Re: [PATCH v6 2/2] usb: typec: hd3ss3220: Enable VBUS based on ID pin state

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

Hi Krishna,

Sun, Nov 02, 2025 at 10:18:19PM +0530, Krishna Kurapati kirjoitti:
> 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@oss.qualcomm.com>
> ---
>  drivers/usb/typec/hd3ss3220.c | 72 +++++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/drivers/usb/typec/hd3ss3220.c b/drivers/usb/typec/hd3ss3220.c
> index 3ecc688dda82..75fbda42eaf4 100644
> --- a/drivers/usb/typec/hd3ss3220.c
> +++ b/drivers/usb/typec/hd3ss3220.c
> @@ -15,6 +15,9 @@
>  #include <linux/usb/typec.h>
>  #include <linux/delay.h>
>  #include <linux/workqueue.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/of_graph.h>
>  
>  #define HD3SS3220_REG_CN_STAT		0x08
>  #define HD3SS3220_REG_CN_STAT_CTRL	0x09
> @@ -54,6 +57,11 @@ 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 +327,44 @@ 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 (!hd3ss3220->vbus)
> +		return IRQ_HANDLED;

If you don't need this routine unless there is a vbus regulator, then
don't register it at all if there is no vbus regulator.

> +	id = hd3ss3220->id_gpiod ? gpiod_get_value_cansleep(hd3ss3220->id_gpiod) : 1;

You still don't need to check for hd3ss3220->id_gpiod - this function
will not get called unless it's there.

        if (gpiod_get_value_cansleep(hd3ss3220->id_gpiod))
                ret = regulator_disable(hd3ss3220->vbus);
        else
                ret = regulator_enable(hd3ss3220->vbus);

Note:

If you are concerned that the reference to the id_gpiod may be
released before this routine is unregistered, then that condition will
not help. The hd3ss3220->id_gpiod member is _not_ NULL after the
reference is released.

If you need a specific order in which the references are released,
then you can't use the resource management (devm_*) to automate things
for you.

> +	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_get_vbus_supply(struct hd3ss3220 *hd3ss3220,
> +				     struct fwnode_handle *connector)
> +{
> +	int ret  = 0;
> +
> +	hd3ss3220->vbus = devm_of_regulator_get_optional(hd3ss3220->dev,
> +							 to_of_node(connector),
> +							 "vbus");
> +	if (PTR_ERR(hd3ss3220->vbus) == -ENODEV)
> +		hd3ss3220->vbus = NULL;
> +	else if (IS_ERR(hd3ss3220->vbus))
> +		ret = PTR_ERR(hd3ss3220->vbus);

So the regulator API's optional functions return -ENODEV instead of NULL :(
In any case, don't double assign the member. Use local variable.

        struct regulator *vbus;

        vbus = devm_of_regulator_get_optional(...
        if (IS_ERR(vbus) && vbus != ERR_PTR(-ENODEV))
                return PTR_ERR(vbus);

        hd3ss3220->vbus = vbus;
        return 0;

I don't think you need this function - just do that in the probe function.

> +	return ret;
> +}
> +
>  static int hd3ss3220_probe(struct i2c_client *client)
>  {
>  	struct typec_capability typec_cap = { };
> @@ -354,11 +400,37 @@ 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)
> +			return dev_err_probe(hd3ss3220->dev, hd3ss3220->id_irq,
> +					     "failed to get ID gpio\n");
> +
> +		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)
> +			return dev_err_probe(hd3ss3220->dev, ret, "failed to get ID irq\n");
> +	}
> +
>  	if (IS_ERR(hd3ss3220->role_sw)) {
>  		ret = PTR_ERR(hd3ss3220->role_sw);
>  		goto err_put_fwnode;
>  	}
>  
> +	ret = hd3ss3220_get_vbus_supply(hd3ss3220, connector);
> +	if (ret) {
> +		dev_err(hd3ss3220->dev, "failed to get vbus: %d\n", ret);
> +		goto err_put_fwnode;
> +	}
> +
>  	typec_cap.prefer_role = TYPEC_NO_PREFERRED_ROLE;
>  	typec_cap.driver_data = hd3ss3220;
>  	typec_cap.type = TYPEC_PORT_DRP;
> -- 
> 2.34.1

thanks,

-- 
heikki