[PATCH 2/2] usb: dwc3: core: add external vBus supply support for ulpi phy

[Piyush Mehta <piyush.mehta@amd.com>]

Some ULPI USB PHY does not support internal VBUS supply, to drive the CPEN
pin, which requires the configuration of the ULPI DRVVBUSEXTERNAL bit of
OTG_CTRL register.

Added 'snps,ulpi-ext-vbus-drv' a DT property to configure the USB2 PHY to
drive VBUS with an external supply, by setting the USB2 PHY ULPIEXTVBUSDRV
bit[:17] of the GUSB2PHYCFG register to drive VBUS with an external supply.

Signed-off-by: Piyush Mehta <piyush.mehta@amd.com>
---
 drivers/usb/dwc3/core.c | 12 ++++++++++++
 drivers/usb/dwc3/core.h |  4 ++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 476b63618511..ed0ab90d3fac 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -800,6 +800,16 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->dis_u2_freeclk_exists_quirk || dwc->gfladj_refclk_lpm_sel)
 		reg &= ~DWC3_GUSB2PHYCFG_U2_FREECLK_EXISTS;
 
+	/*
+	 * Some ULPI USB PHY does not support internal VBUS supply, to drive
+	 * the CPEN pin requires the configuration of the ULPI DRVVBUSEXTERNAL
+	 * bit of OTG_CTRL register. Controller configures the USB2 PHY
+	 * ULPIEXTVBUSDRV bit[17] of the GUSB2PHYCFG register to drive vBus
+	 * with an external supply.
+	 */
+	if (dwc->ulpi_ext_vbus_drv)
+		reg |= DWC3_GUSB2PHYCFG_ULPIEXTVBUSDRV;
+
 	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
 
 	return 0;
@@ -1553,6 +1563,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				"snps,dis-tx-ipgap-linecheck-quirk");
 	dwc->resume_hs_terminations = device_property_read_bool(dev,
 				"snps,resume-hs-terminations");
+	dwc->ulpi_ext_vbus_drv = device_property_read_bool(dev,
+				"snps,ulpi-ext-vbus-drv");
 	dwc->parkmode_disable_ss_quirk = device_property_read_bool(dev,
 				"snps,parkmode-disable-ss-quirk");
 	dwc->gfladj_refclk_lpm_sel = device_property_read_bool(dev,
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 8f9959ba9fd4..9d5487b377b7 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -280,6 +280,7 @@
 /* Global USB2 PHY Configuration Register */
 #define DWC3_GUSB2PHYCFG_PHYSOFTRST	BIT(31)
 #define DWC3_GUSB2PHYCFG_U2_FREECLK_EXISTS	BIT(30)
+#define DWC3_GUSB2PHYCFG_ULPIEXTVBUSDRV	BIT(17)
 #define DWC3_GUSB2PHYCFG_SUSPHY		BIT(6)
 #define DWC3_GUSB2PHYCFG_ULPI_UTMI	BIT(4)
 #define DWC3_GUSB2PHYCFG_ENBLSLPM	BIT(8)
@@ -1100,6 +1101,8 @@ struct dwc3_scratchpad_array {
  *			check during HS transmit.
  * @resume-hs-terminations: Set if we enable quirk for fixing improper crc
  *			generation after resume from suspend.
+ * @ulpi_ext_vbus_drv: Set to confiure the upli chip to drives CPEN pin
+ *			VBUS with an external supply.
  * @parkmode_disable_ss_quirk: set if we need to disable all SuperSpeed
  *			instances in park mode.
  * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
@@ -1316,6 +1319,7 @@ struct dwc3 {
 	unsigned		dis_del_phy_power_chg_quirk:1;
 	unsigned		dis_tx_ipgap_linecheck_quirk:1;
 	unsigned		resume_hs_terminations:1;
+	unsigned		ulpi_ext_vbus_drv:1;
 	unsigned		parkmode_disable_ss_quirk:1;
 	unsigned		gfladj_refclk_lpm_sel:1;
 
-- 
2.17.1