Re: [PATCH v1 2/2] usb: typec: mux: tusb1046: support HPD_IN override

[Heikki Krogerus]

On Wed, Nov 04, 2026 at 01:12:02PM +0530, Ajit Singh wrote:
> For boards where HPD_IN is not asserted by hardware, software can
> force it high over I2C using the HPDIN_OVERRIDE bit in the General
> register (0x0A).
> 
> Add support for the optional ti,hpd-in-override property to force
> HPD_IN high when DisplayPort mode is selected. Clear the override
> when switching to USB or Safe mode, and preserve the existing
> bit value when the property is absent.
> 
> Signed-off-by: Ajit Singh <blfizzyy@xxxxxxxxx>

Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/mux/tusb1046.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/usb/typec/mux/tusb1046.c b/drivers/usb/typec/mux/tusb1046.c
> index 34ef81f75693..c21b1f8b9786 100644
> --- a/drivers/usb/typec/mux/tusb1046.c
> +++ b/drivers/usb/typec/mux/tusb1046.c
> @@ -21,6 +21,7 @@
>  /* General register bits */
>  #define TUSB1046_GENERAL_FLIPSEL BIT(2)
>  #define TUSB1046_GENERAL_CTLSEL  GENMASK(1, 0)
> +#define TUSB1046_GENERAL_HPDIN_OVERRIDE BIT(3)
>  
>  /* Mux modes */
>  #define TUSB1046_CTLSEL_DISABLED          0x0
> @@ -32,6 +33,7 @@ struct tusb1046_priv {
>  	struct i2c_client *client;
>  	struct typec_switch_dev *sw;
>  	struct typec_mux_dev *mux;
> +	bool hpdin_override;
>  
>  	/* Lock General register during accesses */
>  	struct mutex general_reg_lock;
> @@ -44,6 +46,7 @@ static int tusb1046_mux_set(struct typec_mux_dev *mux,
>  	struct i2c_client *client = priv->client;
>  	struct device *dev = &client->dev;
>  	int mode, val, ret = 0;
> +	bool dp_active = false;
>  
>  	if (state->mode >= TYPEC_STATE_MODAL &&
>  	    state->alt->svid != USB_TYPEC_DP_SID)
> @@ -67,9 +70,11 @@ static int tusb1046_mux_set(struct typec_mux_dev *mux,
>  	case TYPEC_DP_STATE_C:
>  	case TYPEC_DP_STATE_E:
>  		mode = TUSB1046_CTLSEL_4LANE_DP;
> +		dp_active = true;
>  		break;
>  	case TYPEC_DP_STATE_D:
>  		mode = TUSB1046_CTLSEL_USB3_AND_2LANE_DP;
> +		dp_active = true;
>  		break;
>  	case TYPEC_STATE_SAFE:
>  	default:
> @@ -80,6 +85,13 @@ static int tusb1046_mux_set(struct typec_mux_dev *mux,
>  	val &= ~TUSB1046_GENERAL_CTLSEL;
>  	val |= mode;
>  
> +	if (priv->hpdin_override) {
> +		if (dp_active)
> +			val |= TUSB1046_GENERAL_HPDIN_OVERRIDE;
> +		else
> +			val &= ~TUSB1046_GENERAL_HPDIN_OVERRIDE;
> +	}
> +
>  	ret = i2c_smbus_write_byte_data(client, TUSB1046_REG_GENERAL, val);
>  
>  out_unlock:
> @@ -131,6 +143,8 @@ static int tusb1046_i2c_probe(struct i2c_client *client)
>  		return -ENOMEM;
>  
>  	priv->client = client;
> +	priv->hpdin_override =
> +		device_property_read_bool(dev, "ti,hpd-in-override");
>  
>  	mutex_init(&priv->general_reg_lock);
>  
> -- 
> 2.50.1 (Apple Git-155)
> 

-- 
heikki