Re: [PATCH 1/2] usb: dwc3-meson-gxl: force mode on child add/removal

[Mattijs Korpershoek <mkorpershoek@baylibre.com>]

On Tue, Jan 17, 2023 at 10:11, Neil Armstrong <neil.armstrong@linaro.org> wrote:

> arch/mach-meson has some custom usb logic, in particular:
> * on board_usb_init(), we force USB_DR_MODE_PERIPHERAL
> * on board_usb_cleanup(), we force USB_DR_MODE_HOST
>
> With DM_USB_GADGET=y, board_usb_init/cleanup() are no
> longer used when we call usb_gadget_initialize().
> Instead, the generic (from udc-uclass) initialization/release is
> called, which itself calls the controller driver's probe()/remove().
>
> Therefore, enabling DM_USB_GADGET=y will mean that this mode
> switching will break.
>
> To prepare for enabling DM_USB_GADGET, perform the mode switching
> when the "amlogic,meson-g12a-usb" (dwc2) driver is
> probed()/removed() instead.
>
> This is achieved via the glue driver, which gets notified each time one
> of its children is probed()/removed.
>
> Note: this change should be harmless without DM_USB_GADGET=y
> because the amlogic-g12a-usb driver is not probed via driver model.
>
> Thanks for Mattijs for the original work at [1].
>
> [1] https://lore.kernel.org/all/20221024-meson-dm-usb-v1-1-2ab077a503b9@baylibre.com/
>
> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

Thank you for mentioning me, I appreciate it.

Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

> ---
>  drivers/usb/dwc3/dwc3-meson-gxl.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/drivers/usb/dwc3/dwc3-meson-gxl.c b/drivers/usb/dwc3/dwc3-meson-gxl.c
> index 6c6d463203..d56f2747b6 100644
> --- a/drivers/usb/dwc3/dwc3-meson-gxl.c
> +++ b/drivers/usb/dwc3/dwc3-meson-gxl.c
> @@ -408,6 +408,22 @@ static int dwc3_meson_gxl_remove(struct udevice *dev)
>  	return dm_scan_fdt_dev(dev);
>  }
>  
> +static int dwc3_meson_gxl_child_pre_probe(struct udevice *dev)
> +{
> +	if (ofnode_device_is_compatible(dev_ofnode(dev), "amlogic,meson-g12a-usb"))
> +		return dwc3_meson_gxl_force_mode(dev->parent, USB_DR_MODE_PERIPHERAL);
> +
> +	return 0;
> +}
> +
> +static int dwc3_meson_gxl_child_post_remove(struct udevice *dev)
> +{
> +	if (ofnode_device_is_compatible(dev_ofnode(dev), "amlogic,meson-g12a-usb"))
> +		return dwc3_meson_gxl_force_mode(dev->parent, USB_DR_MODE_HOST);
> +
> +	return 0;
> +}
> +
>  static const struct udevice_id dwc3_meson_gxl_ids[] = {
>  	{ .compatible = "amlogic,meson-axg-usb-ctrl" },
>  	{ .compatible = "amlogic,meson-gxl-usb-ctrl" },
> @@ -421,6 +437,8 @@ U_BOOT_DRIVER(dwc3_generic_wrapper) = {
>  	.of_match = dwc3_meson_gxl_ids,
>  	.probe = dwc3_meson_gxl_probe,
>  	.remove = dwc3_meson_gxl_remove,
> +	.child_pre_probe = dwc3_meson_gxl_child_pre_probe,
> +	.child_post_remove = dwc3_meson_gxl_child_post_remove,
>  	.plat_auto	= sizeof(struct dwc3_meson_gxl),
>  
>  };
>
> -- 
> 2.34.1