linux/drivers/regulator/aat2870-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

202 lines
5.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/regulator/aat2870-regulator.c
*
* Copyright (c) 2011, NVIDIA Corporation.
* Author: Jin Park <jinyoungp@nvidia.com>
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/mfd/aat2870.h>
struct aat2870_regulator {
struct aat2870_data *aat2870;
struct regulator_desc desc;
u8 enable_addr;
u8 enable_shift;
u8 enable_mask;
u8 voltage_addr;
u8 voltage_shift;
u8 voltage_mask;
};
static int aat2870_ldo_set_voltage_sel(struct regulator_dev *rdev,
unsigned selector)
{
struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
struct aat2870_data *aat2870 = ri->aat2870;
return aat2870->update(aat2870, ri->voltage_addr, ri->voltage_mask,
selector << ri->voltage_shift);
}
static int aat2870_ldo_get_voltage_sel(struct regulator_dev *rdev)
{
struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
struct aat2870_data *aat2870 = ri->aat2870;
u8 val;
int ret;
ret = aat2870->read(aat2870, ri->voltage_addr, &val);
if (ret)
return ret;
return (val & ri->voltage_mask) >> ri->voltage_shift;
}
static int aat2870_ldo_enable(struct regulator_dev *rdev)
{
struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
struct aat2870_data *aat2870 = ri->aat2870;
return aat2870->update(aat2870, ri->enable_addr, ri->enable_mask,
ri->enable_mask);
}
static int aat2870_ldo_disable(struct regulator_dev *rdev)
{
struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
struct aat2870_data *aat2870 = ri->aat2870;
return aat2870->update(aat2870, ri->enable_addr, ri->enable_mask, 0);
}
static int aat2870_ldo_is_enabled(struct regulator_dev *rdev)
{
struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
struct aat2870_data *aat2870 = ri->aat2870;
u8 val;
int ret;
ret = aat2870->read(aat2870, ri->enable_addr, &val);
if (ret)
return ret;
return val & ri->enable_mask ? 1 : 0;
}
static const struct regulator_ops aat2870_ldo_ops = {
.list_voltage = regulator_list_voltage_table,
.map_voltage = regulator_map_voltage_ascend,
.set_voltage_sel = aat2870_ldo_set_voltage_sel,
.get_voltage_sel = aat2870_ldo_get_voltage_sel,
.enable = aat2870_ldo_enable,
.disable = aat2870_ldo_disable,
.is_enabled = aat2870_ldo_is_enabled,
};
static const unsigned int aat2870_ldo_voltages[] = {
1200000, 1300000, 1500000, 1600000,
1800000, 2000000, 2200000, 2500000,
2600000, 2700000, 2800000, 2900000,
3000000, 3100000, 3200000, 3300000,
};
#define AAT2870_LDO(ids) \
{ \
.desc = { \
.name = #ids, \
.id = AAT2870_ID_##ids, \
.n_voltages = ARRAY_SIZE(aat2870_ldo_voltages), \
.volt_table = aat2870_ldo_voltages, \
.ops = &aat2870_ldo_ops, \
.type = REGULATOR_VOLTAGE, \
.owner = THIS_MODULE, \
}, \
}
static struct aat2870_regulator aat2870_regulators[] = {
AAT2870_LDO(LDOA),
AAT2870_LDO(LDOB),
AAT2870_LDO(LDOC),
AAT2870_LDO(LDOD),
};
static struct aat2870_regulator *aat2870_get_regulator(int id)
{
struct aat2870_regulator *ri = NULL;
int i;
for (i = 0; i < ARRAY_SIZE(aat2870_regulators); i++) {
ri = &aat2870_regulators[i];
if (ri->desc.id == id)
break;
}
if (i == ARRAY_SIZE(aat2870_regulators))
return NULL;
ri->enable_addr = AAT2870_LDO_EN;
ri->enable_shift = id - AAT2870_ID_LDOA;
ri->enable_mask = 0x1 << ri->enable_shift;
ri->voltage_addr = (id - AAT2870_ID_LDOA) / 2 ?
AAT2870_LDO_CD : AAT2870_LDO_AB;
ri->voltage_shift = (id - AAT2870_ID_LDOA) % 2 ? 0 : 4;
ri->voltage_mask = 0xF << ri->voltage_shift;
return ri;
}
static int aat2870_regulator_probe(struct platform_device *pdev)
{
struct aat2870_regulator *ri;
struct regulator_config config = { };
struct regulator_dev *rdev;
ri = aat2870_get_regulator(pdev->id);
if (!ri) {
dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
return -EINVAL;
}
ri->aat2870 = dev_get_drvdata(pdev->dev.parent);
config.dev = &pdev->dev;
config.driver_data = ri;
config.init_data = dev_get_platdata(&pdev->dev);
rdev = devm_regulator_register(&pdev->dev, &ri->desc, &config);
if (IS_ERR(rdev)) {
dev_err(&pdev->dev, "Failed to register regulator %s\n",
ri->desc.name);
return PTR_ERR(rdev);
}
platform_set_drvdata(pdev, rdev);
return 0;
}
static struct platform_driver aat2870_regulator_driver = {
.driver = {
.name = "aat2870-regulator",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
.probe = aat2870_regulator_probe,
};
static int __init aat2870_regulator_init(void)
{
return platform_driver_register(&aat2870_regulator_driver);
}
subsys_initcall(aat2870_regulator_init);
static void __exit aat2870_regulator_exit(void)
{
platform_driver_unregister(&aat2870_regulator_driver);
}
module_exit(aat2870_regulator_exit);
MODULE_DESCRIPTION("AnalogicTech AAT2870 Regulator");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
MODULE_ALIAS("platform:aat2870-regulator");