linux-kernel - Re: gpio-sch GPIO

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

Message-ID: <5113C595.3070402@linux.intel.com>
Date:	Thu, 07 Feb 2013 07:17:41 -0800
From:	Darren Hart <dvhart@...ux.intel.com>
To:	Linus Walleij <linus.walleij@...aro.org>
CC:	"lkml," <linux-kernel@...r.kernel.org>,
	Grant Likely <grant.likely@...retlab.ca>,
	Denis Turischev <denis@...pulab.co.il>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: gpio-sch GPIO_SYSFS access

On 02/07/2013 02:09 AM, Linus Walleij wrote:
> On Thu, Feb 7, 2013 at 1:58 AM, Darren Hart <dvhart@...ux.intel.com> wrote:
> 
>> Is it that some other driver has claimed these GPIO lines? If so, how do
>> I determine which one?
> 
> Yes I think that could be it, the driver would need to call
> gpio_export() for it to also be accessible in sysfs.

Do you mean gpiochip_export()?

Hrm, neither gpio-pch nor gpio-sch call gpiochip_export() directly. They
both call gpiochip_add() and that calls gpiochip_export() unconditionally.
As far as I could tell, both drivers call gpiochip_export().

I thought maybe the sch happened to early, maybe hitting the the
pre-driver-model-support note in gpiochip_export(), but it runs after
the pch chip for some reason, and that one is fine. I suppose I could be
failing on device_create or sysfs_create_group and just not seeing the
output. I'll try to get DYNAMIC_DEBUG and pr_debug in gpiolib.c working
(that always seems to be an unnecessarily arduous exercise).

> 
> Configure in debugfs and check the file "gpio" in debugfs
> to figure out the client.

That file contained only the gpiochip244 from the gpio-pch driver,
nothing from the sch.

Thanks!

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Technical Lead - Linux Kernel
--
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/