cleanup: rename Rp enum values for clarity

The tcpc_cc_voltage_status enum contains different values for different
detected resister values of the port partner. Both Ra and Rd values
contained that in the name, but Rp values did not. Update _SNK_ tag to
_RP_ tag to make it more clear what resistor is being applied by port
partner.

Also adding a few more comments in usb_pd_tcpm.h for clarify on the
different uses of CC resistor enums.

BRANCH=none
BUG=none
TEST=builds. just a rename change.

Change-Id: Id5f7bb502f735bef5937585e2e8bd516ad428a99
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1278103
Reviewed-by: Scott Collyer <scollyer@chromium.org>

6 files changed, 31 insertions, 28 deletions

diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index c5ab8ca9a2..d5937eaa29 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -767,8 +767,8 @@ static int pd_transmit(int port, enum tcpm_transmit_type type,
 			int cc2;
 
 			tcpm_get_cc(port, &cc1, &cc2);
-			if (cc1 == TYPEC_CC_VOLT_SNK_1_5 ||
-				cc2 == TYPEC_CC_VOLT_SNK_1_5) {
+			if (cc1 == TYPEC_CC_VOLT_RP_1_5 ||
+				cc2 == TYPEC_CC_VOLT_RP_1_5) {
 				/* Sink can't transmit now. */
 				/* Check if message is already buffered. */
 				if (pd[port].ca_buffered)
@@ -821,8 +821,8 @@ static void pd_ca_send_pending(int port)
 		return;
 
 	tcpm_get_cc(port, &cc1, &cc2);
-	if ((cc1 != TYPEC_CC_VOLT_SNK_1_5) &&
-			(cc2 != TYPEC_CC_VOLT_SNK_1_5))
+	if ((cc1 != TYPEC_CC_VOLT_RP_1_5) &&
+			(cc2 != TYPEC_CC_VOLT_RP_1_5))
 		if (pd_transmit(port, pd[port].ca_type,
 				pd[port].ca_header,
 				pd[port].ca_buffer) < 0)
@@ -2242,8 +2242,8 @@ static void pd_partner_port_reset(int port)
  */
 static inline int cc_is_rp(int cc)
 {
-	return (cc == TYPEC_CC_VOLT_SNK_DEF) || (cc == TYPEC_CC_VOLT_SNK_1_5) ||
-	       (cc == TYPEC_CC_VOLT_SNK_3_0);
+	return (cc == TYPEC_CC_VOLT_RP_DEF) || (cc == TYPEC_CC_VOLT_RP_1_5) ||
+	       (cc == TYPEC_CC_VOLT_RP_3_0);
 }
 
 #ifdef CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE
@@ -2356,9 +2356,9 @@ void pd_ping_enable(int port, int enable)
 static inline int get_snk_polarity(int cc1, int cc2)
 {
 	/* the following assumes:
-	 * TYPEC_CC_VOLT_SNK_3_0 > TYPEC_CC_VOLT_SNK_1_5
-	 * TYPEC_CC_VOLT_SNK_1_5 > TYPEC_CC_VOLT_SNK_DEF
-	 * TYPEC_CC_VOLT_SNK_DEF > TYPEC_CC_VOLT_OPEN
+	 * TYPEC_CC_VOLT_RP_3_0 > TYPEC_CC_VOLT_RP_1_5
+	 * TYPEC_CC_VOLT_RP_1_5 > TYPEC_CC_VOLT_RP_DEF
+	 * TYPEC_CC_VOLT_RP_DEF > TYPEC_CC_VOLT_OPEN
 	 */
 	return (cc2 > cc1);
 }
@@ -2373,9 +2373,9 @@ static typec_current_t get_typec_current_limit(int polarity, int cc1, int cc2)
 	int cc = polarity ? cc2 : cc1;
 	int cc_alt = polarity ? cc1 : cc2;
 
-	if (cc == TYPEC_CC_VOLT_SNK_3_0 && cc_alt != TYPEC_CC_VOLT_SNK_1_5)
+	if (cc == TYPEC_CC_VOLT_RP_3_0 && cc_alt != TYPEC_CC_VOLT_RP_1_5)
 		charge = 3000;
-	else if (cc == TYPEC_CC_VOLT_SNK_1_5)
+	else if (cc == TYPEC_CC_VOLT_RP_1_5)
 		charge = 1500;
 	else
 		charge = 0;
diff --git a/common/usb_pd_tcpc.c b/common/usb_pd_tcpc.c
index 11bc399b5e..3e79569e2e 100644
--- a/common/usb_pd_tcpc.c
+++ b/common/usb_pd_tcpc.c
@@ -746,11 +746,11 @@ static int cc_voltage_to_status(int port, int cc_volt, int cc_sel)
 #ifdef CONFIG_USB_PD_DUAL_ROLE
 	else if (pd[port].cc_pull == TYPEC_CC_RD) {
 		if (cc_volt >= TYPE_C_SRC_3000_THRESHOLD)
-			return TYPEC_CC_VOLT_SNK_3_0;
+			return TYPEC_CC_VOLT_RP_3_0;
 		else if (cc_volt >= TYPE_C_SRC_1500_THRESHOLD)
-			return TYPEC_CC_VOLT_SNK_1_5;
+			return TYPEC_CC_VOLT_RP_1_5;
 		else if (CC_RP(cc_volt))
-			return TYPEC_CC_VOLT_SNK_DEF;
+			return TYPEC_CC_VOLT_RP_DEF;
 		else
 			return TYPEC_CC_VOLT_OPEN;
 	}
diff --git a/driver/tcpm/anx74xx.c b/driver/tcpm/anx74xx.c
index e0c01f52dc..22f1f51e77 100644
--- a/driver/tcpm/anx74xx.c
+++ b/driver/tcpm/anx74xx.c
@@ -587,15 +587,15 @@ static int anx74xx_check_cc_type(int cc_reg)
 		break;
 
 	case BIT_VALUE_OF_SNK_CC_DEFAULT:
-		cc = TYPEC_CC_VOLT_SNK_DEF;
+		cc = TYPEC_CC_VOLT_RP_DEF;
 		break;
 
 	case BIT_VALUE_OF_SNK_CC_1_P_5:
-		cc = TYPEC_CC_VOLT_SNK_1_5;
+		cc = TYPEC_CC_VOLT_RP_1_5;
 		break;
 
 	case BIT_VALUE_OF_SNK_CC_3_P_0:
-		cc = TYPEC_CC_VOLT_SNK_3_0;
+		cc = TYPEC_CC_VOLT_RP_3_0;
 		break;
 
 	default:
diff --git a/driver/tcpm/fusb302.c b/driver/tcpm/fusb302.c
index 68cf14774d..7b736e5b23 100644
--- a/driver/tcpm/fusb302.c
+++ b/driver/tcpm/fusb302.c
@@ -91,11 +91,11 @@ static int convert_bc_lvl(int port, int bc_lvl)
 			ret = TYPEC_CC_VOLT_RD;
 	} else {
 		if (bc_lvl == 0x1)
-			ret = TYPEC_CC_VOLT_SNK_DEF;
+			ret = TYPEC_CC_VOLT_RP_DEF;
 		else if (bc_lvl == 0x2)
-			ret = TYPEC_CC_VOLT_SNK_1_5;
+			ret = TYPEC_CC_VOLT_RP_1_5;
 		else if (bc_lvl == 0x3)
-			ret = TYPEC_CC_VOLT_SNK_3_0;
+			ret = TYPEC_CC_VOLT_RP_3_0;
 	}
 
 	return ret;
diff --git a/driver/tcpm/it83xx.c b/driver/tcpm/it83xx.c
index 8fb6b985c0..f4783c1725 100644
--- a/driver/tcpm/it83xx.c
+++ b/driver/tcpm/it83xx.c
@@ -84,13 +84,13 @@ static enum tcpc_cc_voltage_status it83xx_get_cc(
 
 		switch (ufp_volt) {
 		case USBPD_UFP_STATE_SNK_DEF:
-			cc_state |= (TYPEC_CC_VOLT_SNK_DEF & 3);
+			cc_state |= (TYPEC_CC_VOLT_RP_DEF & 3);
 			break;
 		case USBPD_UFP_STATE_SNK_1_5:
-			cc_state |= (TYPEC_CC_VOLT_SNK_1_5 & 3);
+			cc_state |= (TYPEC_CC_VOLT_RP_1_5 & 3);
 			break;
 		case USBPD_UFP_STATE_SNK_3_0:
-			cc_state |= (TYPEC_CC_VOLT_SNK_3_0 & 3);
+			cc_state |= (TYPEC_CC_VOLT_RP_3_0 & 3);
 			break;
 		case USBPD_UFP_STATE_SNK_OPEN:
 			cc_state = TYPEC_CC_VOLT_OPEN;
diff --git a/include/usb_pd_tcpm.h b/include/usb_pd_tcpm.h
index 290261c081..d46aef454d 100644
--- a/include/usb_pd_tcpm.h
+++ b/include/usb_pd_tcpm.h
@@ -16,15 +16,17 @@
 /* Time to wait for TCPC to complete transmit */
 #define PD_T_TCPC_TX_TIMEOUT  (100*MSEC)
 
+/* Detected resistor values of port partner */
 enum tcpc_cc_voltage_status {
 	TYPEC_CC_VOLT_OPEN = 0,
-	TYPEC_CC_VOLT_RA = 1,	   /* Port partner is applying Ra */
-	TYPEC_CC_VOLT_RD = 2,	   /* Port partner is applying Rd */
-	TYPEC_CC_VOLT_SNK_DEF = 5, /* Port partner is applying Rp (0.5A) */
-	TYPEC_CC_VOLT_SNK_1_5 = 6, /* Port partner is applying Rp (1.5A) */
-	TYPEC_CC_VOLT_SNK_3_0 = 7, /* Port partner is applying Rp (3.0A) */
+	TYPEC_CC_VOLT_RA = 1,	  /* Port partner is applying Ra */
+	TYPEC_CC_VOLT_RD = 2,	  /* Port partner is applying Rd */
+	TYPEC_CC_VOLT_RP_DEF = 5, /* Port partner is applying Rp (0.5A) */
+	TYPEC_CC_VOLT_RP_1_5 = 6, /* Port partner is applying Rp (1.5A) */
+	TYPEC_CC_VOLT_RP_3_0 = 7, /* Port partner is applying Rp (3.0A) */
 };
 
+/* Resistor types we apply on our side of the CC lines */
 enum tcpc_cc_pull {
 	TYPEC_CC_RA = 0,
 	TYPEC_CC_RP = 1,
@@ -32,6 +34,7 @@ enum tcpc_cc_pull {
 	TYPEC_CC_OPEN = 3,
 };
 
+/* Pull-up values we apply as a SRC to advertise different current limits */
 enum tcpc_rp_value {
 	TYPEC_RP_USB = 0,
 	TYPEC_RP_1A5 = 1,