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

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 <redacted>
---
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;
+}
+

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);

+	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);

}

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)