linux/drivers/regulator/fixed.c
Peng Fan f7907e57ae
regulator: fixed: add off-on-delay
Depends on board design, the gpio controlling regulator may
connects with a big capacitance. When need off, it takes some time
to let the regulator to be truly off. If not add enough delay, the
regulator might have always been on, so introduce off-on-delay to
handle such case.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1572311875-22880-3-git-send-email-peng.fan@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2019-10-29 12:32:12 +00:00

302 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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/fixed.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/machine.h>
#include <linux/clk.h>
struct fixed_voltage_data {
struct regulator_desc desc;
struct regulator_dev *dev;
struct clk *enable_clock;
unsigned int clk_enable_counter;
};
struct fixed_dev_type {
bool has_enable_clock;
};
static const struct fixed_dev_type fixed_voltage_data = {
.has_enable_clock = false,
};
static const struct fixed_dev_type fixed_clkenable_data = {
.has_enable_clock = true,
};
static int reg_clock_enable(struct regulator_dev *rdev)
{
struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
int ret = 0;
ret = clk_prepare_enable(priv->enable_clock);
if (ret)
return ret;
priv->clk_enable_counter++;
return ret;
}
static int reg_clock_disable(struct regulator_dev *rdev)
{
struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
clk_disable_unprepare(priv->enable_clock);
priv->clk_enable_counter--;
return 0;
}
static int reg_clock_is_enabled(struct regulator_dev *rdev)
{
struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
return priv->clk_enable_counter > 0;
}
/**
* of_get_fixed_voltage_config - extract fixed_voltage_config structure info
* @dev: device requesting for fixed_voltage_config
* @desc: regulator description
*
* Populates fixed_voltage_config structure by extracting data from device
* tree node, returns a pointer to the populated structure of NULL if memory
* alloc fails.
*/
static struct fixed_voltage_config *
of_get_fixed_voltage_config(struct device *dev,
const struct regulator_desc *desc)
{
struct fixed_voltage_config *config;
struct device_node *np = dev->of_node;
struct regulator_init_data *init_data;
config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
GFP_KERNEL);
if (!config)
return ERR_PTR(-ENOMEM);
config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
if (!config->init_data)
return ERR_PTR(-EINVAL);
init_data = config->init_data;
init_data->constraints.apply_uV = 0;
config->supply_name = init_data->constraints.name;
if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
config->microvolts = init_data->constraints.min_uV;
} else {
dev_err(dev,
"Fixed regulator specified with variable voltages\n");
return ERR_PTR(-EINVAL);
}
if (init_data->constraints.boot_on)
config->enabled_at_boot = true;
of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
of_property_read_u32(np, "off-on-delay-us", &config->off_on_delay);
if (of_find_property(np, "vin-supply", NULL))
config->input_supply = "vin";
return config;
}
static struct regulator_ops fixed_voltage_ops = {
};
static struct regulator_ops fixed_voltage_clkenabled_ops = {
.enable = reg_clock_enable,
.disable = reg_clock_disable,
.is_enabled = reg_clock_is_enabled,
};
static int reg_fixed_voltage_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct fixed_voltage_config *config;
struct fixed_voltage_data *drvdata;
const struct fixed_dev_type *drvtype = of_device_get_match_data(dev);
struct regulator_config cfg = { };
enum gpiod_flags gflags;
int ret;
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
if (pdev->dev.of_node) {
config = of_get_fixed_voltage_config(&pdev->dev,
&drvdata->desc);
if (IS_ERR(config))
return PTR_ERR(config);
} else {
config = dev_get_platdata(&pdev->dev);
}
if (!config)
return -ENOMEM;
drvdata->desc.name = devm_kstrdup(&pdev->dev,
config->supply_name,
GFP_KERNEL);
if (drvdata->desc.name == NULL) {
dev_err(&pdev->dev, "Failed to allocate supply name\n");
return -ENOMEM;
}
drvdata->desc.type = REGULATOR_VOLTAGE;
drvdata->desc.owner = THIS_MODULE;
if (drvtype && drvtype->has_enable_clock) {
drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
drvdata->enable_clock = devm_clk_get(dev, NULL);
if (IS_ERR(drvdata->enable_clock)) {
dev_err(dev, "Cant get enable-clock from devicetree\n");
return -ENOENT;
}
} else {
drvdata->desc.ops = &fixed_voltage_ops;
}
drvdata->desc.enable_time = config->startup_delay;
drvdata->desc.off_on_delay = config->off_on_delay;
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 (config->microvolts)
drvdata->desc.n_voltages = 1;
drvdata->desc.fixed_uV = config->microvolts;
/*
* The signal will be inverted by the GPIO core if flagged so in the
* decriptor.
*/
if (config->enabled_at_boot)
gflags = GPIOD_OUT_HIGH;
else
gflags = GPIOD_OUT_LOW;
/*
* Some fixed regulators share the enable line between two
* regulators which makes it necessary to get a handle on the
* same descriptor for two different consumers. This will get
* the GPIO descriptor, but only the first call will initialize
* it so any flags such as inversion or open drain will only
* be set up by the first caller and assumed identical on the
* next caller.
*
* FIXME: find a better way to deal with this.
*/
gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
/*
* Do not use devm* here: the regulator core takes over the
* lifecycle management of the GPIO descriptor.
*/
cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags);
if (IS_ERR(cfg.ena_gpiod))
return PTR_ERR(cfg.ena_gpiod);
cfg.dev = &pdev->dev;
cfg.init_data = config->init_data;
cfg.driver_data = drvdata;
cfg.of_node = pdev->dev.of_node;
drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
&cfg);
if (IS_ERR(drvdata->dev)) {
ret = PTR_ERR(drvdata->dev);
dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, drvdata);
dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
drvdata->desc.fixed_uV);
return 0;
}
#if defined(CONFIG_OF)
static const struct of_device_id fixed_of_match[] = {
{
.compatible = "regulator-fixed",
.data = &fixed_voltage_data,
},
{
.compatible = "regulator-fixed-clock",
.data = &fixed_clkenable_data,
},
{
},
};
MODULE_DEVICE_TABLE(of, fixed_of_match);
#endif
static struct platform_driver regulator_fixed_voltage_driver = {
.probe = reg_fixed_voltage_probe,
.driver = {
.name = "reg-fixed-voltage",
.of_match_table = of_match_ptr(fixed_of_match),
},
};
static int __init regulator_fixed_voltage_init(void)
{
return platform_driver_register(&regulator_fixed_voltage_driver);
}
subsys_initcall(regulator_fixed_voltage_init);
static void __exit regulator_fixed_voltage_exit(void)
{
platform_driver_unregister(&regulator_fixed_voltage_driver);
}
module_exit(regulator_fixed_voltage_exit);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("Fixed voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:reg-fixed-voltage");