Re: [PATCH 3/3] usb: typec: ucsi: retry find role swithch when module load late

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

On Tue, Apr 12, 2022 at 06:30:07PM +0800, Linyu Yuan wrote:
> When role switch enabled, return -EAGAIN if fail to find it due to
> module load ordering issue, then restart ucsi init work to find
> it again every 100ms.
> 
> It also means change ucsi init work to delayed_work.
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---
>  drivers/usb/typec/ucsi/ucsi.c | 28 ++++++++++++++++------------
>  drivers/usb/typec/ucsi/ucsi.h |  2 +-
>  2 files changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index 684fc4f..fabd4df 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",
> +			index + 1);
> +		return -EAGAIN;
> +	}

No, this is wrong. If there is a role switch assigned in the firmware
for the port, then fwnode_usb_role_switch_get() will return
-EPROBE_DEFER until the switch has been registered.

So I think what you want to do is just make the failure to get the
role switch fatal in this driver. Just return PTR_ERR(con->usb_role_sw).

thanks,

-- 
heikki