Re: [PATCH v3] usb: typec: get the vbus source and charge values from the devicetree

From: Angus Ainslie
Date: Wed Sep 12 2018 - 12:09:01 EST

On 2018-09-11 09:33, Guenter Roeck wrote:
I cant put my finger on it but this seems wrong. As i said both src
and sink should never be true at the same time. I also dinât
understand why turning off src should power off your board. Ultimately
my concern is that we may be just painting over the real problem, and
that would be really bad to do with dt properties.

I agree that this doesn't seem like the correct way of solving the problem. On this HW (Emcraft iMX8M BSB) I think the PTN5110 chip has been connected correctly so I'm assuming that it is some quirk of the PTN5110.

I didn't design the HW or the chip. This is a workaround for "quirky" hardware and there may be others that don't behave exactly as expected.

Note that sending to groeck7@ makes it hard for me to see your emails
and to reply. Using linux@xxxxxxxxxxxx would be much better.

Ok, I think that email was grabbed from the driver source.


Sent from my iPhone

On Sep 11, 2018, at 7:59 AM, Angus Ainslie (Purism) <angus@xxxxxxxx> wrote:

If the board is being powered by USB disabling the source and sink
can remove power from the board. Allow the source and sink to be
initallized based on devicetree values.

Changed since V2:

Change the devicetree documentation.
Change the devicetree property names.

Changed since V1:

use devicetree values instead of hardcoded initialization.

Signed-off-by: Angus Ainslie (Purism) <angus@xxxxxxxx>
.../devicetree/bindings/usb/typec-tcpci.txt | 6 ++++++
drivers/usb/typec/tcpm.c | 14 +++++++++++---
2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/typec-tcpci.txt b/Documentation/devicetree/bindings/usb/typec-tcpci.txt
index 0dd1469e7318..b07418ae6482 100644
--- a/Documentation/devicetree/bindings/usb/typec-tcpci.txt
+++ b/Documentation/devicetree/bindings/usb/typec-tcpci.txt
@@ -15,6 +15,12 @@ Required sub-node:
of connector node are specified in

+Optional properties for usb-c-connector sub-node:
+- init-vbus-source: set the initalization value for vbus-source to true.
+ If this property is not present the initial value will be false.
+- init-vbus-sink: set the initalization value for vbus-sink to true.
+ If this property is not present the initial value will be false.

ptn5110@50 {
diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index ca7bedb46f7f..10c14ece3858 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -2462,9 +2462,7 @@ static int tcpm_init_vbus(struct tcpm_port *port)
int ret;

- ret = port->tcpc->set_vbus(port->tcpc, false, false);
- port->vbus_source = false;
- port->vbus_charge = false;
+ ret = port->tcpc->set_vbus(port->tcpc, port->vbus_source, port->vbus_charge);
return ret;

@@ -4266,6 +4264,16 @@ static int tcpm_fw_get_caps(struct tcpm_port *port,
return -EINVAL;
port->port_type = port->typec_caps.type;

+ if (fwnode_property_present(fwnode, "init-vbus-source"))
+ port->vbus_source = true;
+ else
+ port->vbus_source = false;
+ if (fwnode_property_present(fwnode, "init-vbus-sink"))
+ port->vbus_charge = true;
+ else
+ port->vbus_charge = false;
if (port->port_type == TYPEC_PORT_SNK)
goto sink;