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 04:53:38 -0700
From: Wren Turkal <wt@...guintechs.org>
To: Bartosz Golaszewski <brgl@...ev.pl>
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 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.

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.

@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.

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