Re: [PATCH v3 08/11] Bluetooth: hci_qca: Support QCA2066 on M.2 connector via pwrseq

[Chen-Yu Tsai <wenst@chromium.org>]

On Fri, Jul 10, 2026 at 11:57:34AM +0200, Loic Poulain wrote:
> For QCA2066 (and other QCA chips) on M.2 connectors, the UART enable is
> controlled by the W_DISABLE2# signal managed by the pcie-m2 power sequencer
> rather than a dedicated BT enable GPIO.
> 
> When the serdev controller has an OF graph (indicating it is connected to
> an M.2 connector), acquire the 'uart' pwrseq target from the connector's
> power sequencer and use it to control BT power instead of the bt-enable
> GPIO. This is factored out into qca_serdev_get_m2_pwrseq().
> 
> Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
> Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
> ---
>  drivers/bluetooth/hci_qca.c | 35 ++++++++++++++++++++++++-----------
>  1 file changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 24dc5bf6d192be7e1d500df6bdf36e6184f9eaf7..f6529d359ffbd97f8a3c4c0593680ab200215b36 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1872,6 +1872,9 @@ static int qca_power_on(struct hci_dev *hdev)
>  			/* Controller needs time to bootup. */
>  			msleep(150);
>  		}
> +
> +		if (qcadev->bt_power.pwrseq)
> +			pwrseq_power_on(qcadev->bt_power.pwrseq);
>  	}
>  
>  	clear_bit(QCA_BT_OFF, &qca->flags);
> @@ -2387,6 +2390,20 @@ static int qca_init_regulators(struct qca_power *qca,
>  	return 0;
>  }
>  
> +static int qca_serdev_get_m2_pwrseq(struct qca_serdev *qcadev)
> +{
> +	struct serdev_device *serdev = qcadev->serdev_hu.serdev;
> +
> +	if (!of_graph_is_present(dev_of_node(&serdev->ctrl->dev)))
> +		return 0;
> +
> +	qcadev->bt_power.pwrseq = devm_pwrseq_get(&serdev->ctrl->dev, "uart");

Note that this ultimately ties the lifecycle of the returned pwrseq
descriptor to the uart, which is probably not what you want.

I ended up manually doing pwrseq_get() with devm_add_action_or_reset()
so that the descriptor is released when the serdev driver is unbound.
This was for the Realtek driver. I haven't sent patches yet.

> +	if (IS_ERR(qcadev->bt_power.pwrseq))
> +		return PTR_ERR(qcadev->bt_power.pwrseq);
> +
> +	return 0;
> +}
> +
>  static int qca_serdev_probe(struct serdev_device *serdev)
>  {
>  	struct qca_serdev *qcadev;
> @@ -2417,6 +2434,10 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  	else
>  		qcadev->btsoc_type = QCA_ROME;
>  
> +	err = qca_serdev_get_m2_pwrseq(qcadev);
> +	if (err)
> +		return err;
> +
>  	switch (qcadev->btsoc_type) {
>  	case QCA_WCN3950:
>  	case QCA_WCN3988:
> @@ -2426,17 +2447,9 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  	case QCA_WCN6750:
>  	case QCA_WCN6855:
>  	case QCA_WCN7850:
> -		/*
> -		 * OF graph link is only present for BT devices attached through
> -		 * the M.2 Key E connector.
> -		 */
> -		if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
> -			qcadev->bt_power.pwrseq = devm_pwrseq_get(&serdev->ctrl->dev,
> -								  "uart");

It's already incorrect here. But I think the original patch that
introduces this hasn't landed?


ChenYu

> -			if (IS_ERR(qcadev->bt_power.pwrseq))
> -				return PTR_ERR(qcadev->bt_power.pwrseq);
> +		/* M.2 connector modules are powered by the pwrseq acquired above. */
> +		if (qcadev->bt_power.pwrseq)
>  			break;
> -		}
>  
>  		if (!device_property_present(&serdev->dev, "enable-gpios")) {
>  			/*
> @@ -2528,7 +2541,7 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  			return PTR_ERR(qcadev->susclk);
>  		}
>  	}
> -	
> +
>  	if (qcadev->bt_power.pwrseq) {
>  		bt_en_available = pwrseq_power_is_controllable(qcadev->bt_power.pwrseq);
>  		if (!bt_en_available) {
> 
> -- 
> 2.34.1
>