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Message-ID: <59a1921a-343a-46cb-9a9c-6a18f63a02b3@quicinc.com>
Date: Thu, 18 Apr 2024 07:44:15 +0800
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Subject: Re: [PATCH] Revert "Bluetooth: hci_qca: don't use IS_ERR_OR_NULL()
 with gpiod_get_optional()"
To: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
CC: <luiz.dentz@gmail.com>, <luiz.von.dentz@intel.com>, <marcel@holtmann.org>,
        <linux-bluetooth@vger.kernel.org>, <wt@penguintechs.org>
References: <1713354823-17826-1-git-send-email-quic_zijuhu@quicinc.com>
 <CACMJSeuQMz-JCK7tqiQCmt7z37L1UncNK0un28JHAa8qRhnp-g@mail.gmail.com>
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From: quic_zijuhu <quic_zijuhu@quicinc.com>
In-Reply-To: <CACMJSeuQMz-JCK7tqiQCmt7z37L1UncNK0un28JHAa8qRhnp-g@mail.gmail.com>
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On 4/18/2024 2:59 AM, Bartosz Golaszewski wrote:
> 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.
> 
we need to treat below tow cases equivalently.
1) BT reset pin is NOT configured, devm_gpiod_get_optional() return NULL.
2) BT reset pin is configured, but failed to be got, devm_gpiod_get_optional() return ERROR.

FOR above two cases, hci_qca driver doesn't get available BT reset pin for H/W reset.
so we use IS_ERR_OR_NULL() instead of IS_ERR().

is it not right ?


>> 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.
> 
your concern is that the prompt message is printed by wrong way or the prompt message is not precise.
is it right ?

> Bartosz
> 
>>                 }
>> --
>> 2.7.4
>>