linux-kernel - Re: [PATCH] hwmon: (max6650) Add support for gpiodef

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 14 Nov 2013 20:26:23 +0000
From:	Laszlo Papp <lpapp@....org>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	hjk@...sjkoch.de, lm-sensors@...sensors.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon: (max6650) Add support for gpiodef

On Thu, Nov 14, 2013 at 7:00 PM, Guenter Roeck <linux@...ck-us.net> wrote:
> What are those pins used for ?

I would like to drive them dynamically like the rest of the features
exposed to the sysfs in a similar way.

For instance, one may need to output a logic-low level on the pin 0 to
get an operation working. One use case could be (and is) enabling or
disabling the fans dynamically based on the temperature, etc
condition. Imagine that if you have a 12 V fan with 5 V board power
supply, and such a pin would be useful to establish the bridge between
them with diodes.

This is just one use case of those, you could also use it for
non-generic gpio functionality, like alarm, "full-on", internal clock,
external clock, etc. I believe it is always a bit tricky with MFD. I
personally prefer to put it into the chip driver because this is not
clearly a generic gpio interface here, and I need to drive it
dynamically.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/