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linux/drivers/regulator/ltc3676.c
Marek Vasut d2a66ddfe8
regulator: ltc3676: Assure PGOOD mask is set before changing voltage 
Make sure the DVBxB bit 5, PGOOD mask, is set before changing voltage
on the buck converters. If the PGOOD mask bit is not set, the PMIC may
deassert the PGOOD signal during the voltage transition.

On systems that use the PGOOD signal as a power OK indication for the
board or SoC, which should be the case on correct designs, deasserting
the PGOOD signal will lead to system reset or shutdown, which is not
the expected behavior when changing PMIC buck converter voltage.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-05-02 06:00:20 +09:00

446 lines
12 KiB
C
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/*
* Copyright (C) 2016 Gateworks Corporation, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#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 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_writeable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTC3676_IRQSTAT:
case LTC3676_BUCK1:
case LTC3676_BUCK2:
case LTC3676_BUCK3:
case LTC3676_BUCK4:
case LTC3676_LDOA:
case LTC3676_LDOB:
case LTC3676_SQD1:
case LTC3676_SQD2:
case LTC3676_CNTRL:
case LTC3676_DVB1A:
case LTC3676_DVB1B:
case LTC3676_DVB2A:
case LTC3676_DVB2B:
case LTC3676_DVB3A:
case LTC3676_DVB3B:
case LTC3676_DVB4A:
case LTC3676_DVB4B:
case LTC3676_MSKIRQ:
case LTC3676_MSKPG:
case LTC3676_USER:
case LTC3676_HRST:
case LTC3676_CLIRQ:
return true;
}
return false;
}
static bool ltc3676_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case LTC3676_IRQSTAT:
case LTC3676_BUCK1:
case LTC3676_BUCK2:
case LTC3676_BUCK3:
case LTC3676_BUCK4:
case LTC3676_LDOA:
case LTC3676_LDOB:
case LTC3676_SQD1:
case LTC3676_SQD2:
case LTC3676_CNTRL:
case LTC3676_DVB1A:
case LTC3676_DVB1B:
case LTC3676_DVB2A:
case LTC3676_DVB2B:
case LTC3676_DVB3A:
case LTC3676_DVB3B:
case LTC3676_DVB4A:
case LTC3676_DVB4B:
case LTC3676_MSKIRQ:
case LTC3676_MSKPG:
case LTC3676_USER:
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:
case LTC3676_PGSTATL:
case LTC3676_PGSTATRT:
return true;
}
return false;
}
static const struct regmap_config ltc3676_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.writeable_reg = ltc3676_writeable_reg,
.readable_reg = ltc3676_readable_reg,
.volatile_reg = ltc3676_volatile_reg,
.max_register = LTC3676_CLIRQ,
.use_single_rw = 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,
const struct i2c_device_id *id)
{
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 ltc3676_of_match[] = {
{ .compatible = "lltc,ltc3676" },
{ },
};
MODULE_DEVICE_TABLE(of, ltc3676_of_match);
static struct i2c_driver ltc3676_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = of_match_ptr(ltc3676_of_match),
},
.probe = 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 LTC1376");
MODULE_LICENSE("GPL v2");
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