Re: [PATCH v5 3/4] usb: host: xhci-plat: Create platform device for onboard hubs in probe()

From: Greg Kroah-Hartman
Date: Thu Feb 11 2021 - 01:59:21 EST


On Wed, Feb 10, 2021 at 09:10:38AM -0800, Matthias Kaehlcke wrote:
> Check during probe() if a hub supported by the onboard_usb_hub
> driver is connected to the controller. If such a hub is found
> create the corresponding platform device. This requires the
> device tree to have a node for the hub with its vendor and
> product id (which is not common for USB devices). Further the
> platform device is only created when CONFIG_USB_ONBOARD_HUB=y/m.
>
> Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> ---
>
> Changes in v5:
> - patch added to the series
>
> drivers/usb/host/xhci-plat.c | 16 ++++++++++++++++
> include/linux/usb/hcd.h | 2 ++
> 2 files changed, 18 insertions(+)
>
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 4d34f6005381..e785fa109eea 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -15,6 +15,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> +#include <linux/usb/onboard_hub.h>
> #include <linux/usb/phy.h>
> #include <linux/slab.h>
> #include <linux/acpi.h>
> @@ -184,6 +185,7 @@ static int xhci_plat_probe(struct platform_device *pdev)
> int ret;
> int irq;
> struct xhci_plat_priv *priv = NULL;
> + struct device_node *np;
>
>
> if (usb_disabled())
> @@ -356,6 +358,17 @@ static int xhci_plat_probe(struct platform_device *pdev)
> */
> pm_runtime_forbid(&pdev->dev);
>
> + np = usb_of_get_device_node(hcd->self.root_hub, hcd->self.busnum);
> + if (np && of_is_onboard_usb_hub(np)) {
> + struct platform_device *pdev;
> +
> + pdev = of_platform_device_create(np, NULL, NULL);

A platform device is a child of another platform device? Ok, but
really, why? What uses this device?

thanks,

greg k-h