linux-kernel - Re: [PATCH v1] Bluetooth: hci_qca: Enable clocks required for BT SOC

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Date:   Thu, 14 Nov 2019 09:55:41 +0100
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Balakrishna Godavarthi <bgodavar@...eaurora.org>
Cc:     Johan Hedberg <johan.hedberg@...il.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        lkml <linux-kernel@...r.kernel.org>,
        linux-bluetooth@...r.kernel.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org, tientzu@...omium.org,
        seanpaul@...omium.org
Subject: Re: [PATCH v1] Bluetooth: hci_qca: Enable clocks required for BT SOC

Hi Balakrishna,

> Instead of relying on other subsytem to turn ON clocks
> required for BT SoC to operate, voting them from the driver.
> 
> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
> ---
> drivers/bluetooth/hci_qca.c | 31 +++++++++++++++++++++++++++++--
> 1 file changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index f10bdf8e1fc5..dc95e378574b 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -164,6 +164,7 @@ struct qca_serdev {
> };
> 
> static int qca_regulator_enable(struct qca_serdev *qcadev);
> +static int qca_power_on(struct qca_serdev *qcadev);

I really dislike forward declaration. Only use them if they are really really needed. That said, this driver might actually need cleanups since I just realized it has tons of forward declarations.

> static void qca_regulator_disable(struct qca_serdev *qcadev);
> static void qca_power_shutdown(struct hci_uart *hu);
> static int qca_power_off(struct hci_dev *hdev);
> @@ -528,7 +529,7 @@ static int qca_open(struct hci_uart *hu)
> 		} else {
> 			hu->init_speed = qcadev->init_speed;
> 			hu->oper_speed = qcadev->oper_speed;
> -			ret = qca_regulator_enable(qcadev);
> +			ret = qca_power_on(qcadev);
> 			if (ret) {
> 				destroy_workqueue(qca->workqueue);
> 				kfree_skb(qca->rx_skb);
> @@ -1214,7 +1215,7 @@ static int qca_wcn3990_init(struct hci_uart *hu)
> 	qcadev = serdev_device_get_drvdata(hu->serdev);
> 	if (!qcadev->bt_power->vregs_on) {
> 		serdev_device_close(hu->serdev);
> -		ret = qca_regulator_enable(qcadev);
> +		ret = qca_power_on(qcadev);
> 		if (ret)
> 			return ret;
> 
> @@ -1408,6 +1409,9 @@ static void qca_power_shutdown(struct hci_uart *hu)
> 	host_set_baudrate(hu, 2400);
> 	qca_send_power_pulse(hu, false);
> 	qca_regulator_disable(qcadev);
> +
> +	if (qcadev->susclk)
> +		clk_disable_unprepare(qcadev->susclk);
> }
> 
> static int qca_power_off(struct hci_dev *hdev)
> @@ -1423,6 +1427,20 @@ static int qca_power_off(struct hci_dev *hdev)
> 	return 0;
> }
> 
> +static int qca_power_on(struct qca_serdev *qcadev)
> +{
> +	int err;
> +
> +	if (qcadev->susclk) {
> +		err = clk_prepare_enable(qcadev->susclk);
> +		if (err)
> +			return err;
> +	}
> +
> +	qca_regulator_enable(qcadev);
> +	return 0;
> +}
> +
> static int qca_regulator_enable(struct qca_serdev *qcadev)
> {
> 	struct qca_power *power = qcadev->bt_power;
> @@ -1523,6 +1541,15 @@ static int qca_serdev_probe(struct serdev_device *serdev)
> 
> 		qcadev->bt_power->vregs_on = false;
> 
> +		if (qcadev->btsoc_type == QCA_WCN3990 ||
> +		    qcadev->btsoc_type == QCA_WCN3991) {

There comes a point when using a switch statement is a lot easier to read. See if that has been reached and if there are other places that would benefit from a cleanup patch.

Regards

Marcel