[PATCH 0/2] phy: qcom-usb-hs: Add DT controlled VBUS pullup waggle

[PATCH 0/2] phy: qcom-usb-hs: Add DT controlled VBUS pullup waggle

[Bryan O'Donoghue]

On an MSM8939 we have a system behind both a type-c controller and a USB
Hub. VBUS is not connected to the PHY and no GPIO is available to signal
VBUS state to the USB controller and PHY.

In this case we've used USB role-switching to transition between
host and device mode.

The current code in qcom-usb-hs only touches the VBUS pullup control bits
if we have an extcon but, setting those bits is still required on the
example I gave of the MSM8939.

This series takes the downstream concept of a DT driven flag for the VBUS
pullup bits and applies it to upstream in the poweron/poweroff path of the
PHY.

I've opted to unset the bits on PHY poweroff though in downstream the bits
are only ever switched on if the flag is present, downstream never switches
the bits off again. I think though, setting the bits off on PHY power-off
is the right thing to do, so I've done it.

Bryan O'Donoghue (2):
  dt-bindings: phy-qcom-usb-hs-phy: Add qcom,enable-vbus-pullup
  phy: qcom-usb-hs: Add qcom,enable-vbus-pullup support

 .../bindings/phy/qcom,usb-hs-phy.txt          |  8 +++++
 drivers/phy/qualcomm/phy-qcom-usb-hs.c        | 36 +++++++++++++++++++
 2 files changed, 44 insertions(+)

-- 
2.25.1

[PATCH 1/2] dt-bindings: phy-qcom-usb-hs-phy: Add qcom,enable-vbus-pullup

[Bryan O'Donoghue]

This patch adds a dt-binding for qcom,enable-vbus-pullup. The binding
qcom,enable-vbus-pullup tells the HS USB PHY driver whether it should set
and unset the internal VBUS pullup bits when starting/stopping the USB PHY.

Setting the pullup bits is something you want to do if you have not routed
VBUS to a GPIO on the SoC and thus cannot use extcon with the current
switching logic in the PHY.

Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt b/Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt
index b3b75c1e6285..77e9bf1f8ba2 100644
--- a/Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt
+++ b/Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt
@@ -64,6 +64,12 @@ PROPERTIES
                 from the ULPI_EXT_VENDOR_SPECIFIC address, for example,
                 <0x1 0x53> would mean "write the value 0x53 to address 0x81".
 
+- qcom,enable-vbus-pullup:
+   Usage: optional
+   Value type: <bool>
+   Definition: Flag to indicate if the USB PHY driver should toggle internal
+               VBUS line pullup bits when powering the PHY on or off.
+
 EXAMPLE
 
 otg: usb-controller {
-- 
2.25.1

Re: [PATCH 1/2] dt-bindings: phy-qcom-usb-hs-phy: Add qcom,enable-vbus-pullup

[Rob Herring]

On Thu, 21 May 2020 01:50:30 +0100, Bryan O'Donoghue wrote:
> This patch adds a dt-binding for qcom,enable-vbus-pullup. The binding
> qcom,enable-vbus-pullup tells the HS USB PHY driver whether it should set
> and unset the internal VBUS pullup bits when starting/stopping the USB PHY.
> 
> Setting the pullup bits is something you want to do if you have not routed
> VBUS to a GPIO on the SoC and thus cannot use extcon with the current
> switching logic in the PHY.
> 
> Cc: Andy Gross <agross@kernel.org>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Kishon Vijay Abraham I <kishon@ti.com>
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> ---
>  Documentation/devicetree/bindings/phy/qcom,usb-hs-phy.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

[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@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 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