usb: typec: tcpm: Stay in SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS till Rp is seen

TD.4.7.3. Try SNK DRP Connect Try.SRC DRP fails. The compliance
tester mimics being a Try.SRC USB-C port.
The failure is due to TCPM exiting SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS
when VBUS is not present eventhough when SNK.Rp is seen. Exit to
SRC_TRYWAIT from SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS only when SNK.Rp
is not seen for PD_T_TRY_CC_DEBOUNCE.

>From the spec:
The port shall then transition to Attached.SNK when the SNK.Rp state
is detected on exactly one of the CC1 or CC2 pins for at least
tTryCCDebounce and VBUS is detected. Alternatively, the port shall
transition to TryWait.SRC if SNK.Rp state is not detected for
tTryCCDebounce.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20201125014804.1596719-1-badhri@google.com
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 277b9d4..3bbc1f1 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -3124,15 +3124,13 @@ static void run_state_machine(struct tcpm_port *port)
                break;
        case SNK_TRY_WAIT_DEBOUNCE:
                tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS,
-                              PD_T_PD_DEBOUNCE);
+                              PD_T_TRY_CC_DEBOUNCE);
                break;
        case SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS:
-               if (port->vbus_present && tcpm_port_is_sink(port)) {
+               if (port->vbus_present && tcpm_port_is_sink(port))
                        tcpm_set_state(port, SNK_ATTACHED, 0);
-               } else {
-                       tcpm_set_state(port, SRC_TRYWAIT, 0);
+               else
                        port->max_wait = 0;
-               }
                break;
        case SRC_TRYWAIT:
                tcpm_set_cc(port, tcpm_rp_cc(port));
@@ -4053,6 +4051,12 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
                if (!tcpm_port_is_sink(port))
                        tcpm_set_state(port, SNK_TRYWAIT_DEBOUNCE, 0);
                break;
+       case SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS:
+               if (!tcpm_port_is_sink(port))
+                       tcpm_set_state(port, SRC_TRYWAIT, PD_T_TRY_CC_DEBOUNCE);
+               else
+                       tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS, 0);
+               break;
        case SNK_TRYWAIT:
                /* Do nothing, waiting for tCCDebounce */
                break;
@@ -4139,6 +4143,10 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
        case SNK_TRYWAIT_DEBOUNCE:
                /* Do nothing, waiting for Rp */
                break;
+       case SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS:
+               if (port->vbus_present && tcpm_port_is_sink(port))
+                       tcpm_set_state(port, SNK_ATTACHED, 0);
+               break;
        case SRC_TRY_WAIT:
        case SRC_TRY_DEBOUNCE:
                /* Do nothing, waiting for sink detection */

diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index 3a805e2..63a66dd 100644 (file)
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -484,6 +484,7 @@ static inline unsigned int rdo_max_power(u32 rdo)
 
 #define PD_T_CC_DEBOUNCE       200     /* 100 - 200 ms */
 #define PD_T_PD_DEBOUNCE       20      /* 10 - 20 ms */
+#define PD_T_TRY_CC_DEBOUNCE   15      /* 10 - 20 ms */
 
 #define PD_N_CAPS_COUNT                (PD_T_NO_RESPONSE / PD_T_SEND_SOURCE_CAP)
 #define PD_N_HARD_RESET_COUNT  2