Re: [PATCH 7/7] hwmon: (max31790) Add support for fanX_min attributes

Václav Kubernát
2021-06-01T08:20:10Z

fanX_min works fine.

Tested-by: Václav Kubernát <kubernat@cesnet.cz>

st 26. 5. 2021 v 17:41 odesílatel Guenter Roeck <linux@roeck-us.net> napsal:
>
> The minimum fan speed is closely correlated to the target fan speed.
> The correlation depends on the pwm mode. It is essential to be able
> to read and to set it to be able to control when a channel will report
> a fan fault.
>
> Since the minimum fan speed also applies to channels 7..12, make it
> visible but read-only for those channels as well.
>
> Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
> Cc: Václav Kubernát <kubernat@cesnet.cz>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Documentation/hwmon/max31790.rst | 9 ++++
> drivers/hwmon/max31790.c | 70 ++++++++++++++++++++++++--------
> 2 files changed, 61 insertions(+), 18 deletions(-)
>
> diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst
> index b43aa32813fd..9225c2a78b68 100644
> --- a/Documentation/hwmon/max31790.rst
> +++ b/Documentation/hwmon/max31790.rst
> @@ -40,6 +40,15 @@ fan[1-12]_enable RW 0=disable fan speed monitoring, 1=enable fan speed monito
> channels, the value matches the value of the primary channel.
> fan[1-12]_input RO fan tachometer speed in RPM
> fan[1-12]_fault RO fan experienced fault
> +fan[1-12]_min RW minimum fan speed in RPM. Equivalent to target fan speed
> + in PWM mode and if PWM support is disabled for a channel.
> + Equivalent to half the target fan speed in RPM mode.
> + The value is RO for companion channels (7-12). For those
> + channels, the value matches the value of the primary channel.
> + Note: In RPM mode, if the pwm duty cycle is 100%, the
> + minimum fan speed is equivalent to the target fan speed,
> + and the chip will report a fault condition if the fan
> + speed is below the target fan speed.
> fan[1-6]_target RW desired fan speed in RPM
> 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,
> diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
> index 91fe419b596c..db97ee99515a 100644
> --- a/drivers/hwmon/max31790.c
> +++ b/drivers/hwmon/max31790.c
> @@ -111,13 +111,11 @@ static struct max31790_data *max31790_update_device(struct device *dev)
> if (rv < 0)
> goto abort;
> data->pwm[i] = rv;
> -
> - rv = i2c_smbus_read_word_swapped(client,
> - MAX31790_REG_TARGET_COUNT(i));
> - if (rv < 0)
> - goto abort;
> - data->target_count[i] = rv;
> }
> + rv = i2c_smbus_read_word_swapped(client, MAX31790_REG_TARGET_COUNT(i));
> + if (rv < 0)
> + goto abort;
> + data->target_count[i] = rv;
> }
>
> data->last_updated = jiffies;
> @@ -183,6 +181,21 @@ static int max31790_read_fan(struct device *dev, u32 attr, int channel,
> rpm = RPM_FROM_REG(data->tach[channel], sr);
> *val = rpm;
> return 0;
> + case hwmon_fan_min:
> + channel %= NR_CHANNEL;
> + sr = get_tach_period(data->fan_dynamics[channel]);
> + if (!(data->fan_config[channel] & MAX31790_FAN_CFG_RPM_MODE) ||
> + (data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT)) {
> + /* pwm mode: target == min */
> + rpm = RPM_FROM_REG(data->target_count[channel], sr);
> + } else {
> + /* rpm mode: min tach count is twice target count */
> + u16 tach = min(data->target_count[channel] * 2, FAN_COUNT_REG_MAX);
> +
> + rpm = RPM_FROM_REG(tach, sr);
> + }
> + *val = rpm;
> + return 0;
> case hwmon_fan_target:
> sr = get_tach_period(data->fan_dynamics[channel]);
> rpm = RPM_FROM_REG(data->target_count[channel], sr);
> @@ -243,6 +256,20 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
> data->fan_config[channel] = config;
> }
> break;
> + case hwmon_fan_min:
> + /*
> + * The minimum fan speed is the same as the target fan speed in
> + * PWM mode and if a PWM channel is disabled, or it is half the
> + * target fan speed in RPM mode.
> + */
> + if (!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT) &&
> + (data->fan_config[channel] & MAX31790_FAN_CFG_RPM_MODE)) {
> + /* partial clamp to avoid overflow */
> + if (val > FAN_RPM_MAX / 2)
> + val = FAN_RPM_MAX / 2;
> + val *= 2;
> + }
> + fallthrough;
> case hwmon_fan_target:
> val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
> bits = bits_for_tach_period(val);
> @@ -282,6 +309,7 @@ static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
> u8 fan_config = data->fan_config[channel % NR_CHANNEL];
>
> switch (attr) {
> + case hwmon_fan_min:
> case hwmon_fan_enable:
> if (channel < NR_CHANNEL)
> return 0644;
> @@ -452,18 +480,24 @@ static umode_t max31790_is_visible(const void *data,
>
> static const struct hwmon_channel_info *max31790_info[] = {
> HWMON_CHANNEL_INFO(fan,
> - 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_TARGET | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT,
> - HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_FAULT),
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_TARGET |
> + HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT,
> + HWMON_F_ENABLE | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_FAULT),
> HWMON_CHANNEL_INFO(pwm,
> HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
> HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
> --
> 2.25.1
>