Re: [PATCH] usb: misc: add support for new OF onboard hub binding

[Sascha Hauer <sha@pengutronix.de>]

On Fri, Feb 17, 2023 at 09:26:20PM +0100, Ahmad Fatoum wrote:
> The new binding allows describing hubs that lacks a control bus (e.g.
> I2C) in the DT and thus replaces the ugly hack of specifying USB hub
> resets as gpio-hogs. It's already in use for boards we support, like the
> STM32MP13/5 Discovery kits and will be useful for the i.MX8MP Debix
> board, so port over the driver from Linux.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/usb/core/usb.c             |  2 +
>  drivers/usb/misc/Kconfig           | 10 ++++
>  drivers/usb/misc/Makefile          |  1 +
>  drivers/usb/misc/onboard_usb_hub.c | 86 ++++++++++++++++++++++++++++++
>  drivers/usb/misc/onboard_usb_hub.h | 36 +++++++++++++
>  include/usb/usb.h                  |  8 +++
>  6 files changed, 143 insertions(+)
>  create mode 100644 drivers/usb/misc/onboard_usb_hub.c
>  create mode 100644 drivers/usb/misc/onboard_usb_hub.h

Applied, thanks

Sascha

> 
> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> index 7c589ec06f24..a974614c062e 100644
> --- a/drivers/usb/core/usb.c
> +++ b/drivers/usb/core/usb.c
> @@ -576,6 +576,8 @@ int usb_host_detect(struct usb_host *host)
>  {
>  	int ret;
>  
> +	of_usb_host_probe_hubs(host);
> +
>  	if (!host->root_dev) {
>  		if (host->init) {
>  			ret = host->init(host);
> diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
> index 9799af47256e..fde57fd74309 100644
> --- a/drivers/usb/misc/Kconfig
> +++ b/drivers/usb/misc/Kconfig
> @@ -14,3 +14,13 @@ config USB_HUB_USB251XB
>  	  Microchip USB251x/xBi USB 2.0 Hub Controller series. Configuration
>  	  parameters may be set in devicetree or platform data.
>  	  Say Y or M here if you need to configure such a device via SMBus.
> +
> +config USB_ONBOARD_HUB
> +	bool "Onboard USB hub support"
> +	depends on OFDEVICE || COMPILE_TEST
> +	help
> +	  Say Y here if you want to support discrete onboard USB hubs that
> +	  don't require an additional control bus for initialization, but
> +	  need some non-trivial form of initialization, such as enabling a
> +	  power regulator. An example for such a hub is the Realtek
> +	  RTS5411.
> diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
> index be5c044f5a57..e00f66a5ed1c 100644
> --- a/drivers/usb/misc/Makefile
> +++ b/drivers/usb/misc/Makefile
> @@ -4,3 +4,4 @@
>  # (the ones that don't fit into any other categories)
>  #
>  obj-$(CONFIG_USB_HUB_USB251XB)		+= usb251xb.o
> +obj-$(CONFIG_USB_ONBOARD_HUB)		+= onboard_usb_hub.o
> diff --git a/drivers/usb/misc/onboard_usb_hub.c b/drivers/usb/misc/onboard_usb_hub.c
> new file mode 100644
> index 000000000000..0b847f06ad45
> --- /dev/null
> +++ b/drivers/usb/misc/onboard_usb_hub.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Driver for onboard USB hubs
> + *
> + * Copyright (c) 2022, Google LLC
> + */
> +
> +#include <driver.h>
> +#include <gpiod.h>
> +#include <init.h>
> +#include <of.h>
> +#include <linux/printk.h>
> +#include <of_device.h>
> +#include <regulator.h>
> +#include <usb/usb.h>
> +
> +#include "onboard_usb_hub.h"
> +
> +void of_usb_host_probe_hubs(struct usb_host *host)
> +{
> +	struct device_node *np;
> +
> +	np = dev_of_node(host->hw_dev);
> +	if (!np)
> +		return;
> +
> +	of_platform_populate(np, onboard_hub_match, host->hw_dev);
> +}
> +
> +struct onboard_hub {
> +	struct regulator *vdd;
> +	struct device *dev;
> +	const struct onboard_hub_pdata *pdata;
> +	int reset_gpio;
> +};
> +
> +static int onboard_hub_power_on(struct onboard_hub *hub)
> +{
> +	int err;
> +
> +	err = regulator_enable(hub->vdd);
> +	if (err) {
> +		dev_err(hub->dev, "failed to enable regulator: %pe\n",
> +			ERR_PTR(err));
> +		return err;
> +	}
> +
> +	udelay(hub->pdata->reset_us);
> +	gpiod_set_value(hub->reset_gpio, 0);
> +
> +	return 0;
> +}
> +
> +static int onboard_hub_probe(struct device *dev)
> +{
> +	struct onboard_hub *hub;
> +
> +	hub = xzalloc(sizeof(*hub));
> +
> +	hub->pdata = device_get_match_data(dev);
> +	if (!hub->pdata)
> +		return -EINVAL;
> +
> +	hub->vdd = regulator_get(dev, "vdd");
> +	if (IS_ERR(hub->vdd))
> +		return PTR_ERR(hub->vdd);
> +
> +	hub->reset_gpio = gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (hub->reset_gpio < 0 && hub->reset_gpio != -ENOENT)
> +		return dev_err_probe(dev, hub->reset_gpio, "failed to get reset GPIO\n");
> +
> +	hub->dev = dev;
> +
> +	return onboard_hub_power_on(hub);
> +}
> +
> +static struct driver onboard_hub_driver = {
> +	.name = "onboard-usb-hub",
> +	.probe = onboard_hub_probe,
> +	.of_compatible = onboard_hub_match,
> +};
> +device_platform_driver(onboard_hub_driver);
> +
> +MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
> +MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/usb/misc/onboard_usb_hub.h b/drivers/usb/misc/onboard_usb_hub.h
> new file mode 100644
> index 000000000000..e90be47b6735
> --- /dev/null
> +++ b/drivers/usb/misc/onboard_usb_hub.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (c) 2022, Google LLC
> + */
> +
> +#ifndef _USB_MISC_ONBOARD_USB_HUB_H
> +#define _USB_MISC_ONBOARD_USB_HUB_H
> +
> +struct onboard_hub_pdata {
> +	unsigned long reset_us;		/* reset pulse width in us */
> +};
> +
> +static const struct onboard_hub_pdata microchip_usb424_data = {
> +	.reset_us = 1,
> +};
> +
> +static const struct onboard_hub_pdata realtek_rts5411_data = {
> +	.reset_us = 0,
> +};
> +
> +static const struct onboard_hub_pdata ti_tusb8041_data = {
> +	.reset_us = 3000,
> +};
> +
> +const struct of_device_id onboard_hub_match[] = {
> +	{ .compatible = "usb424,2514", .data = &microchip_usb424_data, },
> +	{ .compatible = "usb451,8140", .data = &ti_tusb8041_data, },
> +	{ .compatible = "usb451,8142", .data = &ti_tusb8041_data, },
> +	{ .compatible = "usbbda,411", .data = &realtek_rts5411_data, },
> +	{ .compatible = "usbbda,5411", .data = &realtek_rts5411_data, },
> +	{ .compatible = "usbbda,414", .data = &realtek_rts5411_data, },
> +	{ .compatible = "usbbda,5414", .data = &realtek_rts5411_data, },
> +	{}
> +};
> +
> +#endif /* _USB_MISC_ONBOARD_USB_HUB_H */
> diff --git a/include/usb/usb.h b/include/usb/usb.h
> index 9b36122436d5..717bcf935a42 100644
> --- a/include/usb/usb.h
> +++ b/include/usb/usb.h
> @@ -484,4 +484,12 @@ extern struct list_head usb_device_list;
>  
>  bool usb_hub_is_root_hub(struct usb_device *hdev);
>  
> +#ifdef CONFIG_USB_ONBOARD_HUB
> +void of_usb_host_probe_hubs(struct usb_host *host);
> +#else
> +static inline void of_usb_host_probe_hubs(struct usb_host *host)
> +{
> +}
> +#endif
> +
>  #endif /*_USB_H_ */
> -- 
> 2.30.2
> 
> 
> 

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