6.12-stable review patch. If anyone has any objections, please let me know.
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From: Kyle Tso kyletso@google.com
commit 4d27afbf256028a1f54363367f30efc8854433c3 upstream.
The Source can drop its output voltage to the minimum of the requested PPS APDO voltage range when it is in Current Limit Mode. If this voltage falls within the range of vPpsShutdown, the Source initiates a Hard Reset and discharges Vbus. However, currently the Sink may disconnect before the voltage reaches vPpsShutdown, leading to unexpected behavior.
Prevent premature disconnection by setting the Sink's disconnect threshold to the minimum vPpsShutdown value. Additionally, consider the voltage drop due to IR drop when calculating the appropriate threshold. This ensures a robust and reliable interaction between the Source and Sink during SPR PPS Current Limit Mode operation.
Fixes: 4288debeaa4e ("usb: typec: tcpci: Fix up sink disconnect thresholds for PD") Cc: stable stable@kernel.org Signed-off-by: Kyle Tso kyletso@google.com Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Badhri Jagan Sridharan badhri@google.com Link: https://lore.kernel.org/r/20250114142435.2093857-1-kyletso@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/tcpm/tcpci.c | 13 +++++++++---- drivers/usb/typec/tcpm/tcpm.c | 8 +++++--- include/linux/usb/tcpm.h | 3 ++- 3 files changed, 16 insertions(+), 8 deletions(-)
--- a/drivers/usb/typec/tcpm/tcpci.c +++ b/drivers/usb/typec/tcpm/tcpci.c @@ -27,6 +27,7 @@ #define VPPS_NEW_MIN_PERCENT 95 #define VPPS_VALID_MIN_MV 100 #define VSINKDISCONNECT_PD_MIN_PERCENT 90 +#define VPPS_SHUTDOWN_MIN_PERCENT 85
struct tcpci { struct device *dev; @@ -366,7 +367,8 @@ static int tcpci_enable_auto_vbus_discha }
static int tcpci_set_auto_vbus_discharge_threshold(struct tcpc_dev *dev, enum typec_pwr_opmode mode, - bool pps_active, u32 requested_vbus_voltage_mv) + bool pps_active, u32 requested_vbus_voltage_mv, + u32 apdo_min_voltage_mv) { struct tcpci *tcpci = tcpc_to_tcpci(dev); unsigned int pwr_ctrl, threshold = 0; @@ -388,9 +390,12 @@ static int tcpci_set_auto_vbus_discharge threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV; } else if (mode == TYPEC_PWR_MODE_PD) { if (pps_active) - threshold = ((VPPS_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) - - VSINKPD_MIN_IR_DROP_MV - VPPS_VALID_MIN_MV) * - VSINKDISCONNECT_PD_MIN_PERCENT / 100; + /* + * To prevent disconnect when the source is in Current Limit Mode. + * Set the threshold to the lowest possible voltage vPpsShutdown (min) + */ + threshold = VPPS_SHUTDOWN_MIN_PERCENT * apdo_min_voltage_mv / 100 - + VSINKPD_MIN_IR_DROP_MV; else threshold = ((VSRC_NEW_MIN_PERCENT * requested_vbus_voltage_mv / 100) - VSINKPD_MIN_IR_DROP_MV - VSRC_VALID_MIN_MV) * --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -2928,10 +2928,12 @@ static int tcpm_set_auto_vbus_discharge_ return 0;
ret = port->tcpc->set_auto_vbus_discharge_threshold(port->tcpc, mode, pps_active, - requested_vbus_voltage); + requested_vbus_voltage, + port->pps_data.min_volt); tcpm_log_force(port, - "set_auto_vbus_discharge_threshold mode:%d pps_active:%c vbus:%u ret:%d", - mode, pps_active ? 'y' : 'n', requested_vbus_voltage, ret); + "set_auto_vbus_discharge_threshold mode:%d pps_active:%c vbus:%u pps_apdo_min_volt:%u ret:%d", + mode, pps_active ? 'y' : 'n', requested_vbus_voltage, + port->pps_data.min_volt, ret);
return ret; } --- a/include/linux/usb/tcpm.h +++ b/include/linux/usb/tcpm.h @@ -163,7 +163,8 @@ struct tcpc_dev { void (*frs_sourcing_vbus)(struct tcpc_dev *dev); int (*enable_auto_vbus_discharge)(struct tcpc_dev *dev, bool enable); int (*set_auto_vbus_discharge_threshold)(struct tcpc_dev *dev, enum typec_pwr_opmode mode, - bool pps_active, u32 requested_vbus_voltage); + bool pps_active, u32 requested_vbus_voltage, + u32 pps_apdo_min_voltage); bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev); void (*set_partner_usb_comm_capable)(struct tcpc_dev *dev, bool enable); void (*check_contaminant)(struct tcpc_dev *dev);