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linux/drivers/regulator/ltc3676.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

385 lines
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C
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
*/
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#define DRIVER_NAME "ltc3676"
/* LTC3676 Registers */
#define LTC3676_BUCK1 0x01
#define LTC3676_BUCK2 0x02
#define LTC3676_BUCK3 0x03
#define LTC3676_BUCK4 0x04
#define LTC3676_LDOA 0x05
#define LTC3676_LDOB 0x06
#define LTC3676_SQD1 0x07
#define LTC3676_SQD2 0x08
#define LTC3676_CNTRL 0x09
#define LTC3676_DVB1A 0x0A
#define LTC3676_DVB1B 0x0B
#define LTC3676_DVB2A 0x0C
#define LTC3676_DVB2B 0x0D
#define LTC3676_DVB3A 0x0E
#define LTC3676_DVB3B 0x0F
#define LTC3676_DVB4A 0x10
#define LTC3676_DVB4B 0x11
#define LTC3676_MSKIRQ 0x12
#define LTC3676_MSKPG 0x13
#define LTC3676_USER 0x14
#define LTC3676_IRQSTAT 0x15
#define LTC3676_PGSTATL 0x16
#define LTC3676_PGSTATRT 0x17
#define LTC3676_HRST 0x1E
#define LTC3676_CLIRQ 0x1F
#define LTC3676_DVBxA_REF_SELECT BIT(5)
#define LTC3676_DVBxB_PGOOD_MASK BIT(5)
#define LTC3676_IRQSTAT_PGOOD_TIMEOUT BIT(3)
#define LTC3676_IRQSTAT_UNDERVOLT_WARN BIT(4)
#define LTC3676_IRQSTAT_UNDERVOLT_FAULT BIT(5)
#define LTC3676_IRQSTAT_THERMAL_WARN BIT(6)
#define LTC3676_IRQSTAT_THERMAL_FAULT BIT(7)
enum ltc3676_reg {
LTC3676_SW1,
LTC3676_SW2,
LTC3676_SW3,
LTC3676_SW4,
LTC3676_LDO1,
LTC3676_LDO2,
LTC3676_LDO3,
LTC3676_LDO4,
LTC3676_NUM_REGULATORS,
};
struct ltc3676 {
struct regmap *regmap;
struct device *dev;
struct regulator_desc regulator_descs[LTC3676_NUM_REGULATORS];
struct regulator_dev *regulators[LTC3676_NUM_REGULATORS];
};
static int ltc3676_set_suspend_voltage(struct regulator_dev *rdev, int uV)
{
struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
struct device *dev = ltc3676->dev;
int dcdc = rdev_get_id(rdev);
int sel;
dev_dbg(dev, "%s id=%d uV=%d\n", __func__, dcdc, uV);
sel = regulator_map_voltage_linear(rdev, uV, uV);
if (sel < 0)
return sel;
/* DVBB register follows right after the corresponding DVBA register */
return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
rdev->desc->vsel_mask, sel);
}
static int ltc3676_set_suspend_mode(struct regulator_dev *rdev,
unsigned int mode)
{
struct ltc3676 *ltc3676= rdev_get_drvdata(rdev);
struct device *dev = ltc3676->dev;
int mask, val;
int dcdc = rdev_get_id(rdev);
dev_dbg(dev, "%s id=%d mode=%d\n", __func__, dcdc, mode);
mask = LTC3676_DVBxA_REF_SELECT;
switch (mode) {
case REGULATOR_MODE_STANDBY:
val = 0; /* select DVBxA */
break;
case REGULATOR_MODE_NORMAL:
val = LTC3676_DVBxA_REF_SELECT; /* select DVBxB */
break;
default:
dev_warn(&rdev->dev, "%s: regulator mode: 0x%x not supported\n",
rdev->desc->name, mode);
return -EINVAL;
}
return regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg,
mask, val);
}
static int ltc3676_set_voltage_sel(struct regulator_dev *rdev, unsigned selector)
{
struct ltc3676 *ltc3676 = rdev_get_drvdata(rdev);
struct device *dev = ltc3676->dev;
int ret, dcdc = rdev_get_id(rdev);
dev_dbg(dev, "%s id=%d selector=%d\n", __func__, dcdc, selector);
ret = regmap_update_bits(ltc3676->regmap, rdev->desc->vsel_reg + 1,
LTC3676_DVBxB_PGOOD_MASK,
LTC3676_DVBxB_PGOOD_MASK);
if (ret)
return ret;
return regulator_set_voltage_sel_regmap(rdev, selector);
}
static inline unsigned int ltc3676_scale(unsigned int uV, u32 r1, u32 r2)
{
uint64_t tmp;
if (uV == 0)
return 0;
tmp = (uint64_t)uV * r1;
do_div(tmp, r2);
return uV + (unsigned int)tmp;
}
static int ltc3676_of_parse_cb(struct device_node *np,
const struct regulator_desc *desc,
struct regulator_config *config)
{
struct ltc3676 *ltc3676 = config->driver_data;
struct regulator_desc *rdesc = &ltc3676->regulator_descs[desc->id];
u32 r[2];
int ret;
/* LDO3 has a fixed output */
if (desc->id == LTC3676_LDO3)
return 0;
ret = of_property_read_u32_array(np, "lltc,fb-voltage-divider", r, 2);
if (ret) {
dev_err(ltc3676->dev, "Failed to parse voltage divider: %d\n",
ret);
return ret;
}
rdesc->min_uV = ltc3676_scale(desc->min_uV, r[0], r[1]);
rdesc->uV_step = ltc3676_scale(desc->uV_step, r[0], r[1]);
rdesc->fixed_uV = ltc3676_scale(desc->fixed_uV, r[0], r[1]);
return 0;
}
/* SW1, SW2, SW3, SW4 linear 0.8V-3.3V with scalar via R1/R2 feeback res */
static const struct regulator_ops ltc3676_linear_regulator_ops = {
.enable = regulator_enable_regmap,
.disable = regulator_disable_regmap,
.is_enabled = regulator_is_enabled_regmap,
.list_voltage = regulator_list_voltage_linear,
.set_voltage_sel = ltc3676_set_voltage_sel,
.get_voltage_sel = regulator_get_voltage_sel_regmap,
.set_suspend_voltage = ltc3676_set_suspend_voltage,
.set_suspend_mode = ltc3676_set_suspend_mode,
};
/* LDO1 always on fixed 0.8V-3.3V via scalar via R1/R2 feeback res */
static const struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
};
/* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
static const struct regulator_ops ltc3676_fixed_regulator_ops = {
.enable = regulator_enable_regmap,
.disable = regulator_disable_regmap,
.is_enabled = regulator_is_enabled_regmap,
};
#define LTC3676_REG(_id, _name, _ops, en_reg, en_bit, dvba_reg, dvb_mask) \
[LTC3676_ ## _id] = { \
.name = #_name, \
.of_match = of_match_ptr(#_name), \
.regulators_node = of_match_ptr("regulators"), \
.of_parse_cb = ltc3676_of_parse_cb, \
.n_voltages = (dvb_mask) + 1, \
.min_uV = (dvba_reg) ? 412500 : 0, \
.uV_step = (dvba_reg) ? 12500 : 0, \
.ramp_delay = (dvba_reg) ? 800 : 0, \
.fixed_uV = (dvb_mask) ? 0 : 725000, \
.ops = &ltc3676_ ## _ops ## _regulator_ops, \
.type = REGULATOR_VOLTAGE, \
.id = LTC3676_ ## _id, \
.owner = THIS_MODULE, \
.vsel_reg = (dvba_reg), \
.vsel_mask = (dvb_mask), \
.enable_reg = (en_reg), \
.enable_mask = (1 << en_bit), \
}
#define LTC3676_LINEAR_REG(_id, _name, _en, _dvba) \
LTC3676_REG(_id, _name, linear, \
LTC3676_ ## _en, 7, \
LTC3676_ ## _dvba, 0x1f)
#define LTC3676_FIXED_REG(_id, _name, _en_reg, _en_bit) \
LTC3676_REG(_id, _name, fixed, LTC3676_ ## _en_reg, _en_bit, 0, 0)
static const struct regulator_desc ltc3676_regulators[LTC3676_NUM_REGULATORS] = {
LTC3676_LINEAR_REG(SW1, sw1, BUCK1, DVB1A),
LTC3676_LINEAR_REG(SW2, sw2, BUCK2, DVB2A),
LTC3676_LINEAR_REG(SW3, sw3, BUCK3, DVB3A),
LTC3676_LINEAR_REG(SW4, sw4, BUCK4, DVB4A),
LTC3676_REG(LDO1, ldo1, fixed_standby, 0, 0, 0, 0),
LTC3676_FIXED_REG(LDO2, ldo2, LDOA, 2),
LTC3676_FIXED_REG(LDO3, ldo3, LDOA, 5),
LTC3676_FIXED_REG(LDO4, ldo4, LDOB, 2),
};
static bool ltc3676_readable_writeable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTC3676_BUCK1 ... LTC3676_IRQSTAT:
case LTC3676_HRST:
case LTC3676_CLIRQ:
return true;
}
return false;
}
static bool ltc3676_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTC3676_IRQSTAT ... LTC3676_PGSTATRT:
return true;
}
return false;
}
static const struct regmap_config ltc3676_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.writeable_reg = ltc3676_readable_writeable_reg,
.readable_reg = ltc3676_readable_writeable_reg,
.volatile_reg = ltc3676_volatile_reg,
.max_register = LTC3676_CLIRQ,
.use_single_read = true,
.use_single_write = true,
.cache_type = REGCACHE_RBTREE,
};
static irqreturn_t ltc3676_isr(int irq, void *dev_id)
{
struct ltc3676 *ltc3676 = dev_id;
struct device *dev = ltc3676->dev;
unsigned int i, irqstat, event;
regmap_read(ltc3676->regmap, LTC3676_IRQSTAT, &irqstat);
dev_dbg(dev, "irq%d irqstat=0x%02x\n", irq, irqstat);
if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) {
dev_warn(dev, "Over-temperature Warning\n");
event = REGULATOR_EVENT_OVER_TEMP;
for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
regulator_notifier_call_chain(ltc3676->regulators[i],
event, NULL);
}
if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) {
dev_info(dev, "Undervoltage Warning\n");
event = REGULATOR_EVENT_UNDER_VOLTAGE;
for (i = 0; i < LTC3676_NUM_REGULATORS; i++)
regulator_notifier_call_chain(ltc3676->regulators[i],
event, NULL);
}
/* Clear warning condition */
regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
return IRQ_HANDLED;
}
static int ltc3676_regulator_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct regulator_init_data *init_data = dev_get_platdata(dev);
struct regulator_desc *descs;
struct ltc3676 *ltc3676;
int i, ret;
ltc3676 = devm_kzalloc(dev, sizeof(*ltc3676), GFP_KERNEL);
if (!ltc3676)
return -ENOMEM;
i2c_set_clientdata(client, ltc3676);
ltc3676->dev = dev;
descs = ltc3676->regulator_descs;
memcpy(descs, ltc3676_regulators, sizeof(ltc3676_regulators));
descs[LTC3676_LDO3].fixed_uV = 1800000; /* LDO3 is fixed 1.8V */
ltc3676->regmap = devm_regmap_init_i2c(client, &ltc3676_regmap_config);
if (IS_ERR(ltc3676->regmap)) {
ret = PTR_ERR(ltc3676->regmap);
dev_err(dev, "failed to initialize regmap: %d\n", ret);
return ret;
}
for (i = 0; i < LTC3676_NUM_REGULATORS; i++) {
struct regulator_desc *desc = &ltc3676->regulator_descs[i];
struct regulator_config config = { };
if (init_data)
config.init_data = &init_data[i];
config.dev = dev;
config.driver_data = ltc3676;
ltc3676->regulators[i] = devm_regulator_register(dev, desc,
&config);
if (IS_ERR(ltc3676->regulators[i])) {
ret = PTR_ERR(ltc3676->regulators[i]);
dev_err(dev, "failed to register regulator %s: %d\n",
desc->name, ret);
return ret;
}
}
regmap_write(ltc3676->regmap, LTC3676_CLIRQ, 0);
if (client->irq) {
ret = devm_request_threaded_irq(dev, client->irq, NULL,
ltc3676_isr,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
client->name, ltc3676);
if (ret) {
dev_err(dev, "Failed to request IRQ: %d\n", ret);
return ret;
}
}
return 0;
}
static const struct i2c_device_id ltc3676_i2c_id[] = {
{ "ltc3676" },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc3676_i2c_id);
static const struct of_device_id __maybe_unused ltc3676_of_match[] = {
{ .compatible = "lltc,ltc3676" },
{ },
};
MODULE_DEVICE_TABLE(of, ltc3676_of_match);
static struct i2c_driver ltc3676_driver = {
.driver = {
.name = DRIVER_NAME,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(ltc3676_of_match),
},
.probe_new = ltc3676_regulator_probe,
.id_table = ltc3676_i2c_id,
};
module_i2c_driver(ltc3676_driver);
MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
MODULE_DESCRIPTION("Regulator driver for Linear Technology LTC3676");
MODULE_LICENSE("GPL v2");
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