Re: [PATCH 09/10] input: iqs5xx: Make reset GPIO optional

From: Jeff LaBundy <jeff@labundy.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: linux-input@vger.kernel.org
Subject: Re: [PATCH 09/10] input: iqs5xx: Make reset GPIO optional
Date: Mon, 25 Jan 2021 21:10:32 -0600	[thread overview]
Message-ID: <20210126031032.GB6155@labundy.com> (raw)
In-Reply-To: <YA5Mgtct6WFsxFVi@google.com>

Hi Dmitry,

On Sun, Jan 24, 2021 at 08:43:46PM -0800, Dmitry Torokhov wrote:
> On Mon, Jan 18, 2021 at 02:43:45PM -0600, Jeff LaBundy wrote:
> > The device's hardware reset pin is only required if the platform
> > must be able to update the device's firmware on the fly.
> > 
> > As such, demote the reset GPIO to optional in support of devices
> > that ship with pre-programmed firmware and don't route the reset
> > pin back to the SOC.
> > 
> > If user space attempts to push updated firmware which would rely
> > upon the reset pin to wake the bootloader, attempts to reach the
> > bootloader are simply NAK'd and the device resumes normally.
> 
> Can we maybe make the firmware attribute invisible in this case? Or
> return early instead of failing to enter bootloader mode?

I almost sent the second alternative, but instead I liked the idea of
restricting the check for reset_gpio to the only method that actually
uses it. That way, nothing outside of iqs5xx_reset() has to check for
the GPIO and can just fail gracefully in its absence.

That being said, either of your suggestions work just as well; let me
take another stab at it.

> 
> Thanks.
> 
> -- 
> Dmitry

Kind regards,
Jeff LaBundy