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From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Date: Wed, 17 Apr 2024 20:59:42 +0200
Message-ID: <CACMJSeuQMz-JCK7tqiQCmt7z37L1UncNK0un28JHAa8qRhnp-g@mail.gmail.com>
Subject: Re: [PATCH] Revert "Bluetooth: hci_qca: don't use IS_ERR_OR_NULL()
 with gpiod_get_optional()"
To: Zijun Hu <quic_zijuhu@quicinc.com>
Cc: luiz.dentz@gmail.com, luiz.von.dentz@intel.com, marcel@holtmann.org, 
	linux-bluetooth@vger.kernel.org, wt@penguintechs.org
Content-Type: text/plain; charset="UTF-8"

On Wed, 17 Apr 2024 at 13:53, Zijun Hu <quic_zijuhu@quicinc.com> wrote:
>
> This reverts commit 56d074d26c5828773b00b2185dd7e1d08273b8e8.
>
> Commit 56d074d26c58 ("Bluetooth: hci_qca: don't use IS_ERR_OR_NULL()
> with gpiod_get_optional()") will cause serious regression issue for
> several QCA controllers such as QCA_WCN6750,QCA_WCN6855,QCA_ROME,
> QCA_QCA6390 and QCA_QCA2066, the regression issue is that BT can't be
> enabled any more once BT is disabled if BT reset pin is not configured
> by DT or ACPI.
>
> if BT reset pin is not configured, devm_gpiod_get_optional() will return
> NULL, and we should NOT set quirk HCI_QUIRK_NON_PERSISTENT_SETUP, but the
> reverted commit SET the quirk since NULL is not a error case, and cause
> qca_setup() call failure triggered by the 2nd and later BT enable
> operations since there are no available BT reset pin to clear BT firmware
> downloaded by the 1st enable operation, fixed by reverting the commit.
>

Then you just go back to bad usage of the GPIO API. Please see my
suggestion below.

> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218726
> Fixes: 56d074d26c58 ("Bluetooth: hci_qca: don't use IS_ERR_OR_NULL() with gpiod_get_optional()")
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
>  drivers/bluetooth/hci_qca.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 92fa20f5ac7d..160175a23a49 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2323,7 +2323,7 @@ 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) &&
> +               if (IS_ERR_OR_NULL(qcadev->bt_en) &&
>                     (data->soc_type == QCA_WCN6750 ||
>                      data->soc_type == QCA_WCN6855)) {
>                         dev_err(&serdev->dev, "failed to acquire BT_EN gpio\n");
> @@ -2332,7 +2332,7 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>
>                 qcadev->sw_ctrl = devm_gpiod_get_optional(&serdev->dev, "swctrl",
>                                                GPIOD_IN);
> -               if (IS_ERR(qcadev->sw_ctrl) &&
> +               if (IS_ERR_OR_NULL(qcadev->sw_ctrl) &&
>                     (data->soc_type == QCA_WCN6750 ||
>                      data->soc_type == QCA_WCN6855 ||
>                      data->soc_type == QCA_WCN7850))
> @@ -2354,7 +2354,7 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>         default:
>                 qcadev->bt_en = devm_gpiod_get_optional(&serdev->dev, "enable",
>                                                GPIOD_OUT_LOW);
> -               if (IS_ERR(qcadev->bt_en)) {
> +               if (IS_ERR_OR_NULL(qcadev->bt_en)) {
>                         dev_warn(&serdev->dev, "failed to acquire enable gpio\n");
>                         power_ctrl_enabled = false;

Can you just move this out of this block? Or just simply check the
presence of the GPIO descriptor in the if block setting the quirk bit?
Warning on a missing *optional* GPIO is wrong. It's not an unexpected
situation, it's normal.

Bartosz

>                 }
> --
> 2.7.4
>