Re: [PATCH v2 3/4] Bluetooth: hci_qca: Support QCA2066 on M.2 connector via pwrseq

[Manivannan Sadhasivam <mani@kernel.org>]

On Thu, Jul 02, 2026 at 12:46:15PM +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.
> 
> Also allocate bt_power unconditionally for all SOC types since the
> pwrseq path is independent of the SOC type switch.
> 
> Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

- Mani

> ---
>  drivers/bluetooth/hci_qca.c | 81 ++++++++++++++++++++++++---------------------
>  1 file changed, 43 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index e09debdb00a1b8e74ccd5de6147e240e533b4594..b04593a96e14ac9e87ae76fa00eda308e81dea25 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);
> @@ -2256,7 +2259,7 @@ static void qca_power_off(struct hci_uart *hu)
>  		break;
>  	}
>  
> -	if (power && power->pwrseq) {
> +	if (power->pwrseq) {
>  		pwrseq_power_off(power->pwrseq);
>  		set_bit(QCA_BT_OFF, &qca->flags);
>  		return;
> @@ -2387,6 +2390,35 @@ static int qca_init_regulators(struct qca_power *qca,
>  	return 0;
>  }
>  
> +/*
> + * Acquire the M.2 connector power sequencer.
> + *
> + * An OF graph link on the serdev controller is only present when the BT
> + * device is attached through an M.2 Key E connector. In that case the UART
> + * enable (W_DISABLE2#) is driven by the pcie-m2 power sequencer instead of a
> + * dedicated BT enable GPIO, so grab the "uart" pwrseq target from it.
> + *
> + * Returns 0 if no M.2 connector is present (nothing to do), a negative errno
> + * on error, otherwise 0 with qcadev->bt_power->pwrseq populated.
> + */
> +static int qca_serdev_get_m2_pwrseq(struct qca_serdev *qcadev, bool *bt_en_available)
> +{
> +	struct serdev_device *serdev = qcadev->serdev_hu.serdev;
> +	struct device *dev;
> +
> +	if (!of_graph_is_present(dev_of_node(&serdev->ctrl->dev)))
> +		return 0;
> +
> +	qcadev->bt_power->pwrseq = devm_pwrseq_get(&serdev->ctrl->dev, "uart");
> +	if (IS_ERR(qcadev->bt_power->pwrseq))
> +		return PTR_ERR(qcadev->bt_power->pwrseq);
> +
> +	dev = pwrseq_to_device(qcadev->bt_power->pwrseq);
> +	*bt_en_available = device_property_present(dev, "w-disable2-gpios");
> +
> +	return 0;
> +}
> +
>  static int qca_serdev_probe(struct serdev_device *serdev)
>  {
>  	struct qca_serdev *qcadev;
> @@ -2417,25 +2449,13 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  	else
>  		qcadev->btsoc_type = QCA_ROME;
>  
> -	switch (qcadev->btsoc_type) {
> -	case QCA_QCA6390:
> -	case QCA_WCN3950:
> -	case QCA_WCN3988:
> -	case QCA_WCN3990:
> -	case QCA_WCN3991:
> -	case QCA_WCN3998:
> -	case QCA_WCN6750:
> -	case QCA_WCN6855:
> -	case QCA_WCN7850:
> -		qcadev->bt_power = devm_kzalloc(&serdev->dev,
> -						sizeof(struct qca_power),
> -						GFP_KERNEL);
> -		if (!qcadev->bt_power)
> -			return -ENOMEM;
> -		break;
> -	default:
> -		break;
> -	}
> +	qcadev->bt_power = devm_kzalloc(&serdev->dev, sizeof(struct qca_power), GFP_KERNEL);
> +	if (!qcadev->bt_power)
> +		return -ENOMEM;
> +
> +	err = qca_serdev_get_m2_pwrseq(qcadev, &bt_en_available);
> +	if (err)
> +		return err;
>  
>  	switch (qcadev->btsoc_type) {
>  	case QCA_WCN3950:
> @@ -2446,24 +2466,9 @@ 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))) {
> -			struct device *dev;
> -
> -			qcadev->bt_power->pwrseq = devm_pwrseq_get(&serdev->ctrl->dev,
> -								   "uart");
> -			if (IS_ERR(qcadev->bt_power->pwrseq))
> -				return PTR_ERR(qcadev->bt_power->pwrseq);
> -
> -			dev = pwrseq_to_device(qcadev->bt_power->pwrseq);
> -			if (!device_property_present(dev, "w-disable2-gpios"))
> -				bt_en_available = false;
> -
> +		/* 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")) {
>  			/*
> @@ -2545,7 +2550,7 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  			return PTR_ERR(qcadev->bt_en);
>  		}
>  
> -		if (!qcadev->bt_en)
> +		if (!qcadev->bt_en && !qcadev->bt_power->pwrseq)
>  			bt_en_available = false;
>  
>  		qcadev->susclk = devm_clk_get_optional_enabled_with_rate(
> 
> -- 
> 2.34.1
> 

-- 
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