linux-kernel - Re: [PATCH v8 08/11] usb: roles: get usb-role-switch from parent

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Date:   Mon, 29 Jul 2019 17:25:00 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Chunfeng Yun <chunfeng.yun@...iatek.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Biju Das <biju.das@...renesas.com>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        Li Jun <jun.li@....com>,
        Badhri Jagan Sridharan <badhri@...gle.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Min Guo <min.guo@...iatek.com>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v8 08/11] usb: roles: get usb-role-switch from parent

On Wed, Jul 24, 2019 at 04:50:42PM +0800, Chunfeng Yun wrote:
> when the USB host controller is the parent of the connector,
> usually type-B, sometimes don't need the graph, so we should
> check whether it's parent registers usb-role-switch or not
> firstly, and get it if exists.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

I don't think I actually wrote the patch. I may have proposed the code
for you, but I never prepared a patch out out that. Please drop the
above Signed-off-by line if that is the case. I case I really did
write the patch, then you are missing the "From: Heikki..." first
line, but I really don't remember preparing the patch.

If the idea came from me, you can use for example the suggested-by
tag: "Suggested-by: Heikki Krogerus <heikki.krogerus...".

> Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> ---
> v8: no changes
> v7:
>   add signed-off-by Chunfeng
> 
> v6:
>   new patch
> ---
>  drivers/usb/roles/class.c | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index 5b637aaf311f..87439a84c983 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -114,6 +114,19 @@ static void *usb_role_switch_match(struct device_connection *con, int ep,
>  	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
>  }
>  
> +static struct usb_role_switch *
> +usb_role_switch_is_parent(struct fwnode_handle *fwnode)
> +{
> +	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
> +	struct device *dev;
> +
> +	if (!parent || !fwnode_property_present(parent, "usb-role-switch"))
> +		return NULL;
> +
> +	dev = class_find_device(role_class, NULL, parent, switch_fwnode_match);
> +	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
> +}
> +
>  /**
>   * usb_role_switch_get - Find USB role switch linked with the caller
>   * @dev: The caller device
> @@ -125,8 +138,10 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
>  {
>  	struct usb_role_switch *sw;
>  
> -	sw = device_connection_find_match(dev, "usb-role-switch", NULL,
> -					  usb_role_switch_match);
> +	sw = usb_role_switch_is_parent(dev_fwnode(dev));
> +	if (!sw)
> +		sw = device_connection_find_match(dev, "usb-role-switch", NULL,
> +						  usb_role_switch_match);
>  
>  	if (!IS_ERR_OR_NULL(sw))
>  		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
> @@ -146,8 +161,10 @@ struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
>  {
>  	struct usb_role_switch *sw;
>  
> -	sw = fwnode_connection_find_match(fwnode, "usb-role-switch", NULL,
> -					  usb_role_switch_match);
> +	sw = usb_role_switch_is_parent(fwnode);
> +	if (!sw)
> +		sw = fwnode_connection_find_match(fwnode, "usb-role-switch",
> +						  NULL, usb_role_switch_match);
>  	if (!IS_ERR_OR_NULL(sw))
>  		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
>  
> -- 
> 2.21.0

thanks,

-- 
heikki