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pinctrl: pinmux: Add pinmux-select debugfs file

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Add "pinmux-select" to debugfs which will activate a pin function for a
given pin group:

  echo "<group-name function-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 on group pinmux-i2c1-pins:

  echo "pinmux-i2c1-pins pinmux-i2c1" > pinmux-select

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Drew Fustini <drew@beagleboard.org>
Link: https://lore.kernel.org/r/20210302053059.1049035-3-drew@beagleboard.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Drew Fustini 2021-03-01 21:30:57 -08:00 committed by Linus Walleij
parent 47473813bd
commit 6199f6becc
1 changed files with 102 additions and 0 deletions
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102
drivers/pinctrl/pinmux.c
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@ -12,6 +12,7 @@
*/
#define pr_fmt(fmt) "pinmux core: " fmt
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.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 128
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, *gname, *fname;
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 */
gname = strstrip(buf);
if (*gname == '\0') {
ret = -EINVAL;
goto exit_free_buf;
}
/* find a separator which is a spacelike character */
for (fname = gname; !isspace(*fname); fname++) {
if (*fname == '\0') {
ret = -EINVAL;
goto exit_free_buf;
}
}
*fname = '\0';
/* drop extra spaces between function and group names */
fname = skip_spaces(fname + 1);
if (*fname == '\0') {
ret = -EINVAL;
goto exit_free_buf;
}
ret = pinmux_func_name_to_selector(pctldev, fname);
if (ret < 0) {
dev_err(pctldev->dev, "invalid function %s in map table\n", fname);
goto exit_free_buf;
}
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;
}
ret = pinctrl_get_group_selector(pctldev, gname);
if (ret < 0) {
dev_err(pctldev->dev, "failed to get group selector for %s", gname);
goto exit_free_buf;
}
gsel = ret;
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 */