2021-06-15 17:44:55

by Badhri Jagan Sridharan

Subject: [PATCH v1] usb: typec: tcpci: Fix up sink disconnect thresholds for PD

"Table 4-3 VBUS Sink Characteristics" of "Type-C Cable and Connector
Specification" defines the disconnect voltage thresholds of various
configurations. This change fixes the disconnect threshold voltage
calculation based on vSinkPD_min and vSinkDisconnectPD as defined
by the table.

Fixes: e1a97bf80a022 ("usb: typec: tcpci: Implement Auto discharge disconnect callbacks")
Signed-off-by: Badhri Jagan Sridharan <[email protected]>
---
drivers/usb/typec/tcpm/tcpci.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index 22862345d1ab..9858716698df 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -21,8 +21,12 @@
#define PD_RETRY_COUNT_DEFAULT 3
#define PD_RETRY_COUNT_3_0_OR_HIGHER 2
#define AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV 3500
-#define AUTO_DISCHARGE_PD_HEADROOM_MV 850
-#define AUTO_DISCHARGE_PPS_HEADROOM_MV 1250
+#define VSINKPD_MIN_IR_DROP_MV 750
+#define VSRC_NEW_MIN_PERCENT 95
+#define VSRC_VALID_MIN_MV 500
+#define VPPS_NEW_MIN_PERCENT 95
+#define VPPS_VALID_MIN_MV 100
+#define VSINKDISCONNECT_PD_MIN_PERCENT 90

#define tcpc_presenting_rd(reg, cc) \
(!(TCPC_ROLE_CTRL_DRP & (reg)) && \
@@ -351,11 +355,13 @@ static int tcpci_set_auto_vbus_discharge_threshold(struct tcpc_dev *dev, enum ty
threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
} else if (mode == TYPEC_PWR_MODE_PD) {
if (pps_active)
- threshold = (95 * requested_vbus_voltage_mv / 100) -
- AUTO_DISCHARGE_PD_HEADROOM_MV;
+ threshold = ((VPPS_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) -
+ VSINKPD_MIN_IR_DROP_MV - VPPS_VALID_MIN_MV) *
+ VSINKDISCONNECT_PD_MIN_PERCENT / 100;
else
- threshold = (95 * requested_vbus_voltage_mv / 100) -
- AUTO_DISCHARGE_PPS_HEADROOM_MV;
+ threshold = ((VSRC_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) -
+ VSINKPD_MIN_IR_DROP_MV - VSRC_VALID_MIN_MV) *
+ VSINKDISCONNECT_PD_MIN_PERCENT / 100;
} else {
/* 3.5V for non-pd sink */
threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
--
2.32.0.272.g935e593368-goog

2021-06-16 18:52:11

by Heikki Krogerus

Subject: Re: [PATCH v1] usb: typec: tcpci: Fix up sink disconnect thresholds for PD

On Tue, Jun 15, 2021 at 10:43:23AM -0700, Badhri Jagan Sridharan wrote:
> "Table 4-3 VBUS Sink Characteristics" of "Type-C Cable and Connector
> Specification" defines the disconnect voltage thresholds of various
> configurations. This change fixes the disconnect threshold voltage
> calculation based on vSinkPD_min and vSinkDisconnectPD as defined
> by the table.
>
> Fixes: e1a97bf80a022 ("usb: typec: tcpci: Implement Auto discharge disconnect callbacks")
> Signed-off-by: Badhri Jagan Sridharan <[email protected]>

Acked-by: Heikki Krogerus <[email protected]>

> ---
> drivers/usb/typec/tcpm/tcpci.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> index 22862345d1ab..9858716698df 100644
> --- a/drivers/usb/typec/tcpm/tcpci.c
> +++ b/drivers/usb/typec/tcpm/tcpci.c
> @@ -21,8 +21,12 @@
> #define PD_RETRY_COUNT_DEFAULT 3
> #define PD_RETRY_COUNT_3_0_OR_HIGHER 2
> #define AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV 3500
> -#define AUTO_DISCHARGE_PD_HEADROOM_MV 850
> -#define AUTO_DISCHARGE_PPS_HEADROOM_MV 1250
> +#define VSINKPD_MIN_IR_DROP_MV 750
> +#define VSRC_NEW_MIN_PERCENT 95
> +#define VSRC_VALID_MIN_MV 500
> +#define VPPS_NEW_MIN_PERCENT 95
> +#define VPPS_VALID_MIN_MV 100
> +#define VSINKDISCONNECT_PD_MIN_PERCENT 90
>
> #define tcpc_presenting_rd(reg, cc) \
> (!(TCPC_ROLE_CTRL_DRP & (reg)) && \
> @@ -351,11 +355,13 @@ static int tcpci_set_auto_vbus_discharge_threshold(struct tcpc_dev *dev, enum ty
> threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
> } else if (mode == TYPEC_PWR_MODE_PD) {
> if (pps_active)
> - threshold = (95 * requested_vbus_voltage_mv / 100) -
> - AUTO_DISCHARGE_PD_HEADROOM_MV;
> + threshold = ((VPPS_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) -
> + VSINKPD_MIN_IR_DROP_MV - VPPS_VALID_MIN_MV) *
> + VSINKDISCONNECT_PD_MIN_PERCENT / 100;
> else
> - threshold = (95 * requested_vbus_voltage_mv / 100) -
> - AUTO_DISCHARGE_PPS_HEADROOM_MV;
> + threshold = ((VSRC_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) -
> + VSINKPD_MIN_IR_DROP_MV - VSRC_VALID_MIN_MV) *
> + VSINKDISCONNECT_PD_MIN_PERCENT / 100;
> } else {
> /* 3.5V for non-pd sink */
> threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
> --
> 2.32.0.272.g935e593368-goog

--
heikki