From: Greg KH <greg@kroah.com>
To: Pelle Windestam <Pelle.Windestam@tagmaster.com>
Cc: "kernelnewbies@kernelnewbies.org" <kernelnewbies@kernelnewbies.org>
Subject: Re: Accessing rpmsg_device in sysfs attribute functions
Date: Tue, 24 Mar 2020 07:31:13 +0100 [thread overview]
Message-ID: <20200324063113.GA1978604@kroah.com> (raw)
In-Reply-To: <117a9e9d420f444ea814a37596fe5693@tagmaster.com>
On Tue, Mar 24, 2020 at 05:34:44AM +0000, Pelle Windestam wrote:
> Hi,
>
> I am trying to develop a simple driver for the rpmsg bus, in order to send various commands from user space in Linux to a secondary CPU (A Cortex M4). I'm trying to keep things as simple as possible, so my idea was to create a driver that just has a few attributes which can be set in /sys which would trigger commands to be sent to the M4 CPU. I have the communication between the CPU:s up and running, but where I'm having trouble moving forward is how to access the "struct rpmsg_device *" that I need in order to communicate with the endpoint for the M4 CPU from the store/show function of the sysfs attributes. What my driver does is to register a rpmsg_driver in the init function:
>
> register_rpmsg_driver(&pwm_rpmsg_driver);
>
> the device_driver member of my rpmsg_driver struct has its groups member set to my driver attribute groups array:
> static struct rpmsg_driver pwm_rpmsg_driver = {
> .probe = pwm_rpmsg_probe,
> .remove = pwm_rpmsg_remove,
> .callback = pwm_rpmsg_cb,
> .id_table = pwm_rpmsg_device_id_table,
> .drv = {
> .groups = driver_pwm_groups,
> .name = "pwm_rpmsg",
> },
> };
>
> My issue is that that I am not sure how to access the struct "rpmsg_device *" (i.e. from the probe() function) in the show/store functions for the sysfs attributes, which have a "struct device_driver *" argument:
That is because you have created a driver attribute, not a device
attribute. Create device attributes and you should be fine, they bind
to the device your driver is passed.
good luck!
greg k-h
_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
next prev parent reply other threads:[~2020-03-24 6:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 5:34 Accessing rpmsg_device in sysfs attribute functions Pelle Windestam
2020-03-24 6:31 ` Greg KH [this message]
2020-03-24 9:49 ` Martin Kaiser
2020-03-24 10:23 ` Greg KH
2020-03-24 12:02 ` Pelle Windestam
2020-03-24 12:31 ` Greg KH
2020-03-24 13:05 ` Pelle Windestam
2020-03-24 13:15 ` Greg KH
2020-03-24 13:35 ` Pelle Windestam
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=20200324063113.GA1978604@kroah.com \
--to=greg@kroah.com \
--cc=Pelle.Windestam@tagmaster.com \
--cc=kernelnewbies@kernelnewbies.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).