Re: [PATCH v2 2/3] usb: Add LED trigger for USB host activity

[Bryan Wu <cooloney@gmail.com>]

On Fri, Aug 22, 2014 at 5:08 PM, Michal Sojka <sojka@merica.cz> wrote:
> With this patch, USB host activity can be signaled by blinking a LED.
>
> This should work with all host controllers. Tested only with musb.
>
> Signed-off-by: Michal Sojka <sojka@merica.cz>
> ---
>  drivers/usb/core/Kconfig  |  9 +++++++++
>  drivers/usb/core/Makefile |  1 +
>  drivers/usb/core/hcd.c    |  2 ++
>  drivers/usb/core/led.c    | 38 ++++++++++++++++++++++++++++++++++++++
>  include/linux/usb/hcd.h   |  6 ++++++
>  5 files changed, 56 insertions(+)
>  create mode 100644 drivers/usb/core/led.c
>
> diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
> index 1060657..8295f65 100644
> --- a/drivers/usb/core/Kconfig
> +++ b/drivers/usb/core/Kconfig
> @@ -90,3 +90,12 @@ config USB_OTG_FSM
>           Implements OTG Finite State Machine as specified in On-The-Go
>           and Embedded Host Supplement to the USB Revision 2.0 Specification.
>
> +config USB_HOST_LED
> +       bool "USB Host LED Trigger"
> +       depends on LEDS_CLASS
> +       select LEDS_TRIGGERS
> +       help
> +         This option adds a LED trigger for USB host controllers.
> +
> +         Say Y here if you are working on a system with led-class supported
> +         LEDs and you want to use them as USB host activity indicators.
> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
> index 2f6f932..324c8c9 100644
> --- a/drivers/usb/core/Makefile
> +++ b/drivers/usb/core/Makefile
> @@ -9,5 +9,6 @@ usbcore-y += port.o
>
>  usbcore-$(CONFIG_PCI)          += hcd-pci.o
>  usbcore-$(CONFIG_ACPI)         += usb-acpi.o
> +usbcore-$(CONFIG_USB_HOST_LED) += led.o
>
>  obj-$(CONFIG_USB)              += usbcore.o
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index 487abcf..46d9f3a 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -1664,6 +1664,8 @@ static void __usb_hcd_giveback_urb(struct urb *urb)
>         usbmon_urb_complete(&hcd->self, urb, status);
>         usb_anchor_suspend_wakeups(anchor);
>         usb_unanchor_urb(urb);
> +       if (status == 0)
> +               usb_hcd_led_activity();
>
>         /* pass ownership to the completion handler */
>         urb->status = status;
> diff --git a/drivers/usb/core/led.c b/drivers/usb/core/led.c
> new file mode 100644
> index 0000000..49ff76c
> --- /dev/null
> +++ b/drivers/usb/core/led.c
> @@ -0,0 +1,38 @@
> +/*
> + * LED Trigger for USB Host Activity
> + *
> + * Copyright 2014 Michal Sojka <sojka@merica.cz>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/leds.h>
> +#include <linux/usb/hcd.h>
> +
> +#define BLINK_DELAY 30
> +
> +DEFINE_LED_TRIGGER(ledtrig_usb_hcd);

Add one more trigger named ledtrig_usb_gadget

> +static unsigned long usb_hcd_blink_delay = BLINK_DELAY;
> +
> +void usb_hcd_led_activity(void)

Give an input parameter like emum usb_led_event.
USB_LED_EVENT_HOST = 0
USB_LED_EVENT_GADGET = 1


> +{

Add case for USB_LED_EVENT_HOST:
> +       led_trigger_blink_oneshot(ledtrig_usb_hcd,
> +                                 &usb_hcd_blink_delay, &usb_hcd_blink_delay, 0);

Add case for USB_LED_EVENT_GADGET:
 led_trigger_blink_oneshot(ledtrig_usb_gadget,
                             &usb_gadget_blink_delay,
&usb_gadget_blink_delay, 0);

> +}
> +
> +int __init ledtrig_usb_hcd_init(void)
> +{
> +       led_trigger_register_simple("usb-host", &ledtrig_usb_hcd);
register one more trigger for gadget.

> +       return 0;
> +}
> +
> +void __exit ledtrig_usb_hcd_exit(void)
> +{
> +       led_trigger_unregister_simple(ledtrig_usb_hcd);
unregister one more trigger for gadget.

> +}
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index b43f0fe..eb5fa0f 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -700,6 +700,12 @@ extern struct rw_semaphore ehci_cf_port_reset_rwsem;
>  #define USB_EHCI_LOADED                2
>  extern unsigned long usb_hcds_loaded;
>
> +#ifdef CONFIG_USB_HOST_LED
> +extern void usb_hcd_led_activity(void);

User can call usb_led_activity(USB_LED_EVENT_HOST);
or usb_led_activity(USB_LED_EVENT_GADGET);

> +#else
> +static inline void usb_hcd_led_activity(void) {}
> +#endif
> +
>  #endif /* __KERNEL__ */
>
>  #endif /* __USB_CORE_HCD_H */
> --
> 2.1.0
>