Re: [PATCH 6/7] usb: dwc3: add spacemit dwc3 glue layer driver

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Mon, Apr 07, 2025, Ze Huang wrote:
> Add SpacemiT glue logic to support dwc3 HC on K1 SoC. The driver manages
> clock, reset and interrupt resource.
> 
> Signed-off-by: Ze Huang <huangze@whut.edu.cn>
> ---
>  drivers/usb/dwc3/Kconfig         |   7 +++
>  drivers/usb/dwc3/Makefile        |   1 +
>  drivers/usb/dwc3/dwc3-spacemit.c | 127 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 135 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
> index 310d182e10b50b253d7e5a51674806e6ec442a2a..3c30680fa4f83565fc03c6800e867c6ced0fe101 100644
> --- a/drivers/usb/dwc3/Kconfig
> +++ b/drivers/usb/dwc3/Kconfig
> @@ -189,4 +189,11 @@ config USB_DWC3_RTK
>  	  or dual-role mode.
>  	  Say 'Y' or 'M' if you have such device.
>  
> +config USB_DWC3_SPACEMIT
> +	tristate "Spacemit Platforms"

Does this depend on other configs like OF and COMMON_CLK?

> +	default USB_DWC3
> +	help
> +	  Support SPACEMIT platforms with DesignWare Core USB3 IP.
> +	  Say 'Y' or 'M' here if you have one such device
> +
>  endif
> diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
> index 124eda2522d9c1f4caab222ec9770d0deaf655fc..61a87765c0c591e0a53c33b5a6544db056166f96 100644
> --- a/drivers/usb/dwc3/Makefile
> +++ b/drivers/usb/dwc3/Makefile
> @@ -56,3 +56,4 @@ obj-$(CONFIG_USB_DWC3_IMX8MP)		+= dwc3-imx8mp.o
>  obj-$(CONFIG_USB_DWC3_XILINX)		+= dwc3-xilinx.o
>  obj-$(CONFIG_USB_DWC3_OCTEON)		+= dwc3-octeon.o
>  obj-$(CONFIG_USB_DWC3_RTK)		+= dwc3-rtk.o
> +obj-$(CONFIG_USB_DWC3_SPACEMIT)		+= dwc3-spacemit.o
> diff --git a/drivers/usb/dwc3/dwc3-spacemit.c b/drivers/usb/dwc3/dwc3-spacemit.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..4574ad3b34a200ffe999c7da61b74c2ef33c0483
> --- /dev/null
> +++ b/drivers/usb/dwc3/dwc3-spacemit.c
> @@ -0,0 +1,127 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * dwc3-spacemit.c - Spacemit DWC3 Specific Glue layer
> + *
> + * Copyright (C) 2025 SpacemiT (Hangzhou) Technology Co. Ltd
> + *
> + * Author: Wilson <long.wan@spacemit.com>
> + * Contributor: Ze Huang <huangze@whut.edu.cn>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +struct dwc3_spacemit {
> +	struct device		*dev;
> +	struct clk		*clk;
> +	struct reset_control	*reset;
> +};
> +
> +static int dwc3_spacemit_init(struct dwc3_spacemit *data)
> +{
> +	struct device *dev = data->dev;
> +	int ret = 0;
> +
> +	data->reset = devm_reset_control_get(dev, NULL);
> +	if (IS_ERR(data->reset))
> +		return dev_err_probe(dev, PTR_ERR(data->reset), "failed to get reset\n");
> +
> +	ret = reset_control_assert(data->reset);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to assert reset\n");
> +
> +	usleep_range(10, 20);
> +
> +	ret = reset_control_deassert(data->reset);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to deassert reset\n");
> +
> +	return 0;
> +}
> +
> +static int dwc3_spacemit_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct dwc3_spacemit *spacemit;
> +	int ret;
> +
> +	spacemit = devm_kzalloc(dev, sizeof(*spacemit), GFP_KERNEL);
> +	if (!spacemit)
> +		return -ENOMEM;
> +
> +	spacemit->dev = dev;
> +
> +	platform_set_drvdata(pdev, spacemit);
> +
> +	spacemit->clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(spacemit->clk))
> +		return dev_err_probe(dev, PTR_ERR(spacemit->clk), "Failed to get clock\n");
> +
> +	ret = dwc3_spacemit_init(spacemit);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to init SpacemiT USB3 glue\n");
> +
> +	ret = of_platform_populate(node, NULL, NULL, dev);
> +	if (ret)
> +		dev_err_probe(dev, ret, "failed to add dwc3 core\n");
> +
> +	return 0;
> +}
> +
> +static void dwc3_spacemit_remove(struct platform_device *pdev)
> +{
> +	of_platform_depopulate(&pdev->dev);
> +}
> +
> +static const struct of_device_id spacemit_dwc3_match[] = {
> +	{ .compatible = "spacemit,k1-dwc3", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, spacemit_dwc3_match);
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int dwc3_spacemit_suspend(struct device *dev)
> +{
> +	struct dwc3_spacemit *spacemit = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(spacemit->clk);
> +
> +	return 0;
> +}
> +
> +static int dwc3_spacemit_resume(struct device *dev)
> +{
> +	struct dwc3_spacemit *spacemit = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(spacemit->clk);
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops dwc3_spacemit_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(dwc3_spacemit_suspend, dwc3_spacemit_resume)
> +};
> +#endif /* CONFIG_PM_SLEEP */
> +

Use DEFINE_SIMPLE_DEV_PM_OPS to remove the CONFIG_PM_SLEEP guards. 

> +static struct platform_driver dwc3_spacemit_driver = {
> +	.probe		= dwc3_spacemit_probe,
> +	.remove		= dwc3_spacemit_remove,
> +	.driver		= {
> +		.name	= "spacemit-dwc3",
> +		.of_match_table = spacemit_dwc3_match,
> +#ifdef CONFIG_PM_SLEEP
> +		.pm	= &dwc3_spacemit_dev_pm_ops,
> +#endif /* CONFIG_PM_SLEEP */
> +	},
> +};
> +module_platform_driver(dwc3_spacemit_driver);
> +
> +MODULE_AUTHOR("Wilson <long.wan@spacemit.com>");

The author is different than the commiter? Also, is there a last name?

> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("DesignWare USB3 Spacemit Glue Layer");
> 
> -- 
> 2.49.0
> 

The logic in this glue driver looks quite simple. Can this platform work
as dwc3-of-simple?

Thanks,
Thinh