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linux/drivers/regulator/virtual.c
Uwe Kleine-König d637a75ede regulator: virtual: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://msgid.link/r/d9954f02ae51b1b0b0077c710d16bfaeafa216ec.1701778038.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-12-11 12:54:31 +00:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* reg-virtual-consumer.c
*
* Copyright 2008 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*/
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
struct virtual_consumer_data {
struct mutex lock;
struct regulator *regulator;
bool enabled;
int min_uV;
int max_uV;
int min_uA;
int max_uA;
unsigned int mode;
};
static void update_voltage_constraints(struct device *dev,
struct virtual_consumer_data *data)
{
int ret;
if (data->min_uV && data->max_uV
&& data->min_uV <= data->max_uV) {
dev_dbg(dev, "Requesting %d-%duV\n",
data->min_uV, data->max_uV);
ret = regulator_set_voltage(data->regulator,
data->min_uV, data->max_uV);
if (ret != 0) {
dev_err(dev,
"regulator_set_voltage() failed: %d\n", ret);
return;
}
}
if (data->min_uV && data->max_uV && !data->enabled) {
dev_dbg(dev, "Enabling regulator\n");
ret = regulator_enable(data->regulator);
if (ret == 0)
data->enabled = true;
else
dev_err(dev, "regulator_enable() failed: %d\n",
ret);
}
if (!(data->min_uV && data->max_uV) && data->enabled) {
dev_dbg(dev, "Disabling regulator\n");
ret = regulator_disable(data->regulator);
if (ret == 0)
data->enabled = false;
else
dev_err(dev, "regulator_disable() failed: %d\n",
ret);
}
}
static void update_current_limit_constraints(struct device *dev,
struct virtual_consumer_data *data)
{
int ret;
if (data->max_uA
&& data->min_uA <= data->max_uA) {
dev_dbg(dev, "Requesting %d-%duA\n",
data->min_uA, data->max_uA);
ret = regulator_set_current_limit(data->regulator,
data->min_uA, data->max_uA);
if (ret != 0) {
dev_err(dev,
"regulator_set_current_limit() failed: %d\n",
ret);
return;
}
}
if (data->max_uA && !data->enabled) {
dev_dbg(dev, "Enabling regulator\n");
ret = regulator_enable(data->regulator);
if (ret == 0)
data->enabled = true;
else
dev_err(dev, "regulator_enable() failed: %d\n",
ret);
}
if (!(data->min_uA && data->max_uA) && data->enabled) {
dev_dbg(dev, "Disabling regulator\n");
ret = regulator_disable(data->regulator);
if (ret == 0)
data->enabled = false;
else
dev_err(dev, "regulator_disable() failed: %d\n",
ret);
}
}
static ssize_t show_min_uV(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", data->min_uV);
}
static ssize_t set_min_uV(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
long val;
if (kstrtol(buf, 10, &val) != 0)
return count;
mutex_lock(&data->lock);
data->min_uV = val;
update_voltage_constraints(dev, data);
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_max_uV(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", data->max_uV);
}
static ssize_t set_max_uV(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
long val;
if (kstrtol(buf, 10, &val) != 0)
return count;
mutex_lock(&data->lock);
data->max_uV = val;
update_voltage_constraints(dev, data);
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_min_uA(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", data->min_uA);
}
static ssize_t set_min_uA(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
long val;
if (kstrtol(buf, 10, &val) != 0)
return count;
mutex_lock(&data->lock);
data->min_uA = val;
update_current_limit_constraints(dev, data);
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_max_uA(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", data->max_uA);
}
static ssize_t set_max_uA(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
long val;
if (kstrtol(buf, 10, &val) != 0)
return count;
mutex_lock(&data->lock);
data->max_uA = val;
update_current_limit_constraints(dev, data);
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_mode(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
switch (data->mode) {
case REGULATOR_MODE_FAST:
return sprintf(buf, "fast\n");
case REGULATOR_MODE_NORMAL:
return sprintf(buf, "normal\n");
case REGULATOR_MODE_IDLE:
return sprintf(buf, "idle\n");
case REGULATOR_MODE_STANDBY:
return sprintf(buf, "standby\n");
default:
return sprintf(buf, "unknown\n");
}
}
static ssize_t set_mode(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct virtual_consumer_data *data = dev_get_drvdata(dev);
unsigned int mode;
int ret;
/*
* sysfs_streq() doesn't need the \n's, but we add them so the strings
* will be shared with show_mode(), above.
*/
if (sysfs_streq(buf, "fast\n"))
mode = REGULATOR_MODE_FAST;
else if (sysfs_streq(buf, "normal\n"))
mode = REGULATOR_MODE_NORMAL;
else if (sysfs_streq(buf, "idle\n"))
mode = REGULATOR_MODE_IDLE;
else if (sysfs_streq(buf, "standby\n"))
mode = REGULATOR_MODE_STANDBY;
else {
dev_err(dev, "Configuring invalid mode\n");
return count;
}
mutex_lock(&data->lock);
ret = regulator_set_mode(data->regulator, mode);
if (ret == 0)
data->mode = mode;
else
dev_err(dev, "Failed to configure mode: %d\n", ret);
mutex_unlock(&data->lock);
return count;
}
static DEVICE_ATTR(min_microvolts, 0664, show_min_uV, set_min_uV);
static DEVICE_ATTR(max_microvolts, 0664, show_max_uV, set_max_uV);
static DEVICE_ATTR(min_microamps, 0664, show_min_uA, set_min_uA);
static DEVICE_ATTR(max_microamps, 0664, show_max_uA, set_max_uA);
static DEVICE_ATTR(mode, 0664, show_mode, set_mode);
static struct attribute *regulator_virtual_attributes[] = {
&dev_attr_min_microvolts.attr,
&dev_attr_max_microvolts.attr,
&dev_attr_min_microamps.attr,
&dev_attr_max_microamps.attr,
&dev_attr_mode.attr,
NULL
};
static const struct attribute_group regulator_virtual_attr_group = {
.attrs = regulator_virtual_attributes,
};
#ifdef CONFIG_OF
static const struct of_device_id regulator_virtual_consumer_of_match[] = {
{ .compatible = "regulator-virtual-consumer" },
{},
};
MODULE_DEVICE_TABLE(of, regulator_virtual_consumer_of_match);
#endif
static int regulator_virtual_probe(struct platform_device *pdev)
{
char *reg_id = dev_get_platdata(&pdev->dev);
struct virtual_consumer_data *drvdata;
static bool warned;
int ret;
if (!warned) {
warned = true;
pr_warn("**********************************************************\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("** **\n");
pr_warn("** regulator-virtual-consumer is only for testing and **\n");
pr_warn("** debugging. Do not use it in a production kernel. **\n");
pr_warn("** **\n");
pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
pr_warn("**********************************************************\n");
}
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct virtual_consumer_data),
GFP_KERNEL);
if (drvdata == NULL)
return -ENOMEM;
/*
* This virtual consumer does not have any hardware-defined supply
* name, so just allow the regulator to be specified in a property
* named "default-supply" when we're being probed from devicetree.
*/
if (!reg_id && pdev->dev.of_node)
reg_id = "default";
mutex_init(&drvdata->lock);
drvdata->regulator = devm_regulator_get(&pdev->dev, reg_id);
if (IS_ERR(drvdata->regulator))
return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->regulator),
"Failed to obtain supply '%s'\n",
reg_id);
ret = sysfs_create_group(&pdev->dev.kobj,
&regulator_virtual_attr_group);
if (ret != 0) {
dev_err(&pdev->dev,
"Failed to create attribute group: %d\n", ret);
return ret;
}
drvdata->mode = regulator_get_mode(drvdata->regulator);
platform_set_drvdata(pdev, drvdata);
return 0;
}
static void regulator_virtual_remove(struct platform_device *pdev)
{
struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);
sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);
if (drvdata->enabled)
regulator_disable(drvdata->regulator);
}
static struct platform_driver regulator_virtual_consumer_driver = {
.probe = regulator_virtual_probe,
.remove_new = regulator_virtual_remove,
.driver = {
.name = "reg-virt-consumer",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(regulator_virtual_consumer_of_match),
},
};
module_platform_driver(regulator_virtual_consumer_driver);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("Virtual regulator consumer");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:reg-virt-consumer");
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