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linux-next/drivers/regulator/ltc3676.c
Tim Harvey 37b918a034 regulator: Add LTC3676 support 
This patch adds support for the Linear Technology LTC3676
8-output I2C voltage regulator IC.

Cc: Jaffer Kapasi <jkapasi@linear.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-08-16 12:28:00 +01:00

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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_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 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 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 = regulator_set_voltage_sel_regmap,
.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 struct regulator_ops ltc3676_fixed_standby_regulator_ops = {
};
/* LDO2, LDO3 fixed (LDO2 has external scalar via R1/R2 feedback res) */
static 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 struct i2c_driver ltc3676_driver = {
.driver = {
.name = DRIVER_NAME,
},
.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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