ppc/syv682x: support C version

C version won't block I2C accessing to CONTROL4(to on/off Vconn) reg
when smart discahrge enabled. This allows us to re-enable the smart
discahrge on boards using SYV682C. This CL support the feature by
adding:
1. CONFIG_USBC_PPC_SYV682C
2. CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE

also, hayato uses different SYV682 versions across revisions, add a
overridable function syv682x_board_is_syv682c() for handling
board revision issue.

BUG=b:160548079 b:176876036
TEST=Hayato meets tVconnOff, and tVbusDischarge
BRANCH=asurada

Change-Id: I89b57b8c20907249d5d97140289fb0570bd58b46
Signed-off-by: Eric Yilun Lin <yllin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2738506
Reviewed-by: Ting Shen <phoenixshen@chromium.org>

3 files changed, 61 insertions, 11 deletions

diff --git a/driver/ppc/syv682x.c b/driver/ppc/syv682x.c
index e66411fd0a..0e49abdf6a 100644
--- a/driver/ppc/syv682x.c
+++ b/driver/ppc/syv682x.c
@@ -82,16 +82,29 @@ static int read_reg(uint8_t port, int reg, int *regval)
 			 regval);
 }
 
+#ifdef CONFIG_USBC_PPC_SYV682C
+__overridable int syv682x_board_is_syv682c(int port)
+{
+	return true;
+}
+#endif
+
 /*
- * During channel transition or discharge, the SYV682A silently ignores I2C
+ * During channel transition or discharge, the SYV682X silently ignores I2C
  * writes. Poll the BUSY bit until the SYV682A is ready.
  */
-static int syv682x_wait_for_ready(int port)
+static int syv682x_wait_for_ready(int port, int reg)
 {
 	int regval;
 	int rv;
 	timestamp_t deadline;
 
+#ifdef CONFIG_USBC_PPC_SYV682C
+	/* On SYV682C, busy bit is not applied to CONTROL_4 */
+	if (syv682x_board_is_syv682c(port) && reg == SYV682X_CONTROL_4_REG)
+		return EC_SUCCESS;
+#endif
+
 	deadline.val = get_time().val
 			+ (SYV682X_MAX_VBUS_DISCHARGE_TIME_MS * MSEC);
 
@@ -118,7 +131,7 @@ static int write_reg(uint8_t port, int reg, int regval)
 {
 	int rv;
 
-	rv = syv682x_wait_for_ready(port);
+	rv = syv682x_wait_for_ready(port, reg);
 	if (rv)
 		return rv;
 
@@ -135,6 +148,7 @@ static int syv682x_is_sourcing_vbus(int port)
 
 static int syv682x_discharge_vbus(int port, int enable)
 {
+#ifndef CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE
 	int regval;
 	int rv;
 
@@ -148,7 +162,12 @@ static int syv682x_discharge_vbus(int port, int enable)
 		regval &= ~SYV682X_CONTROL_2_FDSG;
 
 	return write_reg(port, SYV682X_CONTROL_2_REG, regval);
-
+#else
+	/*
+	 * Smart discharge mode is enabled, nothing to do
+	 */
+	return EC_SUCCESS;
+#endif
 }
 
 static int syv682x_vbus_source_enable(int port, int enable)
@@ -654,6 +673,7 @@ static int syv682x_set_frs_enable(int port, int enable)
 }
 #endif /*CONFIG_USB_PD_FRS_PPC*/
 
+#ifndef CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE
 static int syv682x_dev_is_connected(int port, enum ppc_device_role dev)
 {
 	/*
@@ -667,6 +687,7 @@ static int syv682x_dev_is_connected(int port, enum ppc_device_role dev)
 
 	return EC_SUCCESS;
 }
+#endif
 
 static bool syv682x_is_sink(uint8_t control_1)
 {
@@ -745,15 +766,19 @@ static int syv682x_init(int port)
 		return rv;
 
 	/*
-	 * Set Control Reg 2 to defaults.
-	 * Note: do not enable smart discharge since it would block
-	 * i2c transactions for 50ms (discharge time) and this prevents
-	 * us from disabling Vconn when stop sourcing Vbus and has tVconnOff
-	 * (35ms) timeout.
+	 * Set Control Reg 2 to defaults except 50ms smart discharge time.
+	 * Note: On SYV682A/B, enable smart discharge would block i2c
+	 * transactions for 50ms (discharge time) and this
+	 * prevents us from disabling Vconn when stop sourcing Vbus and has
+	 * tVconnOff (35ms) timeout.
+	 * On SYV682C, we are allowed to access CONTROL4 while the i2c busy.
 	 */
 	regval = (SYV682X_OC_DELAY_10MS << SYV682X_OC_DELAY_SHIFT)
-		| (SYV682X_DSG_TIME_200MS << SYV682X_DSG_TIME_SHIFT)
-		| (SYV682X_DSG_RON_200_OHM << SYV682X_DSG_RON_SHIFT);
+		| (SYV682X_DSG_RON_200_OHM << SYV682X_DSG_RON_SHIFT)
+		| (SYV682X_DSG_TIME_50MS << SYV682X_DSG_TIME_SHIFT);
+
+	if (IS_ENABLED(CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE))
+		regval |= SYV682X_CONTROL_2_SDSG;
 
 	rv = write_reg(port, SYV682X_CONTROL_2_REG, regval);
 	if (rv)
@@ -800,7 +825,9 @@ const struct ppc_drv syv682x_drv = {
 #endif /* defined(CONFIG_USB_PD_VBUS_DETECT_PPC) */
 	.set_vbus_source_current_limit = &syv682x_set_vbus_source_current_limit,
 	.discharge_vbus = &syv682x_discharge_vbus,
+#ifndef CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE
 	.dev_is_connected = &syv682x_dev_is_connected,
+#endif /* defined(CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE) */
 #ifdef CONFIG_USBC_PPC_POLARITY
 	.set_polarity = &syv682x_set_polarity,
 #endif
diff --git a/driver/ppc/syv682x.h b/driver/ppc/syv682x.h
index 3ecbede18c..d9416f47f1 100644
--- a/driver/ppc/syv682x.h
+++ b/driver/ppc/syv682x.h
@@ -8,6 +8,7 @@
 #ifndef __CROS_EC_SYV682X_H
 #define __CROS_EC_SYV682X_H
 
+#include "common.h"
 #include "driver/ppc/syv682x_public.h"
 
 /* Source OC deglitch implemented in HW for SYV682B */
@@ -97,4 +98,15 @@
 #define SYV682X_CONTROL_4_CC_FRS	BIT(1)
 #define SYV682X_CONTROL_4_INT_MASK	0x0c
 
+/*
+ * syv682x_board_is_syv682c
+ *
+ * b:160548079 This is a function to workaround that some board revisions
+ * might have different SYV682 sub-version.
+ *
+ * @param port the query port
+ * @return 1 if the PPC is SYV682C else 0
+ */
+__override_proto int syv682x_board_is_syv682c(int port);
+
 #endif /* defined(__CROS_EC_SYV682X_H) */
diff --git a/include/config.h b/include/config.h
index ef029f2b45..c0a88cda53 100644
--- a/include/config.h
+++ b/include/config.h
@@ -4574,6 +4574,7 @@
 #undef CONFIG_USBC_PPC_NX20P3481
 #undef CONFIG_USBC_PPC_NX20P3483
 #undef CONFIG_USBC_PPC_SN5S330
+#undef CONFIG_USBC_PPC_SYV682C
 #undef CONFIG_USBC_PPC_SYV682X
 
 /*
@@ -4585,6 +4586,9 @@
 /* SYV682 does not pass through CC, instead it bypasses to the TCPC */
 #undef CONFIG_SYV682X_NO_CC
 
+/* Define to enable SYV682X VBUS smart discharge. */
+#undef CONFIG_USBC_PPC_SYV682X_SMART_DISCHARGE
+
 /* PPC is capable of gating the SBU lines. */
 #undef CONFIG_USBC_PPC_SBU
 
@@ -5498,6 +5502,13 @@
 #define CONFIG_USBC_PPC_VCONN
 #endif
 
+
+/*****************************************************************************/
+/* PPC SYV682C is a subset of SYV682X. */
+#if defined(CONFIG_USBC_PPC_SYV682C)
+#define CONFIG_USBC_PPC_SYV682X
+#endif
+
 /*
  * The SYV682X supports VCONN and needs to be informed of CC polarity.
  * There is a 3.6V limit on the HOST_CC signals, so the TCPC should not source