linux-kernel - [PATCH 05/11 v3] staging: typec: tcpm: Follow Try.SRC exit requirements

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Message-Id: <20170828172322.7166-5-Badhri@google.com>
Date:   Mon, 28 Aug 2017 10:23:16 -0700
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Badhri Jagan Sridharan <Badhri@...gle.com>
Subject: [PATCH 05/11 v3] staging: typec: tcpm: Follow Try.SRC exit requirements

According to spec:
" 4.5.2.2.9.2 Exiting from Try.SRC State:
The port shall transition to Attached.SRC when the SRC.Rd
state is detected on exactly one of the CC1 or CC2 pins for
at least tPDDebounce. The port shall transition to
TryWait.SNK after tDRPTry and the SRC.Rd state has not been
detected."

Signed-off-by: Badhri Jagan Sridharan <Badhri@...gle.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
---
Changelog since v1:
- Corrected  tag

Changelog since v2:
- added Reviewed-by: Guenter Roeck <linux@...ck-us.net>
- fixed version/sequence numbers

 drivers/staging/typec/tcpm.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
index 7eed04698ebe..fc179bdea7e4 100644
--- a/drivers/staging/typec/tcpm.c
+++ b/drivers/staging/typec/tcpm.c
@@ -112,6 +112,7 @@
 	S(SRC_TRYWAIT_UNATTACHED),		\
 						\
 	S(SRC_TRY),				\
+	S(SRC_TRY_WAIT),                        \
 	S(SRC_TRY_DEBOUNCE),			\
 	S(SNK_TRYWAIT),				\
 	S(SNK_TRYWAIT_DEBOUNCE),		\
@@ -2158,6 +2159,7 @@ static void run_state_machine(struct tcpm_port *port)
 {
 	int ret;
 	enum typec_pwr_opmode opmode;
+	unsigned int msecs;
 
 	port->enter_state = port->state;
 	switch (port->state) {
@@ -2379,7 +2381,22 @@ static void run_state_machine(struct tcpm_port *port)
 	case SRC_TRY:
 		port->try_src_count++;
 		tcpm_set_cc(port, tcpm_rp_cc(port));
-		tcpm_set_state(port, SNK_TRYWAIT, PD_T_DRP_TRY);
+		port->max_wait = 0;
+		tcpm_set_state(port, SRC_TRY_WAIT, 0);
+		break;
+	case SRC_TRY_WAIT:
+		if (port->max_wait == 0) {
+			port->max_wait = jiffies +
+					 msecs_to_jiffies(PD_T_DRP_TRY);
+			msecs = PD_T_DRP_TRY;
+		} else {
+			if (time_is_after_jiffies(port->max_wait))
+				msecs = jiffies_to_msecs(port->max_wait -
+							 jiffies);
+			else
+				msecs = 0;
+		}
+		tcpm_set_state(port, SNK_TRYWAIT, msecs);
 		break;
 	case SRC_TRY_DEBOUNCE:
 		tcpm_set_state(port, SRC_ATTACHED, PD_T_PD_DEBOUNCE);
@@ -2935,12 +2952,12 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
 			tcpm_set_state(port, SRC_TRYWAIT, 0);
 		}
 		break;
-	case SRC_TRY:
+	case SRC_TRY_WAIT:
 		if (tcpm_port_is_source(port))
 			tcpm_set_state(port, SRC_TRY_DEBOUNCE, 0);
 		break;
 	case SRC_TRY_DEBOUNCE:
-		tcpm_set_state(port, SRC_TRY, 0);
+		tcpm_set_state(port, SRC_TRY_WAIT, 0);
 		break;
 	case SNK_TRYWAIT_DEBOUNCE:
 		if (port->vbus_present) {
@@ -3015,7 +3032,10 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
 	case SNK_TRYWAIT:
 		tcpm_set_state(port, SNK_TRYWAIT_VBUS, 0);
 		break;
-
+	case SRC_TRY_WAIT:
+	case SRC_TRY_DEBOUNCE:
+		/* Do nothing, waiting for sink detection */
+		break;
 	default:
 		break;
 	}
@@ -3069,7 +3089,10 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 	case PORT_RESET_WAIT_OFF:
 		tcpm_set_state(port, tcpm_default_state(port), 0);
 		break;
-
+	case SRC_TRY_WAIT:
+	case SRC_TRY_DEBOUNCE:
+		/* Do nothing, waiting for sink detection */
+		break;
 	default:
 		if (port->pwr_role == TYPEC_SINK &&
 		    port->attached)
-- 
2.14.1.342.g6490525c54-goog