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

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Date:   Fri, 31 Jan 2020 13:08:54 +0530
From:   Venkata Lakshmi Narayana Gubba <gubbaven@...eaurora.org>
To:     marcel@...tmann.org, johan.hedberg@...il.com
Cc:     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,
        Venkata Lakshmi Narayana Gubba <gubbaven@...eaurora.org>
Subject: [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 <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;
+}
+
 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)
-- 
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