Re: [PATCH 4/6] staging: usb: tcpm: usb: type-c: tcpm: Check for Rp for tPDDebounce
From: Guenter Roeck
Date: Sun Aug 27 2017 - 13:22:01 EST
On Sat, Aug 26, 2017 at 10:24:49PM -0700, Badhri Jagan Sridharan wrote:
> According the spec, the following is the conditions for exiting Try.SNK
> state:
> "The port shall wait for tDRPTry and only then begin monitoring the CC1 and
> CC2 pins for the SNK.Rp state. 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 tPDDebounce and V BUS is detected. Alternatively,
> the port shall transition to TryWait.SRC if SNK.Rp state is not detected
> for tPDDebounce."
>
> Signed-off-by: Badhri Jagan Sridharan <Badhri@xxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/staging/typec/tcpm.c | 68 ++++++++++++++++----------------------------
> 1 file changed, 24 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
> index d45ffa8f2cfd..7eed04698ebe 100644
> --- a/drivers/staging/typec/tcpm.c
> +++ b/drivers/staging/typec/tcpm.c
> @@ -105,6 +105,8 @@
> \
> S(SNK_TRY), \
> S(SNK_TRY_WAIT), \
> + S(SNK_TRY_WAIT_DEBOUNCE), \
> + S(SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS), \
> S(SRC_TRYWAIT), \
> S(SRC_TRYWAIT_DEBOUNCE), \
> S(SRC_TRYWAIT_UNATTACHED), \
> @@ -2202,18 +2204,24 @@ static void run_state_machine(struct tcpm_port *port)
> tcpm_set_state(port, SNK_TRY_WAIT, PD_T_DRP_TRY);
> break;
> case SNK_TRY_WAIT:
> + if (tcpm_port_is_sink(port)) {
> + tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE, 0);
> + } else {
> + tcpm_set_state(port, SRC_TRYWAIT, 0);
> + port->max_wait = 0;
> + }
> + break;
> + case SNK_TRY_WAIT_DEBOUNCE:
> + tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS,
> + PD_T_PD_DEBOUNCE);
> + 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;
> - }
> - if (!tcpm_port_is_sink(port)) {
> - tcpm_set_state(port, SRC_TRYWAIT,
> - PD_T_PD_DEBOUNCE);
> + } else {
> + tcpm_set_state(port, SRC_TRYWAIT, 0);
> port->max_wait = 0;
> - break;
> }
> - /* No vbus, cc state is sink or open */
> - tcpm_set_state(port, SRC_TRYWAIT_UNATTACHED, PD_T_DRP_TRYWAIT);
> break;
> case SRC_TRYWAIT:
> tcpm_set_cc(port, tcpm_rp_cc(port));
> @@ -2921,20 +2929,12 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
> if (port->vbus_present || !tcpm_port_is_source(port))
> tcpm_set_state(port, SRC_TRYWAIT, 0);
> break;
> - case SNK_TRY_WAIT:
> - if (port->vbus_present && tcpm_port_is_sink(port)) {
> - tcpm_set_state(port, SNK_ATTACHED, 0);
> - break;
> + case SNK_TRY_WAIT_DEBOUNCE:
> + if (!tcpm_port_is_sink(port)) {
> + port->max_wait = 0;
> + tcpm_set_state(port, SRC_TRYWAIT, 0);
> }
> - if (!tcpm_port_is_sink(port))
> - new_state = SRC_TRYWAIT;
> - else
> - new_state = SRC_TRYWAIT_UNATTACHED;
> -
> - if (new_state != port->delayed_state)
> - tcpm_set_state(port, SNK_TRY_WAIT, 0);
> break;
> -
> case SRC_TRY:
> if (tcpm_port_is_source(port))
> tcpm_set_state(port, SRC_TRY_DEBOUNCE, 0);
> @@ -2974,8 +2974,6 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
>
> static void _tcpm_pd_vbus_on(struct tcpm_port *port)
> {
> - enum tcpm_state new_state;
> -
> tcpm_log_force(port, "VBUS on");
> port->vbus_present = true;
> switch (port->state) {
> @@ -3011,18 +3009,8 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
> case SRC_TRYWAIT_DEBOUNCE:
> tcpm_set_state(port, SRC_TRYWAIT, 0);
> break;
> - case SNK_TRY_WAIT:
> - if (tcpm_port_is_sink(port)) {
> - tcpm_set_state(port, SNK_ATTACHED, 0);
> - break;
> - }
> - if (!tcpm_port_is_sink(port))
> - new_state = SRC_TRYWAIT;
> - else
> - new_state = SRC_TRYWAIT_UNATTACHED;
> -
> - if (new_state != port->delayed_state)
> - tcpm_set_state(port, SNK_TRY_WAIT, 0);
> + case SNK_TRY_WAIT_DEBOUNCE:
> + /* Do nothing, waiting for PD_DEBOUNCE to do be done */
> break;
> case SNK_TRYWAIT:
> tcpm_set_state(port, SNK_TRYWAIT_VBUS, 0);
> @@ -3035,8 +3023,6 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
>
> static void _tcpm_pd_vbus_off(struct tcpm_port *port)
> {
> - enum tcpm_state new_state;
> -
> tcpm_log_force(port, "VBUS off");
> port->vbus_present = false;
> port->vbus_never_low = false;
> @@ -3058,14 +3044,8 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
> if (tcpm_port_is_source(port))
> tcpm_set_state(port, SRC_TRYWAIT_DEBOUNCE, 0);
> break;
> - case SNK_TRY_WAIT:
> - if (!tcpm_port_is_sink(port))
> - new_state = SRC_TRYWAIT;
> - else
> - new_state = SRC_TRYWAIT_UNATTACHED;
> -
> - if (new_state != port->delayed_state)
> - tcpm_set_state(port, SNK_TRY_WAIT, 0);
> + case SNK_TRY_WAIT_DEBOUNCE:
> + /* Do nothing, waiting for PD_DEBOUNCE to do be done */
> break;
> case SNK_TRYWAIT_VBUS:
> tcpm_set_state(port, SNK_TRYWAIT, 0);
> --
> 2.14.1.342.g6490525c54-goog
>