Re: [PATCH v5 3/3] usb: typec: ucsi: Wait for the USB role switches

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

On Fri, Apr 22, 2022 at 11:10:22AM +0800, Linyu Yuan wrote:
> When role switch module probe late than ucsi module,
> fwnode_usb_role_switch_get() will return -EPROBE_DEFER,
> it is better to restart ucsi init work to find
> it again every 100ms, total wait time is 10 second.
> 
> It also means change ucsi init work to delayed_work.
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> v2: keep original con->num in debug log
> v3: change return value from -EAGAIN to PTR_ERR()
> v4: change subject line,
>     add counter for retry limit,
>     correct commit descripton to match change in V3
> v5: small update of commit description
> 
>  drivers/usb/typec/ucsi/ucsi.c | 32 ++++++++++++++++++++------------
>  drivers/usb/typec/ucsi/ucsi.h |  6 +++++-
>  2 files changed, 25 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index ce9192e..11f8808 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1053,6 +1053,14 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>  	con->num = index + 1;
>  	con->ucsi = ucsi;
>  
> +	cap->fwnode = ucsi_find_fwnode(con);
> +	con->usb_role_sw = fwnode_usb_role_switch_get(cap->fwnode);
> +	if (IS_ERR(con->usb_role_sw)) {
> +		dev_err(ucsi->dev, "con%d: failed to get usb role switch\n",
> +			con->num);
> +		return PTR_ERR(con->usb_role_sw);
> +	}
> +
>  	/* Delay other interactions with the con until registration is complete */
>  	mutex_lock(&con->lock);
>  
> @@ -1088,7 +1096,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>  	if (con->cap.op_mode & UCSI_CONCAP_OPMODE_DEBUG_ACCESSORY)
>  		*accessory = TYPEC_ACCESSORY_DEBUG;
>  
> -	cap->fwnode = ucsi_find_fwnode(con);
>  	cap->driver_data = con;
>  	cap->ops = &ucsi_ops;
>  
> @@ -1147,13 +1154,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>  		ucsi_port_psy_changed(con);
>  	}
>  
> -	con->usb_role_sw = fwnode_usb_role_switch_get(cap->fwnode);
> -	if (IS_ERR(con->usb_role_sw)) {
> -		dev_err(ucsi->dev, "con%d: failed to get usb role switch\n",
> -			con->num);
> -		con->usb_role_sw = NULL;
> -	}
> -
>  	/* Only notify USB controller if partner supports USB data */
>  	if (!(UCSI_CONSTAT_PARTNER_FLAGS(con->status.flags) & UCSI_CONSTAT_PARTNER_FLAG_USB))
>  		u_role = USB_ROLE_NONE;
> @@ -1286,12 +1286,20 @@ static int ucsi_init(struct ucsi *ucsi)
>  
>  static void ucsi_init_work(struct work_struct *work)
>  {
> -	struct ucsi *ucsi = container_of(work, struct ucsi, work);
> +	struct ucsi *ucsi = container_of(work, struct ucsi, work.work);
>  	int ret;
>  
>  	ret = ucsi_init(ucsi);
>  	if (ret)
>  		dev_err(ucsi->dev, "PPM init failed (%d)\n", ret);
> +
> +	if (ret == -EPROBE_DEFER) {
> +		if (ucsi->work_count++ > UCSI_ROLE_SWITCH_WAIT_COUNT)
> +			return;
> +
> +		queue_delayed_work(system_long_wq, &ucsi->work,
> +				   UCSI_ROLE_SWITCH_INTERVAL);
> +	}
>  }
>  
>  /**
> @@ -1331,7 +1339,7 @@ struct ucsi *ucsi_create(struct device *dev, const struct ucsi_operations *ops)
>  	if (!ucsi)
>  		return ERR_PTR(-ENOMEM);
>  
> -	INIT_WORK(&ucsi->work, ucsi_init_work);
> +	INIT_DELAYED_WORK(&ucsi->work, ucsi_init_work);
>  	mutex_init(&ucsi->ppm_lock);
>  	ucsi->dev = dev;
>  	ucsi->ops = ops;
> @@ -1366,7 +1374,7 @@ int ucsi_register(struct ucsi *ucsi)
>  	if (!ucsi->version)
>  		return -ENODEV;
>  
> -	queue_work(system_long_wq, &ucsi->work);
> +	queue_delayed_work(system_long_wq, &ucsi->work, 0);
>  
>  	return 0;
>  }
> @@ -1383,7 +1391,7 @@ void ucsi_unregister(struct ucsi *ucsi)
>  	u64 cmd = UCSI_SET_NOTIFICATION_ENABLE;
>  
>  	/* Make sure that we are not in the middle of driver initialization */
> -	cancel_work_sync(&ucsi->work);
> +	cancel_delayed_work_sync(&ucsi->work);
>  
>  	/* Disable notifications */
>  	ucsi->ops->async_write(ucsi, UCSI_CONTROL, &cmd, sizeof(cmd));
> diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
> index 280f1e1..8eb391e 100644
> --- a/drivers/usb/typec/ucsi/ucsi.h
> +++ b/drivers/usb/typec/ucsi/ucsi.h
> @@ -287,7 +287,11 @@ struct ucsi {
>  	struct ucsi_capability cap;
>  	struct ucsi_connector *connector;
>  
> -	struct work_struct work;
> +	struct delayed_work work;
> +	int work_count;
> +#define UCSI_ROLE_SWITCH_RETRY_PER_HZ	10
> +#define UCSI_ROLE_SWITCH_INTERVAL	(HZ / UCSI_ROLE_SWITCH_RETRY_PER_HZ)
> +#define UCSI_ROLE_SWITCH_WAIT_COUNT	(10 * UCSI_ROLE_SWITCH_RETRY_PER_HZ)
>  
>  	/* PPM Communication lock */
>  	struct mutex ppm_lock;
> -- 
> 2.7.4

-- 
heikki