linux-stable/drivers/regulator/userspace-consumer.c
Douglas Anderson 259b93b21a
regulator: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in 4.14
Probing of regulators can be a slow operation and can contribute to
slower boot times. This is especially true if a regulator is turned on
at probe time (with regulator-boot-on or regulator-always-on) and the
regulator requires delays (off-on-time, ramp time, etc).

While the overall kernel is not ready to switch to async probe by
default, as per the discussion on the mailing lists [1] it is believed
that the regulator subsystem is in good shape and we can move
regulator drivers over wholesale. There is no way to just magically
opt in all regulators (regulators are just normal drivers like
platform_driver), so we set PROBE_PREFER_ASYNCHRONOUS for all
regulators found in 'drivers/regulator' individually.

Given the number of drivers touched and the impossibility to test this
ahead of time, it wouldn't be shocking at all if this caused a
regression for someone. If there is a regression caused by this patch,
it's likely to be one of the cases talked about in [1]. As a "quick
fix", drivers involved in the regression could be fixed by changing
them to PROBE_FORCE_SYNCHRONOUS. That being said, the correct fix
would be to directly fix the problem that caused the issue with async
probe.

The approach here follows a similar approach that was used for the mmc
subsystem several years ago [2]. In fact, I ran nearly the same python
script to auto-generate the changes. The only thing I changed was to
search for "i2c_driver", "spmi_driver", and "spi_driver" in addition
to "platform_driver".

[1] https://lore.kernel.org/r/06db017f-e985-4434-8d1d-02ca2100cca0@sirena.org.uk
[2] https://lore.kernel.org/r/20200903232441.2694866-1-dianders@chromium.org/

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230316125351.1.I2a4677392a38db5758dee0788b2cea5872562a82@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-20 13:11:25 +00:00

228 lines
5.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* userspace-consumer.c
*
* Copyright 2009 CompuLab, Ltd.
*
* Author: Mike Rapoport <mike@compulab.co.il>
*
* Based of virtual consumer driver:
* Copyright 2008 Wolfson Microelectronics PLC.
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*/
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/userspace-consumer.h>
#include <linux/slab.h>
struct userspace_consumer_data {
const char *name;
struct mutex lock;
bool enabled;
bool no_autoswitch;
int num_supplies;
struct regulator_bulk_data *supplies;
};
static ssize_t name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct userspace_consumer_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", data->name);
}
static ssize_t state_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct userspace_consumer_data *data = dev_get_drvdata(dev);
if (data->enabled)
return sprintf(buf, "enabled\n");
return sprintf(buf, "disabled\n");
}
static ssize_t state_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct userspace_consumer_data *data = dev_get_drvdata(dev);
bool enabled;
int ret;
/*
* sysfs_streq() doesn't need the \n's, but we add them so the strings
* will be shared with show_state(), above.
*/
if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
enabled = true;
else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
enabled = false;
else {
dev_err(dev, "Configuring invalid mode\n");
return count;
}
mutex_lock(&data->lock);
if (enabled != data->enabled) {
if (enabled)
ret = regulator_bulk_enable(data->num_supplies,
data->supplies);
else
ret = regulator_bulk_disable(data->num_supplies,
data->supplies);
if (ret == 0)
data->enabled = enabled;
else
dev_err(dev, "Failed to configure state: %d\n", ret);
}
mutex_unlock(&data->lock);
return count;
}
static DEVICE_ATTR_RO(name);
static DEVICE_ATTR_RW(state);
static struct attribute *attributes[] = {
&dev_attr_name.attr,
&dev_attr_state.attr,
NULL,
};
static umode_t attr_visible(struct kobject *kobj, struct attribute *attr, int idx)
{
struct device *dev = kobj_to_dev(kobj);
struct userspace_consumer_data *data = dev_get_drvdata(dev);
/* If a name hasn't been set, don't bother with the attribute */
if (attr == &dev_attr_name.attr && !data->name)
return 0;
return attr->mode;
}
static const struct attribute_group attr_group = {
.attrs = attributes,
.is_visible = attr_visible,
};
static int regulator_userspace_consumer_probe(struct platform_device *pdev)
{
struct regulator_userspace_consumer_data tmpdata;
struct regulator_userspace_consumer_data *pdata;
struct userspace_consumer_data *drvdata;
int ret;
pdata = dev_get_platdata(&pdev->dev);
if (!pdata) {
if (!pdev->dev.of_node)
return -EINVAL;
pdata = &tmpdata;
memset(pdata, 0, sizeof(*pdata));
pdata->no_autoswitch = true;
pdata->num_supplies = 1;
pdata->supplies = devm_kzalloc(&pdev->dev, sizeof(*pdata->supplies), GFP_KERNEL);
if (!pdata->supplies)
return -ENOMEM;
pdata->supplies[0].supply = "vout";
}
if (pdata->num_supplies < 1) {
dev_err(&pdev->dev, "At least one supply required\n");
return -EINVAL;
}
drvdata = devm_kzalloc(&pdev->dev,
sizeof(struct userspace_consumer_data),
GFP_KERNEL);
if (drvdata == NULL)
return -ENOMEM;
drvdata->name = pdata->name;
drvdata->num_supplies = pdata->num_supplies;
drvdata->supplies = pdata->supplies;
drvdata->no_autoswitch = pdata->no_autoswitch;
mutex_init(&drvdata->lock);
ret = devm_regulator_bulk_get_exclusive(&pdev->dev, drvdata->num_supplies,
drvdata->supplies);
if (ret) {
dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, drvdata);
ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
if (ret != 0)
return ret;
if (pdata->init_on && !pdata->no_autoswitch) {
ret = regulator_bulk_enable(drvdata->num_supplies,
drvdata->supplies);
if (ret) {
dev_err(&pdev->dev,
"Failed to set initial state: %d\n", ret);
goto err_enable;
}
}
ret = regulator_is_enabled(pdata->supplies[0].consumer);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to get regulator status\n");
goto err_enable;
}
drvdata->enabled = !!ret;
return 0;
err_enable:
sysfs_remove_group(&pdev->dev.kobj, &attr_group);
return ret;
}
static int regulator_userspace_consumer_remove(struct platform_device *pdev)
{
struct userspace_consumer_data *data = platform_get_drvdata(pdev);
sysfs_remove_group(&pdev->dev.kobj, &attr_group);
if (data->enabled && !data->no_autoswitch)
regulator_bulk_disable(data->num_supplies, data->supplies);
return 0;
}
static const struct of_device_id regulator_userspace_consumer_of_match[] = {
{ .compatible = "regulator-output", },
{},
};
static struct platform_driver regulator_userspace_consumer_driver = {
.probe = regulator_userspace_consumer_probe,
.remove = regulator_userspace_consumer_remove,
.driver = {
.name = "reg-userspace-consumer",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = regulator_userspace_consumer_of_match,
},
};
module_platform_driver(regulator_userspace_consumer_driver);
MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
MODULE_LICENSE("GPL");