linux-kernel - Re: [PATCH] Bluetooth: qca: set power_ctrl_enabled on NULL returned by gpiod_get

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Date: Wed, 24 Apr 2024 13:56:07 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Wren Turkal <wt@...guintechs.org>
Cc: linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, Zijun Hu <quic_zijuhu@...cinc.com>, 
	Marcel Holtmann <marcel@...tmann.org>, Luiz Augusto von Dentz <luiz.dentz@...il.com>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: Re: [PATCH] Bluetooth: qca: set power_ctrl_enabled on NULL returned
 by gpiod_get_optional()

On Wed, Apr 24, 2024 at 1:53 PM Wren Turkal <wt@...guintechs.org> wrote:
>
> On 4/24/24 4:16 AM, Wren Turkal wrote:
> > On 4/24/24 2:04 AM, Bartosz Golaszewski wrote:
> >> On Wed, 24 Apr 2024 07:07:05 +0200, Wren Turkal<wt@...guintechs.org>
> >> said:
> >>> On 4/22/24 6:00 AM, Bartosz Golaszewski wrote:
> >>>> From: Bartosz Golaszewski<bartosz.golaszewski@...aro.org>
> >>>>
> >>>> Any return value from gpiod_get_optional() other than a pointer to a
> >>>> GPIO descriptor or a NULL-pointer is an error and the driver should
> >>>> abort probing. That being said: commit 56d074d26c58 ("Bluetooth:
> >>>> hci_qca:
> >>>> don't use IS_ERR_OR_NULL() with gpiod_get_optional()") no longer sets
> >>>> power_ctrl_enabled on NULL-pointer returned by
> >>>> devm_gpiod_get_optional(). Restore this behavior but bail-out on
> >>>> errors.
> >>> Nack. This patch does fixes neither the disable/re-enable problem nor
> >>> the warm boot problem.
> >>>
> >>> Zijun replied to this patch also with what I think is the proper
> >>> reasoning for why it doesn't fix my setup.
> >>>
> >> Indeed, I only addressed a single issue here and not the code under the
> >> default: label of the switch case. Sorry.
> >>
> >> Could you give the following diff a try?
> >
> > I had a feeling that was what was going on. I'll give the patch a shot.
> >
> > wt
>
> Considering this patch is basically equivalent to patch 1/2 from Zijun,
> I am not surprised that is works similarly. I.e. on a cold boot, I can
> disable/re-enable bluetooth as many time as I want.
>

Zijun didn't bail out on errors which is the issue the original patch
tried to address and this one preserves.

> However, since this patch doesn't include the quirk fix from Zijun's
> patchset (patch 2/2), bluetooth fails to work after a warm boot.
>

That's OK, we have the first part right. Let's now see if we can reuse
patch 2/2 from Zijun.

> @Zijun, this patch looks more idiomatic when I look at the surrounding
> code than your patch 1/2. Notice how it doesn't use the "else if"
> construct. It does the NULL test separately after checking for errors.
>
> --
> You're more amazing than you think!

Bart