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linux/drivers/hwmon/mlxreg-fan.c
Vadim Pasternak dadca53dd9 hwmon: (mlxreg-fan) Extend number of supported fans 
Some new big modular systems can be equipped with up to 24 fans.
Extend maximum number of fans accordingly.

Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20230824164006.26868-1-vadimp@nvidia.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-08-25 07:43:04 -07:00

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// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
//
// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
// Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/platform_data/mlxreg.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/thermal.h>
#define MLXREG_FAN_MAX_TACHO 24
#define MLXREG_FAN_MAX_PWM 4
#define MLXREG_FAN_PWM_NOT_CONNECTED 0xff
#define MLXREG_FAN_MAX_STATE 10
#define MLXREG_FAN_MIN_DUTY 51 /* 20% */
#define MLXREG_FAN_MAX_DUTY 255 /* 100% */
#define MLXREG_FAN_SPEED_MIN_LEVEL 2 /* 20 percent */
#define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF 44
#define MLXREG_FAN_TACHO_DIV_MIN 283
#define MLXREG_FAN_TACHO_DIV_DEF (MLXREG_FAN_TACHO_DIV_MIN * 4)
#define MLXREG_FAN_TACHO_DIV_SCALE_MAX 64
/*
* FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.
* The logic in a programmable device measures the time t-high by sampling the
* tachometer every t-sample (with the default value 11.32 uS) and increment
* a counter (N) as long as the pulse has not change:
* RPM = 15 / (t-sample * (K + Regval)), where:
* Regval: is the value read from the programmable device register;
* - 0xff - represents tachometer fault;
* - 0xfe - represents tachometer minimum value , which is 4444 RPM;
* - 0x00 - represents tachometer maximum value , which is 300000 RPM;
* K: is 44 and it represents the minimum allowed samples per pulse;
* N: is equal K + Regval;
* In order to calculate RPM from the register value the following formula is
* used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in the
* default case is modified to:
* RPM = 15000000 * 100 / ((Regval + 44) * 1132);
* - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;
* - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;
* In common case the formula is modified to:
* RPM = 15000000 * 100 / ((Regval + samples) * divider).
*/
#define MLXREG_FAN_GET_RPM(rval, d, s) (DIV_ROUND_CLOSEST(15000000 * 100, \
((rval) + (s)) * (d)))
#define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))
#define MLXREG_FAN_PWM_DUTY2STATE(duty) (DIV_ROUND_CLOSEST((duty) * \
MLXREG_FAN_MAX_STATE, \
MLXREG_FAN_MAX_DUTY))
#define MLXREG_FAN_PWM_STATE2DUTY(stat) (DIV_ROUND_CLOSEST((stat) * \
MLXREG_FAN_MAX_DUTY, \
MLXREG_FAN_MAX_STATE))
struct mlxreg_fan;
/*
* struct mlxreg_fan_tacho - tachometer data (internal use):
*
* @connected: indicates if tachometer is connected;
* @reg: register offset;
* @mask: fault mask;
* @prsnt: present register offset;
*/
struct mlxreg_fan_tacho {
bool connected;
u32 reg;
u32 mask;
u32 prsnt;
};
/*
* struct mlxreg_fan_pwm - PWM data (internal use):
*
* @fan: private data;
* @connected: indicates if PWM is connected;
* @reg: register offset;
* @cooling: cooling device levels;
* @last_hwmon_state: last cooling state set by hwmon subsystem;
* @last_thermal_state: last cooling state set by thermal subsystem;
* @cdev: cooling device;
*/
struct mlxreg_fan_pwm {
struct mlxreg_fan *fan;
bool connected;
u32 reg;
unsigned long last_hwmon_state;
unsigned long last_thermal_state;
struct thermal_cooling_device *cdev;
};
/*
* struct mlxreg_fan - private data (internal use):
*
* @dev: basic device;
* @regmap: register map of parent device;
* @tacho: tachometer data;
* @pwm: PWM data;
* @tachos_per_drwr - number of tachometers per drawer;
* @samples: minimum allowed samples per pulse;
* @divider: divider value for tachometer RPM calculation;
*/
struct mlxreg_fan {
struct device *dev;
void *regmap;
struct mlxreg_core_platform_data *pdata;
struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
struct mlxreg_fan_pwm pwm[MLXREG_FAN_MAX_PWM];
int tachos_per_drwr;
int samples;
int divider;
};
static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state);
static int
mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long *val)
{
struct mlxreg_fan *fan = dev_get_drvdata(dev);
struct mlxreg_fan_tacho *tacho;
struct mlxreg_fan_pwm *pwm;
u32 regval;
int err;
switch (type) {
case hwmon_fan:
tacho = &fan->tacho[channel];
switch (attr) {
case hwmon_fan_input:
/*
* Check FAN presence: FAN related bit in presence register is one,
* if FAN is physically connected, zero - otherwise.
*/
if (tacho->prsnt && fan->tachos_per_drwr) {
err = regmap_read(fan->regmap, tacho->prsnt, &regval);
if (err)
return err;
/*
* Map channel to presence bit - drawer can be equipped with
* one or few FANs, while presence is indicated per drawer.
*/
if (BIT(channel / fan->tachos_per_drwr) & regval) {
/* FAN is not connected - return zero for FAN speed. */
*val = 0;
return 0;
}
}
err = regmap_read(fan->regmap, tacho->reg, &regval);
if (err)
return err;
if (MLXREG_FAN_GET_FAULT(regval, tacho->mask)) {
/* FAN is broken - return zero for FAN speed. */
*val = 0;
return 0;
}
*val = MLXREG_FAN_GET_RPM(regval, fan->divider,
fan->samples);
break;
case hwmon_fan_fault:
err = regmap_read(fan->regmap, tacho->reg, &regval);
if (err)
return err;
*val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
break;
default:
return -EOPNOTSUPP;
}
break;
case hwmon_pwm:
pwm = &fan->pwm[channel];
switch (attr) {
case hwmon_pwm_input:
err = regmap_read(fan->regmap, pwm->reg, &regval);
if (err)
return err;
*val = regval;
break;
default:
return -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int
mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long val)
{
struct mlxreg_fan *fan = dev_get_drvdata(dev);
struct mlxreg_fan_pwm *pwm;
switch (type) {
case hwmon_pwm:
switch (attr) {
case hwmon_pwm_input:
if (val < MLXREG_FAN_MIN_DUTY ||
val > MLXREG_FAN_MAX_DUTY)
return -EINVAL;
pwm = &fan->pwm[channel];
/* If thermal is configured - handle PWM limit setting. */
if (IS_REACHABLE(CONFIG_THERMAL)) {
pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(val);
/*
* Update PWM only in case requested state is not less than the
* last thermal state.
*/
if (pwm->last_hwmon_state >= pwm->last_thermal_state)
return mlxreg_fan_set_cur_state(pwm->cdev,
pwm->last_hwmon_state);
return 0;
}
return regmap_write(fan->regmap, pwm->reg, val);
default:
return -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
return -EOPNOTSUPP;
}
static umode_t
mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
int channel)
{
switch (type) {
case hwmon_fan:
if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
return 0;
switch (attr) {
case hwmon_fan_input:
case hwmon_fan_fault:
return 0444;
default:
break;
}
break;
case hwmon_pwm:
if (!(((struct mlxreg_fan *)data)->pwm[channel].connected))
return 0;
switch (attr) {
case hwmon_pwm_input:
return 0644;
default:
break;
}
break;
default:
break;
}
return 0;
}
static char *mlxreg_fan_name[] = {
"mlxreg_fan",
"mlxreg_fan1",
"mlxreg_fan2",
"mlxreg_fan3",
};
static const struct hwmon_channel_info * const mlxreg_fan_hwmon_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_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_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_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_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),
NULL
};
static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
.is_visible = mlxreg_fan_is_visible,
.read = mlxreg_fan_read,
.write = mlxreg_fan_write,
};
static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
.ops = &mlxreg_fan_hwmon_hwmon_ops,
.info = mlxreg_fan_hwmon_info,
};
static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
*state = MLXREG_FAN_MAX_STATE;
return 0;
}
static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct mlxreg_fan_pwm *pwm = cdev->devdata;
struct mlxreg_fan *fan = pwm->fan;
u32 regval;
int err;
err = regmap_read(fan->regmap, pwm->reg, &regval);
if (err) {
dev_err(fan->dev, "Failed to query PWM duty\n");
return err;
}
*state = MLXREG_FAN_PWM_DUTY2STATE(regval);
return 0;
}
static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct mlxreg_fan_pwm *pwm = cdev->devdata;
struct mlxreg_fan *fan = pwm->fan;
int err;
if (state > MLXREG_FAN_MAX_STATE)
return -EINVAL;
/* Save thermal state. */
pwm->last_thermal_state = state;
state = max_t(unsigned long, state, pwm->last_hwmon_state);
err = regmap_write(fan->regmap, pwm->reg,
MLXREG_FAN_PWM_STATE2DUTY(state));
if (err) {
dev_err(fan->dev, "Failed to write PWM duty\n");
return err;
}
return 0;
}
static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
.get_max_state = mlxreg_fan_get_max_state,
.get_cur_state = mlxreg_fan_get_cur_state,
.set_cur_state = mlxreg_fan_set_cur_state,
};
static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
struct mlxreg_core_data *data)
{
u32 regval;
int err;
err = regmap_read(fan->regmap, data->capability, &regval);
if (err) {
dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
data->capability);
return err;
}
return !!(regval & data->bit);
}
static int mlxreg_pwm_connect_verify(struct mlxreg_fan *fan,
struct mlxreg_core_data *data)
{
u32 regval;
int err;
err = regmap_read(fan->regmap, data->reg, &regval);
if (err) {
dev_err(fan->dev, "Failed to query pwm register 0x%08x\n",
data->reg);
return err;
}
return regval != MLXREG_FAN_PWM_NOT_CONNECTED;
}
static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
struct mlxreg_core_data *data)
{
u32 regval;
int err;
err = regmap_read(fan->regmap, data->capability, &regval);
if (err) {
dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
data->capability);
return err;
}
/*
* Set divider value according to the capability register, in case it
* contains valid value. Otherwise use default value. The purpose of
* this validation is to protect against the old hardware, in which
* this register can return zero.
*/
if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
return 0;
}
static int mlxreg_fan_config(struct mlxreg_fan *fan,
struct mlxreg_core_platform_data *pdata)
{
int tacho_num = 0, tacho_avail = 0, pwm_num = 0, i;
struct mlxreg_core_data *data = pdata->data;
bool configured = false;
int err;
fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
for (i = 0; i < pdata->counter; i++, data++) {
if (strnstr(data->label, "tacho", sizeof(data->label))) {
if (tacho_num == MLXREG_FAN_MAX_TACHO) {
dev_err(fan->dev, "too many tacho entries: %s\n",
data->label);
return -EINVAL;
}
if (data->capability) {
err = mlxreg_fan_connect_verify(fan, data);
if (err < 0)
return err;
else if (!err) {
tacho_num++;
continue;
}
}
fan->tacho[tacho_num].reg = data->reg;
fan->tacho[tacho_num].mask = data->mask;
fan->tacho[tacho_num].prsnt = data->reg_prsnt;
fan->tacho[tacho_num++].connected = true;
tacho_avail++;
} else if (strnstr(data->label, "pwm", sizeof(data->label))) {
if (pwm_num == MLXREG_FAN_MAX_TACHO) {
dev_err(fan->dev, "too many pwm entries: %s\n",
data->label);
return -EINVAL;
}
/* Validate if more then one PWM is connected. */
if (pwm_num) {
err = mlxreg_pwm_connect_verify(fan, data);
if (err < 0)
return err;
else if (!err)
continue;
}
fan->pwm[pwm_num].reg = data->reg;
fan->pwm[pwm_num].connected = true;
pwm_num++;
} else if (strnstr(data->label, "conf", sizeof(data->label))) {
if (configured) {
dev_err(fan->dev, "duplicate conf entry: %s\n",
data->label);
return -EINVAL;
}
/* Validate that conf parameters are not zeros. */
if (!data->mask && !data->bit && !data->capability) {
dev_err(fan->dev, "invalid conf entry params: %s\n",
data->label);
return -EINVAL;
}
if (data->capability) {
err = mlxreg_fan_speed_divider_get(fan, data);
if (err)
return err;
} else {
if (data->mask)
fan->samples = data->mask;
if (data->bit)
fan->divider = data->bit;
}
configured = true;
} else {
dev_err(fan->dev, "invalid label: %s\n", data->label);
return -EINVAL;
}
}
if (pdata->capability) {
int drwr_avail;
u32 regval;
/* Obtain the number of FAN drawers, supported by system. */
err = regmap_read(fan->regmap, pdata->capability, &regval);
if (err) {
dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
pdata->capability);
return err;
}
drwr_avail = hweight32(regval);
if (!tacho_avail || !drwr_avail || tacho_avail < drwr_avail) {
dev_err(fan->dev, "Configuration is invalid: drawers num %d tachos num %d\n",
drwr_avail, tacho_avail);
return -EINVAL;
}
/* Set the number of tachometers per one drawer. */
fan->tachos_per_drwr = tacho_avail / drwr_avail;
}
return 0;
}
static int mlxreg_fan_cooling_config(struct device *dev, struct mlxreg_fan *fan)
{
int i;
for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {
struct mlxreg_fan_pwm *pwm = &fan->pwm[i];
if (!pwm->connected)
continue;
pwm->fan = fan;
pwm->cdev = devm_thermal_of_cooling_device_register(dev, NULL, mlxreg_fan_name[i],
pwm, &mlxreg_fan_cooling_ops);
if (IS_ERR(pwm->cdev)) {
dev_err(dev, "Failed to register cooling device\n");
return PTR_ERR(pwm->cdev);
}
/* Set minimal PWM speed. */
pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(MLXREG_FAN_MIN_DUTY);
}
return 0;
}
static int mlxreg_fan_probe(struct platform_device *pdev)
{
struct mlxreg_core_platform_data *pdata;
struct device *dev = &pdev->dev;
struct mlxreg_fan *fan;
struct device *hwm;
int err;
pdata = dev_get_platdata(dev);
if (!pdata) {
dev_err(dev, "Failed to get platform data.\n");
return -EINVAL;
}
fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
if (!fan)
return -ENOMEM;
fan->dev = dev;
fan->regmap = pdata->regmap;
err = mlxreg_fan_config(fan, pdata);
if (err)
return err;
hwm = devm_hwmon_device_register_with_info(dev, "mlxreg_fan",
fan,
&mlxreg_fan_hwmon_chip_info,
NULL);
if (IS_ERR(hwm)) {
dev_err(dev, "Failed to register hwmon device\n");
return PTR_ERR(hwm);
}
if (IS_REACHABLE(CONFIG_THERMAL))
err = mlxreg_fan_cooling_config(dev, fan);
return err;
}
static struct platform_driver mlxreg_fan_driver = {
.driver = {
.name = "mlxreg-fan",
},
.probe = mlxreg_fan_probe,
};
module_platform_driver(mlxreg_fan_driver);
MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
MODULE_DESCRIPTION("Mellanox FAN driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mlxreg-fan");
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