usb: dwc3: Add dis_enblslpm_quirk

Add a quirk to clear the GUSB2PHYCFG.ENBLSLPM bit, which controls
whether the PHY receives the suspend signal from the controller.

Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/dwc3.txt

@@ -35,6 +35,8 @@ Optional properties:
 			LTSSM during USB3 Compliance mode.
  - snps,dis_u3_susphy_quirk: when set core will disable USB3 suspend phy.
  - snps,dis_u2_susphy_quirk: when set core will disable USB2 suspend phy.
+ - snps,dis_enblslpm_quirk: when set clears the enblslpm in GUSB2PHYCFG,
+			disabling the suspend signal to the PHY.
  - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
 			utmi_l1_suspend_n, false when asserts utmi_sleep_n
  - snps,hird-threshold: HIRD threshold

drivers/usb/dwc3/core.c

@@ -515,6 +515,9 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->dis_u2_susphy_quirk)
 		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
 
+	if (dwc->dis_enblslpm_quirk)
+		reg &= ~DWC3_GUSB2PHYCFG_ENBLSLPM;
+
 	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
 
 	return 0;
@@ -912,6 +915,8 @@ static int dwc3_probe(struct platform_device *pdev)
 				"snps,dis_u3_susphy_quirk");
 	dwc->dis_u2_susphy_quirk = device_property_read_bool(dev,
 				"snps,dis_u2_susphy_quirk");
+	dwc->dis_enblslpm_quirk = device_property_read_bool(dev,
+				"snps,dis_enblslpm_quirk");
 
 	dwc->tx_de_emphasis_quirk = device_property_read_bool(dev,
 				"snps,tx_de_emphasis_quirk");
@@ -945,6 +950,7 @@ static int dwc3_probe(struct platform_device *pdev)
 		dwc->rx_detect_poll_quirk = pdata->rx_detect_poll_quirk;
 		dwc->dis_u3_susphy_quirk = pdata->dis_u3_susphy_quirk;
 		dwc->dis_u2_susphy_quirk = pdata->dis_u2_susphy_quirk;
+		dwc->dis_enblslpm_quirk = pdata->dis_enblslpm_quirk;
 
 		dwc->tx_de_emphasis_quirk = pdata->tx_de_emphasis_quirk;
 		if (pdata->tx_de_emphasis)

drivers/usb/dwc3/core.h

@@ -179,6 +179,7 @@
 #define DWC3_GUSB2PHYCFG_PHYSOFTRST	(1 << 31)
 #define DWC3_GUSB2PHYCFG_SUSPHY		(1 << 6)
 #define DWC3_GUSB2PHYCFG_ULPI_UTMI	(1 << 4)
+#define DWC3_GUSB2PHYCFG_ENBLSLPM	(1 << 8)
 
 /* Global USB2 PHY Vendor Control Register */
 #define DWC3_GUSB2PHYACC_NEWREGREQ	(1 << 25)
@@ -720,6 +721,8 @@ struct dwc3_scratchpad_array {
  * @rx_detect_poll_quirk: set if we enable rx_detect to polling lfps quirk
  * @dis_u3_susphy_quirk: set if we disable usb3 suspend phy
  * @dis_u2_susphy_quirk: set if we disable usb2 suspend phy
+ * @dis_enblslpm_quirk: set if we clear enblslpm in GUSB2PHYCFG,
+ *                      disabling the suspend signal to the PHY.
  * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
  * @tx_de_emphasis: Tx de-emphasis value
  * 	0	- -6dB de-emphasis
@@ -864,6 +867,7 @@ struct dwc3 {
 	unsigned		rx_detect_poll_quirk:1;
 	unsigned		dis_u3_susphy_quirk:1;
 	unsigned		dis_u2_susphy_quirk:1;
+	unsigned		dis_enblslpm_quirk:1;
 
 	unsigned		tx_de_emphasis_quirk:1;
 	unsigned		tx_de_emphasis:2;

drivers/usb/dwc3/platform_data.h

@@ -42,6 +42,7 @@ struct dwc3_platform_data {
 	unsigned rx_detect_poll_quirk:1;
 	unsigned dis_u3_susphy_quirk:1;
 	unsigned dis_u2_susphy_quirk:1;
+	unsigned dis_enblslpm_quirk:1;
 
 	unsigned tx_de_emphasis_quirk:1;
 	unsigned tx_de_emphasis:2;