RE: [RFC PATCH 0/6] AXI FAN new features and improvements

-----Original Message-----
From: Guenter Roeck <redacted> On Behalf Of Guenter
Roeck
Sent: Wednesday, July 28, 2021 8:38 PM
To: Sa, Nuno <Nuno.Sa@analog.com>; linux-hwmon@vger.kernel.org;
devicetree@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>; Jean Delvare
[off-list ref]
Subject: Re: [RFC PATCH 0/6] AXI FAN new features and
improvements

[External]

Hi,

On 7/27/21 1:42 AM, Sa, Nuno wrote:

quoted

Hi Guenter,

quoted

From: Nuno Sá <nuno.sa@analog.com>
Sent: Thursday, July 8, 2021 2:01 PM
To: linux-hwmon@vger.kernel.org; devicetree@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>; Rob Herring
[off-list ref]; Jean Delvare [off-list ref]
Subject: [RFC PATCH 0/6] AXI FAN new features and improvements

This series adds some new features to the axi-fan-control driver.

On

quoted

quoted

top
of that, the HW had some changes (basically it now starts

automatically

quoted

quoted

out of reset) so that the driver needed some minor refactoring. The
reason I'm sending this as RFC, is mainly because of the last patch
("hwmon: axi-fan-control: support temperature vs pwm points").

The

quoted

quoted

core
has some predefined values which define a temperature vs pwm
curve [1].
It also exposes registers so that users can change it according to

their

quoted

quoted

needs. As I could not find standard attributes in the subsystem, I'm
proposing some "raw" sysfs files. Looking at [2], the

pwm_auto_point

quoted

quoted

stuff looked to be what I want. Obviously I might be wrong :). If this
is accepted, I will add a proper sysfs DOC file describing the new

files

quoted

quoted

(being lazy in the RFC).

For patch 5 ("hwmon: axi-fan-control: clear the fan fault irq at
startup"),
it's also arguable if we really need it. The main reason I have it is
because of some userland apps that might take some drastic

measures

quoted

quoted

by
just reading 1 fan_fault alarm. Obviously, we can argue that the
problem
is in the app and not in the driver. Though it's such a minimal change
that I decided to include it (I'm more than fine in dropping the

patch).

quoted

quoted

[1]: https://wiki.analog.com/resources/fpga/docs/axi_fan_control
[2]:

https://urldefense.com/v3/__https://www.kernel.org/doc/Documen

quoted

quoted

tation/hwmon/sysfs-

interface__;!!A3Ni8CS0y2Y!uwjpaOT8QEBVfKTCWELJNbjJJ69iR7S3tKS

quoted

quoted

WV4B0K742CtcARkTtAqMxknnpPw$

Nuno Sá (6):
   hwmon: axi-fan-control: make sure the clock is enabled
   hwmon: axi-fan-control: add tacho devicetree properties
   dt-bindings: axi-fan-control: add tacho properties
   hwmon: axi-fan-control: handle irqs in natural order
   hwmon: axi-fan-control: clear the fan fault irq at startup
   hwmon: axi-fan-control: support temperature vs pwm points

The HW guy is willing to change how the core works. This means,
that all that unstable pwm - rpm points will go away and we will
have a register where we can set the minimum fan speed for
evaluating the FAN. He also said that the default value for the
this setting will be pretty low so that we should only have _real_
faults at startup which means patch 5 should not be needed
anymore...

Anyways, I will send a new pull with patches 1,3 and 5 and

That kind of contradicts what you say above, that patch 5 won't be
needed anymore. Am I missing something ?

My bad... I meant patch 6 and not 5.

- Nuno Sá