Re: [PATCH v14 4/7] usb: core: add power sequence handling for USB devices

[Peter Chen]

On Thu, May 18, 2017 at 08:49:00AM +0800, Peter Chen wrote:
> Some hard-wired USB devices need to do power sequence to let the
> device work normally, the typical power sequence like: enable USB
> PHY clock, toggle reset pin, etc. But current Linux USB driver
> lacks of such code to do it, it may cause some hard-wired USB devices
> works abnormal or can't be recognized by controller at all.
> 
> In this patch, it calls power sequence library APIs to finish
> the power sequence events. It will do power on sequence at hub's
> probe for all devices under this hub (includes root hub).
> At hub_disconnect, it will do power off sequence which is at powered
> on list.
> 

Greg, Alan, would you please help on reviewing it? It seems Rafael
is waiting for USB MAINTAINERS's comments or ack. It resolves some
USB HUB issues for several persons.

Peter

> Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> Tested-by Joshua Clayton <stillcompiling@xxxxxxxxx>
> Tested-by: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Vaibhav Hiremath <hvaibhav.linux@xxxxxxxxx>
> ---
>  drivers/usb/Kconfig    |  1 +
>  drivers/usb/core/hub.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
>  drivers/usb/core/hub.h |  1 +
>  3 files changed, 47 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
> index 939a63b..b6f626e 100644
> --- a/drivers/usb/Kconfig
> +++ b/drivers/usb/Kconfig
> @@ -39,6 +39,7 @@ config USB
>  	tristate "Support for Host-side USB"
>  	depends on USB_ARCH_HAS_HCD
>  	select USB_COMMON
> +	select POWER_SEQUENCE
>  	select NLS  # for UTF-8 strings
>  	---help---
>  	  Universal Serial Bus (USB) is a specification for a serial bus
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 9dca59e..7a67296 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -28,6 +28,7 @@
>  #include <linux/mutex.h>
>  #include <linux/random.h>
>  #include <linux/pm_qos.h>
> +#include <linux/power/pwrseq.h>
>  
>  #include <linux/uaccess.h>
>  #include <asm/byteorder.h>
> @@ -1619,6 +1620,7 @@ static void hub_disconnect(struct usb_interface *intf)
>  	hub->error = 0;
>  	hub_quiesce(hub, HUB_DISCONNECT);
>  
> +	of_pwrseq_off_list(&hub->pwrseq_on_list);
>  	mutex_lock(&usb_port_peer_mutex);
>  
>  	/* Avoid races with recursively_mark_NOTATTACHED() */
> @@ -1646,12 +1648,42 @@ static void hub_disconnect(struct usb_interface *intf)
>  	kref_put(&hub->kref, hub_release);
>  }
>  
> +#ifdef CONFIG_OF
> +static int hub_of_pwrseq_on(struct usb_hub *hub)
> +{
> +	struct device *parent;
> +	struct usb_device *hdev = hub->hdev;
> +	struct device_node *np;
> +	int ret;
> +
> +	if (hdev->parent)
> +		parent = &hdev->dev;
> +	else
> +		parent = bus_to_hcd(hdev->bus)->self.sysdev;
> +
> +	for_each_child_of_node(parent->of_node, np) {
> +		ret = of_pwrseq_on_list(np, &hub->pwrseq_on_list);
> +		/* Maybe no power sequence library is chosen */
> +		if (ret && ret != -ENOENT)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int hub_of_pwrseq_on(struct usb_hub *hub)
> +{
> +	return 0;
> +}
> +#endif
> +
>  static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
>  {
>  	struct usb_host_interface *desc;
>  	struct usb_endpoint_descriptor *endpoint;
>  	struct usb_device *hdev;
>  	struct usb_hub *hub;
> +	int ret = -ENODEV;
>  
>  	desc = intf->cur_altsetting;
>  	hdev = interface_to_usbdev(intf);
> @@ -1756,6 +1788,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
>  	INIT_DELAYED_WORK(&hub->leds, led_work);
>  	INIT_DELAYED_WORK(&hub->init_work, NULL);
>  	INIT_WORK(&hub->events, hub_event);
> +	INIT_LIST_HEAD(&hub->pwrseq_on_list);
>  	usb_get_intf(intf);
>  	usb_get_dev(hdev);
>  
> @@ -1769,11 +1802,14 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
>  	if (id->driver_info & HUB_QUIRK_CHECK_PORT_AUTOSUSPEND)
>  		hub->quirk_check_port_auto_suspend = 1;
>  
> -	if (hub_configure(hub, endpoint) >= 0)
> -		return 0;
> +	if (hub_configure(hub, endpoint) >= 0) {
> +		ret = hub_of_pwrseq_on(hub);
> +		if (!ret)
> +			return 0;
> +	}
>  
>  	hub_disconnect(intf);
> -	return -ENODEV;
> +	return ret;
>  }
>  
>  static int
> @@ -3593,14 +3629,19 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
>  
>  	/* stop hub_wq and related activity */
>  	hub_quiesce(hub, HUB_SUSPEND);
> -	return 0;
> +	return pwrseq_suspend_list(&hub->pwrseq_on_list);
>  }
>  
>  static int hub_resume(struct usb_interface *intf)
>  {
>  	struct usb_hub *hub = usb_get_intfdata(intf);
> +	int ret;
>  
>  	dev_dbg(&intf->dev, "%s\n", __func__);
> +	ret = pwrseq_resume_list(&hub->pwrseq_on_list);
> +	if (ret)
> +		return ret;
> +
>  	hub_activate(hub, HUB_RESUME);
>  	return 0;
>  }
> diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
> index 34c1a7e..cd86f91 100644
> --- a/drivers/usb/core/hub.h
> +++ b/drivers/usb/core/hub.h
> @@ -78,6 +78,7 @@ struct usb_hub {
>  	struct delayed_work	init_work;
>  	struct work_struct      events;
>  	struct usb_port		**ports;
> +	struct list_head	pwrseq_on_list; /* powered pwrseq node list */
>  };
>  
>  /**
> -- 
> 2.7.4
> 
> 
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-- 

Best Regards,
Peter Chen