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 12:55:37 +0800
From: quic_zijuhu <quic_zijuhu@...cinc.com>
To: Bartosz Golaszewski <brgl@...ev.pl>,
        Marcel Holtmann
	<marcel@...tmann.org>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
CC: <linux-bluetooth@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Bartosz
 Golaszewski <bartosz.golaszewski@...aro.org>,
        Wren Turkal
	<wt@...guintechs.org>,
        Greg KH <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] Bluetooth: qca: set power_ctrl_enabled on NULL returned
 by gpiod_get_optional()

On 4/22/2024 9:00 PM, 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.
> 
> Reported-by: Wren Turkal <wt@...guintechs.org>
> Reported-by: Zijun Hu <quic_zijuhu@...cinc.com>
> Closes: https://lore.kernel.org/linux-bluetooth/1713449192-25926-2-git-send-email-quic_zijuhu@quicinc.com/
> Fixes: 56d074d26c58 ("Bluetooth: hci_qca: don't use IS_ERR_OR_NULL() with gpiod_get_optional()")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>  drivers/bluetooth/hci_qca.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 92fa20f5ac7d..739248c6d6b9 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2327,9 +2327,12 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  		    (data->soc_type == QCA_WCN6750 ||
>  		     data->soc_type == QCA_WCN6855)) {
>  			dev_err(&serdev->dev, "failed to acquire BT_EN gpio\n");
> -			power_ctrl_enabled = false;
> +			return PTR_ERR(qcadev->bt_en);
>  		}
>  
For QCA6390, control logic do not reach here, so it has no any help for
QCA6390.
> +		if (!qcadev->bt_en)
> +			power_ctrl_enabled = false;
> +
property enable-gpios are obviously marked as required for WCN6750 and
WCN6855 by dts binding spec as shown by below link:
https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/tree/Documentation/devicetree/bindings/net/bluetooth/qualcomm-bluetooth.yaml

if user don't config the property then "qcadev->bt_en is NULL", can we
still treat this case as good case?

that is why i changed my fix from reverting the wrong commit to only
focusing on QCA6390.

i will give different fix for other impacted QCA controllers.

>  		qcadev->sw_ctrl = devm_gpiod_get_optional(&serdev->dev, "swctrl",
>  					       GPIOD_IN);
>  		if (IS_ERR(qcadev->sw_ctrl) &&

NAK as explained above.