From: John Keeping <john@metanate.com>
To: Mark Brown <broonie@kernel.org>
Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
Daniel Beer <daniel.beer@igorinstitute.com>,
Takashi Iwai <tiwai@suse.com>,
Liam Girdwood <lgirdwood@gmail.com>
Subject: Re: [PATCH v2] ASoC: tas5805m: fix pdn polarity
Date: Wed, 9 Mar 2022 20:16:07 +0000 [thread overview]
Message-ID: <YikLB4+xHVxjFTSL@donbot> (raw)
In-Reply-To: <YijVrgZ+Ysv9J/8E@sirena.org.uk>
On Wed, Mar 09, 2022 at 04:28:30PM +0000, Mark Brown wrote:
> On Wed, Mar 09, 2022 at 04:19:31PM +0000, John Keeping wrote:
> > On Wed, Mar 09, 2022 at 03:56:12PM +0000, Mark Brown wrote:
>
> > > I'm still not seeing the functional change here. The actual state of
> > > the GPIO is identical in both cases, all that's changing is the logical
> > > view internally to the kernel.
>
> > Ah, sorry, I'm considering it functional since it changes the device
> > tree ABI.
>
> > Used with the same device tree with, say, GPIO_ACTIVE_HIGH the physical
> > state of the GPIO will change as a result of this patch and the device
> > tree needs to be updated to use GPIO_ACTIVE_LOW.
>
> I think the device tree binding needs to be clarified here to be
> explicit about this since there's obviously some room for user confusion
> here. We can probably get away with a change at this point since it's
> not hit a release but we do need to try to avoid the situation where any
> other implementations use active high polarity for the bindings.
Taking a quick survey of the other devices that have a pdn-gpios
property:
- tvp5150 is correct with the driver setting 0 to make the device active
- tas571x also sets 0 to make the device active
- ak4375 uses the opposite sense setting PDN = 1 to make the device
active; this has no in-tree users and was merged as part of v5.17-rc1
so it's not in a released kernel yet
WARNING: multiple messages have this Message-ID (diff)
From: John Keeping <john@metanate.com>
To: Mark Brown <broonie@kernel.org>
Cc: alsa-devel@alsa-project.org, Liam Girdwood <lgirdwood@gmail.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Daniel Beer <daniel.beer@igorinstitute.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ASoC: tas5805m: fix pdn polarity
Date: Wed, 9 Mar 2022 20:16:07 +0000 [thread overview]
Message-ID: <YikLB4+xHVxjFTSL@donbot> (raw)
In-Reply-To: <YijVrgZ+Ysv9J/8E@sirena.org.uk>
On Wed, Mar 09, 2022 at 04:28:30PM +0000, Mark Brown wrote:
> On Wed, Mar 09, 2022 at 04:19:31PM +0000, John Keeping wrote:
> > On Wed, Mar 09, 2022 at 03:56:12PM +0000, Mark Brown wrote:
>
> > > I'm still not seeing the functional change here. The actual state of
> > > the GPIO is identical in both cases, all that's changing is the logical
> > > view internally to the kernel.
>
> > Ah, sorry, I'm considering it functional since it changes the device
> > tree ABI.
>
> > Used with the same device tree with, say, GPIO_ACTIVE_HIGH the physical
> > state of the GPIO will change as a result of this patch and the device
> > tree needs to be updated to use GPIO_ACTIVE_LOW.
>
> I think the device tree binding needs to be clarified here to be
> explicit about this since there's obviously some room for user confusion
> here. We can probably get away with a change at this point since it's
> not hit a release but we do need to try to avoid the situation where any
> other implementations use active high polarity for the bindings.
Taking a quick survey of the other devices that have a pdn-gpios
property:
- tvp5150 is correct with the driver setting 0 to make the device active
- tas571x also sets 0 to make the device active
- ak4375 uses the opposite sense setting PDN = 1 to make the device
active; this has no in-tree users and was merged as part of v5.17-rc1
so it's not in a released kernel yet
next prev parent reply other threads:[~2022-03-09 20:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-09 13:56 [PATCH v2] ASoC: tas5805m: fix pdn polarity John Keeping
2022-03-09 13:56 ` John Keeping
2022-03-09 15:56 ` Mark Brown
2022-03-09 15:56 ` Mark Brown
2022-03-09 16:19 ` John Keeping
2022-03-09 16:19 ` John Keeping
2022-03-09 16:28 ` Mark Brown
2022-03-09 16:28 ` Mark Brown
2022-03-09 20:16 ` John Keeping [this message]
2022-03-09 20:16 ` John Keeping
2022-03-09 21:55 ` Mark Brown
2022-03-09 21:55 ` Mark Brown
2022-03-10 20:09 ` John Keeping
2022-03-10 20:09 ` John Keeping
2022-03-11 12:03 ` Mark Brown
2022-03-11 12:03 ` Mark Brown
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