On 5/17/22 07:26, Alexander Stein wrote:
This adds the enable attribute which is used to differentiate if PWM duty
means to switch off regulator and PWM or to keep them enabled but
at inactive PWM output level.
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
---
Documentation/hwmon/pwm-fan.rst | 10 ++++
drivers/hwmon/pwm-fan.c | 95 +++++++++++++++++++++++++++++----
2 files changed, 95 insertions(+), 10 deletions(-)
diff --git a/Documentation/hwmon/pwm-fan.rst b/Documentation/hwmon/pwm-fan.rst
index 82fe96742fee..0083480068d1 100644
--- a/Documentation/hwmon/pwm-fan.rst
+++ b/Documentation/hwmon/pwm-fan.rst
@@ -18,3 +18,13 @@ the hwmon's sysfs interface.
The fan rotation speed returned via the optional 'fan1_input' is extrapolated
from the sampled interrupts from the tachometer signal within 1 second.
+
+The driver provides the following sensor accesses in sysfs:
+
+=============== ======= =======================================================
+fan1_input ro fan tachometer speed in RPM
+pwm1_enable rw keep enable mode, defines behaviour when pwm1=0
+ 0=switch off regulator and disable PWM
+ 1=keep regulator enabled and set PWM to inactive level
Unless I am missing something, I think we have (at least) three
conditions to handle:
- regulator disabled (independent of pwm value)
- regulator enabled, pwm output disabled if pwm=0
- regulator enabled, pwm output enabled and set to 0 (or, if inverted,
to maximum) if pwm=0
plus possibly:
- regulator disabled, pwm output disabled if pwm=0
Guenter
