From: Sven Van Asbroeck <thesven73@gmail.com>
To: gregkh@linuxfoundation.org
Cc: "Sven Van Asbroeck" <svendev@arcx.com>,
robh+dt@kernel.org, "Linus Walleij" <linus.walleij@linaro.org>,
"Lee Jones" <lee.jones@linaro.org>,
mark.rutland@arm.com, "Andreas Färber" <afaerber@suse.de>,
treding@nvidia.com, "David Lechner" <david@lechnology.com>,
noralf@tronnes.org, johan@kernel.org,
"Michal Simek" <monstr@monstr.eu>,
michal.vokac@ysoft.com, "Arnd Bergmann" <arnd@arndb.de>,
john.garry@huawei.com, geert+renesas@glider.be,
robin.murphy@arm.com, paul.gortmaker@windriver.com,
sebastien.bourdelin@savoirfairelinux.com, icenowy@aosc.io,
"Stuart Yoder" <stuyoder@gmail.com>,
maxime.ripard@bootlin.com,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>
Subject: Re: [PATCH anybus v4 1/7] fieldbus_dev: add Fieldbus Device subsystem.
Date: Wed, 28 Nov 2018 10:39:41 -0500 [thread overview]
Message-ID: <CAGngYiUL7bZVEehj4LGC2H+kv+Z4v_s=tG4uosOp1-Rc4_pGWw@mail.gmail.com> (raw)
In-Reply-To: <20181127075431.GG13965@kroah.com>
Wow Greg, thanks for the review, this is awesome !!
On Tue, Nov 27, 2018 at 2:54 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>> + cdev_init(&fb->cdev, &fieldbus_fops);
>> + err = cdev_add(&fb->cdev, devno, 1);
>> + if (err) {
>> + pr_err("fieldbus_dev%d unable to add device %d:%d\n",
>> + fb->id, MAJOR(fieldbus_devt), fb->id);
>> + goto err_cdev;
>> + }
>
> Why do you have a static cdev?
The proposed fieldbus API needs a single /dev/fieldbus_devX node for every
device. I just looked around the drivers/ tree to see how others accomplish
this.
Is there a better way?
>> + fb->online_sd = sysfs_get_dirent(fb->dev->kobj.sd, "online");
>
> Ick, what? Why? Why are you messing around with a raw sysfs attribute?
The proposed fieldbus API has a sysfs attribute that can be poll/select'ed on.
Is this behaviour still allowed / ok?
If so, you're saying that I should not store the raw attribute, but just do:
sysfs_notify(&fb->dev->kobj, NULL, "online") ?
Now that I (hopefully) have a few seconds of your attention...
I suppose the fieldbus API in this patch can't go anywhere, without buy-in from
multiple people who also want to use fieldbus. Right now, there are none.
This might be a chicken-and-egg problem. Perhaps here are no fieldbus
devices because
there's no good general API. There's no good general API because there are no
fieldbus devices yet.
Is there a tried and tested way to break this deadlock?
next prev parent reply other threads:[~2018-11-28 15:39 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 15:07 [PATCH anybus v4 0/7] Add Fieldbus subsystem + support HMS Profinet card thesven73
2018-11-21 15:07 ` [PATCH anybus v4 1/7] fieldbus_dev: add Fieldbus Device subsystem thesven73
2018-11-27 7:47 ` Greg KH
2018-11-27 7:47 ` Greg KH
2018-11-27 7:54 ` Greg KH
2018-11-28 15:39 ` Sven Van Asbroeck [this message]
2018-11-28 17:42 ` Greg KH
2018-11-28 18:19 ` Sven Van Asbroeck
2018-11-28 18:36 ` Greg KH
2018-11-28 19:39 ` Sven Van Asbroeck
2018-11-21 15:07 ` [PATCH anybus v4 2/7] fieldbus: support the Arcx anybus bridge thesven73
2018-11-21 15:07 ` [PATCH anybus v4 3/7] dt-bindings: Add vendor prefix for arcx / Archronix thesven73
2018-11-21 15:07 ` [PATCH anybus v4 4/7] dt-bindings: anybus-bridge: document devicetree binding thesven73
2018-11-21 15:07 ` [PATCH anybus v4 5/7] fieldbus: support HMS Anybus-S bus thesven73
2018-11-21 15:07 ` [PATCH anybus v4 6/7] dt-bindings: anybuss-host: document devicetree binding thesven73
2018-11-26 22:08 ` Rob Herring
2018-11-28 15:38 ` Sven Van Asbroeck
2018-11-28 16:36 ` Rob Herring
2018-11-29 20:59 ` Sven Van Asbroeck
2018-11-30 1:39 ` Rob Herring
2018-11-21 15:07 ` [PATCH anybus v4 7/7] fieldbus_dev: support HMS Profinet IRT industrial controller thesven73
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