linux-kernel - Re: [PATCH v2] extcon: usbc-tusb320: unregister typec port on driver removal

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Date:   Thu, 16 Mar 2023 05:50:11 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Alvin Šipraga <alvin@...s.dk>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Marek Vasut <marex@...x.de>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Alvin Šipraga <alsi@...g-olufsen.dk>
Cc:     linux-usb@...r.kernel.org, stable@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] extcon: usbc-tusb320: unregister typec port on driver
 removal

On 23. 3. 15. 23:15, Alvin Šipraga wrote:
> From: Alvin Šipraga <alsi@...g-olufsen.dk>
> 
> The driver can register a typec port if suitable firmware properties are
> present. But if the driver is removed through sysfs unbind, rmmod or
> similar, then it does not clean up after itself and the typec port
> device remains registered. This can be seen in sysfs, where stale typec
> ports get left over in /sys/class/typec.
> 
> In order to fix this we have to add an i2c_driver remove function and
> call typec_unregister_port(), which is a no-op in the case where no
> typec port is created and the pointer remains NULL.
> 
> In the process we should also put the fwnode_handle when the typec port
> isn't registered anymore, including if an error occurs during probe. The
> typec subsystem does not increase or decrease the reference counter for
> us, so we track it in the driver's private data.
> 
> Note that the conditional check on TYPEC_PWR_MODE_PD was removed in the
> probe path because a call to tusb320_set_adv_pwr_mode() will perform an
> even more robust validation immediately after, hence there is no
> functional change here.
> 
> Fixes: bf7571c00dca ("extcon: usbc-tusb320: Add USB TYPE-C support")
> Cc: stable@...r.kernel.org
> Signed-off-by: Alvin Šipraga <alsi@...g-olufsen.dk>
> ---
> v2: properly assign priv->connector_fwnode = connector;
> ---
>  drivers/extcon/extcon-usbc-tusb320.c | 42 ++++++++++++++++++++++------
>  1 file changed, 34 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c
> index b408ce989c22..10dff1c512c4 100644
> --- a/drivers/extcon/extcon-usbc-tusb320.c
> +++ b/drivers/extcon/extcon-usbc-tusb320.c
> @@ -78,6 +78,7 @@ struct tusb320_priv {
>  	struct typec_capability	cap;
>  	enum typec_port_type port_type;
>  	enum typec_pwr_opmode pwr_opmode;
> +	struct fwnode_handle *connector_fwnode;
>  };
>  
>  static const char * const tusb_attached_states[] = {
> @@ -391,27 +392,25 @@ static int tusb320_typec_probe(struct i2c_client *client,
>  	/* Type-C connector found. */
>  	ret = typec_get_fw_cap(&priv->cap, connector);
>  	if (ret)
> -		return ret;
> +		goto err_put;
>  
>  	priv->port_type = priv->cap.type;
>  
>  	/* This goes into register 0x8 field CURRENT_MODE_ADVERTISE */
>  	ret = fwnode_property_read_string(connector, "typec-power-opmode", &cap_str);
>  	if (ret)
> -		return ret;
> +		goto err_put;
>  
>  	ret = typec_find_pwr_opmode(cap_str);
>  	if (ret < 0)
> -		return ret;
> -	if (ret == TYPEC_PWR_MODE_PD)
> -		return -EINVAL;
> +		goto err_put;
>  
>  	priv->pwr_opmode = ret;
>  
>  	/* Initialize the hardware with the devicetree settings. */
>  	ret = tusb320_set_adv_pwr_mode(priv);
>  	if (ret)
> -		return ret;
> +		goto err_put;
>  
>  	priv->cap.revision		= USB_TYPEC_REV_1_1;
>  	priv->cap.accessory[0]		= TYPEC_ACCESSORY_AUDIO;
> @@ -422,10 +421,25 @@ static int tusb320_typec_probe(struct i2c_client *client,
>  	priv->cap.fwnode		= connector;
>  
>  	priv->port = typec_register_port(&client->dev, &priv->cap);
> -	if (IS_ERR(priv->port))
> -		return PTR_ERR(priv->port);
> +	if (IS_ERR(priv->port)) {
> +		ret = PTR_ERR(priv->port);
> +		goto err_put;
> +	}
> +
> +	priv->connector_fwnode = connector;
>  
>  	return 0;
> +
> +err_put:
> +	fwnode_handle_put(connector);
> +
> +	return ret;
> +}
> +
> +static void tusb320_typec_remove(struct tusb320_priv *priv)
> +{
> +	typec_unregister_port(priv->port);
> +	fwnode_handle_put(priv->connector_fwnode);
>  }
>  
>  static int tusb320_probe(struct i2c_client *client)
> @@ -438,7 +452,9 @@ static int tusb320_probe(struct i2c_client *client)
>  	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
>  		return -ENOMEM;
> +
>  	priv->dev = &client->dev;
> +	i2c_set_clientdata(client, priv);
>  
>  	priv->regmap = devm_regmap_init_i2c(client, &tusb320_regmap_config);
>  	if (IS_ERR(priv->regmap))
> @@ -489,10 +505,19 @@ static int tusb320_probe(struct i2c_client *client)
>  					tusb320_irq_handler,
>  					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>  					client->name, priv);
> +	if (ret)
> +		tusb320_typec_remove(priv);
>  
>  	return ret;
>  }
>  
> +static void tusb320_remove(struct i2c_client *client)
> +{
> +	struct tusb320_priv *priv = i2c_get_clientdata(client);
> +
> +	tusb320_typec_remove(priv);
> +}
> +
>  static const struct of_device_id tusb320_extcon_dt_match[] = {
>  	{ .compatible = "ti,tusb320", .data = &tusb320_ops, },
>  	{ .compatible = "ti,tusb320l", .data = &tusb320l_ops, },
> @@ -502,6 +527,7 @@ MODULE_DEVICE_TABLE(of, tusb320_extcon_dt_match);
>  
>  static struct i2c_driver tusb320_extcon_driver = {
>  	.probe_new	= tusb320_probe,
> +	.remove		= tusb320_remove,
>  	.driver		= {
>  		.name	= "extcon-tusb320",
>  		.of_match_table = tusb320_extcon_dt_match,

Applied it. Thanks.

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi