[PATCH 2/2] phy: qcom-usb-hs: Add qcom,enable-vbus-pullup support

[Bryan O'Donoghue]

Downstream has a flag called qcom,dp-manual-pullup which informs the
downstream driver if it should toggle ULPI_MISC_A_VBUSVLDEXTSEL and
ULPI_MISC_A_VBUSVLDEXT.

Downstream states:

"qcom,dp-manual-pullup: If present, vbus is not routed to USB
        controller/phy and controller driver therefore enables pull-up
        explicitly before starting controller using usbcmd run/stop bit."

Working with a type-c controller which handles VBUS entirely means there's
a need to replicate similar logic in upstream.

The current PHY code waggles these bits if an extcon associated with VBUS
exists but, that is not the case when using a full-fat type-c controller
i.e. there's no VBUS line routed to a SoC pad to sense.

This patch enables and disables the VBUS pullup bits on PHY power_on and
power_off respectively if the DT has declared the bool
"qcom,enable-vbus-pullup".

Cc: Andy Gross <agross@xxxxxxxxxx>
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Cc: Kishon Vijay Abraham I <kishon@xxxxxx>
Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: linux-arm-msm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
 drivers/phy/qualcomm/phy-qcom-usb-hs.c | 36 ++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-usb-hs.c b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
index 61054272a7c8..578a4e1fc539 100644
--- a/drivers/phy/qualcomm/phy-qcom-usb-hs.c
+++ b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
@@ -37,6 +37,7 @@ struct qcom_usb_hs_phy {
 	struct ulpi_seq *init_seq;
 	struct extcon_dev *vbus_edev;
 	struct notifier_block vbus_notify;
+	u8 enable_vbus_pullup:1;
 };
 
 static int qcom_usb_hs_phy_set_mode(struct phy *phy,
@@ -104,6 +105,23 @@ qcom_usb_hs_phy_vbus_notifier(struct notifier_block *nb, unsigned long event,
 	return ulpi_write(uphy->ulpi, addr, ULPI_MISC_A_VBUSVLDEXT);
 }
 
+static int qcom_usb_hs_phy_enable_vbus_pullup(struct ulpi *ulpi, bool enable)
+{
+	u8 addr;
+	int ret;
+
+	if (enable)
+		addr = ULPI_SET(ULPI_MISC_A);
+	else
+		addr = ULPI_CLR(ULPI_MISC_A);
+
+	ret = ulpi_write(ulpi, addr, ULPI_MISC_A_VBUSVLDEXTSEL);
+	if (ret)
+		return ret;
+
+	return ulpi_write(ulpi, addr, ULPI_MISC_A_VBUSVLDEXT);
+}
+
 static int qcom_usb_hs_phy_power_on(struct phy *phy)
 {
 	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
@@ -153,6 +171,12 @@ static int qcom_usb_hs_phy_power_on(struct phy *phy)
 			goto err_ulpi;
 	}
 
+	if (uphy->enable_vbus_pullup) {
+		ret = qcom_usb_hs_phy_enable_vbus_pullup(ulpi, true);
+		if (ret)
+			goto err_ulpi;
+	}
+
 	if (uphy->vbus_edev) {
 		state = extcon_get_state(uphy->vbus_edev, EXTCON_USB);
 		/* setup initial state */
@@ -179,10 +203,19 @@ static int qcom_usb_hs_phy_power_on(struct phy *phy)
 static int qcom_usb_hs_phy_power_off(struct phy *phy)
 {
 	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+	struct ulpi *ulpi = uphy->ulpi;
+	int ret;
 
 	if (uphy->vbus_edev)
 		extcon_unregister_notifier(uphy->vbus_edev, EXTCON_USB,
 					   &uphy->vbus_notify);
+
+	if (uphy->enable_vbus_pullup) {
+		ret = qcom_usb_hs_phy_enable_vbus_pullup(ulpi, false);
+		if (ret)
+			return ret;
+	}
+
 	regulator_disable(uphy->v3p3);
 	regulator_disable(uphy->v1p8);
 	clk_disable_unprepare(uphy->sleep_clk);
@@ -228,6 +261,9 @@ static int qcom_usb_hs_phy_probe(struct ulpi *ulpi)
 	/* NUL terminate */
 	uphy->init_seq[size / 2].addr = uphy->init_seq[size / 2].val = 0;
 
+	if (of_property_read_bool(ulpi->dev.of_node, "qcom,enable-vbus-pullup"))
+		uphy->enable_vbus_pullup = 1;
+
 	uphy->ref_clk = clk = devm_clk_get(&ulpi->dev, "ref");
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);
-- 
2.25.1