Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
Date:   Mon, 2 Oct 2023 12:05:11 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Kent Gibson <warthog618@gmail.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
        Yury Norov <yury.norov@gmail.com>, linux-gpio@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>,
        Srinivas Neeli <srinivas.neeli@amd.com>,
        Michal Simek <michal.simek@amd.com>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Marek =?iso-8859-1?Q?Beh=FAn?= <kabel@kernel.org>
Subject: Re: [PATCH v1 5/5] gpiolib: cdev: Utilize more bitmap APIs
Message-ID: <ZRqHx+Ihcxor2Jz4@smile.fi.intel.com>
References: <20230926052007.3917389-1-andriy.shevchenko@linux.intel.com>
 <20230926052007.3917389-6-andriy.shevchenko@linux.intel.com>
 <ZROGG44v5kfktdVs@sol>
 <ZRQdQnL5VbX659cl@smile.fi.intel.com>
 <ZRQy795YoPOKsOcz@sol>
 <ZRQ1RpHEapodQ0xU@smile.fi.intel.com>
 <ZRQ60KBtY09uPxp6@sol>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZRQ60KBtY09uPxp6@sol>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Wed, Sep 27, 2023 at 10:23:12PM +0800, Kent Gibson wrote:
> On Wed, Sep 27, 2023 at 04:59:34PM +0300, Andy Shevchenko wrote:
> > On Wed, Sep 27, 2023 at 09:49:35PM +0800, Kent Gibson wrote:
> > > On Wed, Sep 27, 2023 at 03:17:06PM +0300, Andy Shevchenko wrote:
> > > > On Wed, Sep 27, 2023 at 09:32:11AM +0800, Kent Gibson wrote:

...

> > > > Yet, it opens a way to scale this in case we might have v3 ABI that let's say
> > > > allows to work with 512 GPIOs at a time. With your code it will be much harder
> > > > to achieve and see what you wrote about maintenance (in that case).
> > > 
> > > v3 ABI?? libgpiod v2 is barely out the door!
> > > Do you have any cases where 64 lines per request is limiting?
> > 
> > IIRC it was SO question where the OP asks exactly about breaking the 64 lines
> > limitation in the current ABI.
> > 
> > > If that sort of speculation isn't premature optimisation then I don't know
> > > what is.
> > 
> > No, based on the real question / discussion, just have no link at hand.
> > But it's quite a niche, I can agree.
> 
> Let me know if you find a ref to that discussion - I'm curious.

Here it is (read comments as well):
https://stackoverflow.com/questions/76307370/control-gpio-from-linux-userspace-with-linux-gpio-h

-- 
With Best Regards,
Andy Shevchenko