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From: Rick Altherr <raltherr-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: Stuart Longland
	<stuartl-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org>
Cc: "Linus Walleij"
	<linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	"Oleksandr Shamray"
	<oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"Jiří Pírko" <jiri-rHqAuBHg3fBzbRFIqnYvSA@public.gmane.org>,
	"Arnd Bergmann" <arnd-r2nGTMty4D4@public.gmane.org>,
	system-sw-low-level-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org,
	"Greg KH"
	<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
	"OpenBMC Maillist"
	<openbmc-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	openocd-devel-owner-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	mec-WqBc5aa1uDFeoWH0uzbU5w@public.gmane.org,
	"Rob Herring" <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"Tobias Klauser"
	<tklauser-93Khv+1bN0NyDzI6CaY1VQ@public.gmane.org>,
	"linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [patch v6 0/3] JTAG driver introduction
Date: Fri, 25 Aug 2017 09:53:40 -0700	[thread overview]
Message-ID: <CAPLgG=ke+5kX5TuTtciVCxtCr6agpFMo-6peXfhbE0UCvy6M3w@mail.gmail.com> (raw)
In-Reply-To: <593cd0d3-8e06-0992-c155-1322014c0477-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org>

On Fri, Aug 25, 2017 at 1:50 AM, Stuart Longland
<stuartl-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org> wrote:
> [Note: dropping vadimp-45czdsxZ+A5DPfheJLI6IQ@public.gmane.org as SMTP server complained about the
> DNS server returning NXDOMAIN.  Apologies.]
> On 25/08/17 18:32, Linus Walleij wrote:
>> Gnah!
>> Whoever writes a slot-in replacement making the character device
>> take precendence wins lots of karma.
>
> What would such a replacement look like though?

See Linus's comments about using the existing kernel GPIO chardev
interface.  It already supports requesting multiple GPIO line state
changes in a single request.

>
> Some sort of system whereby you can read/write single-line commands as
> if talking to a GPIO expander over a UART?
>
> Would you access the GPIOs one by one, or would you perhaps map them
> into a bitmap (maybe arbitrarily, up to 64-bits wide) and perform masked
> operations on the bitmap?
>
> I'm no fan of the sysfs GPIO interface, but it beats poking around at
> registers behind the kernel's back.
> --
> Stuart Longland (aka Redhatter, VK4MSL)
>
> I haven't lost my mind...
>   ...it's backed up on a tape somewhere.
>

  parent reply	other threads:[~2017-08-25 16:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-22 16:10 [patch v6 0/3] JTAG driver introduction Oleksandr Shamray
2017-08-22 16:10 ` [patch v6 2/3] drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master driver Oleksandr Shamray
2017-08-22 16:10 ` [patch v6 3/3] Doccumentation: jtag: Add bindings for " Oleksandr Shamray
2017-08-28  8:36   ` Tobias Klauser
     [not found] ` <1503418256-5215-1-git-send-email-oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2017-08-22 16:10   ` [patch v6 1/3] drivers: jtag: Add JTAG core driver Oleksandr Shamray
2017-08-24 21:07   ` [patch v6 0/3] JTAG driver introduction Linus Walleij
     [not found]     ` <CACRpkdZePXyo8Q36mBH7OnJU3E=yWPWSGkGUOH=zJFMjM=Yrhw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-08-24 21:37       ` Rick Altherr
2017-08-25  8:32         ` Linus Walleij
2017-08-25  8:50           ` Stuart Longland
     [not found]             ` <593cd0d3-8e06-0992-c155-1322014c0477-3e+Fe6x+DsgJbe36r25VNhCuuivNXqWP@public.gmane.org>
2017-08-25 16:53               ` Rick Altherr [this message]
2017-08-27 22:25               ` Linus Walleij
     [not found]           ` <CACRpkdbozWaL0RXyZXjzxYK3JHiqYziSkTGSgGORdptX-rwR8A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-08-25 16:52             ` Rick Altherr
     [not found]               ` <CAPLgG=mv1p98e4Vzso1N-VU=1MSotkTmnF+DcDTXPcd3q-n8HA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-08-27 22:30                 ` Linus Walleij
     [not found]                   ` <CACRpkdb75L5BrYN+V-BMwzrRm8_Wtymr3d08eMWt43FiBpH5Qg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-08-28  2:55                     ` Rick Altherr

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