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Date: Wed, 17 Feb 2021 12:10:10 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Drew Fustini <drew@...gleboard.org>
Cc: Linus Walleij <linus.walleij@...aro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Tony Lindgren <tony@...mide.com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
Jason Kridner <jkridner@...gleboard.org>,
Robert Nelson <robertcnelson@...gleboard.org>,
Joe Perches <joe@...ches.com>,
Dan Carpenter <dan.carpenter@...cle.com>,
Jonathan Corbet <corbet@....net>,
Linux Documentation List <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v6 2/3] pinctrl: pinmux: Add pinmux-select debugfs file
On Wed, Feb 17, 2021 at 12:45 AM Drew Fustini <drew@...gleboard.org> wrote:
>
> Add "pinmux-select" to debugfs which will activate a function and group:
>
> echo "<function-name group-name>" > pinmux-select
>
> The write operation pinmux_select() handles this by checking that the
> names map to valid selectors and then calling ops->set_mux().
>
> The existing "pinmux-functions" debugfs file lists the pin functions
> registered for the pin controller. For example:
>
> function: pinmux-uart0, groups = [ pinmux-uart0-pins ]
> function: pinmux-mmc0, groups = [ pinmux-mmc0-pins ]
> function: pinmux-mmc1, groups = [ pinmux-mmc1-pins ]
> function: pinmux-i2c0, groups = [ pinmux-i2c0-pins ]
> function: pinmux-i2c1, groups = [ pinmux-i2c1-pins ]
> function: pinmux-spi1, groups = [ pinmux-spi1-pins ]
>
> To activate function pinmux-i2c1 and group pinmux-i2c1-pins:
>
> echo "pinmux-i2c1 pinmux-i2c1-pins" > pinmux-select
Thanks, looks almost good to me (few nit-picks below)
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Drew Fustini <drew@...gleboard.org>
> ---
> drivers/pinctrl/pinmux.c | 102 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 102 insertions(+)
>
> diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
> index c651b2db0925..08f336e4246c 100644
> --- a/drivers/pinctrl/pinmux.c
> +++ b/drivers/pinctrl/pinmux.c
> @@ -23,6 +23,7 @@
> #include <linux/string.h>
> #include <linux/debugfs.h>
> #include <linux/seq_file.h>
> +#include <linux/ctype.h>
Perhaps squeeze it to look slightly more ordered?
> #include <linux/pinctrl/machine.h>
> #include <linux/pinctrl/pinmux.h>
> #include "core.h"
> @@ -673,6 +674,105 @@ void pinmux_show_setting(struct seq_file *s,
> DEFINE_SHOW_ATTRIBUTE(pinmux_functions);
> DEFINE_SHOW_ATTRIBUTE(pinmux_pins);
> +#define PINMUX_SELECT_MAX 50
Why suddenly this number? Maybe 64 for the sake of good power of 2?
> +static ssize_t pinmux_select(struct file *file, const char __user *user_buf,
> + size_t len, loff_t *ppos)
> +{
> + struct seq_file *sfile = file->private_data;
> + struct pinctrl_dev *pctldev = sfile->private;
> + const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
> + const char *const *groups;
> + char *buf, *fname, *gname;
> + unsigned int num_groups;
> + int fsel, gsel, ret;
> +
> + if (len > PINMUX_SELECT_MAX)
> + return -ENOMEM;
> +
> + buf = kzalloc(PINMUX_SELECT_MAX, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + ret = strncpy_from_user(buf, user_buf, PINMUX_SELECT_MAX);
> + if (ret < 0)
> + goto exit_free_buf;
> + buf[len-1] = '\0';
> +
> + /* remove leading and trailing spaces of input buffer */
> + fname = strstrip(buf);
> + if (*fname == '\0') {
> + ret = -EINVAL;
> + goto exit_free_buf;
> + }
> +
> + /* find a separator like a space character */
"find a separator which is a spacelike character" ?
> + for (gname = fname; !isspace(*gname); gname++) {
> + if (*gname == '\0') {
> + ret = -EINVAL;
> + goto exit_free_buf;
> + }
> + }
> + *gname = '\0';
> +
> + /* drop extra spaces between function and group name */
names
> + gname = skip_spaces(gname + 1);
> + if (*gname == '\0') {
> + ret = -EINVAL;
> + goto exit_free_buf;
> + }
> +
> + fsel = pinmux_func_name_to_selector(pctldev, fname);
> + if (fsel < 0) {
> + dev_err(pctldev->dev, "invalid function %s in map table\n", fname);
> + ret = fsel;
> + goto exit_free_buf;
> + }
Here and below you could do other way around, i.e.
ret = ...
if (ret < 0) {
...
}
fsel = ret;
> + ret = pmxops->get_function_groups(pctldev, fsel, &groups, &num_groups);
> + if (ret) {
> + dev_err(pctldev->dev, "no groups for function %d (%s)", fsel, fname);
> + goto exit_free_buf;
> + }
> +
> + ret = match_string(groups, num_groups, gname);
> + if (ret < 0) {
> + dev_err(pctldev->dev, "invalid group %s", gname);
> + goto exit_free_buf;
> + }
> +
> + gsel = pinctrl_get_group_selector(pctldev, gname);
> + if (gsel < 0) {
> + dev_err(pctldev->dev, "failed to get group selector for %s", gname);
> + ret = gsel;
> + goto exit_free_buf;
> + }
> +
> + ret = pmxops->set_mux(pctldev, fsel, gsel);
> + if (ret) {
> + dev_err(pctldev->dev, "set_mux() failed: %d", ret);
> + goto exit_free_buf;
> + }
> + ret = len;
> +
> +exit_free_buf:
> + kfree(buf);
> +
> + return ret;
> +}
> +
> +static int pinmux_select_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, NULL, inode->i_private);
> +}
> +
> +static const struct file_operations pinmux_select_ops = {
> + .owner = THIS_MODULE,
> + .open = pinmux_select_open,
> + .write = pinmux_select,
> + .llseek = no_llseek,
> + .release = single_release,
> +};
> +
> void pinmux_init_device_debugfs(struct dentry *devroot,
> struct pinctrl_dev *pctldev)
> {
> @@ -680,6 +780,8 @@ void pinmux_init_device_debugfs(struct dentry *devroot,
> devroot, pctldev, &pinmux_functions_fops);
> debugfs_create_file("pinmux-pins", 0444,
> devroot, pctldev, &pinmux_pins_fops);
> + debugfs_create_file("pinmux-select", 0200,
> + devroot, pctldev, &pinmux_select_ops);
> }
>
> #endif /* CONFIG_DEBUG_FS */
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
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