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    SubjectRe: [PATCH v6 2/3] pinctrl: pinmux: Add pinmux-select debugfs file
    On Wed, Feb 17, 2021 at 12:45 AM Drew Fustini <drew@beagleboard.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@gmail.com>

    > Signed-off-by: Drew Fustini <drew@beagleboard.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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