[PATCH v6 14/14] usb: typec: tcpci_maxim: Implemnent set_auto_vbus_discharge_threshold

Badhri Jagan Sridharan
2020-09-01T03:00:16Z

Programs VBUS_SINK_DISCONNECT_THRESHOLD based on the power_role,
voltage requested as sink, mode of operation.

The programmed threshold is based on vSinkDisconnect and
vSinkDisconnectPD values.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
Changes since v1:
- Changing patch version to v6 to fix version number confusion.
---
drivers/usb/typec/tcpm/tcpci_maxim.c | 48 ++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.c b/drivers/usb/typec/tcpm/tcpci_maxim.c
index 6ba808ad901a..e35bd995c037 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim.c
+++ b/drivers/usb/typec/tcpm/tcpci_maxim.c
@@ -137,6 +137,52 @@ static void max_tcpci_init_regs(struct max_tcpci_chip *chip)
return;
}

+static int max_tcpci_set_auto_vbus_discharge_threshold(struct tcpci *tcpci, struct tcpci_data *data,
+ enum typec_role port_role,
+ enum typec_pwr_opmode mode, bool pps_active,
+ u32 requested_vbus_voltage_mv)
+{
+ struct max_tcpci_chip *chip = tdata_to_max_tcpci(data);
+ u32 threshold = 0;
+ u8 pwr_ctrl;
+
+ /*
+ * Indicates that vbus is going to go away due PR_SWAP, hard reset etc.
+ * Do not discharge vbus here.
+ */
+ if (requested_vbus_voltage_mv == 0)
+ goto write_thresh;
+
+ if (port_role == TYPEC_SINK) {
+ max_tcpci_read8(chip, TCPC_POWER_CTRL, &pwr_ctrl);
+ if (pwr_ctrl & TCPC_FAST_ROLE_SWAP_EN) {
+ /* To prevent disconnect when the source is fast role swap is capable. */
+ threshold = 3500;
+ } else if (mode == TYPEC_PWR_MODE_PD) {
+ if (pps_active)
+ threshold = (95 * requested_vbus_voltage_mv / 100) - 850;
+ else
+ threshold = (95 * requested_vbus_voltage_mv / 100) - 1250;
+ } else {
+ /* 3.5V for non-pd sink */
+ threshold = 3500;
+ }
+ } else {
+ /* 4V for source */
+ threshold = 4000;
+ }
+
+ threshold = threshold / TCPC_VBUS_SINK_DISCONNECT_THRESH_LSB;
+
+ if (threshold > TCPC_VBUS_SINK_DISCONNECT_THRESH_MAX) {
+ dev_err(chip->dev, "VBUS_SINK_DISCONNECT_THRESH out of range");
+ return -EINVAL;
+ }
+
+write_thresh:
+ return max_tcpci_write16(chip, TCPC_VBUS_SINK_DISCONNECT_THRESH, threshold);
+}
+
static void process_rx(struct max_tcpci_chip *chip, u16 status)
{
struct pd_message msg;
@@ -454,6 +500,8 @@ static int max_tcpci_probe(struct i2c_client *client, const struct i2c_device_id
chip->data.start_drp_toggling = max_tcpci_start_toggling;
chip->data.TX_BUF_BYTE_x_hidden = true;
chip->data.init = tcpci_init;
+ chip->data.set_auto_vbus_discharge_threshold = max_tcpci_set_auto_vbus_discharge_threshold;
+ chip->data.auto_discharge_disconnect = true;

max_tcpci_init_regs(chip);
chip->tcpci = tcpci_register_port(chip->dev, &chip->data);
--
2.28.0.402.g5ffc5be6b7-goog