From: Guenter Roeck linux@roeck-us.net
[ Upstream commit 897f6339893b741a5d68ae8e2475df65946041c2 ]
The MAX31790 has two sets of registers for pwm duty cycles, one to request a duty cycle and one to read the actual current duty cycle. Both do not have to be the same.
When reporting the pwm duty cycle to the user, the actual pwm duty cycle from pwm duty cycle registers needs to be reported. When setting it, the pwm target duty cycle needs to be written. Since we don't know the actual pwm duty cycle after a target pwm duty cycle has been written, set the valid flag to false to indicate that actual pwm duty cycle should be read from the chip instead of using cached values.
Cc: Jan Kundrát jan.kundrat@cesnet.cz Cc: Václav Kubernát kubernat@cesnet.cz Signed-off-by: Guenter Roeck linux@roeck-us.net Tested-by: Václav Kubernát kubernat@ceesnet.cz Reviewed-by: Jan Kundrát jan.kundrat@cesnet.cz Link: https://lore.kernel.org/r/20210526154022.3223012-3-linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/hwmon/max31790.rst | 3 ++- drivers/hwmon/max31790.c | 6 +++--- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/Documentation/hwmon/max31790.rst b/Documentation/hwmon/max31790.rst index 84c62a12ef3a..9f12aac4fab5 100644 --- a/Documentation/hwmon/max31790.rst +++ b/Documentation/hwmon/max31790.rst @@ -39,5 +39,6 @@ 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 pwm[1-6]_enable RW regulator mode, 0=disabled, 1=manual mode, 2=rpm mode -pwm[1-6] RW fan target duty cycle (0-255) +pwm[1-6] RW read: current pwm duty cycle, + write: target pwm duty cycle (0-255) ================== === ======================================================= diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c index 117fb79ef294..344be7829d58 100644 --- a/drivers/hwmon/max31790.c +++ b/drivers/hwmon/max31790.c @@ -104,7 +104,7 @@ static struct max31790_data *max31790_update_device(struct device *dev) data->tach[NR_CHANNEL + i] = rv; } else { rv = i2c_smbus_read_word_swapped(client, - MAX31790_REG_PWMOUT(i)); + MAX31790_REG_PWM_DUTY_CYCLE(i)); if (rv < 0) goto abort; data->pwm[i] = rv; @@ -299,10 +299,10 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel, err = -EINVAL; break; } - data->pwm[channel] = val << 8; + data->valid = false; err = i2c_smbus_write_word_swapped(client, MAX31790_REG_PWMOUT(channel), - data->pwm[channel]); + val << 8); break; case hwmon_pwm_enable: fan_config = data->fan_config[channel];