Re: [PATCH v3 2/2] usb: typec: hd3ss3220: Enable VBUS based on ID pin state

[Krishna Kurapati PSSNV]

On 10/25/2025 12:31 PM, Biju Das wrote:
> > -----Original Message-----
> > From: Krishna Kurapati <krishna.kurapati@xxxxxxxxxxxxxxxx>
> > Sent: 24 October 2025 19:19
> > To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Rob Herring <robh@xxxxxxxxxx>; Krzysztof
> > Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley <conor+dt@xxxxxxxxxx>; Heikki Krogerus
> > <heikki.krogerus@xxxxxxxxxxxxxxx>; Biju Das <biju.das.jz@xxxxxxxxxxxxxx>; Dmitry Baryshkov
> > <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > Cc: linux-usb@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Krishna
> > Kurapati <krishna.kurapati@xxxxxxxxxxxxxxxx>
> > Subject: [PATCH v3 2/2] usb: typec: hd3ss3220: Enable VBUS based on ID pin state
> >
> > There is a ID pin present on HD3SS3220 controller that can be routed to SoC. As per the datasheet:
> >
> > "Upon detecting a UFP device, HD3SS3220 will keep ID pin high if VBUS is not at VSafe0V. Once VBUS is
> > at VSafe0V, the HD3SS3220 will assert ID pin low. This is done to enforce Type-C requirement that VBUS
> > must be at VSafe0V before re-enabling VBUS"
> >
> > Add support to read the ID pin state and enable VBUS accordingly.
> >
> > Signed-off-by: Krishna Kurapati <krishna.kurapati@xxxxxxxxxxxxxxxx>
> > ---
> >   drivers/usb/typec/hd3ss3220.c | 101 ++++++++++++++++++++++++++++++++++
> >   1 file changed, 101 insertions(+)

[...]

> > +static int hd3ss3220_get_vbus_supply(struct hd3ss3220 *hd3ss3220) {
> > +	struct device_node *hd3ss3220_node = hd3ss3220->dev->of_node;
> > +	const char *compat_string;
> > +	struct device_node *np;
> > +	int num_ports = 0;
> > +	int ret = 0;
> > +	int i = 0;
> > +
> > +	num_ports = of_graph_get_port_count(hd3ss3220_node);
> > +
> > +	for (i = 0; i < num_ports; i++) {
> > +		np = of_graph_get_remote_node(hd3ss3220_node, i, 0);
> > +		if (!np) {
> > +			dev_err(hd3ss3220->dev, "failed to get device node");
> > +			ret = -ENODEV;
> > +			goto done;
> > +		}
> > +
> > +		ret = of_property_read_string(np, "compatible", &compat_string);
> > +		if (ret) {
> > +			of_node_put(np);
> > +			dev_err(hd3ss3220->dev, "failed to get compatible string");
> > +			ret = -ENODEV;
> > +			goto done;
> > +		}
> > +
> > +		if (strcmp(compat_string, "usb-c-connector") == 0) {
> > +			hd3ss3220->vbus = of_regulator_get(hd3ss3220->dev, np, "vbus");
> > +			if (PTR_ERR(hd3ss3220->vbus) == -ENODEV)
> > +				hd3ss3220->vbus = NULL;
> > +
> > +			if (IS_ERR(hd3ss3220->vbus))
> > +				ret = -ENODEV;
> > +		}
> > +
> > +		of_node_put(np);
> > +	}
> > +
> > +done:
> > +	return ret;
> > +}
> > +
> >   static int hd3ss3220_probe(struct i2c_client *client)  {
> >   	struct typec_capability typec_cap = { }; @@ -354,6 +427,34 @@ static int hd3ss3220_probe(struct
> > i2c_client *client)
> >   		hd3ss3220->role_sw = usb_role_switch_get(hd3ss3220->dev);
> >   	}
> >
> > +	hd3ss3220->id_gpiod = devm_gpiod_get_optional(hd3ss3220->dev, "id", GPIOD_IN);
> > +	if (IS_ERR(hd3ss3220->id_gpiod))
> > +		return PTR_ERR(hd3ss3220->id_gpiod);
> > +
> > +	if (hd3ss3220->id_gpiod) {
> > +		hd3ss3220->id_irq = gpiod_to_irq(hd3ss3220->id_gpiod);
> > +		if (hd3ss3220->id_irq < 0) {
> > +			dev_err(hd3ss3220->dev, "failed to get ID IRQ\n");
> > +			return hd3ss3220->id_irq;
> > +		}
> > +
> > +		ret = devm_request_threaded_irq(hd3ss3220->dev,
> > +						hd3ss3220->id_irq, NULL,
> > +						hd3ss3220_id_isr,
> > +						IRQF_TRIGGER_RISING |
> > +						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> > +						dev_name(hd3ss3220->dev), hd3ss3220);
> > +		if (ret < 0) {
> > +			dev_err(hd3ss3220->dev, "failed to get id irq\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	ret = hd3ss3220_get_vbus_supply(hd3ss3220);
> > +	if (ret)
> > +		return dev_err_probe(hd3ss3220->dev,
> > +				     PTR_ERR(hd3ss3220->vbus), "failed to get vbus\n");
>
> Does this code backward compatible? There is no vbus definition here [1]
>
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts?h=next-20251024#n208

Hi Biju,

 Yes. If there is no vbus supply in the usb-c-connector node, we just 
mark it as NULL. The ret value would be zero if there is no vbus.

Regards,
Krishna,