diff --git a/Documentation/hwmon/mlxreg-fan b/Documentation/hwmon/mlxreg-fan
new file mode 100644
index 0000000000000000000000000000000000000000..fc531c6978d455d9c42b3e6da08ddf608a47202e
--- /dev/null
+++ b/Documentation/hwmon/mlxreg-fan
@@ -0,0 +1,60 @@
+Kernel driver mlxreg-fan
+========================
+
+Provides FAN control for the next Mellanox systems:
+QMB700, equipped with 40x200GbE InfiniBand ports;
+MSN3700, equipped with 32x200GbE or 16x400GbE Ethernet ports;
+MSN3410, equipped with 6x400GbE plus 48x50GbE Ethernet ports;
+MSN3800, equipped with 64x1000GbE Ethernet ports;
+These are the Top of the Rack systems, equipped with Mellanox switch
+board with Mellanox Quantum or Spectrume-2 devices.
+FAN controller is implemented by the programmable device logic.
+
+The default registers offsets set within the programmable device is as
+following:
+- pwm1 0xe3
+- fan1 (tacho1) 0xe4
+- fan2 (tacho2) 0xe5
+- fan3 (tacho3) 0xe6
+- fan4 (tacho4) 0xe7
+- fan5 (tacho5) 0xe8
+- fan6 (tacho6) 0xe9
+- fan7 (tacho7) 0xea
+- fan8 (tacho8) 0xeb
+- fan9 (tacho9) 0xec
+- fan10 (tacho10) 0xed
+- fan11 (tacho11) 0xee
+- fan12 (tacho12) 0xef
+This setup can be re-programmed with other registers.
+
+Author: Vadim Pasternak <vadimp@mellanox.com>
+
+Description
+-----------
+
+The driver implements a simple interface for driving a fan connected to
+a PWM output and tachometer inputs.
+This driver obtains PWM and tachometers registers location according to
+the system configuration and creates FAN/PWM hwmon objects and a cooling
+device. PWM and tachometers are sensed through the on-board programmable
+device, which exports its register map. This device could be attached to
+any bus type, for which register mapping is supported.
+Single instance is created with one PWM control, up to 12 tachometers and
+one cooling device. It could be as many instances as programmable device
+supports.
+The driver exposes the fan to the user space through the hwmon's and
+thermal's sysfs interfaces.
+
+/sys files in hwmon subsystem
+-----------------------------
+
+fan[1-12]_fault - RO files for tachometers TACH1-TACH12 fault indication
+fan[1-12]_input - RO files for tachometers TACH1-TACH12 input (in RPM)
+pwm1 - RW file for fan[1-12] target duty cycle (0..255)
+
+/sys files in thermal subsystem
+-------------------------------
+
+cur_state - RW file for current cooling state of the cooling device
+ (0..max_state)
+max_state - RO file for maximum cooling state of the cooling device
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index f10840ad465c2bc468f0457bcaa8ec8bbf1c7d0f..fd7fb6c041c2def2779b0c8d1bbf0da12e300e31 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -937,6 +937,18 @@ config SENSORS_MCP3021
This driver can also be built as a module. If so, the module
will be called mcp3021.
+config SENSORS_MLXREG_FAN
+ tristate "Mellanox Mellanox FAN driver"
+ depends on MELLANOX_PLATFORM
+ imply THERMAL
+ select REGMAP
+ help
+ This option enables support for the FAN control on the Mellanox
+ Ethernet and InfiniBand switches. The driver can be activated by the
+ platform device add call. Say Y to enable these. To compile this
+ driver as a module, choose 'M' here: the module will be called
+ mlxreg-fan.
+
config SENSORS_TC654
tristate "Microchip TC654/TC655 and compatibles"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e7d52a36e6c4f1dcea766a35d8ffa2bee1d7ae8e..cac3c06d28328f6ee4529556e9b0c7dca489f8b4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -129,6 +129,7 @@ obj-$(CONFIG_SENSORS_MAX31790) += max31790.o
obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
obj-$(CONFIG_SENSORS_MCP3021) += mcp3021.o
obj-$(CONFIG_SENSORS_TC654) += tc654.o
+obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
obj-$(CONFIG_SENSORS_NCT6683) += nct6683.o
obj-$(CONFIG_SENSORS_NCT6775) += nct6775.o
diff --git a/drivers/hwmon/mlxreg-fan.c b/drivers/hwmon/mlxreg-fan.c
new file mode 100644
index 0000000000000000000000000000000000000000..de46577c7d5a1711447f0f249604635260c8f958
--- /dev/null
+++ b/drivers/hwmon/mlxreg-fan.c
@@ -0,0 +1,489 @@
+// 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 12
+#define MLXREG_FAN_MAX_STATE 10
+#define MLXREG_FAN_MIN_DUTY 51 /* 20% */
+#define MLXREG_FAN_MAX_DUTY 255 /* 100% */
+/*
+ * Minimum and maximum FAN allowed speed in percent: from 20% to 100%. Values
+ * MLXREG_FAN_MAX_STATE + x, where x is between 2 and 10 are used for
+ * setting FAN speed dynamic minimum. For example, if value is set to 14 (40%)
+ * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to
+ * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100.
+ */
+#define MLXREG_FAN_SPEED_MIN (MLXREG_FAN_MAX_STATE + 2)
+#define MLXREG_FAN_SPEED_MAX (MLXREG_FAN_MAX_STATE * 2)
+#define MLXREG_FAN_SPEED_MIN_LEVEL 2 /* 20 percent */
+#define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF 44
+#define MLXREG_FAN_TACHO_DIVIDER_DEF 1132
+/*
+ * 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_tacho - tachometer data (internal use):
+ *
+ * @connected: indicates if tachometer is connected;
+ * @reg: register offset;
+ * @mask: fault mask;
+ */
+struct mlxreg_fan_tacho {
+ bool connected;
+ u32 reg;
+ u32 mask;
+};
+
+/*
+ * struct mlxreg_fan_pwm - PWM data (internal use):
+ *
+ * @connected: indicates if PWM is connected;
+ * @reg: register offset;
+ */
+struct mlxreg_fan_pwm {
+ bool connected;
+ u32 reg;
+};
+
+/*
+ * struct mlxreg_fan - private data (internal use):
+ *
+ * @dev: basic device;
+ * @regmap: register map of parent device;
+ * @tacho: tachometer data;
+ * @pwm: PWM data;
+ * @samples: minimum allowed samples per pulse;
+ * @divider: divider value for tachometer RPM calculation;
+ * @cooling: cooling device levels;
+ * @cdev: cooling device;
+ */
+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;
+ int samples;
+ int divider;
+ u8 cooling_levels[MLXREG_FAN_MAX_STATE + 1];
+ struct thermal_cooling_device *cdev;
+};
+
+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;
+ u32 regval;
+ int err;
+
+ switch (type) {
+ case hwmon_fan:
+ tacho = &fan->tacho[channel];
+ switch (attr) {
+ case hwmon_fan_input:
+ err = regmap_read(fan->regmap, tacho->reg, ®val);
+ if (err)
+ return err;
+
+ *val = MLXREG_FAN_GET_RPM(regval, fan->divider,
+ fan->samples);
+ break;
+
+ case hwmon_fan_fault:
+ err = regmap_read(fan->regmap, tacho->reg, ®val);
+ if (err)
+ return err;
+
+ *val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
+ break;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+ break;
+
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ err = regmap_read(fan->regmap, fan->pwm.reg, ®val);
+ 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);
+
+ switch (type) {
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ if (val < MLXREG_FAN_MIN_DUTY ||
+ val > MLXREG_FAN_MAX_DUTY)
+ return -EINVAL;
+ return regmap_write(fan->regmap, fan->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.connected))
+ return 0;
+
+ switch (attr) {
+ case hwmon_pwm_input:
+ return 0644;
+ default:
+ break;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static const u32 mlxreg_fan_hwmon_fan_config[] = {
+ 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,
+ 0
+};
+
+static const struct hwmon_channel_info mlxreg_fan_hwmon_fan = {
+ .type = hwmon_fan,
+ .config = mlxreg_fan_hwmon_fan_config,
+};
+
+static const u32 mlxreg_fan_hwmon_pwm_config[] = {
+ HWMON_PWM_INPUT,
+ 0
+};
+
+static const struct hwmon_channel_info mlxreg_fan_hwmon_pwm = {
+ .type = hwmon_pwm,
+ .config = mlxreg_fan_hwmon_pwm_config,
+};
+
+static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
+ &mlxreg_fan_hwmon_fan,
+ &mlxreg_fan_hwmon_pwm,
+ 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 *fan = cdev->devdata;
+ u32 regval;
+ int err;
+
+ err = regmap_read(fan->regmap, fan->pwm.reg, ®val);
+ 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 *fan = cdev->devdata;
+ unsigned long cur_state;
+ u32 regval;
+ int i;
+ int err;
+
+ /*
+ * Verify if this request is for changing allowed FAN dynamical
+ * minimum. If it is - update cooling levels accordingly and update
+ * state, if current state is below the newly requested minimum state.
+ * For example, if current state is 5, and minimal state is to be
+ * changed from 4 to 6, fan->cooling_levels[0 to 5] will be changed all
+ * from 4 to 6. And state 5 (fan->cooling_levels[4]) should be
+ * overwritten.
+ */
+ if (state >= MLXREG_FAN_SPEED_MIN && state <= MLXREG_FAN_SPEED_MAX) {
+ state -= MLXREG_FAN_MAX_STATE;
+ for (i = 0; i < state; i++)
+ fan->cooling_levels[i] = state;
+ for (i = state; i <= MLXREG_FAN_MAX_STATE; i++)
+ fan->cooling_levels[i] = i;
+
+ err = regmap_read(fan->regmap, fan->pwm.reg, ®val);
+ if (err) {
+ dev_err(fan->dev, "Failed to query PWM duty\n");
+ return err;
+ }
+
+ cur_state = MLXREG_FAN_PWM_DUTY2STATE(regval);
+ if (state < cur_state)
+ return 0;
+
+ state = cur_state;
+ }
+
+ if (state > MLXREG_FAN_MAX_STATE)
+ return -EINVAL;
+
+ /* Normalize the state to the valid speed range. */
+ state = fan->cooling_levels[state];
+ err = regmap_write(fan->regmap, fan->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_config(struct mlxreg_fan *fan,
+ struct mlxreg_core_platform_data *pdata)
+{
+ struct mlxreg_core_data *data = pdata->data;
+ bool configured = false;
+ int tacho_num = 0, i;
+
+ fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
+ fan->divider = MLXREG_FAN_TACHO_DIVIDER_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;
+ }
+ fan->tacho[tacho_num].reg = data->reg;
+ fan->tacho[tacho_num].mask = data->mask;
+ fan->tacho[tacho_num++].connected = true;
+ } else if (strnstr(data->label, "pwm", sizeof(data->label))) {
+ if (fan->pwm.connected) {
+ dev_err(fan->dev, "duplicate pwm entry: %s\n",
+ data->label);
+ return -EINVAL;
+ }
+ fan->pwm.reg = data->reg;
+ fan->pwm.connected = true;
+ } 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) {
+ dev_err(fan->dev, "invalid conf entry params: %s\n",
+ data->label);
+ return -EINVAL;
+ }
+ fan->samples = data->mask;
+ fan->divider = data->bit;
+ configured = true;
+ } else {
+ dev_err(fan->dev, "invalid label: %s\n", data->label);
+ return -EINVAL;
+ }
+ }
+
+ /* Init cooling levels per PWM state. */
+ for (i = 0; i < MLXREG_FAN_SPEED_MIN_LEVEL; i++)
+ fan->cooling_levels[i] = MLXREG_FAN_SPEED_MIN_LEVEL;
+ for (i = MLXREG_FAN_SPEED_MIN_LEVEL; i <= MLXREG_FAN_MAX_STATE; i++)
+ fan->cooling_levels[i] = i;
+
+ return 0;
+}
+
+static int mlxreg_fan_probe(struct platform_device *pdev)
+{
+ struct mlxreg_core_platform_data *pdata;
+ struct mlxreg_fan *fan;
+ struct device *hwm;
+ int err;
+
+ pdata = dev_get_platdata(&pdev->dev);
+ if (!pdata) {
+ dev_err(&pdev->dev, "Failed to get platform data.\n");
+ return -EINVAL;
+ }
+
+ fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
+ if (!fan)
+ return -ENOMEM;
+
+ fan->dev = &pdev->dev;
+ fan->regmap = pdata->regmap;
+ platform_set_drvdata(pdev, fan);
+
+ err = mlxreg_fan_config(fan, pdata);
+ if (err)
+ return err;
+
+ hwm = devm_hwmon_device_register_with_info(&pdev->dev, "mlxreg_fan",
+ fan,
+ &mlxreg_fan_hwmon_chip_info,
+ NULL);
+ if (IS_ERR(hwm)) {
+ dev_err(&pdev->dev, "Failed to register hwmon device\n");
+ return PTR_ERR(hwm);
+ }
+
+ if (IS_REACHABLE(CONFIG_THERMAL)) {
+ fan->cdev = thermal_cooling_device_register("mlxreg_fan", fan,
+ &mlxreg_fan_cooling_ops);
+ if (IS_ERR(fan->cdev)) {
+ dev_err(&pdev->dev, "Failed to register cooling device\n");
+ return PTR_ERR(fan->cdev);
+ }
+ }
+
+ return 0;
+}
+
+static int mlxreg_fan_remove(struct platform_device *pdev)
+{
+ struct mlxreg_fan *fan = platform_get_drvdata(pdev);
+
+ if (IS_REACHABLE(CONFIG_THERMAL))
+ thermal_cooling_device_unregister(fan->cdev);
+
+ return 0;
+}
+
+static struct platform_driver mlxreg_fan_driver = {
+ .driver = {
+ .name = "mlxreg-fan",
+ },
+ .probe = mlxreg_fan_probe,
+ .remove = mlxreg_fan_remove,
+};
+
+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");