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

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Message-ID: <aOZGgZc1F968uoR6@kuha.fi.intel.com>
Date: Wed, 8 Oct 2025 14:09:53 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Krishna Kurapati <krishna.kurapati@....qualcomm.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 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.

> 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?

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

-- 
heikki