From: Dario Binacchi <dariobin@libero.it>
To: Andy Shevchenko <andy.shevchenko@gmail.com>,
Drew Fustini <drew@beagleboard.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH 1/2] pinctrl: core: configure pinmux from pins debug file
Date: Tue, 18 May 2021 15:57:42 +0200 (CEST) [thread overview]
Message-ID: <1735504854.166374.1621346262270@mail1.libero.it> (raw)
In-Reply-To: <CAHp75Vd8875hRNk1JK6gkmfxjqxBSu4cRNE1zJt9TyEW7TvsMg@mail.gmail.com>
Hi,
> Il 17/05/2021 22:02 Andy Shevchenko <andy.shevchenko@gmail.com> ha scritto:
>
>
> On Sun, May 16, 2021 at 7:43 PM Dario Binacchi <dariobin@libero.it> wrote:
> >
> > The MPUs of some architectures (e.g AM335x) must be in privileged
> > operating mode to write on the pinmux
>
> pinmux is not pin configuration. You need to rethink the approach.
>
> > registers. In such cases, where
> > writes will not work from user space, now it can be done from the pins
> > debug file if the platform driver exports the pin_dbg_set() helper among
> > the registered operations.
>
> Drew, is it similar to what you are trying to achieve?
>
> ...
>
> > +static ssize_t pinctrl_pins_write(struct file *file,
> > + const char __user *user_buf, size_t count,
> > + loff_t *ppos)
> > +{
> > + struct seq_file *s = file->private_data;
> > + struct pinctrl_dev *pctldev = s->private;
> > + const struct pinctrl_ops *ops = pctldev->desc->pctlops;
> > + char buf[32];
> > + char *c = &buf[0];
> > + char *token;
> > + int ret, buf_size;
> > + unsigned int i, pin;
> > +
> > + if (!ops->pin_dbg_set)
> > + return -EFAULT;
> > +
> > + /* Get userspace string and assure termination */
> > + buf_size = min(count, sizeof(buf) - 1);
> > + if (copy_from_user(buf, user_buf, buf_size))
> > + return -EFAULT;
> > +
> > + buf[buf_size] = 0;
>
> Can't you use strncpy_from_user() ?
Ok, I'll use strncpy_from_user() in the next version of the patch
>
>
> > + token = strsep(&c, " ");
>
> > + if (kstrtouint(token, 0, &pin))
> > + return -EINVAL;
>
> Don't shadow an error code.
You are right
>
> > + for (i = 0; i < pctldev->desc->npins; i++) {
> > + if (pin != pctldev->desc->pins[i].number)
> > + continue;
>
> Hmm... I don't get this. Why is it needed?
I want to make sure the pin is managed
Thanks and regards,
Dario
>
> > + ret = ops->pin_dbg_set(pctldev, pin, c);
> > + if (ret)
> > + return ret;
> > +
> > + return count;
> > + }
> > +
> > + return -EINVAL;
> > +}
>
> ...
>
> > - debugfs_create_file("pins", 0444,
> > + debugfs_create_file("pins", 0644,
> > device_root, pctldev, &pinctrl_pins_fops);
>
> Why is it in this file?
>
>
>
> --
> With Best Regards,
> Andy Shevchenko
next prev parent reply other threads:[~2021-05-18 13:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-16 13:55 [PATCH 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
2021-05-16 13:55 ` [PATCH 1/2] pinctrl: core: configure pinmux " Dario Binacchi
2021-05-17 20:02 ` Andy Shevchenko
2021-05-17 22:57 ` Drew Fustini
2021-05-18 9:38 ` Dario Binacchi
2021-05-18 10:21 ` Drew Fustini
2021-05-18 10:41 ` Andy Shevchenko
2021-05-18 13:57 ` Dario Binacchi [this message]
2021-05-18 14:01 ` Andy Shevchenko
2021-05-19 10:02 ` Drew Fustini
2021-05-19 11:27 ` Andy Shevchenko
2021-05-20 4:17 ` Drew Fustini
2021-05-20 8:10 ` Andy Shevchenko
2021-05-16 13:55 ` [PATCH 2/2] pinctrl: single: set " Dario Binacchi
2021-05-17 5:57 ` Tony Lindgren
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=1735504854.166374.1621346262270@mail1.libero.it \
--to=dariobin@libero.it \
--cc=andy.shevchenko@gmail.com \
--cc=drew@beagleboard.org \
--cc=linus.walleij@linaro.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.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).