[PATCH v2] usb: typec: tps6598x: Add USB role switching logic

From: Bryan O'Donoghue
Date: Thu May 07 2020 - 17:59:12 EST


This patch adds USB role switch support to the tps6598x.

The setup to initiate or accept a data-role switch is both assumed and
currently required to be baked-into the firmware as described in TI's
document here.

Link: https://www.ti.com/lit/an/slva843a/slva843a.pdf

With this change its possible to use the USB role-switch API to detect and
notify role-switches to downstream consumers.

Tested with a ChipIdea controller on a Qualcomm MSM8939.

Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: linux-usb@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
drivers/usb/typec/tps6598x.c | 56 +++++++++++++++++++++++++++++++-----
1 file changed, 49 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/typec/tps6598x.c b/drivers/usb/typec/tps6598x.c
index defa651282b0..b190097c9dba 100644
--- a/drivers/usb/typec/tps6598x.c
+++ b/drivers/usb/typec/tps6598x.c
@@ -12,6 +12,7 @@
#include <linux/regmap.h>
#include <linux/interrupt.h>
#include <linux/usb/typec.h>
+#include <linux/usb/role.h>

/* Register offsets */
#define TPS_REG_VID 0x00
@@ -94,6 +95,7 @@ struct tps6598x {
struct typec_port *port;
struct typec_partner *partner;
struct usb_pd_identity partner_identity;
+ struct usb_role_switch *role_sw;
};

/*
@@ -190,6 +192,23 @@ static int tps6598x_read_partner_identity(struct tps6598x *tps)
return 0;
}

+static void tps6598x_set_data_role(struct tps6598x *tps,
+ enum typec_data_role role, bool connected)
+{
+ enum usb_role role_val;
+
+ if (role == TYPEC_HOST)
+ role_val = USB_ROLE_HOST;
+ else
+ role_val = USB_ROLE_DEVICE;
+
+ if (!connected)
+ role_val = USB_ROLE_NONE;
+
+ usb_role_switch_set_role(tps->role_sw, role_val);
+ typec_set_data_role(tps->port, role);
+}
+
static int tps6598x_connect(struct tps6598x *tps, u32 status)
{
struct typec_partner_desc desc;
@@ -220,7 +239,7 @@ static int tps6598x_connect(struct tps6598x *tps, u32 status)
typec_set_pwr_opmode(tps->port, mode);
typec_set_pwr_role(tps->port, TPS_STATUS_PORTROLE(status));
typec_set_vconn_role(tps->port, TPS_STATUS_VCONN(status));
- typec_set_data_role(tps->port, TPS_STATUS_DATAROLE(status));
+ tps6598x_set_data_role(tps, TPS_STATUS_DATAROLE(status), true);

tps->partner = typec_register_partner(tps->port, &desc);
if (IS_ERR(tps->partner))
@@ -240,7 +259,7 @@ static void tps6598x_disconnect(struct tps6598x *tps, u32 status)
typec_set_pwr_opmode(tps->port, TYPEC_PWR_MODE_USB);
typec_set_pwr_role(tps->port, TPS_STATUS_PORTROLE(status));
typec_set_vconn_role(tps->port, TPS_STATUS_VCONN(status));
- typec_set_data_role(tps->port, TPS_STATUS_DATAROLE(status));
+ tps6598x_set_data_role(tps, TPS_STATUS_DATAROLE(status), false);
}

static int tps6598x_exec_cmd(struct tps6598x *tps, const char *cmd,
@@ -328,7 +347,7 @@ static int tps6598x_dr_set(struct typec_port *port, enum typec_data_role role)
goto out_unlock;
}

- typec_set_data_role(tps->port, role);
+ tps6598x_set_data_role(tps, role, true);

out_unlock:
mutex_unlock(&tps->lock);
@@ -452,6 +471,7 @@ static int tps6598x_probe(struct i2c_client *client)
{
struct typec_capability typec_cap = { };
struct tps6598x *tps;
+ struct fwnode_handle *fwnode;
u32 status;
u32 conf;
u32 vid;
@@ -495,11 +515,21 @@ static int tps6598x_probe(struct i2c_client *client)
if (ret < 0)
return ret;

+ fwnode = device_get_named_child_node(&client->dev, "connector");
+ if (!IS_ERR_OR_NULL(fwnode)) {
+ tps->role_sw = fwnode_usb_role_switch_get(fwnode);
+ if (IS_ERR(tps->role_sw)) {
+ ret = PTR_ERR(tps->role_sw);
+ goto err_fwnode_put;
+ }
+ }
+
typec_cap.revision = USB_TYPEC_REV_1_2;
typec_cap.pd_revision = 0x200;
typec_cap.prefer_role = TYPEC_NO_PREFERRED_ROLE;
typec_cap.driver_data = tps;
typec_cap.ops = &tps6598x_ops;
+ typec_cap.fwnode = fwnode;

switch (TPS_SYSCONF_PORTINFO(conf)) {
case TPS_PORTINFO_SINK_ACCESSORY:
@@ -525,12 +555,16 @@ static int tps6598x_probe(struct i2c_client *client)
typec_cap.data = TYPEC_PORT_DFP;
break;
default:
- return -ENODEV;
+ ret = -ENODEV;
+ goto err_role_put;
}

tps->port = typec_register_port(&client->dev, &typec_cap);
- if (IS_ERR(tps->port))
- return PTR_ERR(tps->port);
+ if (IS_ERR(tps->port)) {
+ ret = PTR_ERR(tps->port);
+ goto err_role_put;
+ }
+ fwnode_handle_put(fwnode);

if (status & TPS_STATUS_PLUG_PRESENT) {
ret = tps6598x_connect(tps, status);
@@ -545,12 +579,19 @@ static int tps6598x_probe(struct i2c_client *client)
if (ret) {
tps6598x_disconnect(tps, 0);
typec_unregister_port(tps->port);
- return ret;
+ goto err_role_put;
}

i2c_set_clientdata(client, tps);

return 0;
+
+err_role_put:
+ usb_role_switch_put(tps->role_sw);
+err_fwnode_put:
+ fwnode_handle_put(fwnode);
+
+ return ret;
}

static int tps6598x_remove(struct i2c_client *client)
@@ -559,6 +600,7 @@ static int tps6598x_remove(struct i2c_client *client)

tps6598x_disconnect(tps, 0);
typec_unregister_port(tps->port);
+ usb_role_switch_put(tps->role_sw);

return 0;
}
--
2.25.1