linux-stable/drivers/regulator/gpio-regulator.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

391 lines
9.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* gpio-regulator.c
*
* Copyright 2011 Heiko Stuebner <heiko@sntech.de>
*
* based on fixed.c
*
* Copyright 2008 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* Copyright (c) 2009 Nokia Corporation
* Roger Quadros <ext-roger.quadros@nokia.com>
*
* This is useful for systems with mixed controllable and
* non-controllable regulators, as well as for allowing testing on
* systems with no controllable regulators.
*/
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/gpio-regulator.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/of.h>
struct gpio_regulator_data {
struct regulator_desc desc;
struct gpio_desc **gpiods;
int nr_gpios;
struct gpio_regulator_state *states;
int nr_states;
int state;
};
static int gpio_regulator_get_value(struct regulator_dev *dev)
{
struct gpio_regulator_data *data = rdev_get_drvdata(dev);
int ptr;
for (ptr = 0; ptr < data->nr_states; ptr++)
if (data->states[ptr].gpios == data->state)
return data->states[ptr].value;
return -EINVAL;
}
static int gpio_regulator_set_voltage(struct regulator_dev *dev,
int min_uV, int max_uV,
unsigned *selector)
{
struct gpio_regulator_data *data = rdev_get_drvdata(dev);
int ptr, target = 0, state, best_val = INT_MAX;
for (ptr = 0; ptr < data->nr_states; ptr++)
if (data->states[ptr].value < best_val &&
data->states[ptr].value >= min_uV &&
data->states[ptr].value <= max_uV) {
target = data->states[ptr].gpios;
best_val = data->states[ptr].value;
if (selector)
*selector = ptr;
}
if (best_val == INT_MAX)
return -EINVAL;
for (ptr = 0; ptr < data->nr_gpios; ptr++) {
state = (target & (1 << ptr)) >> ptr;
gpiod_set_value_cansleep(data->gpiods[ptr], state);
}
data->state = target;
return 0;
}
static int gpio_regulator_list_voltage(struct regulator_dev *dev,
unsigned selector)
{
struct gpio_regulator_data *data = rdev_get_drvdata(dev);
if (selector >= data->nr_states)
return -EINVAL;
return data->states[selector].value;
}
static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
int min_uA, int max_uA)
{
struct gpio_regulator_data *data = rdev_get_drvdata(dev);
int ptr, target = 0, state, best_val = 0;
for (ptr = 0; ptr < data->nr_states; ptr++)
if (data->states[ptr].value > best_val &&
data->states[ptr].value >= min_uA &&
data->states[ptr].value <= max_uA) {
target = data->states[ptr].gpios;
best_val = data->states[ptr].value;
}
if (best_val == 0)
return -EINVAL;
for (ptr = 0; ptr < data->nr_gpios; ptr++) {
state = (target & (1 << ptr)) >> ptr;
gpiod_set_value_cansleep(data->gpiods[ptr], state);
}
data->state = target;
return 0;
}
static const struct regulator_ops gpio_regulator_voltage_ops = {
.get_voltage = gpio_regulator_get_value,
.set_voltage = gpio_regulator_set_voltage,
.list_voltage = gpio_regulator_list_voltage,
};
static struct gpio_regulator_config *
of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
const struct regulator_desc *desc)
{
struct gpio_regulator_config *config;
const char *regtype;
int proplen, i;
int ngpios;
int ret;
config = devm_kzalloc(dev,
sizeof(struct gpio_regulator_config),
GFP_KERNEL);
if (!config)
return ERR_PTR(-ENOMEM);
config->init_data = of_get_regulator_init_data(dev, np, desc);
if (!config->init_data)
return ERR_PTR(-EINVAL);
config->supply_name = config->init_data->constraints.name;
if (config->init_data->constraints.boot_on)
config->enabled_at_boot = true;
/*
* Do not use: undocumented device tree property.
* This is kept around solely for device tree ABI stability.
*/
if (of_property_read_bool(np, "enable-at-boot"))
config->enabled_at_boot = true;
of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
/* Fetch GPIO init levels */
ngpios = gpiod_count(dev, NULL);
if (ngpios > 0) {
config->gflags = devm_kzalloc(dev,
sizeof(enum gpiod_flags)
* ngpios,
GFP_KERNEL);
if (!config->gflags)
return ERR_PTR(-ENOMEM);
for (i = 0; i < ngpios; i++) {
u32 val;
ret = of_property_read_u32_index(np, "gpios-states", i,
&val);
/* Default to high per specification */
if (ret)
config->gflags[i] = GPIOD_OUT_HIGH;
else
config->gflags[i] =
val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
}
}
config->ngpios = ngpios;
/* Fetch states. */
proplen = of_property_count_u32_elems(np, "states");
if (proplen < 0) {
dev_err(dev, "No 'states' property found\n");
return ERR_PTR(-EINVAL);
}
config->states = devm_kcalloc(dev,
proplen / 2,
sizeof(struct gpio_regulator_state),
GFP_KERNEL);
if (!config->states)
return ERR_PTR(-ENOMEM);
for (i = 0; i < proplen / 2; i++) {
of_property_read_u32_index(np, "states", i * 2,
&config->states[i].value);
of_property_read_u32_index(np, "states", i * 2 + 1,
&config->states[i].gpios);
}
config->nr_states = i;
config->type = REGULATOR_VOLTAGE;
ret = of_property_read_string(np, "regulator-type", &regtype);
if (ret >= 0) {
if (!strncmp("voltage", regtype, 7))
config->type = REGULATOR_VOLTAGE;
else if (!strncmp("current", regtype, 7))
config->type = REGULATOR_CURRENT;
else
dev_warn(dev, "Unknown regulator-type '%s'\n",
regtype);
}
if (of_property_present(np, "vin-supply"))
config->input_supply = "vin";
return config;
}
static const struct regulator_ops gpio_regulator_current_ops = {
.get_current_limit = gpio_regulator_get_value,
.set_current_limit = gpio_regulator_set_current_limit,
};
static int gpio_regulator_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct gpio_regulator_config *config = dev_get_platdata(dev);
struct device_node *np = dev->of_node;
struct gpio_regulator_data *drvdata;
struct regulator_config cfg = { };
struct regulator_dev *rdev;
enum gpiod_flags gflags;
int ptr, ret, state, i;
drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
GFP_KERNEL);
if (drvdata == NULL)
return -ENOMEM;
if (np) {
config = of_get_gpio_regulator_config(dev, np,
&drvdata->desc);
if (IS_ERR(config))
return PTR_ERR(config);
}
drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
if (drvdata->desc.name == NULL) {
dev_err(dev, "Failed to allocate supply name\n");
return -ENOMEM;
}
drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
GFP_KERNEL);
if (config->input_supply) {
drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
config->input_supply,
GFP_KERNEL);
if (!drvdata->desc.supply_name) {
dev_err(&pdev->dev,
"Failed to allocate input supply\n");
return -ENOMEM;
}
}
if (!drvdata->gpiods)
return -ENOMEM;
for (i = 0; i < config->ngpios; i++) {
drvdata->gpiods[i] = devm_gpiod_get_index(dev,
NULL,
i,
config->gflags[i]);
if (IS_ERR(drvdata->gpiods[i]))
return PTR_ERR(drvdata->gpiods[i]);
/* This is good to know */
gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
}
drvdata->nr_gpios = config->ngpios;
drvdata->states = devm_kmemdup(dev,
config->states,
config->nr_states *
sizeof(struct gpio_regulator_state),
GFP_KERNEL);
if (drvdata->states == NULL) {
dev_err(dev, "Failed to allocate state data\n");
return -ENOMEM;
}
drvdata->nr_states = config->nr_states;
drvdata->desc.owner = THIS_MODULE;
drvdata->desc.enable_time = config->startup_delay;
/* handle regulator type*/
switch (config->type) {
case REGULATOR_VOLTAGE:
drvdata->desc.type = REGULATOR_VOLTAGE;
drvdata->desc.ops = &gpio_regulator_voltage_ops;
drvdata->desc.n_voltages = config->nr_states;
break;
case REGULATOR_CURRENT:
drvdata->desc.type = REGULATOR_CURRENT;
drvdata->desc.ops = &gpio_regulator_current_ops;
break;
default:
dev_err(dev, "No regulator type set\n");
return -EINVAL;
}
/* build initial state from gpio init data. */
state = 0;
for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
if (config->gflags[ptr] == GPIOD_OUT_HIGH)
state |= (1 << ptr);
}
drvdata->state = state;
cfg.dev = dev;
cfg.init_data = config->init_data;
cfg.driver_data = drvdata;
cfg.of_node = np;
/*
* The signal will be inverted by the GPIO core if flagged so in the
* descriptor.
*/
if (config->enabled_at_boot)
gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
else
gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
if (IS_ERR(cfg.ena_gpiod))
return PTR_ERR(cfg.ena_gpiod);
rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
if (IS_ERR(rdev)) {
ret = PTR_ERR(rdev);
dev_err(dev, "Failed to register regulator: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, drvdata);
return 0;
}
#if defined(CONFIG_OF)
static const struct of_device_id regulator_gpio_of_match[] = {
{ .compatible = "regulator-gpio", },
{},
};
MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
#endif
static struct platform_driver gpio_regulator_driver = {
.probe = gpio_regulator_probe,
.driver = {
.name = "gpio-regulator",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(regulator_gpio_of_match),
},
};
static int __init gpio_regulator_init(void)
{
return platform_driver_register(&gpio_regulator_driver);
}
subsys_initcall(gpio_regulator_init);
static void __exit gpio_regulator_exit(void)
{
platform_driver_unregister(&gpio_regulator_driver);
}
module_exit(gpio_regulator_exit);
MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
MODULE_DESCRIPTION("gpio voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-regulator");