[PATCH v12 08/10] usb: typec: tcpci: Implement Auto discharge disconnect callbacks

Badhri Jagan Sridharan
2020-10-29T07:57:41Z

vImplement callbacks for enabling/disabling
POWER_CONTROL.AutoDischargeDisconnect.

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

The programmed threshold is based on vSinkDisconnect and
vSinkDisconnectPD values.

Add auto_discharge_disconnect to tdata to allow TCPC chip
level drivers enable AutoDischargeDisconnect.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
Changes since v1:
- Changing patch version to v6 to fix version number confusion.

Changes since v6:
- Rebase on usb-next.

Changes since v7:
Heikki's suggestion:
- Moved the actual write to TCPC_VBUS_SINK_DISCONNECT_THRESH
as it's common to all chip drivers.
- Renaming the tcpci_data callback as
get_auto_vbus_discharge_threshold

Changes since v8:
- Removed get_auto_vbus_discharge_threshold callback and moved the logic
to program the default threshold for TCPC_VBUS_SINK_DISCONNECT_THRESH
into the TCPCI code.

Changes since v9:
- none

Changes since v10:
-Added Reviewed-by: Heikki Krogerus

Changes since v11:
none
---
drivers/usb/typec/tcpm/tcpci.c | 63 +++++++++++++++++++++++++++++++++-
drivers/usb/typec/tcpm/tcpci.h | 14 ++++++--
2 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index f91688e43991..12d983a75510 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -18,7 +18,10 @@

#include "tcpci.h"

-#define PD_RETRY_COUNT 3
+#define PD_RETRY_COUNT 3
+#define AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV 3500
+#define AUTO_DISCHARGE_PD_HEADROOM_MV 850
+#define AUTO_DISCHARGE_PPS_HEADROOM_MV 1250

struct tcpci {
struct device *dev;
@@ -268,6 +271,58 @@ static int tcpci_set_vconn(struct tcpc_dev *tcpc, bool enable)
enable ? TCPC_POWER_CTRL_VCONN_ENABLE : 0);
}

+static int tcpci_enable_auto_vbus_discharge(struct tcpc_dev *dev, bool enable)
+{
+ struct tcpci *tcpci = tcpc_to_tcpci(dev);
+ int ret;
+
+ ret = regmap_update_bits(tcpci->regmap, TCPC_POWER_CTRL, TCPC_POWER_CTRL_AUTO_DISCHARGE,
+ enable ? TCPC_POWER_CTRL_AUTO_DISCHARGE : 0);
+ return ret;
+}
+
+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)
+{
+ struct tcpci *tcpci = tcpc_to_tcpci(dev);
+ unsigned int pwr_ctrl, threshold = 0;
+ int ret;
+
+ /*
+ * 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;
+
+ ret = regmap_read(tcpci->regmap, TCPC_POWER_CTRL, &pwr_ctrl);
+ if (ret < 0)
+ return ret;
+
+ if (pwr_ctrl & TCPC_FAST_ROLE_SWAP_EN) {
+ /* To prevent disconnect when the source is fast role swap is capable. */
+ 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;
+ else
+ threshold = (95 * requested_vbus_voltage_mv / 100) -
+ AUTO_DISCHARGE_PPS_HEADROOM_MV;
+ } else {
+ /* 3.5V for non-pd sink */
+ threshold = AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV;
+ }
+
+ threshold = threshold / TCPC_VBUS_SINK_DISCONNECT_THRESH_LSB_MV;
+
+ if (threshold > TCPC_VBUS_SINK_DISCONNECT_THRESH_MAX)
+ return -EINVAL;
+
+write_thresh:
+ return tcpci_write16(tcpci, TCPC_VBUS_SINK_DISCONNECT_THRESH, threshold);
+}
+
static int tcpci_enable_frs(struct tcpc_dev *dev, bool enable)
{
struct tcpci *tcpci = tcpc_to_tcpci(dev);
@@ -638,6 +693,12 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
tcpci->tcpc.enable_frs = tcpci_enable_frs;
tcpci->tcpc.frs_sourcing_vbus = tcpci_frs_sourcing_vbus;

+ if (tcpci->data->auto_discharge_disconnect) {
+ tcpci->tcpc.enable_auto_vbus_discharge = tcpci_enable_auto_vbus_discharge;
+ tcpci->tcpc.set_auto_vbus_discharge_threshold =
+ tcpci_set_auto_vbus_discharge_threshold;
+ }
+
err = tcpci_parse_config(tcpci);
if (err < 0)
return ERR_PTR(err);
diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
index b418fe11b527..3fe313655f0c 100644
--- a/drivers/usb/typec/tcpm/tcpci.h
+++ b/drivers/usb/typec/tcpm/tcpci.h
@@ -8,6 +8,8 @@
#ifndef __LINUX_USB_TCPCI_H
#define __LINUX_USB_TCPCI_H

+#include <linux/usb/typec.h>
+
#define TCPC_VENDOR_ID 0x0
#define TCPC_PRODUCT_ID 0x2
#define TCPC_BCD_DEV 0x4
@@ -67,6 +69,7 @@

#define TCPC_POWER_CTRL 0x1c
#define TCPC_POWER_CTRL_VCONN_ENABLE BIT(0)
+#define TCPC_POWER_CTRL_AUTO_DISCHARGE BIT(4)
#define TCPC_FAST_ROLE_SWAP_EN BIT(7)

#define TCPC_CC_STATUS 0x1d
@@ -133,6 +136,8 @@

#define TCPC_VBUS_VOLTAGE 0x70
#define TCPC_VBUS_SINK_DISCONNECT_THRESH 0x72
+#define TCPC_VBUS_SINK_DISCONNECT_THRESH_LSB_MV 25
+#define TCPC_VBUS_SINK_DISCONNECT_THRESH_MAX 0x3ff
#define TCPC_VBUS_STOP_DISCHARGE_THRESH 0x74
#define TCPC_VBUS_VOLTAGE_ALARM_HI_CFG 0x76
#define TCPC_VBUS_VOLTAGE_ALARM_LO_CFG 0x78
@@ -140,17 +145,22 @@
/* I2C_WRITE_BYTE_COUNT + 1 when TX_BUF_BYTE_x is only accessible I2C_WRITE_BYTE_COUNT */
#define TCPC_TRANSMIT_BUFFER_MAX_LEN 31

+struct tcpci;
+
/*
- * @TX_BUF_BYTE_x_hidden
+ * @TX_BUF_BYTE_x_hidden:
* optional; Set when TX_BUF_BYTE_x can only be accessed through I2C_WRITE_BYTE_COUNT.
* @frs_sourcing_vbus:
* Optional; Callback to perform chip specific operations when FRS
* is sourcing vbus.
+ * @auto_discharge_disconnect:
+ * Optional; Enables TCPC to autonously discharge vbus on disconnect.
*/
-struct tcpci;
struct tcpci_data {
struct regmap *regmap;
unsigned char TX_BUF_BYTE_x_hidden:1;
+ unsigned char auto_discharge_disconnect:1;
+
int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
bool enable);
--
2.29.1.341.ge80a0c044ae-goog