linux-kernel - Re: [PATCH v2 1/2] Bluetooth: hci_qca: Enable clocks required for BT SOC

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Message-Id: <543135AD-707A-4945-A67D-8912D1C35EED@holtmann.org>
Date:   Fri, 31 Jan 2020 20:51:33 +0100
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Venkata Lakshmi Narayana Gubba <gubbaven@...eaurora.org>
Cc:     Johan Hedberg <johan.hedberg@...il.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        robh@...nel.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org, bgodavar@...eaurora.org,
        tientzu@...omium.org, seanpaul@...omium.org, rjliao@...eaurora.org,
        yshavit@...gle.com
Subject: Re: [PATCH v2 1/2] Bluetooth: hci_qca: Enable clocks required for BT
 SOC

Hi Venkata,

> Instead of relying on other subsytem to turn ON clocks
> required for BT SoC to operate, voting them from the driver.
> 
> Signed-off-by: Venkata Lakshmi Narayana Gubba <gubbaven@...eaurora.org>
> ---
> v2:
>   * addressed forward declarations
>   * updated with devm_clk_get_optional()
> 
> ---
> drivers/bluetooth/hci_qca.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index d6e0c99..73706f3 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1738,6 +1738,15 @@ static int qca_power_off(struct hci_dev *hdev)
> 	return 0;
> }
> 
> +static int qca_setup_clock(struct clk *clk, bool enable)
> +{
> +	if (enable)
> +		return clk_prepare_enable(clk);
> +
> +	clk_disable_unprepare(clk);
> +	return 0;
> +}
> +

this function is pointless and it just complicated the code.

> static int qca_regulator_enable(struct qca_serdev *qcadev)
> {
> 	struct qca_power *power = qcadev->bt_power;
> @@ -1755,6 +1764,13 @@ static int qca_regulator_enable(struct qca_serdev *qcadev)
> 
> 	power->vregs_on = true;
> 
> +	ret = qca_setup_clock(qcadev->susclk, true);

	ret = clk_prepare_enable(qcadev->susclk);

> +	if (ret) {
> +		/* Turn off regulators to overcome power leakage */
> +		qca_regulator_disable(qcadev);
> +		return ret;
> +	}
> +
> 	return 0;
> }
> 
> @@ -1773,6 +1789,9 @@ static void qca_regulator_disable(struct qca_serdev *qcadev)
> 
> 	regulator_bulk_disable(power->num_vregs, power->vreg_bulk);
> 	power->vregs_on = false;
> +
> +	if (qcadev->susclk)
> +		qca_setup_clock(qcadev->susclk, false);

		clk_disable_unprepare(qcadev->susclk);

> }
> 
> static int qca_init_regulators(struct qca_power *qca,
> @@ -1839,6 +1858,12 @@ static int qca_serdev_probe(struct serdev_device *serdev)
> 
> 		qcadev->bt_power->vregs_on = false;
> 
> +		qcadev->susclk = devm_clk_get_optional(&serdev->dev, NULL);
> +		if (IS_ERR(qcadev->susclk)) {
> +			dev_err(&serdev->dev, "failed to acquire clk\n");
> +			return PTR_ERR(qcadev->susclk);
> +		}
> +
> 		device_property_read_u32(&serdev->dev, "max-speed",
> 					 &qcadev->oper_speed);
> 		if (!qcadev->oper_speed)

Regards

Marcel