tcpci: POWER_CTRL auto discharge disconnect init

Change TCPCI to use HOOK_USB_PD_CONNECT/DISCONNECT to
set/clear TCPC_REG_POWER_CTRL_AUTO_DISCHARGE_DISCONNECT
according to the TCPCI spec.

Change the definition of HOOK_USB_PD_CONNECT to occur
after CC and VBus are stable.

BUG=b:144126745,chromium:951683
BRANCH=none
TEST=Charger attach/pull with AP not running

Change-Id: I625efbba80f190322e3e92de6318b710b3ce7ade
Signed-off-by: Denis Brockus <dbrockus@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1940777

6 files changed, 80 insertions, 59 deletions

diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index d4f6f0c06b..cee2c5ca0f 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -28,7 +28,6 @@
 #include "usb_pd_tcpm.h"
 #include "usb_pd_tcpc.h"
 #include "usbc_ppc.h"
-#include "tcpm.h"
 #include "version.h"
 #include "vboot.h"
 
@@ -841,10 +840,10 @@ static inline void set_state(int port, enum pd_states next_state)
 
 		/* Invalidate message IDs. */
 		invalidate_last_message_id(port);
-#ifdef CONFIG_COMMON_RUNTIME
+
 		/* detect USB PD cc disconnect */
-		hook_notify(HOOK_USB_PD_DISCONNECT);
-#endif
+		if (IS_ENABLED(CONFIG_COMMON_RUNTIME))
+			hook_notify(HOOK_USB_PD_DISCONNECT);
 	}
 
 #ifdef CONFIG_LOW_POWER_IDLE
@@ -3314,9 +3313,6 @@ void pd_task(void *u)
 				break;
 
 			/* Debounce complete */
-			if (IS_ENABLED(CONFIG_COMMON_RUNTIME))
-				hook_notify(HOOK_USB_PD_CONNECT);
-
 #ifdef CONFIG_USBC_PPC
 			/*
 			 * If the port is latched off, just continue to
@@ -3400,6 +3396,10 @@ void pd_task(void *u)
 						  PD_FLAGS_CHECK_DR_ROLE;
 				hard_reset_count = 0;
 				timeout = 5*MSEC;
+
+				if (IS_ENABLED(CONFIG_COMMON_RUNTIME))
+					hook_notify(HOOK_USB_PD_CONNECT);
+
 				set_state(port, PD_STATE_SRC_STARTUP);
 			}
 			/*
@@ -3965,8 +3965,6 @@ void pd_task(void *u)
 			}
 
 			/* We are attached */
-			if (IS_ENABLED(CONFIG_COMMON_RUNTIME))
-				hook_notify(HOOK_USB_PD_CONNECT);
 			pd[port].polarity = get_snk_polarity(cc1, cc2);
 			set_polarity(port, pd[port].polarity);
 			/* reset message ID  on connection */
@@ -4001,6 +3999,8 @@ void pd_task(void *u)
 					&pd_usb_billboard_deferred_data,
 					PD_T_AME);
 			}
+			if (IS_ENABLED(CONFIG_COMMON_RUNTIME))
+				hook_notify(HOOK_USB_PD_CONNECT);
 			break;
 		case PD_STATE_SNK_HARD_RESET_RECOVER:
 			if (pd[port].last_state != pd[port].task_state)
diff --git a/driver/tcpm/nct38xx.c b/driver/tcpm/nct38xx.c
index 9d91c21b30..8939c52924 100644
--- a/driver/tcpm/nct38xx.c
+++ b/driver/tcpm/nct38xx.c
@@ -105,29 +105,6 @@ static int nct38xx_tcpm_init(int port)
 	return rv;
 }
 
-static int tcpci_nct38xx_select_rp_value(int port, int rp)
-{
-	selected_rp[port] = rp;
-	return EC_SUCCESS;
-}
-
-static int auto_discharge_disconnect(int port, int enable)
-{
-	int reg, rv;
-
-	rv = tcpc_read(port, TCPC_REG_POWER_CTRL, &reg);
-	if (rv)
-		return rv;
-
-	if (enable)
-		reg = reg | TCPC_REG_POWER_CTRL_AUTO_DISCHARGE_DISCONNECT;
-	else
-		reg = reg & ~TCPC_REG_POWER_CTRL_AUTO_DISCHARGE_DISCONNECT;
-	rv = tcpc_write(port, TCPC_REG_POWER_CTRL, reg);
-	return rv;
-
-}
-
 static int tcpci_nct38xx_check_cable_polarity(int port)
 {
 	int cc, rv;
@@ -222,23 +199,9 @@ static int tcpci_nct38xx_get_cc(int port, enum tcpc_cc_voltage_status *cc1,
 
 int tcpci_nct38xx_drp_toggle(int port)
 {
-	int rv;
-
 	cable_polarity[port] = POLARITY_NONE;
 
-	/*
-	 * The port was disconnected so it is probably a good place to set
-	 * auto-discharge-disconnect to '0'
-	 *
-	 * TODO(crbug.com/951683: this should be removed when common code adds
-	 * auto discharge.
-	 */
-	rv = auto_discharge_disconnect(port, 0);
-	if (rv)
-		return rv;
-
 	return tcpci_tcpc_drp_toggle(port);
-
 }
 
 int tcpci_nct38xx_set_polarity(int port, int polarity)
@@ -252,16 +215,7 @@ int tcpci_nct38xx_set_polarity(int port, int polarity)
 	reg = polarity ? (reg | TCPC_REG_TCPC_CTRL_SET(1)) :
 			  (reg & ~TCPC_REG_TCPC_CTRL_SET(1));
 
-	rv = tcpc_write(port, TCPC_REG_TCPC_CTRL, reg);
-	if (rv)
-		return rv;
-
-	/*
-	 * Polarity is set after connection so it is probably a good time to set
-	 * auto-discharge-disconnect to '1'
-	 */
-	rv = auto_discharge_disconnect(port, 1);
-	return rv;
+	return tcpc_write(port, TCPC_REG_TCPC_CTRL, reg);
 }
 
 int tcpci_nct38xx_transmit(int port, enum tcpm_transmit_type type,
@@ -348,6 +302,7 @@ static void nct38xx_tcpc_alert(int port)
 			nct38xx_ioex_event_handler(port);
 
 }
+
 const struct tcpm_drv nct38xx_tcpm_drv = {
 	.init			= &nct38xx_tcpm_init,
 	.release		= &tcpci_tcpm_release,
@@ -355,7 +310,7 @@ const struct tcpm_drv nct38xx_tcpm_drv = {
 #ifdef CONFIG_USB_PD_VBUS_DETECT_TCPC
 	.get_vbus_level		= &tcpci_tcpm_get_vbus_level,
 #endif
-	.select_rp_value	= &tcpci_nct38xx_select_rp_value,
+	.select_rp_value	= &tcpci_tcpm_select_rp_value,
 	.set_cc			= &tcpci_nct38xx_set_cc,
 	.set_polarity		= &tcpci_nct38xx_set_polarity,
 	.set_vconn		= &tcpci_tcpm_set_vconn,
@@ -367,6 +322,8 @@ const struct tcpm_drv nct38xx_tcpm_drv = {
 #ifdef CONFIG_USB_PD_DISCHARGE_TCPC
 	.tcpc_discharge_vbus	= &tcpci_tcpc_discharge_vbus,
 #endif
+	.tcpc_connect_state_change =
+				  &tcpci_tcpc_connect_state_change,
 #ifdef CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE
 	.drp_toggle		= &tcpci_nct38xx_drp_toggle,
 #endif
diff --git a/driver/tcpm/tcpci.c b/driver/tcpm/tcpci.c
index 9a0e45f1df..74519ef18e 100644
--- a/driver/tcpm/tcpci.c
+++ b/driver/tcpm/tcpci.c
@@ -10,6 +10,7 @@
 #include "compile_time_macros.h"
 #include "console.h"
 #include "ec_commands.h"
+#include "hooks.h"
 #include "ps8xxx.h"
 #include "task.h"
 #include "tcpci.h"
@@ -241,7 +242,6 @@ int tcpci_tcpm_select_rp_value(int port, int rp)
 	return EC_SUCCESS;
 }
 
-#ifdef CONFIG_USB_PD_DISCHARGE_TCPC
 void tcpci_tcpc_discharge_vbus(int port, int enable)
 {
 	int reg;
@@ -256,7 +256,56 @@ void tcpci_tcpc_discharge_vbus(int port, int enable)
 
 	tcpc_write(port, TCPC_REG_POWER_CTRL, reg);
 }
-#endif
+
+/*
+ * On a connection state change, it is necessary for TCPCI devices to
+ * set the AUTO_DISCHARGE_DISCONNECT bit appropriately.
+ */
+void tcpci_tcpc_connect_state_change(int port, int connected)
+{
+	int reg, oldreg, rv;
+
+	rv = tcpc_read(port, TCPC_REG_POWER_CTRL, &oldreg);
+	if (rv) {
+		/* CPRINTS("%s: failed read POWER_CTRL", __func__); */
+		return;
+	}
+
+	if (connected)
+		reg = oldreg | TCPC_REG_POWER_CTRL_AUTO_DISCHARGE_DISCONNECT;
+	else
+		reg = oldreg & ~TCPC_REG_POWER_CTRL_AUTO_DISCHARGE_DISCONNECT;
+
+	if (reg != oldreg) {
+		rv = tcpc_write(port, TCPC_REG_POWER_CTRL, reg);
+		if (rv) {
+			/* CPRINTS("%s: failed write POWER_CTRL", __func__); */
+			return;
+		}
+	}
+}
+
+static void connect_state_change(int port, int connected)
+{
+	const struct tcpm_drv *tcpc = tcpc_config[port].drv;
+
+	if (tcpc->tcpc_connect_state_change)
+		tcpc->tcpc_connect_state_change(port, connected);
+}
+static void connect_hook(void)
+{
+	int port = TASK_ID_TO_PD_PORT(task_get_current());
+
+	connect_state_change(port, 1);
+}
+DECLARE_HOOK(HOOK_USB_PD_CONNECT, connect_hook, HOOK_PRIO_DEFAULT);
+static void disconnect_hook(void)
+{
+	int port = TASK_ID_TO_PD_PORT(task_get_current());
+
+	connect_state_change(port, 0);
+}
+DECLARE_HOOK(HOOK_USB_PD_DISCONNECT, disconnect_hook, HOOK_PRIO_DEFAULT);
 
 static int set_role_ctrl(int port, int toggle, int rp, int pull)
 {
@@ -1016,6 +1065,8 @@ const struct tcpm_drv tcpci_tcpm_drv = {
 #ifdef CONFIG_USB_PD_DISCHARGE_TCPC
 	.tcpc_discharge_vbus	= &tcpci_tcpc_discharge_vbus,
 #endif
+	.tcpc_connect_state_change =
+				  &tcpci_tcpc_connect_state_change,
 #ifdef CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE
 	.drp_toggle		= &tcpci_tcpc_drp_toggle,
 #endif
diff --git a/driver/tcpm/tcpci.h b/driver/tcpm/tcpci.h
index 81baba83bb..46e1d024aa 100644
--- a/driver/tcpm/tcpci.h
+++ b/driver/tcpm/tcpci.h
@@ -183,6 +183,8 @@ int tcpci_enter_low_power_mode(int port);
 void tcpci_tcpc_discharge_vbus(int port, int enable);
 #endif
 
+void tcpci_tcpc_connect_state_change(int port, int connected);
+
 int tcpci_tcpm_mux_init(int i2c_addr);
 int tcpci_tcpm_mux_set(int i2c_addr, mux_state_t mux_state);
 int tcpci_tcpm_mux_get(int i2c_addr, mux_state_t *mux_state);
diff --git a/include/hooks.h b/include/hooks.h
index e30c420fbb..5c699f9555 100644
--- a/include/hooks.h
+++ b/include/hooks.h
@@ -216,6 +216,8 @@ enum hook_type {
 
 	/*
 	 * USB PD cc connection event.
+	 *
+	 * CC lines and VBus are stable when this hook is called.
 	 */
 	HOOK_USB_PD_CONNECT,
 };
diff --git a/include/usb_pd_tcpm.h b/include/usb_pd_tcpm.h
index ab70c9a7f7..7a7bd0b3a1 100644
--- a/include/usb_pd_tcpm.h
+++ b/include/usb_pd_tcpm.h
@@ -266,6 +266,15 @@ struct tcpm_drv {
 	 */
 	void (*tcpc_discharge_vbus)(int port, int enable);
 
+	/**
+	 * Connection State Change
+	 *
+	 * @param port Type-C port number
+	 * @param connected Connection state
+	 */
+	void (*tcpc_connect_state_change)(int port,
+					  int connected);
+
 #ifdef CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE
 	/**
 	 * Enable TCPC auto DRP toggling.