From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Dario Binacchi <dariobin@libero.it>, 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: Mon, 17 May 2021 23:02:00 +0300 [thread overview]
Message-ID: <CAHp75Vd8875hRNk1JK6gkmfxjqxBSu4cRNE1zJt9TyEW7TvsMg@mail.gmail.com> (raw)
In-Reply-To: <20210516135531.2203-2-dariobin@libero.it>
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() ?
> + token = strsep(&c, " ");
> + if (kstrtouint(token, 0, &pin))
> + return -EINVAL;
Don't shadow an error code.
> + 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?
> + 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:[~2021-05-17 20:02 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 [this message]
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
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
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