linux/drivers/regulator/fixed.c
Linus Walleij b0ce7b29bf
regulator/gpio: Allow nonexclusive GPIO access
This allows nonexclusive (simultaneous) access to a single
GPIO line for the fixed regulator enable line. This happens
when several regulators use the same GPIO for enabling and
disabling a regulator, and all need a handle on their GPIO
descriptor.

This solution with a special flag is not entirely elegant
and should ideally be replaced by something more careful as
this makes it possible for several consumers to
enable/disable the same GPIO line to the left and right
without any consistency. The current use inside the regulator
core should however be fine as it takes special care to
handle this.

For the state of the GPIO backend, this is still the
lesser evil compared to going back to global GPIO
numbers.

Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Fixes: efdfeb079c ("regulator: fixed: Convert to use GPIO descriptor only")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-10-12 18:55:02 +02:00

243 lines
6.5 KiB
C

/*
* 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 program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* 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/regulator/of_regulator.h>
#include <linux/regulator/machine.h>
struct fixed_voltage_data {
struct regulator_desc desc;
struct regulator_dev *dev;
};
/**
* 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);
/*
* FIXME: we pulled active low/high and open drain handling into
* gpiolib so it will be handled there. Delete this in the second
* step when we also remove the custom inversion handling for all
* legacy boardfiles.
*/
config->enable_high = 1;
config->gpio_is_open_drain = 0;
if (of_find_property(np, "vin-supply", NULL))
config->input_supply = "vin";
return config;
}
static struct regulator_ops fixed_voltage_ops = {
};
static int reg_fixed_voltage_probe(struct platform_device *pdev)
{
struct fixed_voltage_config *config;
struct fixed_voltage_data *drvdata;
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;
drvdata->desc.ops = &fixed_voltage_ops;
drvdata->desc.enable_time = config->startup_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;
cfg.ena_gpio_invert = !config->enable_high;
if (config->enabled_at_boot) {
if (config->enable_high)
gflags = GPIOD_OUT_HIGH;
else
gflags = GPIOD_OUT_LOW;
} else {
if (config->enable_high)
gflags = GPIOD_OUT_LOW;
else
gflags = GPIOD_OUT_HIGH;
}
if (config->gpio_is_open_drain) {
if (gflags == GPIOD_OUT_HIGH)
gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
else
gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
}
/*
* 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;
cfg.ena_gpiod = devm_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", },
{},
};
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");