TUSB422: Add support for FRS

The TUSB422 does not officially support FRS. support is being added to
workaround bugs in the SYV682.

BUG=b:148144711
TEST=Check that FRS is signaled to the TCPM from the TUSB422 driver when
CONFIG_USB_PD_FRS_TCPC is set
TEST=make buildall
BRANCH=none

Change-Id: I4c8fefbf0f01b327f345d4b4f09b6c422aaa2e5d
Signed-off-by: Eric Herrmann <eherrmann@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2278354
Reviewed-by: Denis Brockus <dbrockus@chromium.org>
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>

3 files changed, 62 insertions, 5 deletions

diff --git a/driver/tcpm/tcpci.h b/driver/tcpm/tcpci.h
index d728b55332..b19aca60a3 100644
--- a/driver/tcpm/tcpci.h
+++ b/driver/tcpm/tcpci.h
@@ -42,6 +42,8 @@
 				      TCPC_REG_ALERT_TX_FAILED)
 
 #define TCPC_REG_ALERT_MASK        0x12
+#define TCPC_REG_ALERT_MASK_VENDOR_DEF   BIT(15)
+
 #define TCPC_REG_POWER_STATUS_MASK 0x14
 #define TCPC_REG_FAULT_STATUS_MASK 0x15
 #define TCPC_REG_EXT_STATUS_MASK   0x16
diff --git a/driver/tcpm/tusb422.c b/driver/tcpm/tusb422.c
index a301a27651..3ab95c9721 100644
--- a/driver/tcpm/tusb422.c
+++ b/driver/tcpm/tusb422.c
@@ -39,10 +39,25 @@ enum vbus_and_vconn_control_mask {
 	INT_VBUSDIS_DISABLE  = BIT(2),
 };
 
+/* The TUSB422 cannot drive an FRS GPIO, but can detect FRS */
+static int tusb422_set_frs_enable(int port, int enable)
+{
+	return tcpc_update8(port, TUSB422_REG_PHY_BMC_RX_CTRL,
+			    TUSB422_REG_PHY_BMC_RX_CTRL_FRS_RX_EN,
+			    enable ? MASK_SET : MASK_CLR);
+}
+
 static int tusb422_tcpci_tcpm_init(int port)
 {
-	int rv = tcpci_tcpm_init(port);
+	int rv;
 
+	/* TUSB422 has a vendor-defined register reset */
+	rv = tcpc_update8(port, TUSB422_REG_CC_GEN_CTRL,
+			  TUSB422_REG_CC_GEN_CTRL_GLOBAL_SW_RST, MASK_SET);
+	if (rv)
+		return rv;
+
+	rv = tcpci_tcpm_init(port);
 	if (rv)
 		return rv;
 
@@ -68,18 +83,26 @@ static int tusb422_tcpci_tcpm_init(int port)
 		tcpc_write(port, TUSB422_REG_VBUS_AND_VCONN_CONTROL,
 				INT_VBUSDIS_DISABLE);
 	}
-
+	if (IS_ENABLED(CONFIG_USB_PD_FRS_TCPC)) {
+		/* Disable FRS detection, and enable the FRS detection alert */
+		tusb422_set_frs_enable(port, 0);
+		tcpc_update16(port, TCPC_REG_ALERT_MASK,
+			      TCPC_REG_ALERT_MASK_VENDOR_DEF, MASK_SET);
+		tcpc_update8(port, TUSB422_REG_VENDOR_INTERRUPTS_MASK,
+			     TUSB422_REG_VENDOR_INTERRUPTS_MASK_FRS_RX,
+			     MASK_SET);
+	}
 	/*
 	 * VBUS detection is supposed to be enabled by default, however the
 	 * TUSB422 has this disabled following reset.
 	 */
 	/* Enable VBUS detection */
-	return tcpc_write16(port, TCPC_REG_COMMAND, 0x33);
+	return tcpc_write16(port, TCPC_REG_COMMAND,
+				TCPC_REG_COMMAND_ENABLE_VBUS_DETECT);
 }
 
 static int tusb422_tcpm_set_cc(int port, int pull)
 {
-
 	/*
 	 * Enable AutoDischargeDisconnect to keep TUSB422 in active mode through
 	 * this transition. Note that the configuration keeps the TCPC from
@@ -108,6 +131,23 @@ static int tusb422_tcpc_drp_toggle(int port)
 }
 #endif
 
+static void tusb422_tcpci_tcpc_alert(int port)
+{
+	if (IS_ENABLED(CONFIG_USB_PD_FRS_TCPC)) {
+		int regval;
+
+		/* FRS detection is a vendor defined alert */
+		tcpc_read(port, TUSB422_REG_VENDOR_INTERRUPTS_STATUS, &regval);
+		if (regval & TUSB422_REG_VENDOR_INTERRUPTS_STATUS_FRS_RX) {
+			tusb422_set_frs_enable(port, 0);
+			tcpc_write(port, TUSB422_REG_VENDOR_INTERRUPTS_STATUS,
+				   regval);
+			pd_got_frs_signal(port);
+		}
+	}
+	tcpci_tcpc_alert(port);
+}
+
 const struct tcpm_drv tusb422_tcpm_drv = {
 	.init			= &tusb422_tcpci_tcpm_init,
 	.release		= &tcpci_tcpm_release,
@@ -123,7 +163,7 @@ const struct tcpm_drv tusb422_tcpm_drv = {
 	.set_rx_enable		= &tcpci_tcpm_set_rx_enable,
 	.get_message_raw	= &tcpci_tcpm_get_message_raw,
 	.transmit		= &tcpci_tcpm_transmit,
-	.tcpc_alert		= &tcpci_tcpc_alert,
+	.tcpc_alert		= &tusb422_tcpci_tcpc_alert,
 #ifdef CONFIG_USB_PD_DISCHARGE_TCPC
 	.tcpc_discharge_vbus	= &tcpci_tcpc_discharge_vbus,
 #endif
@@ -140,4 +180,7 @@ const struct tcpm_drv tusb422_tcpm_drv = {
 #ifdef CONFIG_USB_PD_TCPC_LOW_POWER
 	.enter_low_power_mode	= &tcpci_enter_low_power_mode,
 #endif
+#ifdef CONFIG_USB_PD_FRS_TCPC
+	.set_frs_enable         = &tusb422_set_frs_enable,
+#endif
 };
diff --git a/driver/tcpm/tusb422.h b/driver/tcpm/tusb422.h
index 52d0a079d6..54ae0c7e02 100644
--- a/driver/tcpm/tusb422.h
+++ b/driver/tcpm/tusb422.h
@@ -11,6 +11,18 @@
 /* I2C interface */
 #define TUSB422_I2C_ADDR_FLAGS 0x20
 
+#define TUSB422_REG_VENDOR_INTERRUPTS_STATUS 0x90
+#define TUSB422_REG_VENDOR_INTERRUPTS_STATUS_FRS_RX BIT(0)
+
+#define TUSB422_REG_VENDOR_INTERRUPTS_MASK 0x92
+#define TUSB422_REG_VENDOR_INTERRUPTS_MASK_FRS_RX BIT(0)
+
+#define TUSB422_REG_CC_GEN_CTRL 0x94
+#define TUSB422_REG_CC_GEN_CTRL_GLOBAL_SW_RST BIT(5)
+
+#define TUSB422_REG_PHY_BMC_RX_CTRL 0x96
+#define TUSB422_REG_PHY_BMC_RX_CTRL_FRS_RX_EN BIT(3)
+
 extern const struct tcpm_drv tusb422_tcpm_drv;
 
 #endif /* defined(__CROS_EC_USB_PD_TCPM_TUSB422_H) */