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linux-next/drivers/pinctrl/pinconf.c
Vladimir Zapolskiy e73339037f pinctrl: remove unused 'pinconf-config' debugfs interface
The main goal of the change is to remove .pin_config_dbg_parse_modify
callback before a driver with its support appears. So far the in-kernel
interface did not attract any users since its introduction 5 years ago.

Originally .pin_config_dbg_parse_modify callback and the associated
'pinconf-config' debugfs file were introduced in commit f07512e615
("pinctrl/pinconfig: add debug interface"), a short description of
'pinconf-config' usage for debugging can be expressed this way:

Write to 'pinconf-config' (see pinconf_dbg_config_write() function):

% echo -n modify $map_type $device_name $state_name $pin_name $config > \
	/sys/kernel/debug/pinctrl/$pinctrl/pinconf-config

It supposes to update a global (therefore single!) 'pinconf_dbg_conf'
variable with an alternative setting, the arguments should match
an existing pinconf device and some registered pinctrl mapping 'map':

* $map_type is either 'config_pin' or 'config_group', it should match
  'map->type' value of PIN_MAP_TYPE_CONFIGS_PIN or
   PIN_MAP_TYPE_CONFIGS_GROUP accordingly,
* $device_name should match 'map->dev_name' string value,
* $state_name should match 'map->name' string value,
* $pin_name should match 'map->data.configs.group_or_pin' string value,

If all above has matched, then $config is a new value to be set by calling
pinconfops->pin_config_dbg_parse_modify(pctldev, config, matched_config).

After a successful write into 'pinconf-config' a user can read the file
to get information about that single modified pin configuration.

The fact is .pin_config_dbg_parse_modify callback has never been defined
in 'struct pinconf_ops' of any pinconf driver, thus an actual modification
of a pin or group state on any present pinconf controller does not happen,
and it declares that all related code is no more than dead code.

I discovered the issue while attempting to add .pin_config_dbg_parse_modify
support in some drivers and found that too short 'MAX_NAME_LEN' set by

  drivers/pinctrl/pinconf.c:372:#define MAX_NAME_LEN 15

is practically insufficient to store a regular pinctrl device name,
which are like 'e6060000.pin-controller-sh-pfc' or pin names like
'MX6QDL_PAD_ENET_REF_CLK', thus it is another indicator that the code
is barely usable, insufficiently tested and unprepossessing.

Of course it might be possible to increase MAX_NAME_LEN, and then add
.pin_config_dbg_parse_modify callbacks to the drivers, but the whole
idea of such a limited debug option looks inviable. A more flexible
way to functionally substitute the original approach is to implicitly
or explicitly use pinctrl_select_state() function whenever needed.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: Laurent Meunier <laurent.meunier@st.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2019-01-28 14:39:52 +01:00

381 lines
9.4 KiB
C

/*
* Core driver for the pin config portions of the pin control subsystem
*
* Copyright (C) 2011 ST-Ericsson SA
* Written on behalf of Linaro for ST-Ericsson
*
* Author: Linus Walleij <linus.walleij@linaro.org>
*
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) "pinconfig core: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include "core.h"
#include "pinconf.h"
int pinconf_check_ops(struct pinctrl_dev *pctldev)
{
const struct pinconf_ops *ops = pctldev->desc->confops;
/* We have to be able to config the pins in SOME way */
if (!ops->pin_config_set && !ops->pin_config_group_set) {
dev_err(pctldev->dev,
"pinconf has to be able to set a pins config\n");
return -EINVAL;
}
return 0;
}
int pinconf_validate_map(const struct pinctrl_map *map, int i)
{
if (!map->data.configs.group_or_pin) {
pr_err("failed to register map %s (%d): no group/pin given\n",
map->name, i);
return -EINVAL;
}
if (!map->data.configs.num_configs ||
!map->data.configs.configs) {
pr_err("failed to register map %s (%d): no configs given\n",
map->name, i);
return -EINVAL;
}
return 0;
}
int pin_config_get_for_pin(struct pinctrl_dev *pctldev, unsigned pin,
unsigned long *config)
{
const struct pinconf_ops *ops = pctldev->desc->confops;
if (!ops || !ops->pin_config_get) {
dev_dbg(pctldev->dev,
"cannot get pin configuration, .pin_config_get missing in driver\n");
return -ENOTSUPP;
}
return ops->pin_config_get(pctldev, pin, config);
}
int pin_config_group_get(const char *dev_name, const char *pin_group,
unsigned long *config)
{
struct pinctrl_dev *pctldev;
const struct pinconf_ops *ops;
int selector, ret;
pctldev = get_pinctrl_dev_from_devname(dev_name);
if (!pctldev) {
ret = -EINVAL;
return ret;
}
mutex_lock(&pctldev->mutex);
ops = pctldev->desc->confops;
if (!ops || !ops->pin_config_group_get) {
dev_dbg(pctldev->dev,
"cannot get configuration for pin group, missing group config get function in driver\n");
ret = -ENOTSUPP;
goto unlock;
}
selector = pinctrl_get_group_selector(pctldev, pin_group);
if (selector < 0) {
ret = selector;
goto unlock;
}
ret = ops->pin_config_group_get(pctldev, selector, config);
unlock:
mutex_unlock(&pctldev->mutex);
return ret;
}
int pinconf_map_to_setting(const struct pinctrl_map *map,
struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
int pin;
switch (setting->type) {
case PIN_MAP_TYPE_CONFIGS_PIN:
pin = pin_get_from_name(pctldev,
map->data.configs.group_or_pin);
if (pin < 0) {
dev_err(pctldev->dev, "could not map pin config for \"%s\"",
map->data.configs.group_or_pin);
return pin;
}
setting->data.configs.group_or_pin = pin;
break;
case PIN_MAP_TYPE_CONFIGS_GROUP:
pin = pinctrl_get_group_selector(pctldev,
map->data.configs.group_or_pin);
if (pin < 0) {
dev_err(pctldev->dev, "could not map group config for \"%s\"",
map->data.configs.group_or_pin);
return pin;
}
setting->data.configs.group_or_pin = pin;
break;
default:
return -EINVAL;
}
setting->data.configs.num_configs = map->data.configs.num_configs;
setting->data.configs.configs = map->data.configs.configs;
return 0;
}
void pinconf_free_setting(const struct pinctrl_setting *setting)
{
}
int pinconf_apply_setting(const struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinconf_ops *ops = pctldev->desc->confops;
int ret;
if (!ops) {
dev_err(pctldev->dev, "missing confops\n");
return -EINVAL;
}
switch (setting->type) {
case PIN_MAP_TYPE_CONFIGS_PIN:
if (!ops->pin_config_set) {
dev_err(pctldev->dev, "missing pin_config_set op\n");
return -EINVAL;
}
ret = ops->pin_config_set(pctldev,
setting->data.configs.group_or_pin,
setting->data.configs.configs,
setting->data.configs.num_configs);
if (ret < 0) {
dev_err(pctldev->dev,
"pin_config_set op failed for pin %d\n",
setting->data.configs.group_or_pin);
return ret;
}
break;
case PIN_MAP_TYPE_CONFIGS_GROUP:
if (!ops->pin_config_group_set) {
dev_err(pctldev->dev,
"missing pin_config_group_set op\n");
return -EINVAL;
}
ret = ops->pin_config_group_set(pctldev,
setting->data.configs.group_or_pin,
setting->data.configs.configs,
setting->data.configs.num_configs);
if (ret < 0) {
dev_err(pctldev->dev,
"pin_config_group_set op failed for group %d\n",
setting->data.configs.group_or_pin);
return ret;
}
break;
default:
return -EINVAL;
}
return 0;
}
int pinconf_set_config(struct pinctrl_dev *pctldev, unsigned pin,
unsigned long *configs, size_t nconfigs)
{
const struct pinconf_ops *ops;
ops = pctldev->desc->confops;
if (!ops || !ops->pin_config_set)
return -ENOTSUPP;
return ops->pin_config_set(pctldev, pin, configs, nconfigs);
}
#ifdef CONFIG_DEBUG_FS
static void pinconf_show_config(struct seq_file *s, struct pinctrl_dev *pctldev,
unsigned long *configs, unsigned num_configs)
{
const struct pinconf_ops *confops;
int i;
if (pctldev)
confops = pctldev->desc->confops;
else
confops = NULL;
for (i = 0; i < num_configs; i++) {
seq_puts(s, "config ");
if (confops && confops->pin_config_config_dbg_show)
confops->pin_config_config_dbg_show(pctldev, s,
configs[i]);
else
seq_printf(s, "%08lx", configs[i]);
seq_putc(s, '\n');
}
}
void pinconf_show_map(struct seq_file *s, const struct pinctrl_map *map)
{
struct pinctrl_dev *pctldev;
pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
switch (map->type) {
case PIN_MAP_TYPE_CONFIGS_PIN:
seq_puts(s, "pin ");
break;
case PIN_MAP_TYPE_CONFIGS_GROUP:
seq_puts(s, "group ");
break;
default:
break;
}
seq_printf(s, "%s\n", map->data.configs.group_or_pin);
pinconf_show_config(s, pctldev, map->data.configs.configs,
map->data.configs.num_configs);
}
void pinconf_show_setting(struct seq_file *s,
const struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
struct pin_desc *desc;
switch (setting->type) {
case PIN_MAP_TYPE_CONFIGS_PIN:
desc = pin_desc_get(setting->pctldev,
setting->data.configs.group_or_pin);
seq_printf(s, "pin %s (%d)", desc->name,
setting->data.configs.group_or_pin);
break;
case PIN_MAP_TYPE_CONFIGS_GROUP:
seq_printf(s, "group %s (%d)",
pctlops->get_group_name(pctldev,
setting->data.configs.group_or_pin),
setting->data.configs.group_or_pin);
break;
default:
break;
}
/*
* FIXME: We should really get the pin controller to dump the config
* values, so they can be decoded to something meaningful.
*/
pinconf_show_config(s, pctldev, setting->data.configs.configs,
setting->data.configs.num_configs);
}
static void pinconf_dump_pin(struct pinctrl_dev *pctldev,
struct seq_file *s, int pin)
{
const struct pinconf_ops *ops = pctldev->desc->confops;
/* no-op when not using generic pin config */
pinconf_generic_dump_pins(pctldev, s, NULL, pin);
if (ops && ops->pin_config_dbg_show)
ops->pin_config_dbg_show(pctldev, s, pin);
}
static int pinconf_pins_show(struct seq_file *s, void *what)
{
struct pinctrl_dev *pctldev = s->private;
unsigned i, pin;
seq_puts(s, "Pin config settings per pin\n");
seq_puts(s, "Format: pin (name): configs\n");
mutex_lock(&pctldev->mutex);
/* The pin number can be retrived from the pin controller descriptor */
for (i = 0; i < pctldev->desc->npins; i++) {
struct pin_desc *desc;
pin = pctldev->desc->pins[i].number;
desc = pin_desc_get(pctldev, pin);
/* Skip if we cannot search the pin */
if (!desc)
continue;
seq_printf(s, "pin %d (%s): ", pin, desc->name);
pinconf_dump_pin(pctldev, s, pin);
seq_putc(s, '\n');
}
mutex_unlock(&pctldev->mutex);
return 0;
}
static void pinconf_dump_group(struct pinctrl_dev *pctldev,
struct seq_file *s, unsigned selector,
const char *gname)
{
const struct pinconf_ops *ops = pctldev->desc->confops;
/* no-op when not using generic pin config */
pinconf_generic_dump_pins(pctldev, s, gname, 0);
if (ops && ops->pin_config_group_dbg_show)
ops->pin_config_group_dbg_show(pctldev, s, selector);
}
static int pinconf_groups_show(struct seq_file *s, void *what)
{
struct pinctrl_dev *pctldev = s->private;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
unsigned ngroups = pctlops->get_groups_count(pctldev);
unsigned selector = 0;
seq_puts(s, "Pin config settings per pin group\n");
seq_puts(s, "Format: group (name): configs\n");
while (selector < ngroups) {
const char *gname = pctlops->get_group_name(pctldev, selector);
seq_printf(s, "%u (%s): ", selector, gname);
pinconf_dump_group(pctldev, s, selector, gname);
seq_putc(s, '\n');
selector++;
}
return 0;
}
DEFINE_SHOW_ATTRIBUTE(pinconf_pins);
DEFINE_SHOW_ATTRIBUTE(pinconf_groups);
void pinconf_init_device_debugfs(struct dentry *devroot,
struct pinctrl_dev *pctldev)
{
debugfs_create_file("pinconf-pins", S_IFREG | S_IRUGO,
devroot, pctldev, &pinconf_pins_fops);
debugfs_create_file("pinconf-groups", S_IFREG | S_IRUGO,
devroot, pctldev, &pinconf_groups_fops);
}
#endif