[PATCH] usb: have usb_rescan return count of enumerated devices

[PATCH] usb: have usb_rescan return count of enumerated devices

[Ahmad Fatoum]

Some USB mass storage devices can take a comparatively long time after
vbus is applied until they can be enumerated. Board code can reissue
usb_rescan() to retry enumeration at a later time. It's useful for
board code to check whether any new devices have been detected by a
usb_rescan() call. To facilitate this, have usb_rescan() return the
number of devices found in addition to printing it to the log.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/usb/core/usb.c | 4 +++-
 include/usb/usb.h      | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 34a0f004f7bb..ed3a96cb9e5e 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -599,7 +599,7 @@ int usb_host_detect(struct usb_host *host)
 	return 0;
 }
 
-void usb_rescan(void)
+int usb_rescan(void)
 {
 	struct usb_host *host;
 	int ret;
@@ -613,6 +613,8 @@ void usb_rescan(void)
 	}
 
 	pr_info("%d USB Device(s) found\n", dev_count);
+
+	return dev_count;
 }
 
 /*-------------------------------------------------------------------
diff --git a/include/usb/usb.h b/include/usb/usb.h
index 39f475091617..04b433ba73ca 100644
--- a/include/usb/usb.h
+++ b/include/usb/usb.h
@@ -201,7 +201,7 @@ int usb_clear_halt(struct usb_device *dev, int pipe);
 int usb_string(struct usb_device *dev, int index, char *buf, size_t size);
 int usb_set_interface(struct usb_device *dev, int interface, int alternate);
 
-void usb_rescan(void);
+int usb_rescan(void);
 
 /* big endian -> little endian conversion */
 /* some CPUs are already little endian e.g. the ARM920T */
-- 
2.30.2

Re: [PATCH] usb: have usb_rescan return count of enumerated devices

[Sascha Hauer]

On Thu, Sep 29, 2022 at 12:05:02PM +0200, Ahmad Fatoum wrote:
> Some USB mass storage devices can take a comparatively long time after
> vbus is applied until they can be enumerated. Board code can reissue
> usb_rescan() to retry enumeration at a later time. It's useful for
> board code to check whether any new devices have been detected by a
> usb_rescan() call. To facilitate this, have usb_rescan() return the
> number of devices found in addition to printing it to the log.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/usb/core/usb.c | 4 +++-
>  include/usb/usb.h      | 2 +-
>  2 files changed, 4 insertions(+), 2 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> index 34a0f004f7bb..ed3a96cb9e5e 100644
> --- a/drivers/usb/core/usb.c
> +++ b/drivers/usb/core/usb.c
> @@ -599,7 +599,7 @@ int usb_host_detect(struct usb_host *host)
>  	return 0;
>  }
>  
> -void usb_rescan(void)
> +int usb_rescan(void)
>  {
>  	struct usb_host *host;
>  	int ret;
> @@ -613,6 +613,8 @@ void usb_rescan(void)
>  	}
>  
>  	pr_info("%d USB Device(s) found\n", dev_count);
> +
> +	return dev_count;
>  }
>  
>  /*-------------------------------------------------------------------
> diff --git a/include/usb/usb.h b/include/usb/usb.h
> index 39f475091617..04b433ba73ca 100644
> --- a/include/usb/usb.h
> +++ b/include/usb/usb.h
> @@ -201,7 +201,7 @@ int usb_clear_halt(struct usb_device *dev, int pipe);
>  int usb_string(struct usb_device *dev, int index, char *buf, size_t size);
>  int usb_set_interface(struct usb_device *dev, int interface, int alternate);
>  
> -void usb_rescan(void);
> +int usb_rescan(void);
>  
>  /* big endian -> little endian conversion */
>  /* some CPUs are already little endian e.g. the ARM920T */
> -- 
> 2.30.2
> 
> 
> 

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