LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Muni Sekhar <munisekharrms@gmail.com>
To: Oliver Neukum <oneukum@suse.com>
Cc: kernelnewbies <kernelnewbies@kernelnewbies.org>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: read() via USB bus
Date: Mon, 9 Aug 2021 21:49:07 +0530	[thread overview]
Message-ID: <CAHhAz+hYy6najVa4gt2zkAiipWPCL6X+KH=RFrHZfY1RH13QAw@mail.gmail.com> (raw)
In-Reply-To: <8923f2b8-0be0-ffbf-70a4-c03c9a02d58a@suse.com>

On Mon, Aug 9, 2021 at 1:45 PM Oliver Neukum <oneukum@suse.com> wrote:
>
>
> On 09.08.21 09:58, Muni Sekhar wrote:
> > Hi all,
> >
> > PCIe memory mapped registers can be read via readb(), readw(), readl()
> > kernel API's. Similarly what are the kernel API to read the device
> > registers via USB bus
> >
>
> Hi,
>
> I am afraid this is based on a fundamental misunderstanding on how
> USB works. It is based on passing messages, not reading and writing
> registers.
>
> USB devices are primarily based on endpoints, not registers. A literal
> answer to your question would point you to the clear/set/get_feature
> standard requests of chapter 9 of the specification, but that really
> will not help you, as you are making assumption that fundamentally
> do not apply.
>
> I hope this list stays friendly to newcomers and we will answer
> specific questions, but at this point I must advise you to first
> read an introductory book.
Thank you, I will check it out.
>
>     HTH
>         Oliver
>
>


-- 
Thanks,
Sekhar

  parent reply	other threads:[~2021-08-09 16:20 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-09  7:58 Muni Sekhar
2021-08-09  8:15 ` Oliver Neukum
2021-08-09  8:44   ` Greg KH
2021-08-12  9:45     ` LDD 3rd ed. - It was: " Fabio M. De Francesco
2021-08-12 10:13       ` Valdis Klētnieks
2021-08-12 10:18       ` Greg KH
2021-08-12 10:26         ` Robert P. J. Day
2021-08-09 16:19   ` Muni Sekhar [this message]
2021-08-10 14:13   ` Muni Sekhar
2021-08-10 14:20     ` Oliver Neukum
     [not found]       ` <CAHhAz+ioThu3v4VW6LVqFn9MhgNaqv=qDoxh8Orkw2LOEC_JYA@mail.gmail.com>
2021-08-11 10:04         ` Oliver Neukum

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHhAz+hYy6najVa4gt2zkAiipWPCL6X+KH=RFrHZfY1RH13QAw@mail.gmail.com' \
    --to=munisekharrms@gmail.com \
    --cc=kernelnewbies@kernelnewbies.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=oneukum@suse.com \
    --subject='Re: read() via USB bus' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).