linux-stable/drivers/pinctrl/pinmux.c
Stefan Wahren 472a61e777 pinctrl/gpio: Take MUX usage into account
The user space like gpioinfo only see the GPIO usage but not the
MUX usage (e.g. I2C or SPI usage) of a pin. As a user we want
to know which pin is free/safe to use. So take the MUX usage of
strict pinmux controllers into account to get a more realistic
view for ioctl GPIO_GET_LINEINFO_IOCTL.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
Link: https://lore.kernel.org/r/20190814110035.13451-1-ramon.fried@linux.intel.com
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2019-08-23 11:09:41 +02:00

851 lines
21 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Core driver for the pin muxing portions of the pin control subsystem
*
* Copyright (C) 2011-2012 ST-Ericsson SA
* Written on behalf of Linaro for ST-Ericsson
* Based on bits of regulator core, gpio core and clk core
*
* Author: Linus Walleij <linus.walleij@linaro.org>
*
* Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
*/
#define pr_fmt(fmt) "pinmux core: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/radix-tree.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinmux.h>
#include "core.h"
#include "pinmux.h"
int pinmux_check_ops(struct pinctrl_dev *pctldev)
{
const struct pinmux_ops *ops = pctldev->desc->pmxops;
unsigned nfuncs;
unsigned selector = 0;
/* Check that we implement required operations */
if (!ops ||
!ops->get_functions_count ||
!ops->get_function_name ||
!ops->get_function_groups ||
!ops->set_mux) {
dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
return -EINVAL;
}
/* Check that all functions registered have names */
nfuncs = ops->get_functions_count(pctldev);
while (selector < nfuncs) {
const char *fname = ops->get_function_name(pctldev,
selector);
if (!fname) {
dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
selector);
return -EINVAL;
}
selector++;
}
return 0;
}
int pinmux_validate_map(const struct pinctrl_map *map, int i)
{
if (!map->data.mux.function) {
pr_err("failed to register map %s (%d): no function given\n",
map->name, i);
return -EINVAL;
}
return 0;
}
/**
* pinmux_can_be_used_for_gpio() - check if a specific pin
* is either muxed to a different function or used as gpio.
*
* @pin: the pin number in the global pin space
*
* Controllers not defined as strict will always return true,
* menaning that the gpio can be used.
*/
bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin)
{
struct pin_desc *desc = pin_desc_get(pctldev, pin);
const struct pinmux_ops *ops = pctldev->desc->pmxops;
/* Can't inspect pin, assume it can be used */
if (!desc)
return true;
if (ops->strict && desc->mux_usecount)
return false;
return !(ops->strict && !!desc->gpio_owner);
}
/**
* pin_request() - request a single pin to be muxed in, typically for GPIO
* @pin: the pin number in the global pin space
* @owner: a representation of the owner of this pin; typically the device
* name that controls its mux function, or the requested GPIO name
* @gpio_range: the range matching the GPIO pin if this is a request for a
* single GPIO pin
*/
static int pin_request(struct pinctrl_dev *pctldev,
int pin, const char *owner,
struct pinctrl_gpio_range *gpio_range)
{
struct pin_desc *desc;
const struct pinmux_ops *ops = pctldev->desc->pmxops;
int status = -EINVAL;
desc = pin_desc_get(pctldev, pin);
if (desc == NULL) {
dev_err(pctldev->dev,
"pin %d is not registered so it cannot be requested\n",
pin);
goto out;
}
dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
pin, desc->name, owner);
if ((!gpio_range || ops->strict) &&
desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
dev_err(pctldev->dev,
"pin %s already requested by %s; cannot claim for %s\n",
desc->name, desc->mux_owner, owner);
goto out;
}
if ((gpio_range || ops->strict) && desc->gpio_owner) {
dev_err(pctldev->dev,
"pin %s already requested by %s; cannot claim for %s\n",
desc->name, desc->gpio_owner, owner);
goto out;
}
if (gpio_range) {
desc->gpio_owner = owner;
} else {
desc->mux_usecount++;
if (desc->mux_usecount > 1)
return 0;
desc->mux_owner = owner;
}
/* Let each pin increase references to this module */
if (!try_module_get(pctldev->owner)) {
dev_err(pctldev->dev,
"could not increase module refcount for pin %d\n",
pin);
status = -EINVAL;
goto out_free_pin;
}
/*
* If there is no kind of request function for the pin we just assume
* we got it by default and proceed.
*/
if (gpio_range && ops->gpio_request_enable)
/* This requests and enables a single GPIO pin */
status = ops->gpio_request_enable(pctldev, gpio_range, pin);
else if (ops->request)
status = ops->request(pctldev, pin);
else
status = 0;
if (status) {
dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
module_put(pctldev->owner);
}
out_free_pin:
if (status) {
if (gpio_range) {
desc->gpio_owner = NULL;
} else {
desc->mux_usecount--;
if (!desc->mux_usecount)
desc->mux_owner = NULL;
}
}
out:
if (status)
dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
pin, owner, status);
return status;
}
/**
* pin_free() - release a single muxed in pin so something else can be muxed
* @pctldev: pin controller device handling this pin
* @pin: the pin to free
* @gpio_range: the range matching the GPIO pin if this is a request for a
* single GPIO pin
*
* This function returns a pointer to the previous owner. This is used
* for callers that dynamically allocate an owner name so it can be freed
* once the pin is free. This is done for GPIO request functions.
*/
static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
struct pinctrl_gpio_range *gpio_range)
{
const struct pinmux_ops *ops = pctldev->desc->pmxops;
struct pin_desc *desc;
const char *owner;
desc = pin_desc_get(pctldev, pin);
if (desc == NULL) {
dev_err(pctldev->dev,
"pin is not registered so it cannot be freed\n");
return NULL;
}
if (!gpio_range) {
/*
* A pin should not be freed more times than allocated.
*/
if (WARN_ON(!desc->mux_usecount))
return NULL;
desc->mux_usecount--;
if (desc->mux_usecount)
return NULL;
}
/*
* If there is no kind of request function for the pin we just assume
* we got it by default and proceed.
*/
if (gpio_range && ops->gpio_disable_free)
ops->gpio_disable_free(pctldev, gpio_range, pin);
else if (ops->free)
ops->free(pctldev, pin);
if (gpio_range) {
owner = desc->gpio_owner;
desc->gpio_owner = NULL;
} else {
owner = desc->mux_owner;
desc->mux_owner = NULL;
desc->mux_setting = NULL;
}
module_put(pctldev->owner);
return owner;
}
/**
* pinmux_request_gpio() - request pinmuxing for a GPIO pin
* @pctldev: pin controller device affected
* @pin: the pin to mux in for GPIO
* @range: the applicable GPIO range
*/
int pinmux_request_gpio(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned pin, unsigned gpio)
{
const char *owner;
int ret;
/* Conjure some name stating what chip and pin this is taken by */
owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
if (!owner)
return -ENOMEM;
ret = pin_request(pctldev, pin, owner, range);
if (ret < 0)
kfree(owner);
return ret;
}
/**
* pinmux_free_gpio() - release a pin from GPIO muxing
* @pctldev: the pin controller device for the pin
* @pin: the affected currently GPIO-muxed in pin
* @range: applicable GPIO range
*/
void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
struct pinctrl_gpio_range *range)
{
const char *owner;
owner = pin_free(pctldev, pin, range);
kfree(owner);
}
/**
* pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
* @pctldev: the pin controller handling this pin
* @range: applicable GPIO range
* @pin: the affected GPIO pin in this controller
* @input: true if we set the pin as input, false for output
*/
int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned pin, bool input)
{
const struct pinmux_ops *ops;
int ret;
ops = pctldev->desc->pmxops;
if (ops->gpio_set_direction)
ret = ops->gpio_set_direction(pctldev, range, pin, input);
else
ret = 0;
return ret;
}
static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
const char *function)
{
const struct pinmux_ops *ops = pctldev->desc->pmxops;
unsigned nfuncs = ops->get_functions_count(pctldev);
unsigned selector = 0;
/* See if this pctldev has this function */
while (selector < nfuncs) {
const char *fname = ops->get_function_name(pctldev, selector);
if (!strcmp(function, fname))
return selector;
selector++;
}
return -EINVAL;
}
int pinmux_map_to_setting(const struct pinctrl_map *map,
struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
char const * const *groups;
unsigned num_groups;
int ret;
const char *group;
if (!pmxops) {
dev_err(pctldev->dev, "does not support mux function\n");
return -EINVAL;
}
ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
if (ret < 0) {
dev_err(pctldev->dev, "invalid function %s in map table\n",
map->data.mux.function);
return ret;
}
setting->data.mux.func = ret;
ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
&groups, &num_groups);
if (ret < 0) {
dev_err(pctldev->dev, "can't query groups for function %s\n",
map->data.mux.function);
return ret;
}
if (!num_groups) {
dev_err(pctldev->dev,
"function %s can't be selected on any group\n",
map->data.mux.function);
return -EINVAL;
}
if (map->data.mux.group) {
group = map->data.mux.group;
ret = match_string(groups, num_groups, group);
if (ret < 0) {
dev_err(pctldev->dev,
"invalid group \"%s\" for function \"%s\"\n",
group, map->data.mux.function);
return ret;
}
} else {
group = groups[0];
}
ret = pinctrl_get_group_selector(pctldev, group);
if (ret < 0) {
dev_err(pctldev->dev, "invalid group %s in map table\n",
map->data.mux.group);
return ret;
}
setting->data.mux.group = ret;
return 0;
}
void pinmux_free_setting(const struct pinctrl_setting *setting)
{
/* This function is currently unused */
}
int pinmux_enable_setting(const struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
const struct pinmux_ops *ops = pctldev->desc->pmxops;
int ret = 0;
const unsigned *pins = NULL;
unsigned num_pins = 0;
int i;
struct pin_desc *desc;
if (pctlops->get_group_pins)
ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
&pins, &num_pins);
if (ret) {
const char *gname;
/* errors only affect debug data, so just warn */
gname = pctlops->get_group_name(pctldev,
setting->data.mux.group);
dev_warn(pctldev->dev,
"could not get pins for group %s\n",
gname);
num_pins = 0;
}
/* Try to allocate all pins in this group, one by one */
for (i = 0; i < num_pins; i++) {
ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
if (ret) {
const char *gname;
const char *pname;
desc = pin_desc_get(pctldev, pins[i]);
pname = desc ? desc->name : "non-existing";
gname = pctlops->get_group_name(pctldev,
setting->data.mux.group);
dev_err(pctldev->dev,
"could not request pin %d (%s) from group %s "
" on device %s\n",
pins[i], pname, gname,
pinctrl_dev_get_name(pctldev));
goto err_pin_request;
}
}
/* Now that we have acquired the pins, encode the mux setting */
for (i = 0; i < num_pins; i++) {
desc = pin_desc_get(pctldev, pins[i]);
if (desc == NULL) {
dev_warn(pctldev->dev,
"could not get pin desc for pin %d\n",
pins[i]);
continue;
}
desc->mux_setting = &(setting->data.mux);
}
ret = ops->set_mux(pctldev, setting->data.mux.func,
setting->data.mux.group);
if (ret)
goto err_set_mux;
return 0;
err_set_mux:
for (i = 0; i < num_pins; i++) {
desc = pin_desc_get(pctldev, pins[i]);
if (desc)
desc->mux_setting = NULL;
}
err_pin_request:
/* On error release all taken pins */
while (--i >= 0)
pin_free(pctldev, pins[i], NULL);
return ret;
}
void pinmux_disable_setting(const struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
int ret = 0;
const unsigned *pins = NULL;
unsigned num_pins = 0;
int i;
struct pin_desc *desc;
if (pctlops->get_group_pins)
ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
&pins, &num_pins);
if (ret) {
const char *gname;
/* errors only affect debug data, so just warn */
gname = pctlops->get_group_name(pctldev,
setting->data.mux.group);
dev_warn(pctldev->dev,
"could not get pins for group %s\n",
gname);
num_pins = 0;
}
/* Flag the descs that no setting is active */
for (i = 0; i < num_pins; i++) {
desc = pin_desc_get(pctldev, pins[i]);
if (desc == NULL) {
dev_warn(pctldev->dev,
"could not get pin desc for pin %d\n",
pins[i]);
continue;
}
if (desc->mux_setting == &(setting->data.mux)) {
pin_free(pctldev, pins[i], NULL);
} else {
const char *gname;
gname = pctlops->get_group_name(pctldev,
setting->data.mux.group);
dev_warn(pctldev->dev,
"not freeing pin %d (%s) as part of "
"deactivating group %s - it is already "
"used for some other setting",
pins[i], desc->name, gname);
}
}
}
#ifdef CONFIG_DEBUG_FS
/* Called from pincontrol core */
static int pinmux_functions_show(struct seq_file *s, void *what)
{
struct pinctrl_dev *pctldev = s->private;
const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
unsigned nfuncs;
unsigned func_selector = 0;
if (!pmxops)
return 0;
mutex_lock(&pctldev->mutex);
nfuncs = pmxops->get_functions_count(pctldev);
while (func_selector < nfuncs) {
const char *func = pmxops->get_function_name(pctldev,
func_selector);
const char * const *groups;
unsigned num_groups;
int ret;
int i;
ret = pmxops->get_function_groups(pctldev, func_selector,
&groups, &num_groups);
if (ret) {
seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
func);
func_selector++;
continue;
}
seq_printf(s, "function: %s, groups = [ ", func);
for (i = 0; i < num_groups; i++)
seq_printf(s, "%s ", groups[i]);
seq_puts(s, "]\n");
func_selector++;
}
mutex_unlock(&pctldev->mutex);
return 0;
}
static int pinmux_pins_show(struct seq_file *s, void *what)
{
struct pinctrl_dev *pctldev = s->private;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
unsigned i, pin;
if (!pmxops)
return 0;
seq_puts(s, "Pinmux settings per pin\n");
if (pmxops->strict)
seq_puts(s,
"Format: pin (name): mux_owner|gpio_owner (strict) hog?\n");
else
seq_puts(s,
"Format: pin (name): mux_owner gpio_owner hog?\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;
bool is_hog = false;
pin = pctldev->desc->pins[i].number;
desc = pin_desc_get(pctldev, pin);
/* Skip if we cannot search the pin */
if (desc == NULL)
continue;
if (desc->mux_owner &&
!strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
is_hog = true;
if (pmxops->strict) {
if (desc->mux_owner)
seq_printf(s, "pin %d (%s): device %s%s",
pin, desc->name, desc->mux_owner,
is_hog ? " (HOG)" : "");
else if (desc->gpio_owner)
seq_printf(s, "pin %d (%s): GPIO %s",
pin, desc->name, desc->gpio_owner);
else
seq_printf(s, "pin %d (%s): UNCLAIMED",
pin, desc->name);
} else {
/* For non-strict controllers */
seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name,
desc->mux_owner ? desc->mux_owner
: "(MUX UNCLAIMED)",
desc->gpio_owner ? desc->gpio_owner
: "(GPIO UNCLAIMED)",
is_hog ? " (HOG)" : "");
}
/* If mux: print function+group claiming the pin */
if (desc->mux_setting)
seq_printf(s, " function %s group %s\n",
pmxops->get_function_name(pctldev,
desc->mux_setting->func),
pctlops->get_group_name(pctldev,
desc->mux_setting->group));
else
seq_putc(s, '\n');
}
mutex_unlock(&pctldev->mutex);
return 0;
}
void pinmux_show_map(struct seq_file *s, const struct pinctrl_map *map)
{
seq_printf(s, "group %s\nfunction %s\n",
map->data.mux.group ? map->data.mux.group : "(default)",
map->data.mux.function);
}
void pinmux_show_setting(struct seq_file *s,
const struct pinctrl_setting *setting)
{
struct pinctrl_dev *pctldev = setting->pctldev;
const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
seq_printf(s, "group: %s (%u) function: %s (%u)\n",
pctlops->get_group_name(pctldev, setting->data.mux.group),
setting->data.mux.group,
pmxops->get_function_name(pctldev, setting->data.mux.func),
setting->data.mux.func);
}
DEFINE_SHOW_ATTRIBUTE(pinmux_functions);
DEFINE_SHOW_ATTRIBUTE(pinmux_pins);
void pinmux_init_device_debugfs(struct dentry *devroot,
struct pinctrl_dev *pctldev)
{
debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
devroot, pctldev, &pinmux_functions_fops);
debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
devroot, pctldev, &pinmux_pins_fops);
}
#endif /* CONFIG_DEBUG_FS */
#ifdef CONFIG_GENERIC_PINMUX_FUNCTIONS
/**
* pinmux_generic_get_function_count() - returns number of functions
* @pctldev: pin controller device
*/
int pinmux_generic_get_function_count(struct pinctrl_dev *pctldev)
{
return pctldev->num_functions;
}
EXPORT_SYMBOL_GPL(pinmux_generic_get_function_count);
/**
* pinmux_generic_get_function_name() - returns the function name
* @pctldev: pin controller device
* @selector: function number
*/
const char *
pinmux_generic_get_function_name(struct pinctrl_dev *pctldev,
unsigned int selector)
{
struct function_desc *function;
function = radix_tree_lookup(&pctldev->pin_function_tree,
selector);
if (!function)
return NULL;
return function->name;
}
EXPORT_SYMBOL_GPL(pinmux_generic_get_function_name);
/**
* pinmux_generic_get_function_groups() - gets the function groups
* @pctldev: pin controller device
* @selector: function number
* @groups: array of pin groups
* @num_groups: number of pin groups
*/
int pinmux_generic_get_function_groups(struct pinctrl_dev *pctldev,
unsigned int selector,
const char * const **groups,
unsigned * const num_groups)
{
struct function_desc *function;
function = radix_tree_lookup(&pctldev->pin_function_tree,
selector);
if (!function) {
dev_err(pctldev->dev, "%s could not find function%i\n",
__func__, selector);
return -EINVAL;
}
*groups = function->group_names;
*num_groups = function->num_group_names;
return 0;
}
EXPORT_SYMBOL_GPL(pinmux_generic_get_function_groups);
/**
* pinmux_generic_get_function() - returns a function based on the number
* @pctldev: pin controller device
* @group_selector: function number
*/
struct function_desc *pinmux_generic_get_function(struct pinctrl_dev *pctldev,
unsigned int selector)
{
struct function_desc *function;
function = radix_tree_lookup(&pctldev->pin_function_tree,
selector);
if (!function)
return NULL;
return function;
}
EXPORT_SYMBOL_GPL(pinmux_generic_get_function);
/**
* pinmux_generic_add_function() - adds a function group
* @pctldev: pin controller device
* @name: name of the function
* @groups: array of pin groups
* @num_groups: number of pin groups
* @data: pin controller driver specific data
*/
int pinmux_generic_add_function(struct pinctrl_dev *pctldev,
const char *name,
const char **groups,
const unsigned int num_groups,
void *data)
{
struct function_desc *function;
int selector;
if (!name)
return -EINVAL;
selector = pinmux_func_name_to_selector(pctldev, name);
if (selector >= 0)
return selector;
selector = pctldev->num_functions;
function = devm_kzalloc(pctldev->dev, sizeof(*function), GFP_KERNEL);
if (!function)
return -ENOMEM;
function->name = name;
function->group_names = groups;
function->num_group_names = num_groups;
function->data = data;
radix_tree_insert(&pctldev->pin_function_tree, selector, function);
pctldev->num_functions++;
return selector;
}
EXPORT_SYMBOL_GPL(pinmux_generic_add_function);
/**
* pinmux_generic_remove_function() - removes a numbered function
* @pctldev: pin controller device
* @selector: function number
*
* Note that the caller must take care of locking.
*/
int pinmux_generic_remove_function(struct pinctrl_dev *pctldev,
unsigned int selector)
{
struct function_desc *function;
function = radix_tree_lookup(&pctldev->pin_function_tree,
selector);
if (!function)
return -ENOENT;
radix_tree_delete(&pctldev->pin_function_tree, selector);
devm_kfree(pctldev->dev, function);
pctldev->num_functions--;
return 0;
}
EXPORT_SYMBOL_GPL(pinmux_generic_remove_function);
/**
* pinmux_generic_free_functions() - removes all functions
* @pctldev: pin controller device
*
* Note that the caller must take care of locking. The pinctrl
* functions are allocated with devm_kzalloc() so no need to free
* them here.
*/
void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
{
struct radix_tree_iter iter;
void __rcu **slot;
radix_tree_for_each_slot(slot, &pctldev->pin_function_tree, &iter, 0)
radix_tree_delete(&pctldev->pin_function_tree, iter.index);
pctldev->num_functions = 0;
}
#endif /* CONFIG_GENERIC_PINMUX_FUNCTIONS */