[PATCH 0/3] Docs: usb: Example code updates from usb-skeleton

[PATCH 0/3] Docs: usb: Example code updates from usb-skeleton

[Philipp Hortmann]

Example code updates from usb-skeleton.c

Philipp Hortmann (3):
  Docs: usb: update err() to pr_err() and replace __FILE__
  Docs: usb: update comment and code near increment usage count
  Docs: usb: update writesize, copy_from_user, usb_fill_bulk_urb,
    usb_submit_urb

 .../driver-api/usb/writing_usb_driver.rst     | 32 ++++++++++---------
 1 file changed, 17 insertions(+), 15 deletions(-)

-- 
2.25.1

[PATCH 1/3] Docs: usb: update err() to pr_err() and replace __FILE__

[Philipp Hortmann]

update err() to pr_err() and replace __FILE__

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
---
 Documentation/driver-api/usb/writing_usb_driver.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
index 2176297e5765..5c29e5bdbe88 100644
--- a/Documentation/driver-api/usb/writing_usb_driver.rst
+++ b/Documentation/driver-api/usb/writing_usb_driver.rst
@@ -91,8 +91,8 @@ usually in the driver's init function, as shown here::
 	    /* register this driver with the USB subsystem */
 	    result = usb_register(&skel_driver);
 	    if (result < 0) {
-		    err("usb_register failed for the "__FILE__ "driver."
-			"Error number %d", result);
+		    pr_err("usb_register failed for the %s driver. "
+			   "Error number %d", skel_driver.name, result);
 		    return -1;
 	    }
 
-- 
2.25.1

Re: [PATCH 1/3] Docs: usb: update err() to pr_err() and replace __FILE__

[Sergey Shtylyov]

On 10/29/21 10:39 PM, Philipp Hortmann wrote:

> update err() to pr_err() and replace __FILE__
> 
> Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
> ---
>  Documentation/driver-api/usb/writing_usb_driver.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
> index 2176297e5765..5c29e5bdbe88 100644
> --- a/Documentation/driver-api/usb/writing_usb_driver.rst
> +++ b/Documentation/driver-api/usb/writing_usb_driver.rst
> @@ -91,8 +91,8 @@ usually in the driver's init function, as shown here::
>  	    /* register this driver with the USB subsystem */
>  	    result = usb_register(&skel_driver);
>  	    if (result < 0) {
> -		    err("usb_register failed for the "__FILE__ "driver."
> -			"Error number %d", result);
> +		    pr_err("usb_register failed for the %s driver. "

   Don't break up the kernel message like this. The current code is a bad example --
high time to fix it. :-)

> +			   "Error number %d", skel_driver.name, result);
>  		    return -1;
>  	    }
>  

MBR, Sergey

Re: [PATCH 1/3] Docs: usb: update err() to pr_err() and replace __FILE__

[Sergey Shtylyov]

On 29.10.2021 23:33, Sergey Shtylyov wrote:

[...]
>> update err() to pr_err() and replace __FILE__
>>
>> Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
>> ---
>>   Documentation/driver-api/usb/writing_usb_driver.rst | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
>> index 2176297e5765..5c29e5bdbe88 100644
>> --- a/Documentation/driver-api/usb/writing_usb_driver.rst
>> +++ b/Documentation/driver-api/usb/writing_usb_driver.rst
>> @@ -91,8 +91,8 @@ usually in the driver's init function, as shown here::
>>   	    /* register this driver with the USB subsystem */
>>   	    result = usb_register(&skel_driver);
>>   	    if (result < 0) {
>> -		    err("usb_register failed for the "__FILE__ "driver."
>> -			"Error number %d", result);
>> +		    pr_err("usb_register failed for the %s driver. "
> 
>     Don't break up the kernel message like this. The current code is a bad example --
> high time to fix it. :-)
> 
>> +			   "Error number %d", skel_driver.name, result);

    Oh, and add `\n' at the end of message.

[...]

MBR, Sergey

[PATCH 2/3] Docs: usb: update comment and code near increment usage count

[Philipp Hortmann]

update comment: increment our usage count ..
and code according to usb-skeleton.c

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
---
 Documentation/driver-api/usb/writing_usb_driver.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
index 5c29e5bdbe88..14eda0342649 100644
--- a/Documentation/driver-api/usb/writing_usb_driver.rst
+++ b/Documentation/driver-api/usb/writing_usb_driver.rst
@@ -167,8 +167,8 @@ structure. This is done so that future calls to file operations will
 enable the driver to determine which device the user is addressing. All
 of this is done with the following code::
 
-    /* increment our usage count for the module */
-    ++skel->open_count;
+    /* increment our usage count for the device */
+    kref_get(&dev->kref);
 
     /* save our object in the file's private structure */
     file->private_data = dev;
-- 
2.25.1

[PATCH 3/3] Docs: usb: update writesize, copy_from_user, usb_fill_bulk_urb, usb_submit_urb

[Philipp Hortmann]

update code examples writesize, copy_from_user, usb_fill_bulk_urb,
usb_submit_urb in skel_write() according to usb-skeleton.c

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
---
 .../driver-api/usb/writing_usb_driver.rst     | 24 ++++++++++---------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/usb/writing_usb_driver.rst b/Documentation/driver-api/usb/writing_usb_driver.rst
index 14eda0342649..02c28ee10b91 100644
--- a/Documentation/driver-api/usb/writing_usb_driver.rst
+++ b/Documentation/driver-api/usb/writing_usb_driver.rst
@@ -185,24 +185,26 @@ space, points the urb to the data and submits the urb to the USB
 subsystem. This can be seen in the following code::
 
     /* we can only write as much as 1 urb will hold */
-    bytes_written = (count > skel->bulk_out_size) ? skel->bulk_out_size : count;
+    size_t writesize = min_t(size_t, count, MAX_TRANSFER);
 
     /* copy the data from user space into our urb */
-    copy_from_user(skel->write_urb->transfer_buffer, buffer, bytes_written);
+    copy_from_user(buf, user_buffer, writesize);
 
     /* set up our urb */
-    usb_fill_bulk_urb(skel->write_urb,
-		      skel->dev,
-		      usb_sndbulkpipe(skel->dev, skel->bulk_out_endpointAddr),
-		      skel->write_urb->transfer_buffer,
-		      bytes_written,
+    usb_fill_bulk_urb(urb,
+		      dev->udev,
+		      usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
+		      buf,
+		      writesize,
 		      skel_write_bulk_callback,
-		      skel);
+		      dev);
 
     /* send the data out the bulk port */
-    result = usb_submit_urb(skel->write_urb);
-    if (result) {
-	    err("Failed submitting write urb, error %d", result);
+    retval = usb_submit_urb(urb, GFP_KERNEL);
+    if (retval) {
+	    dev_err(&dev->interface->dev,
+                "%s - failed submitting write urb, error %d\n",
+                __func__, retval);
     }
 
 
-- 
2.25.1