linux-kernel - Re: [PATCH v2] Bluetooth: qca: set power_ctrl_enabled on NULL returned by gpiod_get

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Date: Wed, 24 Apr 2024 11:41:42 -0400
From: Luiz Augusto von Dentz <luiz.dentz@...il.com>
To: quic_zijuhu <quic_zijuhu@...cinc.com>
Cc: Bartosz Golaszewski <brgl@...ev.pl>, Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, Marcel Holtmann <marcel@...tmann.org>, 
	linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Wren Turkal <wt@...guintechs.org>
Subject: Re: [PATCH v2] Bluetooth: qca: set power_ctrl_enabled on NULL
 returned by gpiod_get_optional()

Hi Quic_zijuhu,

On Wed, Apr 24, 2024 at 11:35 AM quic_zijuhu <quic_zijuhu@...cinc.com> wrote:
>
> On 4/24/2024 11:31 PM, Bartosz Golaszewski wrote:
> > On Wed, Apr 24, 2024 at 5:30 PM quic_zijuhu <quic_zijuhu@...cinc.com> wrote:
> >>
> >> On 4/24/2024 11:24 PM, quic_zijuhu wrote:
> >>> On 4/24/2024 10:52 PM, Bartosz Golaszewski wrote:
> >>>> On Wed, 24 Apr 2024 at 16:46, Krzysztof Kozlowski
> >>>> <krzysztof.kozlowski@...aro.org> wrote:
> >>>>>
> >>>>> On 24/04/2024 14:29, Bartosz Golaszewski wrote:
> >>>>>> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >>>>>>
> >>>>>
> >>>>>>               qcadev->susclk = devm_clk_get_optional(&serdev->dev, NULL);
> >>>>>>               if (IS_ERR(qcadev->susclk)) {
> >>>>>> @@ -2355,10 +2360,13 @@ static int qca_serdev_probe(struct serdev_device *serdev)
> >>>>>>               qcadev->bt_en = devm_gpiod_get_optional(&serdev->dev, "enable",
> >>>>>>                                              GPIOD_OUT_LOW);
> >>>>>>               if (IS_ERR(qcadev->bt_en)) {
> >>>>>> -                     dev_warn(&serdev->dev, "failed to acquire enable gpio\n");
> >>>>>> -                     power_ctrl_enabled = false;
> >>>>>> +                     dev_err(&serdev->dev, "failed to acquire enable gpio\n");
> >>>>>> +                     return PTR_ERR(qcadev->bt_en);
> >>> please think about for QCA2066. if it is returned from here.  BT will
> >>> not working at all.  if you don't return here. i will be working fine
> >>> for every BT functionality.
> >> sorry, correct a type error, it is QCA6390 not QCA2066.
> >
> > Doesn't matter. If enable-gpios is not there, gpiod_get_optional()
> > will return NULL and we will not return.
> >
> i think i need to explain more for my consider case.
> let me take QCA6390,  if the property enable-gpios is configured.
> but IS_ERR(qcadev->bt_en) case happens, your change will do error
> return, so BT will not work at all
>
> but if you don't do error return, BT will working fine.
>
> so your fix is not right regarding QCA6390.

Actually I'd say he is probably right with respect to DT because that
seems to require GPIO, we probably need a clearer way to differentiate
if a device is being set up via DT or not (btattach), in any case DT
is probably preferable thus why I went ahead and applied this one.

> > Bart
> >
> >>> NAK again by me.
> >>>
> >>>>>>               }
> >>>>>>
> >>>>>> +             if (!qcadev->bt_en)
> >>>>>> +                     power_ctrl_enabled = false;
> >>>>>
> >>>>> This looks duplicated - you already have such check earlier.
> >>>>>
> >>>>
> >>>> It's under a different switch case!
> >>>>
> >>>> Bartosz
> >>>
> >>>
> >>
>


-- 
Luiz Augusto von Dentz