmon_chip_info emc2305_chip_info = {
.ops = &emc2305_ops,
.info = emc2305_info,
};
static int emc2305_identify(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct emc2305_data *data = i2c_get_clientdata(client);
int ret;
ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID);
if (ret < 0)
return ret;
switch (ret) {
case EMC2305:
data->pwm_num = 5;
break;
case EMC2303:
data->pwm_num = 3;
break;
case EMC2302:
data->pwm_num = 2;
break;
case EMC2301:
data->pwm_num = 1;
break;
default:
return -ENODEV;
}
return 0;
}
static int emc2305_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct device *dev = &client->dev;
struct emc2305_data *data;
struct emc2305_platform_data *pdata;
int vendor;
int ret;
int i;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR);
if (vendor != EMC2305_VENDOR)
return -ENODEV;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
data->client = client;
ret = emc2305_identify(dev);
if (ret)
return ret;
pdata = dev_get_platdata(&client->dev);
if (pdata) {
if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)
return -EINVAL;
data->max_state = pdata->max_state;
/*
* Validate a number of active PWM channels. Note that
* configured number can be less than the actual maximum
* supported by the device.
*/
if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)
return -EINVAL;
data->pwm_num = pdata->pwm_num;
data->pwm_separate = pdata->pwm_separate;
for (i = 0; i < EMC2305_PWM_MAX; i++)
data->pwm_min[i] = pdata->pwm_min[i];
} else {
data->max_state = EMC2305_FAN_MAX_STATE;
data->pwm_separate = false;
for (i = 0; i < EMC2305_PWM_MAX; i++)
data->pwm_min[i] = EMC2305_FAN_MIN;
}
data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data,
&emc2305_chip_info, NULL);
if (IS_ERR(data->hwmon_dev))
return PTR_ERR(data->hwmon_dev);
if (IS_REACHABLE(CONFIG_THERMAL)) {
ret = emc2305_set_tz(dev);
if (ret != 0)
return ret;
}
for (i = 0; i < data->pwm_num; i++) {
ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i),
data->pwm_min[i]);
if (ret < 0)
return ret;
}
return 0;
}
static void emc2305_remove(struct i2c_client *client)
{
struct device *dev = &client->dev;
if (IS_REACHABLE(CONFIG_THERMAL))
emc2305_unset_tz(dev);
}
static struct i2c_driver emc2305_driver = {
.driver = {
.name = "emc2305",
},
.probe = emc2305_probe,
.remove = emc2305_remove,
.id_table = emc2305_ids,
};
module_i2c_driver(emc2305_driver);
MODULE_AUTHOR("Nvidia");
MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver");
MODULE_LICENSE("GPL");
Codebase Browser
linux