Re: [PATCH v2 2/2] usb: gadget: udc: add Axiado AX3000 and AX3005 UDC driver

[Philipp Zabel <p.zabel@pengutronix.de>]

On Mo, 2026-08-17 at 22:57 -0700, Naveen Kumar Rajgiri Bassappa wrote:
> Add a driver for the USB device controller integrated into the Axiado
> AX3000 and AX3005 SoCs.
> 
> The controller is based on the Corigine USB 3.1 device IP core and uses an
> xHCI-like programming model with a command ring, an event ring, and
> per-endpoint transfer rings composed of Transfer Request Blocks (TRBs).
> 
> The driver implements the USB gadget and endpoint operations, including
> endpoint enable and disable, request queue and dequeue, halt and wedge
> handling, and standard endpoint 0 control requests.
> 
> It supports High-Speed and SuperSpeed operation, control, bulk,
> interrupt, and isochronous transfers, and scatter-gather requests.
> 
> Signed-off-by: Naveen Kumar Rajgiri Bassappa <rbnaveenkumar@axiado.com>
> ---
>  MAINTAINERS                      |    2 +
>  drivers/usb/gadget/udc/Kconfig   |   14 +
>  drivers/usb/gadget/udc/Makefile  |    1 +
>  drivers/usb/gadget/udc/crg_udc.c | 4491 ++++++++++++++++++++++++++++++++++++++
>  drivers/usb/gadget/udc/crg_udc.h |  355 +++
>  5 files changed, 4863 insertions(+)
> 
[...]
> diff --git a/drivers/usb/gadget/udc/crg_udc.c b/drivers/usb/gadget/udc/crg_udc.c
> new file mode 100644
> index 000000000000..bb3ed394d984
> --- /dev/null
> +++ b/drivers/usb/gadget/udc/crg_udc.c
> @@ -0,0 +1,4491 @@
[...]
> +static int crg_udc_init_hw(struct crg_gadget_dev *crg_udc)
> +{
> +	struct device *dev = crg_udc->dev;
> +	int ret;
> +
> +	crg_udc->clk = devm_clk_get_optional(dev, NULL);
> +	if (IS_ERR(crg_udc->clk))
> +		return dev_err_probe(dev, PTR_ERR(crg_udc->clk),
> +				     "failed to get clock\n");
> +
> +	ret = clk_prepare_enable(crg_udc->clk);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to enable clock\n");
> +
> +	ret = devm_add_action_or_reset(dev, crg_udc_clk_disable, crg_udc->clk);
> +	if (ret)
> +		return ret;
> +
> +	crg_udc->rst = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(crg_udc->rst))
> +		return dev_err_probe(dev, PTR_ERR(crg_udc->rst),
> +				     "failed to get reset\n");
> +
> +	ret = reset_control_deassert(crg_udc->rst);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to deassert reset\n");
> +
> +	ret = devm_add_action_or_reset(dev, crg_udc_reset_assert, crg_udc->rst);
> +	if (ret)
> +		return ret;

This looks like it could be simplified with
devm_reset_control_get_optional_exclusive_deasserted()

regards
Philipp