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

[Venkatesh Yadav Abbarapu]

[ Piyush: Ported from Linux kernel commit
	  b84ba26c922a ("usb: dwc3: core: add external vBus
				supply support for ulpi phy") ]

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: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
---
 drivers/usb/dwc3/core.c | 13 +++++++++++++
 drivers/usb/dwc3/core.h |  4 ++++
 include/dwc3-uboot.h    |  1 +
 3 files changed, 18 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 49f6a1900b..d59bbefec4 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -529,6 +529,16 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->dis_u2_freeclk_exists_quirk)
 		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);
 
 	mdelay(100);
@@ -888,6 +898,7 @@ int dwc3_uboot_init(struct dwc3_device *dwc3_dev)
 	dwc->dis_tx_ipgap_linecheck_quirk = dwc3_dev->dis_tx_ipgap_linecheck_quirk;
 	dwc->dis_enblslpm_quirk = dwc3_dev->dis_enblslpm_quirk;
 	dwc->dis_u2_freeclk_exists_quirk = dwc3_dev->dis_u2_freeclk_exists_quirk;
+	dwc->ulpi_ext_vbus_drv = dwc3_dev->ulpi_ext_vbus_drv;
 
 	dwc->tx_de_emphasis_quirk = dwc3_dev->tx_de_emphasis_quirk;
 	if (dwc3_dev->tx_de_emphasis)
@@ -1107,6 +1118,8 @@ void dwc3_of_parse(struct dwc3 *dwc)
 				"snps,dis-u2-freeclk-exists-quirk");
 	dwc->tx_de_emphasis_quirk = dev_read_bool(dev,
 				"snps,tx_de_emphasis_quirk");
+	dwc->ulpi_ext_vbus_drv = dev_read_bool(dev,
+				"snps,ulpi-ext-vbus-drv");
 	tmp = dev_read_u8_array_ptr(dev, "snps,tx_de_emphasis", 1);
 	if (tmp)
 		tx_de_emphasis = *tmp;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 532746dd88..54450842e0 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -184,6 +184,7 @@
 /* Global USB2 PHY Configuration Register */
 #define DWC3_GUSB2PHYCFG_PHYSOFTRST	(1 << 31)
 #define DWC3_GUSB2PHYCFG_U2_FREECLK_EXISTS	(1 << 30)
+#define DWC3_GUSB2PHYCFG_ULPIEXTVBUSDRV		BIT(17)
 #define DWC3_GUSB2PHYCFG_SUSPHY		(1 << 6)
 #define DWC3_GUSB2PHYCFG_ENBLSLPM	(1 << 8)
 #define DWC3_GUSB2PHYCFG_PHYIF(n)	((n) << 3)
@@ -742,6 +743,8 @@ struct dwc3_scratchpad_array {
  *	1	- -3.5dB de-emphasis
  *	2	- No de-emphasis
  *	3	- Reserved
+ * @ulpi_ext_vbus_drv: Set to confiure the upli chip to drives CPEN pin
+ *			VBUS with an external supply.
  * @index: index of _this_ controller
  * @list: to maintain the list of dwc3 controllers
  */
@@ -876,6 +879,7 @@ struct dwc3 {
 
 	unsigned		tx_de_emphasis_quirk:1;
 	unsigned		tx_de_emphasis:2;
+	unsigned                ulpi_ext_vbus_drv:1;
 	int			index;
 	struct list_head        list;
 };
diff --git a/include/dwc3-uboot.h b/include/dwc3-uboot.h
index e08530ec4e..722a9352ce 100644
--- a/include/dwc3-uboot.h
+++ b/include/dwc3-uboot.h
@@ -39,6 +39,7 @@ struct dwc3_device {
 	unsigned dis_u2_freeclk_exists_quirk;
 	unsigned tx_de_emphasis_quirk;
 	unsigned tx_de_emphasis;
+	unsigned ulpi_ext_vbus_drv;
 	int index;
 };
 
-- 
2.17.1