stm32mp1: add stusb1600 support for DK1 and DK2 board

The DK1 and DK2 boards use the USB Type-C controller STUSB1600.
This patch updates:
- the device tree to add the I2C node in the DT
- the board stm32mp1 to probe this I2C device and use this controller
  to check cable detection.
- the DWC2 driver to support a new dt property
  "u-boot,force-b-session-valid" which forces B session and
  device mode; it is a workaround because the VBUS sensing and
  ID detection isn't available with stusb1600.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>

arch/arm/dts/stm32mp157-pinctrl.dtsi

@@ -375,6 +375,13 @@
 				};
 			};
 
+			stusb1600_pins_a: stusb1600-0 {
+				pins {
+					pinmux = <STM32_PINMUX('I', 11, ANALOG)>;
+					bias-pull-up;
+				};
+			};
+
 			uart4_pins_a: uart4-0 {
 				pins1 {
 					pinmux = <STM32_PINMUX('G', 11, AF6)>; /* UART4_TX */

arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi

@@ -191,7 +191,7 @@
 };
 
 &usbotg_hs {
-	force-b-session-valid;
+	u-boot,force-b-session-valid;
 	hnp-srp-disable;
 };
 

arch/arm/dts/stm32mp157a-dk1.dts

@@ -67,6 +67,24 @@
 	/delete-property/dmas;
 	/delete-property/dma-names;
 
+	typec: stusb1600@28 {
+		compatible = "st,stusb1600";
+		reg = <0x28>;
+		interrupts = <11 IRQ_TYPE_EDGE_FALLING>;
+		interrupt-parent = <&gpioi>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&stusb1600_pins_a>;
+
+		status = "okay";
+
+		typec_con: connector {
+			compatible = "usb-c-connector";
+			label = "USB-C";
+			power-role = "sink";
+			power-opmode = "default";
+		};
+	};
+
 	pmic: stpmic@33 {
 		compatible = "st,stpmic1";
 		reg = <0x33>;

board/st/stm32mp1/stm32mp1.c

@@ -9,15 +9,18 @@
 #include <dm.h>
 #include <g_dnl.h>
 #include <generic-phy.h>
+#include <i2c.h>
 #include <led.h>
 #include <misc.h>
 #include <phy.h>
 #include <reset.h>
 #include <syscon.h>
+#include <usb.h>
 #include <asm/io.h>
 #include <asm/gpio.h>
 #include <asm/arch/stm32.h>
 #include <power/regulator.h>
+#include <usb/dwc2_udc.h>
 
 /* SYSCFG registers */
 #define SYSCFG_BOOTR		0x00
@@ -151,11 +154,64 @@ static void board_key_check(void)
 
 #if defined(CONFIG_USB_GADGET) && defined(CONFIG_USB_GADGET_DWC2_OTG)
 
+/* STMicroelectronics STUSB1600 Type-C controller */
+#define STUSB1600_CC_CONNECTION_STATUS		0x0E
+
+/* STUSB1600_CC_CONNECTION_STATUS bitfields */
+#define STUSB1600_CC_ATTACH			BIT(0)
+
+static int stusb1600_init(struct udevice **dev_stusb1600)
+{
+	ofnode node;
+	struct udevice *dev, *bus;
+	int ret;
+	u32 chip_addr;
+
+	*dev_stusb1600 = NULL;
+
+	/* if node stusb1600 is present, means DK1 or DK2 board */
+	node = ofnode_by_compatible(ofnode_null(), "st,stusb1600");
+	if (!ofnode_valid(node))
+		return -ENODEV;
+
+	ret = ofnode_read_u32(node, "reg", &chip_addr);
+	if (ret)
+		return -EINVAL;
+
+	ret = uclass_get_device_by_ofnode(UCLASS_I2C, ofnode_get_parent(node),
+					  &bus);
+	if (ret) {
+		printf("bus for stusb1600 not found\n");
+		return -ENODEV;
+	}
+
+	ret = dm_i2c_probe(bus, chip_addr, 0, &dev);
+	if (!ret)
+		*dev_stusb1600 = dev;
+
+	return ret;
+}
+
+static int stusb1600_cable_connected(struct udevice *dev)
+{
+	u8 status;
+
+	if (dm_i2c_read(dev, STUSB1600_CC_CONNECTION_STATUS, &status, 1))
+		return 0;
+
+	return status & STUSB1600_CC_ATTACH;
+}
+
+#include <usb/dwc2_udc.h>
 int g_dnl_board_usb_cable_connected(void)
 {
+	struct udevice *stusb1600;
 	struct udevice *dwc2_udc_otg;
 	int ret;
 
+	if (!stusb1600_init(&stusb1600))
+		return stusb1600_cable_connected(stusb1600);
+
 	ret = uclass_get_device_by_driver(UCLASS_USB_GADGET_GENERIC,
 					  DM_GET_DRIVER(dwc2_udc_otg),
 					  &dwc2_udc_otg);

doc/device-tree-bindings/usb/dwc2.txt

@@ -39,6 +39,8 @@ Refer to phy/phy-bindings.txt for generic phy consumer properties
 - g-tx-fifo-size: size of periodic tx fifo per endpoint (except ep0) in gadget mode.
 - usb33d-supply: external VBUS and ID sensing comparators supply, in order to
   perform OTG operation, used on STM32MP1 SoCs.
+- u-boot,force-b-session-valid: force B-peripheral session instead of relying on
+  VBUS sensing (only valid when dr_mode = "peripheral" and for u-boot).
 
 Deprecated properties:
 - g-use-dma: gadget DMA mode is automatically detected

drivers/usb/gadget/dwc2_udc_otg.c

@@ -1053,7 +1053,7 @@ static int dwc2_udc_otg_ofdata_to_platdata(struct udevice *dev)
 	platdata->tx_fifo_sz = dev_read_u32_default(dev, "g-tx-fifo-size", 0);
 
 	platdata->force_b_session_valid =
-		dev_read_bool(dev, "force-b-session-valid");
+		dev_read_bool(dev, "u-boot,force-b-session-valid");
 
 	/* force platdata according compatible */
 	drvdata = dev_get_driver_data(dev);
@@ -1075,6 +1075,9 @@ static void dwc2_set_stm32mp1_hsotg_params(struct dwc2_plat_otg_data *p)
 		| 0 << 8	/* [0:SRP disable 1:SRP enable]*/
 		| 0 << 6	/* 0: high speed utmi+, 1: full speed serial*/
 		| 0x7 << 0;	/* FS timeout calibration**/
+
+	if (p->force_b_session_valid)
+		p->usb_gusbcfg |= 1 << 30; /* FDMOD: Force device mode */
 }
 
 static int dwc2_udc_otg_reset_init(struct udevice *dev,
@@ -1166,7 +1169,8 @@ static int dwc2_udc_otg_probe(struct udevice *dev)
 
 	if (platdata->force_b_session_valid)
 		/* Override B session bits : value and enable */
-		setbits_le32(&usbotg_reg->gotgctl,  B_VALOEN | B_VALOVAL);
+		setbits_le32(&usbotg_reg->gotgctl,
+			     A_VALOEN | A_VALOVAL | B_VALOEN | B_VALOVAL);
 
 	ret = dwc2_udc_probe(platdata);
 	if (ret)