drivers: usb_c: tcpc: stm32: Add VCONN functionality

Add VCONN discharge functionality to TCPC and driver

Signed-off-by: Sam Hurst <sbh1187@gmail.com>

drivers/usb_c/tcpc/ucpd_stm32.c

@@ -156,10 +156,15 @@ static uint32_t ucpd_get_cc_enable_mask(const struct device *dev)
 	const struct tcpc_config *const config = dev->config;
 	uint32_t mask = UCPD_CR_CCENABLE_Msk;
 
+	/*
+	 * When VCONN is enabled, it is supplied on the CC line that's
+	 * not being used for Power Delivery messages.
+	 */
 	if (data->ucpd_vconn_enable) {
 		uint32_t cr = LL_UCPD_ReadReg(config->ucpd_port, CR);
 		int pol = (cr & UCPD_CR_PHYCCSEL);
 
+		/* Dissable CC line that's used for VCONN */
 		mask &= ~BIT(UCPD_CR_CCENABLE_Pos + !pol);
 	}
 
@@ -281,12 +286,52 @@ static int ucpd_set_vconn(const struct device *dev, bool enable)
 	update_stm32g0x_cc_line(config->ucpd_port);
 #endif
 
+	/* Get CC line that VCONN is active on */
+	data->ucpd_vconn_cc = (cr & UCPD_CR_CCENABLE_0) ?
+				TC_POLARITY_CC2 : TC_POLARITY_CC1;
+
 	/* Call user supplied callback to set vconn */
-	ret = data->vconn_cb(dev, enable);
+	ret = data->vconn_cb(dev, data->ucpd_vconn_cc, enable);
 
 	return ret;
 }
 
+/**
+ * @brief Discharge VCONN
+ *
+ * @retval 0 on success
+ * @retval -EIO on failure
+ * @retval -ENOTSUP if not supported
+ */
+static int ucpd_vconn_discharge(const struct device *dev, bool enable)
+{
+	struct tcpc_data *data = dev->data;
+	const struct tcpc_config *const config = dev->config;
+
+	/* VCONN should not be discharged while it's enabled */
+	if (data->ucpd_vconn_enable) {
+		return -EIO;
+	}
+
+	if (data->vconn_discharge_cb) {
+		/* Use DPM supplied VCONN Discharge */
+		return data->vconn_discharge_cb(dev, data->ucpd_vconn_cc, enable);
+	}
+
+	/* Use TCPC VCONN Discharge */
+	if (enable) {
+		LL_UCPD_VconnDischargeEnable(config->ucpd_port);
+	} else {
+		LL_UCPD_VconnDischargeDisable(config->ucpd_port);
+	}
+
+#ifdef CONFIG_SOC_SERIES_STM32G0X
+	update_stm32g0x_cc_line(config->ucpd_port);
+#endif
+
+	return 0;
+}
+
 /**
  * @brief Sets the value of the CC pull up resistor used when operating as a Source
  *
@@ -1236,6 +1281,20 @@ static void ucpd_set_vconn_cb(const struct device *dev,
 	data->vconn_cb = vconn_cb;
 }
 
+/**
+ * @brief Sets a callback that can discharge VCONN if the TCPC is
+ *        unable to or the system is configured in a way that does not use
+ *        the VCONN discharge capabilities of the TCPC
+ *
+ */
+static void ucpd_set_vconn_discharge_cb(const struct device *dev,
+					tcpc_vconn_discharge_cb_t cb)
+{
+	struct tcpc_data *data = dev->data;
+
+	data->vconn_discharge_cb = cb;
+}
+
 /**
  * @brief UCPD interrupt init
  */
@@ -1344,7 +1403,9 @@ static const struct tcpc_driver_api driver_api = {
 	.set_cc = ucpd_set_cc,
 	.set_roles = ucpd_set_roles,
 	.set_vconn_cb = ucpd_set_vconn_cb,
+	.set_vconn_discharge_cb = ucpd_set_vconn_discharge_cb,
 	.set_vconn = ucpd_set_vconn,
+	.vconn_discharge = ucpd_vconn_discharge,
 	.set_cc_polarity = ucpd_cc_set_polarity,
 	.dump_std_reg = ucpd_dump_std_reg,
 	.set_bist_test_mode = ucpd_set_bist_test_mode,

drivers/usb_c/tcpc/ucpd_stm32_priv.h

@@ -267,6 +267,8 @@ struct tcpc_config {
 struct tcpc_data {
 	/* VCONN callback function */
 	tcpc_vconn_control_cb_t vconn_cb;
+	/* VCONN Discharge callback function */
+	tcpc_vconn_discharge_cb_t vconn_discharge_cb;
 	/* Alert information */
 	struct alert_info alert_info;
 
@@ -309,6 +311,8 @@ struct tcpc_data {
 	struct msg_header_info msg_header;
 	/* Track VCONN on/off state */
 	bool ucpd_vconn_enable;
+	/* Track CC line that VCONN was active on */
+	enum tc_cc_polarity ucpd_vconn_cc;
 
 	/* Timer for amount of time to wait for receiving a GoodCRC */
 	struct k_timer goodcrc_rx_timer;

include/zephyr/drivers/usb_c/usbc_tcpc.h

@@ -116,7 +116,10 @@ struct tcpc_chip_info {
 	};
 };
 
-typedef	int (*tcpc_vconn_control_cb_t)(const struct device *dev, bool enable);
+typedef	int (*tcpc_vconn_control_cb_t)(const struct device *dev,
+		enum tc_cc_polarity pol, bool enable);
+typedef	int (*tcpc_vconn_discharge_cb_t)(const struct device *dev,
+		enum tc_cc_polarity pol, bool enable);
 typedef void (*tcpc_alert_handler_cb_t)(const struct device *dev, void *data,
 		enum tcpc_alert alert);
 
@@ -127,7 +130,9 @@ __subsystem struct tcpc_driver_api {
 	int (*select_rp_value)(const struct device *dev, enum tc_rp_value rp);
 	int (*get_rp_value)(const struct device *dev, enum tc_rp_value *rp);
 	int (*set_cc)(const struct device *dev, enum tc_cc_pull pull);
+	void (*set_vconn_discharge_cb)(const struct device *dev, tcpc_vconn_discharge_cb_t cb);
 	void (*set_vconn_cb)(const struct device *dev, tcpc_vconn_control_cb_t vconn_cb);
+	int (*vconn_discharge)(const struct device *dev, bool enable);
 	int (*set_vconn)(const struct device *dev, bool enable);
 	int (*set_roles)(const struct device *dev, enum tc_power_role power_role,
 			enum tc_data_role data_role);
@@ -350,6 +355,53 @@ static inline void tcpc_set_vconn_cb(const struct device *dev,
 	return api->set_vconn_cb(dev, vconn_cb);
 }
 
+/**
+ * @brief Sets a callback that can enable or discharge VCONN if the TCPC is
+ *	  unable to or the system is configured in a way that does not use
+ *	  the VCONN control capabilities of the TCPC
+ *
+ * The callback is called in the tcpc_vconn_discharge function if cb isn't NULL
+ *
+ * @param dev       Runtime device structure
+ * @param cb  pointer to the callback function that discharges vconn
+ */
+static inline void tcpc_set_vconn_discharge_cb(const struct device *dev,
+				     tcpc_vconn_discharge_cb_t cb)
+{
+	const struct tcpc_driver_api *api =
+		(const struct tcpc_driver_api *)dev->api;
+
+	__ASSERT(api->set_vconn_discharge_cb != NULL,
+		 "Callback pointer should not be NULL");
+
+	return api->set_vconn_discharge_cb(dev, cb);
+}
+
+/**
+ * @brief Discharges VCONN
+ *
+ * This function uses the TCPC to discharge VCONN if possible or calls the
+ * callback function set by tcpc_set_vconn_cb
+ *
+ * @param dev     Runtime device structure
+ * @param enable  VCONN discharge is enabled when true, it's disabled
+ *
+ * @retval 0 on success
+ * @retval -EIO on failure
+ * @retval -ENOSYS if not implemented
+ */
+static inline int tcpc_vconn_discharge(const struct device *dev, bool enable)
+{
+	const struct tcpc_driver_api *api =
+		(const struct tcpc_driver_api *)dev->api;
+
+	if (api->vconn_discharge == NULL) {
+		return -ENOSYS;
+	}
+
+	return api->vconn_discharge(dev, enable);
+}
+
 /**
  * @brief Enables or disables VCONN
  *

include/zephyr/usb_c/usbc.h

@@ -123,6 +123,8 @@ enum usbc_policy_check_t {
 	CHECK_DATA_ROLE_SWAP_TO_UFP,
 	/** Check if Sink is at default level */
 	CHECK_SNK_AT_DEFAULT_LEVEL,
+	/** Check if should control VCONN */
+	CHECK_VCONN_CONTROL,
 };
 
 /**
@@ -213,6 +215,15 @@ void *usbc_get_dpm_data(const struct device *dev);
 void usbc_set_vconn_control_cb(const struct device *dev,
 			       const tcpc_vconn_control_cb_t cb);
 
+/**
+ * @brief Set the callback used to discharge VCONN
+ *
+ * @param dev Runtime device structure
+ * @param cb VCONN discharge callback
+ */
+void usbc_set_vconn_discharge_cb(const struct device *dev,
+				 const tcpc_vconn_discharge_cb_t cb);
+
 /**
  * @brief Set the callback used to check a policy
  *