Re: [PATCH V2 4/8] usb: dwc3: drd: Register the eud connector child node for dwc3

[Rob Herring <robh@kernel.org>]

On Thu, Dec 02, 2021 at 03:21:23PM +0530, Souradeep Chowdhury wrote:
> Register the child node for dwc3 which is the "eud_usb_connector".
> The eud driver will be able to switch the usb role from device to
> host and vice versa using the role switch property of dwc3 node.
> 
> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com>
> ---
>  drivers/usb/dwc3/drd.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index d7f7683..b4ea55c 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -8,6 +8,7 @@
>   */
>  
>  #include <linux/extcon.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_graph.h>
>  #include <linux/platform_device.h>
>  #include <linux/property.h>
> @@ -164,6 +165,27 @@ static int dwc3_otg_get_irq(struct dwc3 *dwc)
>  	return irq;
>  }
>  
> +static int dwc3_register_eud(struct dwc3 *dwc)
> +{
> +	struct device		*dev = dwc->dev;
> +	struct device_node	*np = dev->of_node;
> +	int                     ret;
> +
> +	of_get_child_by_name(np, "eud_usb_connector");

Connector nodes are named 'connector' or possibly 'usb-connector'. If 
you are creating an ABI with the node name, it should be documented. 
However, it's preferred to use 'compatible' for identifying nodes rather 
than a node name.

> +	if (!np) {
> +		dev_dbg(dev, "no usb_connector child node specified\n");
> +		return 0;
> +	}
> +
> +	ret = of_platform_populate(np, NULL, NULL, dev);

But why is any of this needed. The connector doesn't have a driver (I 
expect eventually we will) and the EUD device is not a child.

> +	if (ret) {
> +		dev_err(dev, "failed to register usb_connector - %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  void dwc3_otg_init(struct dwc3 *dwc)
>  {
>  	u32 reg;
> @@ -580,6 +602,10 @@ int dwc3_drd_init(struct dwc3 *dwc)
>  		ret = dwc3_setup_role_switch(dwc);
>  		if (ret < 0)
>  			return ret;
> +
> +		ret = dwc3_register_eud(dwc);
> +		if (ret < 0)
> +			return ret;
>  	} else if (dwc->edev) {
>  		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
>  		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
> -- 
> 2.7.4
> 
>