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

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Message-ID: <1a428b7f-5d20-4d55-aa3a-e4feb580b82e@oss.qualcomm.com>
Date: Wed, 8 Oct 2025 16:45:06 +0530
From: Krishna Kurapati PSSNV <krishna.kurapati@....qualcomm.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>,
        Biju Das <biju.das.jz@...renesas.com>, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] usb: typec: hd3ss3220: Enable VBUS based on ID pin
 state



On 10/8/2025 4:39 PM, Heikki Krogerus wrote:
> On Thu, Oct 02, 2025 at 10:55:39PM +0530, Krishna Kurapati wrote:
>> Enable VBUS on HD3SS3220 when the ID pin is low, as required by the Type-C
>> specification.
> 
> There is not ID pin on Type-C connector.

There is an ID pin coming out from HD3SS3220 controller to SoC that is 
being referred to here.

> 
>> The ID pin stays high when VBUS is not at VSafe0V, and goes
>> low when VBUS is at VSafe0V.
>>
>> Add support to read the ID pin state and enable VBUS accordingly.
> 
> I'm a bit confused about this... Why can't you just check the attached
> state, and if it's DFP, then you drive VBUS?
> 

We could, but checking for DFP doesn't ensure VBUS is at VSafe0V as per 
the datasheet. So using the ID pin to enable vbus.

Regards,
Krishna,

> thanks,
> 
>> Signed-off-by: Krishna Kurapati <krishna.kurapati@....qualcomm.com>
>> ---
>>   drivers/usb/typec/hd3ss3220.c | 58 +++++++++++++++++++++++++++++++++++
>>   1 file changed, 58 insertions(+)
>>
>> diff --git a/drivers/usb/typec/hd3ss3220.c b/drivers/usb/typec/hd3ss3220.c
>> index 3ecc688dda82..44ee0be27644 100644
>> --- a/drivers/usb/typec/hd3ss3220.c
>> +++ b/drivers/usb/typec/hd3ss3220.c
>> @@ -54,6 +54,11 @@ struct hd3ss3220 {
>>   	struct delayed_work output_poll_work;
>>   	enum usb_role role_state;
>>   	bool poll;
>> +
>> +	struct gpio_desc *id_gpiod;
>> +	int id_irq;
>> +
>> +	struct regulator *vbus;
>>   };
>>   
>>   static int hd3ss3220_set_power_opmode(struct hd3ss3220 *hd3ss3220, int power_opmode)
>> @@ -319,6 +324,28 @@ static const struct regmap_config config = {
>>   	.max_register = 0x0A,
>>   };
>>   
>> +static irqreturn_t hd3ss3220_id_isr(int irq, void *dev_id)
>> +{
>> +	struct hd3ss3220 *hd3ss3220 = dev_id;
>> +	int ret;
>> +	int id;
>> +
>> +	if (IS_ERR_OR_NULL(hd3ss3220->vbus))
>> +		return IRQ_HANDLED;
>> +
>> +	id = hd3ss3220->id_gpiod ? gpiod_get_value_cansleep(hd3ss3220->id_gpiod) : 1;
>> +
>> +	if (!id) {
>> +		ret = regulator_enable(hd3ss3220->vbus);
>> +		if (ret)
>> +			dev_err(hd3ss3220->dev, "enable vbus regulator failed\n");
>> +	} else {
>> +		regulator_disable(hd3ss3220->vbus);
>> +	}
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>>   static int hd3ss3220_probe(struct i2c_client *client)
>>   {
>>   	struct typec_capability typec_cap = { };
>> @@ -354,6 +381,37 @@ 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;
>> +		}
>> +	}
>> +
>> +	hd3ss3220->vbus = devm_regulator_get_optional(hd3ss3220->dev, "vbus");
>> +	if (PTR_ERR(hd3ss3220->vbus) == -ENODEV)
>> +		hd3ss3220->vbus = NULL;
>> +
>> +	if (IS_ERR(hd3ss3220->vbus))
>> +		return dev_err_probe(hd3ss3220->dev,
>> +				     PTR_ERR(hd3ss3220->vbus), "failed to get vbus\n");
>> +
>>   	if (IS_ERR(hd3ss3220->role_sw)) {
>>   		ret = PTR_ERR(hd3ss3220->role_sw);
>>   		goto err_put_fwnode;
>> -- 
>> 2.34.1
>