* Need help to understand USB driver mechanism
@ 2012-06-21 10:39 Vishal Nandanwar
[not found] ` <CAKB833mPfX2U6_UA0Fr0CTw623gxCvcYPW3HvfVJWE1Xt7v-UQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
0 siblings, 1 reply; 7+ messages in thread
From: Vishal Nandanwar @ 2012-06-21 10:39 UTC (permalink / raw)
To: Linux USB, Linux Docs, Platform driver x86
Hi,
I am trying to understand the USB device driver writing mechanism and
architecture. I have gone through the LDD book as well.
For learning purpose I am trying to write a driver for a pen drive
i.e. USB mass storage. Linux do have the usb-storage driver which is
used for pen drive. I have gone through the ../driver/usb/storage
folder of Linux source code and found there are few drivers(karma,
freecom) which uses usb-storage to achive there functionality.
what is the mechanism to write a driver for pen drive(USB mass
storage)? Is there any guide/help document which describes how to
create a interface driver on top of usb-storage driver, so when my pen
driver is connected it should use my driver?
Vishal N
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
[not found] ` <CAKB833mPfX2U6_UA0Fr0CTw623gxCvcYPW3HvfVJWE1Xt7v-UQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
@ 2012-06-21 14:40 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1206211036540.1164-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
0 siblings, 1 reply; 7+ messages in thread
From: Alan Stern @ 2012-06-21 14:40 UTC (permalink / raw)
To: Vishal Nandanwar; +Cc: Linux USB, Linux Docs, Platform driver x86
On Thu, 21 Jun 2012, Vishal Nandanwar wrote:
> Hi,
>
> I am trying to understand the USB device driver writing mechanism and
> architecture. I have gone through the LDD book as well.
>
> For learning purpose I am trying to write a driver for a pen drive
> i.e. USB mass storage.
That's a terrible way to learn. The mass-storage driver is one of the
most complicated ones in the USB subsystem. You should start with
something simpler.
> Linux do have the usb-storage driver which is
> used for pen drive. I have gone through the ../driver/usb/storage
> folder of Linux source code and found there are few drivers(karma,
> freecom) which uses usb-storage to achive there functionality.
Yes. Those sub-drivers are needed because their devices don't use the
standard USB mass-storage protocol.
> what is the mechanism to write a driver for pen drive(USB mass
> storage)? Is there any guide/help document which describes how to
> create a interface driver on top of usb-storage driver, so when my pen
> driver is connected it should use my driver?
I can tell you in one word how to write a driver for your pen drive:
Don't!
If you don't write a special driver then the pen drive should work
perfectly well. If you did try to write a special interface sub-driver
for it, you'd find that your driver had nothing to do because
usb-storage already handles everything.
Alan Stern
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
[not found] ` <Pine.LNX.4.44L0.1206211036540.1164-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
@ 2012-06-22 2:05 ` Vishal Nandanwar
[not found] ` <CAKB833k1Q7LoJWxDp6AHdq5H=w=LeeeRQ3sRC_1zXcJ_Lp9mNg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-06-22 13:48 ` Alan Stern
0 siblings, 2 replies; 7+ messages in thread
From: Vishal Nandanwar @ 2012-06-22 2:05 UTC (permalink / raw)
To: Alan Stern; +Cc: Linux USB, Linux Docs, Platform driver x86
Hi Alan,
Thanks for your reply. It really helps.
What approach one should use to learn the device drivers?
Vishal N
On Thu, Jun 21, 2012 at 8:10 PM, Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org> wrote:
> On Thu, 21 Jun 2012, Vishal Nandanwar wrote:
>
>> Hi,
>>
>> I am trying to understand the USB device driver writing mechanism and
>> architecture. I have gone through the LDD book as well.
>>
>> For learning purpose I am trying to write a driver for a pen drive
>> i.e. USB mass storage.
>
> That's a terrible way to learn. The mass-storage driver is one of the
> most complicated ones in the USB subsystem. You should start with
> something simpler.
>
>> Linux do have the usb-storage driver which is
>> used for pen drive. I have gone through the ../driver/usb/storage
>> folder of Linux source code and found there are few drivers(karma,
>> freecom) which uses usb-storage to achive there functionality.
>
> Yes. Those sub-drivers are needed because their devices don't use the
> standard USB mass-storage protocol.
>
>> what is the mechanism to write a driver for pen drive(USB mass
>> storage)? Is there any guide/help document which describes how to
>> create a interface driver on top of usb-storage driver, so when my pen
>> driver is connected it should use my driver?
>
> I can tell you in one word how to write a driver for your pen drive:
>
> Don't!
>
> If you don't write a special driver then the pen drive should work
> perfectly well. If you did try to write a special interface sub-driver
> for it, you'd find that your driver had nothing to do because
> usb-storage already handles everything.
>
> Alan Stern
>
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
[not found] ` <CAKB833k1Q7LoJWxDp6AHdq5H=w=LeeeRQ3sRC_1zXcJ_Lp9mNg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
@ 2012-06-22 2:25 ` Greg KH
2012-06-22 3:03 ` Vishal Nandanwar
0 siblings, 1 reply; 7+ messages in thread
From: Greg KH @ 2012-06-22 2:25 UTC (permalink / raw)
To: Vishal Nandanwar; +Cc: Alan Stern, Linux USB, Linux Docs, Platform driver x86
On Fri, Jun 22, 2012 at 07:35:55AM +0530, Vishal Nandanwar wrote:
> Hi Alan,
>
> Thanks for your reply. It really helps.
>
> What approach one should use to learn the device drivers?
"Linux Device Drivers", third edition, free online. Have you tried
that?
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
2012-06-22 2:25 ` Greg KH
@ 2012-06-22 3:03 ` Vishal Nandanwar
2012-06-22 13:42 ` Greg KH
0 siblings, 1 reply; 7+ messages in thread
From: Vishal Nandanwar @ 2012-06-22 3:03 UTC (permalink / raw)
To: Greg KH; +Cc: Alan Stern, Linux USB, Linux Docs, Platform driver x86
Yes, I am reading it simultaneously.
But to do hands on, which driver one should try as mass storage driver
(for pen driver) is very difficult.
Vishal N
On Fri, Jun 22, 2012 at 7:55 AM, Greg KH <greg@kroah.com> wrote:
> On Fri, Jun 22, 2012 at 07:35:55AM +0530, Vishal Nandanwar wrote:
>> Hi Alan,
>>
>> Thanks for your reply. It really helps.
>>
>> What approach one should use to learn the device drivers?
>
> "Linux Device Drivers", third edition, free online. Have you tried
> that?
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
2012-06-22 3:03 ` Vishal Nandanwar
@ 2012-06-22 13:42 ` Greg KH
0 siblings, 0 replies; 7+ messages in thread
From: Greg KH @ 2012-06-22 13:42 UTC (permalink / raw)
To: Vishal Nandanwar; +Cc: Alan Stern, Linux USB, Linux Docs, Platform driver x86
A: No.
Q: Should I include quotations after my reply?
http://daringfireball.net/2007/07/on_top
On Fri, Jun 22, 2012 at 08:33:50AM +0530, Vishal Nandanwar wrote:
> Yes, I am reading it simultaneously.
>
> But to do hands on, which driver one should try as mass storage driver
> (for pen driver) is very difficult.
Yes, the mass-storage driver is one of the most complex, please stay
away from it unless you understand SCSI very well.
As for what one to pick, I do not know, that is your own choice, not
mine.
good luck,
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Need help to understand USB driver mechanism
2012-06-22 2:05 ` Vishal Nandanwar
[not found] ` <CAKB833k1Q7LoJWxDp6AHdq5H=w=LeeeRQ3sRC_1zXcJ_Lp9mNg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
@ 2012-06-22 13:48 ` Alan Stern
1 sibling, 0 replies; 7+ messages in thread
From: Alan Stern @ 2012-06-22 13:48 UTC (permalink / raw)
To: Vishal Nandanwar; +Cc: Linux USB, Linux Docs, Platform driver x86
On Fri, 22 Jun 2012, Vishal Nandanwar wrote:
> Hi Alan,
>
> Thanks for your reply. It really helps.
>
> What approach one should use to learn the device drivers?
Many of the files in drivers/usb/misc would make a good place to start.
You can also try to figure out the usblp driver.
Alan Stern
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2012-06-22 13:48 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2012-06-21 10:39 Need help to understand USB driver mechanism Vishal Nandanwar
[not found] ` <CAKB833mPfX2U6_UA0Fr0CTw623gxCvcYPW3HvfVJWE1Xt7v-UQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-06-21 14:40 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1206211036540.1164-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2012-06-22 2:05 ` Vishal Nandanwar
[not found] ` <CAKB833k1Q7LoJWxDp6AHdq5H=w=LeeeRQ3sRC_1zXcJ_Lp9mNg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-06-22 2:25 ` Greg KH
2012-06-22 3:03 ` Vishal Nandanwar
2012-06-22 13:42 ` Greg KH
2012-06-22 13:48 ` Alan Stern
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