ppc/rt1739: implement FRS

Implement the set_frs_enable function for rt1739 driver.

BUG=b:218982792
TEST=On Krabby, manually verify that PD state enters FRS mode
BRANCH=none

Signed-off-by: Ting Shen <phoenixshen@google.com>
Change-Id: Ia1ef13ded6f25bc08a9d3d593c1201b2bf15b232
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3463086
Reviewed-by: Eric Yilun Lin <yllin@google.com>
Commit-Queue: Ting Shen <phoenixshen@chromium.org>
Tested-by: Ting Shen <phoenixshen@chromium.org>

2 files changed, 51 insertions, 8 deletions

diff --git a/driver/ppc/rt1739.c b/driver/ppc/rt1739.c
index 14d1242fe9..f12d0b3ab0 100644
--- a/driver/ppc/rt1739.c
+++ b/driver/ppc/rt1739.c
@@ -10,6 +10,7 @@
 #include "console.h"
 #include "driver/ppc/rt1739.h"
 #include "driver/tcpm/tcpci.h"
+#include "gpio.h"
 #include "hooks.h"
 #include "usbc_ppc.h"
 #include "util.h"
@@ -20,6 +21,7 @@
 #endif
 
 #define RT1739_FLAGS_SOURCE_ENABLED BIT(0)
+#define RT1739_FLAGS_FRS_ENABLED BIT(1)
 static atomic_t flags[CONFIG_USB_PD_PORT_MAX_COUNT];
 
 #define CPRINTS(format, args...) cprints(CC_USBPD, format, ## args)
@@ -191,6 +193,34 @@ static int rt1739_workaround(int port)
 	return EC_SUCCESS;
 }
 
+static int rt1739_set_frs_enable(int port, int enable)
+{
+	/* Enable FRS RX detect */
+	RETURN_ERROR(update_reg(port, RT1739_REG_CC_FRS_CTRL1,
+				RT1739_FRS_RX_EN,
+				enable ? MASK_SET : MASK_CLR));
+
+	/*
+	 * To enable FRS, turn on FRS_RX interrupt and disable
+	 * all other interrupts (currently bc1.2 only).
+	 *
+	 * When interrupt triggered, we can always assume it's a FRS
+	 * event without spending extra time to read the flags.
+	 */
+	RETURN_ERROR(update_reg(port, RT1739_REG_INT_MASK5,
+				RT1739_BC12_SNK_DONE_MASK,
+				enable ? MASK_CLR : MASK_SET));
+	RETURN_ERROR(update_reg(port, RT1739_REG_INT_MASK4,
+				RT1739_FRS_RX_MASK,
+				enable ? MASK_SET : MASK_CLR));
+	if (enable)
+		atomic_or(&flags[port], RT1739_FLAGS_FRS_ENABLED);
+	else
+		atomic_clear_bits(&flags[port], RT1739_FLAGS_FRS_ENABLED);
+
+	return EC_SUCCESS;
+}
+
 static int rt1739_init(int port)
 {
 	atomic_clear(&flags[port]);
@@ -201,9 +231,7 @@ static int rt1739_init(int port)
 			       RT1739_OT_EN | RT1739_SHUTDOWN_OFF));
 
 	RETURN_ERROR(rt1739_workaround(port));
-	RETURN_ERROR(update_reg(port, RT1739_REG_INT_MASK5,
-				RT1739_BC12_SNK_DONE_MASK,
-				MASK_SET));
+	RETURN_ERROR(rt1739_set_frs_enable(port, false));
 	RETURN_ERROR(update_reg(port, RT1739_REG_VBUS_DET_EN,
 				RT1739_VBUS_PRESENT_EN,
 				MASK_SET));
@@ -334,7 +362,7 @@ void rt1739_deferred_interrupt(void)
 	atomic_t current = atomic_clear(&pending_events);
 
 	for (int port = 0; port < CONFIG_USB_PD_PORT_MAX_COUNT; ++port) {
-		int reg;
+		int event4, event5;
 
 		if (!(current & BIT(port)))
 			continue;
@@ -342,20 +370,27 @@ void rt1739_deferred_interrupt(void)
 		if (ppc_chips[port].drv != &rt1739_ppc_drv)
 			continue;
 
-		if (read_reg(port, RT1739_REG_INT_EVENT5, &reg))
+		if (read_reg(port, RT1739_REG_INT_EVENT4, &event4))
+			continue;
+		if (read_reg(port, RT1739_REG_INT_EVENT5, &event5))
 			continue;
 
-		if (reg & RT1739_BC12_SNK_DONE_INT)
+		if (event5 & RT1739_BC12_SNK_DONE_INT)
 			task_set_event(USB_CHG_PORT_TO_TASK_ID(port),
 				       USB_CHG_EVENT_BC12);
 
-		write_reg(port, RT1739_REG_INT_EVENT5, reg);
+		/* write to clear EVENT4 since FRS interrupt has been handled */
+		write_reg(port, RT1739_REG_INT_EVENT4, event4);
+		write_reg(port, RT1739_REG_INT_EVENT5, event5);
 	}
 }
 DECLARE_DEFERRED(rt1739_deferred_interrupt);
 
 void rt1739_interrupt(int port)
 {
+	if (flags[port] & RT1739_FLAGS_FRS_ENABLED)
+		pd_got_frs_signal(port);
+
 	atomic_or(&pending_events, BIT(port));
 	hook_call_deferred(&rt1739_deferred_interrupt_data, 0);
 }
@@ -378,7 +413,7 @@ const struct ppc_drv rt1739_ppc_drv = {
 	.set_vconn = &rt1739_set_vconn,
 #endif
 #ifdef CONFIG_USB_PD_FRS_PPC
-	/* TODO: not implemented */
+	.set_frs_enable = &rt1739_set_frs_enable,
 #endif
 };
 
diff --git a/driver/ppc/rt1739.h b/driver/ppc/rt1739.h
index 474c390255..ed16942ec1 100644
--- a/driver/ppc/rt1739.h
+++ b/driver/ppc/rt1739.h
@@ -23,9 +23,14 @@
 #define RT1739_REG_SW_RESET		0x04
 #define RT1739_SW_RESET				BIT(0)
 
+#define RT1739_REG_INT_MASK4		0x0C
+#define RT1739_FRS_RX_MASK			BIT(4)
+
 #define RT1739_REG_INT_MASK5		0x0D
 #define RT1739_BC12_SNK_DONE_MASK		BIT(0)
 
+#define RT1739_REG_INT_EVENT4		0x14
+
 #define RT1739_REG_INT_EVENT5		0x15
 #define RT1739_BC12_SNK_DONE_INT		BIT(0)
 
@@ -81,6 +86,9 @@
 #define RT1739_VBUS_SAFE0V_EN			BIT(1)
 #define RT1739_VBUS_PRESENT_EN			BIT(0)
 
+#define RT1739_REG_CC_FRS_CTRL1		0x2D
+#define RT1739_FRS_RX_EN			BIT(1)
+
 #define RT1739_REG_VCONN_CTRL1		0x31
 #define RT1739_VCONN_ORIENT			BIT(1)
 #define RT1739_VCONN_EN				BIT(0)