Commit 5b38279e authored by Justin Ledford's avatar Justin Ledford Committed by Guenter Roeck
Browse files

hwmon: (max31790) add fanN_enable 



The MAX31790 has a tach input enable bit in each fan's configuration
register. This is only enabled by the driver if RPM mode is selected,
but the driver doesn't provide a way to independently enable tachometer
input regardless of the regulator mode.

By adding the fanN_enable sysfs files, we can decouple the tach input
from the regulator mode. Also update the documentation.

Signed-off-by: default avatarJustin Ledford <justinledford@google.com>
Link: https://lore.kernel.org/r/20220829195930.2521755-1-justinledford@google.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent b5ae0ad5

Documentation/hwmon/max31790.rst

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ Sysfs entries 
fan[1-12]_input    RO  fan tachometer speed in RPM

fan[1-12]_fault    RO  fan experienced fault

fan[1-6]_target    RW  desired fan speed in RPM

fan[1-6]_enable    RW  enable or disable the tachometer input

pwm[1-6]_enable    RW  regulator mode, 0=disabled (duty cycle=0%), 1=manual mode, 2=rpm mode

pwm[1-6]           RW  read: current pwm duty cycle,

                       write: target pwm duty cycle (0-255)

drivers/hwmon/max31790.c

+31 −7
Original line number Diff line number Diff line
@@ -202,6 +202,9 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel, 
		}

		mutex_unlock(&data->update_lock);

		return 0;

	case hwmon_fan_enable:

		*val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);

		return 0;

	default:

		return -EOPNOTSUPP;

	}
@@ -214,7 +217,7 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel, 
	struct i2c_client *client = data->client;

	int target_count;

	int err = 0;

	u8 bits;

	u8 bits, fan_config;

	int sr;



	mutex_lock(&data->update_lock);
@@ -243,6 +246,23 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel, 
					MAX31790_REG_TARGET_COUNT(channel),

					data->target_count[channel]);

		break;

	case hwmon_fan_enable:

		fan_config = data->fan_config[channel];

		if (val == 0) {

			fan_config &= ~MAX31790_FAN_CFG_TACH_INPUT_EN;

		} else if (val == 1) {

			fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN;

		} else {

			err = -EINVAL;

			break;

		}

		if (fan_config != data->fan_config[channel]) {

			err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),

							fan_config);

			if (!err)

				data->fan_config[channel] = fan_config;

		}

		break;

	default:

		err = -EOPNOTSUPP;

		break;
@@ -270,6 +290,10 @@ static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel) 
		    !(fan_config & MAX31790_FAN_CFG_TACH_INPUT))

			return 0644;

		return 0;

	case hwmon_fan_enable:

		if (channel < NR_CHANNEL)

			return 0644;

		return 0;

	default:

		return 0;

	}
@@ -423,12 +447,12 @@ static umode_t max31790_is_visible(const void *data, 


static const struct hwmon_channel_info *max31790_info[] = {

	HWMON_CHANNEL_INFO(fan,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,

			   HWMON_F_INPUT | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_FAULT,

			   HWMON_F_INPUT | HWMON_F_FAULT,