AM437x: USB DWC3: save power during system sleep

Hi,

This series add support to DWC3 core to conserve power during system sleep by setting the USB DRVVBUS line to a lower power consuming state.

Tested to make sure USB host and device works on AM437x with v4.2. Tested for power savings on v4.1 kernel where there is an implementation of suspend- to-RAM for AM437x available.

Dave Gerlach (1):
ARM: dts: am437x-gp-evm: Add pinctrl states for usb

Sekhar Nori (1):
usb: dwc3: support for pinctrl state change during system sleep

 arch/arm/boot/dts/am437x-gp-evm.dts | 30 ++++++++++++++++++++++++++++++
 drivers/usb/dwc3/core.c             |  4 ++++
 2 files changed, 34 insertions(+)

2.4.4.408.g16da57c

Add support for USB DRVVBUS pinctrl state change during suspend/resume. This helps is conserving power during system sleep.

---
 drivers/usb/dwc3/core.c | 4 ++++
 1 file changed, 4 insertions(+)

index ff5773c66b84..a5ffa66e39fb 100644
@@ -1093,6 +1093,8 @@ static int dwc3_suspend(struct device *dev)
 	phy_exit(dwc->usb2_generic_phy);
 	phy_exit(dwc->usb3_generic_phy);
 
+	pinctrl_pm_select_sleep_state(dev);
+
 	return 0;
 }
 

@@ -1102,6 +1104,8 @@ static int dwc3_resume(struct device *dev)
 	unsigned long	flags;
 	int		ret;
 
+	pinctrl_pm_select_default_state(dev);
+
 	usb_phy_init(dwc->usb3_phy);
 	usb_phy_init(dwc->usb2_phy);
 	ret = phy_init(dwc->usb2_generic_phy);

2.4.4.408.g16da57c

From: Dave Gerlach <[email protected]>

Add pinctrl default and sleep states for each usb device. The only pin that can be controlled is USB_DRVVBUS, this must be set to MUX_MODE7 (gpio) during sleep to conserve power.

---
 arch/arm/boot/dts/am437x-gp-evm.dts | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

index 84aa30c3235a..2e990a5f9e95 100644
@@ -409,6 +409,30 @@
 			0x234 (PIN_OUTPUT_PULLDOWN | MUX_MODE0) /* uart3_rtsn.uart3_rtsn */
 		>;
 	};
+
+	usb1_pins_default: usb1_pins_default {
+		pinctrl-single,pins = <
+			0x2c0 (DS0_PULL_UP_DOWN_EN | PIN_INPUT_PULLDOWN | MUX_MODE0)
+		>;
+	};
+
+	usb1_pins_sleep: usb1_pins_sleep {
+		pinctrl-single,pins = <
+			0x2c0 (DS0_PULL_UP_DOWN_EN | PIN_INPUT_PULLDOWN | MUX_MODE7)
+		>;
+	};
+
+	usb2_pins_default: usb2_pins_default {
+		pinctrl-single,pins = <
+			0x2c4 (DS0_PULL_UP_DOWN_EN | PIN_INPUT_PULLDOWN | MUX_MODE0)
+		>;
+	};
+
+	usb2_pins_sleep: usb2_pins_sleep {
+		pinctrl-single,pins = <
+			0x2c4 (DS0_PULL_UP_DOWN_EN | PIN_INPUT_PULLDOWN | MUX_MODE7)
+		>;
+	};
 };
 
 &i2c0 {

@@ -615,6 +639,9 @@
 &usb1 {
 	dr_mode = "peripheral";
 	status = "okay";
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&usb1_pins_default>;
+	pinctrl-1 = <&usb1_pins_sleep>;
 };
 
 &usb2_phy2 {

@@ -624,6 +651,9 @@
 &usb2 {
 	dr_mode = "host";
 	status = "okay";
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&usb2_pins_default>;
+	pinctrl-1 = <&usb2_pins_sleep>;
 };
 
 &mac {

2.4.4.408.g16da57c