[linux-yocto] [PATCH 10/29] usb: dwc3: pci: Enable/disable ulpi phy refclk

[rebecca.swee.fun.chang at intel.com]

From: Maurice Petallo <mauricex.r.petallo at intel.com>

Due to power saving purpose, BIOS disabled ulpi phy refclk by default.
Hence, the refclk will only be enabled during device/driver probing.
and disabled during driver removal.

Signed-off-by: Maurice Petallo <mauricex.r.petallo at intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew at intel.com>
---
 drivers/usb/dwc3/dwc3-pci.c |   23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
index 2357c4e..4ebe49a 100644
--- a/drivers/usb/dwc3/dwc3-pci.c
+++ b/drivers/usb/dwc3/dwc3-pci.c
@@ -51,6 +51,10 @@
 #define PCI_DEVICE_ID_INTEL_BYT		0x0f37
 #define PCI_DEVICE_ID_INTEL_MRFLD	0x119e
 
+#define DWC3_PCI_GEN_REGRW1			0xa0
+#define DWC3_PCI_GEN_REGRW1_REFCLK_EN(n)	(n & 0xfffdffff)
+#define DWC3_PCI_GEN_REGRW1_REFCLK_DIS(n)	(n | 0x020000)
+
 struct dwc3_pci {
 	struct device		*dev;
 	struct platform_device	*dwc3;
@@ -112,6 +116,19 @@ err1:
 	return ret;
 }
 
+static void dwc3_pci_ulpiphy_refclk(struct pci_dev *pci, int enable)
+{
+	u32 val;
+
+	pci_read_config_dword(pci, DWC3_PCI_GEN_REGRW1, &val);
+	if (enable)
+		val = DWC3_PCI_GEN_REGRW1_REFCLK_EN(val);
+	else
+		val = DWC3_PCI_GEN_REGRW1_REFCLK_DIS(val);
+
+	pci_write_config_dword(pci, DWC3_PCI_GEN_REGRW1, val);
+}
+
 static int dwc3_pci_probe(struct pci_dev *pci,
 		const struct pci_device_id *id)
 {
@@ -183,6 +200,9 @@ static int dwc3_pci_probe(struct pci_dev *pci,
 		goto err3;
 	}
 
+	/* enable ulpi phy refclk */
+	dwc3_pci_ulpiphy_refclk(pci, 1);
+
 	return 0;
 
 err3:
@@ -198,6 +218,9 @@ static void dwc3_pci_remove(struct pci_dev *pci)
 {
 	struct dwc3_pci	*glue = pci_get_drvdata(pci);
 
+	/* disable ulpi phy refclk */
+	dwc3_pci_ulpiphy_refclk(pci, 0);
+
 	platform_device_unregister(glue->dwc3);
 	platform_device_unregister(glue->usb2_phy);
 	platform_device_unregister(glue->usb3_phy);
-- 
1.7.10.4