usbc: add support for vbus measurement using TCPCI compliant device

Add support for VBUS measuring part of the TCPCI compliant device.
This device should be used as a child-node for the more specific
TCPC driver and referenced by the vbus property in the usb-c
connector node.

Signed-off-by: Michał Barnaś <barnas@google.com>

drivers/usb_c/vbus/CMakeLists.txt

@@ -4,3 +4,4 @@ zephyr_library()
 
 zephyr_library_sources_ifdef(CONFIG_USBC_VBUS_ADC usbc_vbus_adc.c)
 zephyr_library_sources_ifdef(CONFIG_USBC_VBUS_NUMAKER usbc_vbus_numaker.c)
+zephyr_library_sources_ifdef(CONFIG_USBC_VBUS_TCPCI usbc_vbus_tcpci.c)

drivers/usb_c/vbus/Kconfig

@@ -18,6 +18,7 @@ config USBC_VBUS_INIT_PRIORITY
 
 source "drivers/usb_c/vbus/Kconfig.usbc_vbus_adc"
 source "drivers/usb_c/vbus/Kconfig.numaker"
+source "drivers/usb_c/vbus/Kconfig.usbc_vbus_tcpci"
 
 endif # USBC_VBUS_DRIVER
 

drivers/usb_c/vbus/Kconfig.usbc_vbus_tcpci

@@ -0,0 +1,12 @@
+# USB-C TCPCI VBUS device configuration options
+
+# Copyright 2024 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config USBC_VBUS_TCPCI
+	bool "USB-C VBUS TCPCI"
+	select USBC_TCPC_TCPCI
+	default y
+	depends on DT_HAS_ZEPHYR_USB_C_VBUS_TCPCI_ENABLED
+	help
+	  Measure VBUS using the TCPC chip compliant to TCPCI

drivers/usb_c/vbus/usbc_vbus_tcpci.c

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT zephyr_usb_c_vbus_tcpci
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(usbc_vbus_tcpci, CONFIG_USBC_LOG_LEVEL);
+
+#include <zephyr/device.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/usb_c/tcpci_priv.h>
+#include <zephyr/drivers/usb_c/usbc_vbus.h>
+#include <zephyr/drivers/usb_c/usbc_pd.h>
+#include <zephyr/usb_c/tcpci.h>
+
+/** Configuration structure for device instances */
+struct vbus_tcpci_cfg {
+	/** I2C bus and address used for communication, set from parent node of device. */
+	const struct i2c_dt_spec i2c;
+};
+
+static int tcpci_measure(const struct device *dev, int *vbus_meas)
+{
+	const struct vbus_tcpci_cfg *cfg = dev->config;
+	uint16_t measure;
+	int ret;
+
+	__ASSERT(vbus_meas != NULL, "TCPCI VBUS meas must not be NULL");
+
+	ret = tcpci_read_reg16(&cfg->i2c, TCPC_REG_VBUS_VOLTAGE, &measure);
+	if (ret != 0) {
+		return ret;
+	}
+
+	*vbus_meas = TCPC_REG_VBUS_VOLTAGE_VBUS(measure);
+
+	return 0;
+}
+
+static bool tcpci_check_level(const struct device *dev, enum tc_vbus_level level)
+{
+	int measure;
+	int ret;
+
+	ret = tcpci_measure(dev, &measure);
+	if (ret != 0) {
+		return false;
+	}
+
+	switch (level) {
+	case TC_VBUS_SAFE0V:
+		return (measure < PD_V_SAFE_0V_MAX_MV);
+	case TC_VBUS_PRESENT:
+		return (measure >= PD_V_SAFE_5V_MIN_MV);
+	case TC_VBUS_REMOVED:
+		return (measure < TC_V_SINK_DISCONNECT_MAX_MV);
+	}
+
+	return false;
+}
+
+static int tcpci_discharge(const struct device *dev, bool enable)
+{
+	const struct vbus_tcpci_cfg *cfg = dev->config;
+
+	return tcpci_update_reg8(&cfg->i2c, TCPC_REG_POWER_CTRL,
+				 TCPC_REG_POWER_CTRL_FORCE_DISCHARGE,
+				 (enable) ? TCPC_REG_POWER_CTRL_FORCE_DISCHARGE : 0);
+}
+
+static int tcpci_enable(const struct device *dev, bool enable)
+{
+	const struct vbus_tcpci_cfg *cfg = dev->config;
+
+	return tcpci_update_reg8(&cfg->i2c, TCPC_REG_POWER_CTRL,
+				 TCPC_REG_POWER_CTRL_VBUS_VOL_MONITOR_DIS,
+				 (enable) ? 0 : TCPC_REG_POWER_CTRL_VBUS_VOL_MONITOR_DIS);
+}
+
+static const struct usbc_vbus_driver_api vbus_tcpci_api = {.measure = tcpci_measure,
+							   .check_level = tcpci_check_level,
+							   .discharge = tcpci_discharge,
+							   .enable = tcpci_enable};
+
+static int tcpci_init(const struct device *dev)
+{
+	return 0;
+}
+
+BUILD_ASSERT(DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT) > 0,
+	     "No compatible USB-C VBUS Measurement instance found");
+
+#define VBUS_TCPCI_INIT_CFG(node)                                                                  \
+	{                                                                                          \
+		.i2c = {I2C_DT_SPEC_GET_ON_I2C(DT_PARENT(node))},                                  \
+	}
+
+#define DRIVER_INIT(inst)                                                                          \
+	static const struct vbus_tcpci_cfg drv_config_##inst =                                     \
+		VBUS_TCPCI_INIT_CFG(DT_DRV_INST(inst));                                            \
+	DEVICE_DT_INST_DEFINE(inst, &tcpci_init, NULL, NULL, &drv_config_##inst, POST_KERNEL,      \
+			      CONFIG_USBC_VBUS_INIT_PRIORITY, &vbus_tcpci_api);
+
+DT_INST_FOREACH_STATUS_OKAY(DRIVER_INIT)

dts/bindings/usb-c/zephyr,usb-c-vbus-tcpci.yaml

@@ -0,0 +1,12 @@
+# Copyright 2024 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    This device is used to measure VBUS on a Type-C Port and to
+    discharge VBUS when needed.
+    It should be used as a child node for a specific TCPCI compliant device. The I2C address is
+    taken from the parent of this node.
+
+compatible: "zephyr,usb-c-vbus-tcpci"
+
+include: [base.yaml]