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// SPDX-License-Identifier: GPL-2.0+
/*
* mp5926.c - pmbus driver for mps mp5926
*
* Copyright 2025 Monolithic Power Systems, Inc
*
* Author: Yuxi Wang <Yuxi.Wang@monolithicpower.com>
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pmbus.h>
#include "pmbus.h"
#define PAGE 0x01
#define EFUSE_CFG 0xCF
#define I_SCALE_SEL 0xC6
#define MP5926_FUNC (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
PMBUS_HAVE_IIN | PMBUS_HAVE_PIN | \
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_INPUT | \
PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_VOUT)
struct mp5926_data {
struct pmbus_driver_info info;
u8 vout_mode;
u8 vout_linear_exponent;
};
#define to_mp5926_data(x) container_of(x, struct mp5926_data, info)
static int mp5926_read_byte_data(struct i2c_client *client, int page,
int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct mp5926_data *data = to_mp5926_data(info);
int ret;
switch (reg) {
case PMBUS_VOUT_MODE:
if (data->vout_mode == linear) {
/*
* The VOUT format used by the chip is linear11,
* not linear16. Report that VOUT is in linear mode
* and return exponent value extracted while probing
* the chip.
*/
return data->vout_linear_exponent;
}
return PB_VOUT_MODE_DIRECT;
default:
ret = -ENODATA;
break;
}
return ret;
}
static int mp5926_read_word_data(struct i2c_client *client, int page, int phase,
int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct mp5926_data *data = to_mp5926_data(info);
int ret;
switch (reg) {
case PMBUS_READ_VOUT:
ret = pmbus_read_word_data(client, page, phase, reg);
if (ret < 0)
return ret;
/*
* Because the VOUT format used by the chip is linear11 and not
* linear16, we disregard bits[15:11]. The exponent is reported
* as part of the VOUT_MODE command.
*/
if (data->vout_mode == linear)
ret = ((s16)((ret & 0x7ff) << 5)) >> 5;
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static struct pmbus_driver_info mp5926_info = {
.pages = PAGE,
.format[PSC_VOLTAGE_IN] = direct,
.format[PSC_CURRENT_IN] = direct,
.format[PSC_VOLTAGE_OUT] = direct,
.format[PSC_TEMPERATURE] = direct,
.format[PSC_POWER] = direct,
.m[PSC_VOLTAGE_IN] = 16,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = 0,
.m[PSC_CURRENT_IN] = 16,
.b[PSC_CURRENT_IN] = 0,
.R[PSC_CURRENT_IN] = 0,
.m[PSC_VOLTAGE_OUT] = 16,
.b[PSC_VOLTAGE_OUT] = 0,
.R[PSC_VOLTAGE_OUT] = 0,
.m[PSC_TEMPERATURE] = 4,
.b[PSC_TEMPERATURE] = 0,
.R[PSC_TEMPERATURE] = 0,
.m[PSC_POWER] = 25,
.b[PSC_POWER] = 0,
.R[PSC_POWER] = -2,
.read_word_data = mp5926_read_word_data,
.read_byte_data = mp5926_read_byte_data,
.func[0] = MP5926_FUNC,
};
static int mp5926_probe(struct i2c_client *client)
{
struct mp5926_data *data;
struct pmbus_driver_info *info;
int ret;
data = devm_kzalloc(&client->dev, sizeof(struct mp5926_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
memcpy(&data->info, &mp5926_info, sizeof(*info));
info = &data->info;
ret = i2c_smbus_read_word_data(client, EFUSE_CFG);
if (ret < 0)
return ret;
if (ret & BIT(12)) {
data->vout_mode = linear;
data->info.format[PSC_VOLTAGE_IN] = linear;
data->info.format[PSC_CURRENT_IN] = linear;
data->info.format[PSC_VOLTAGE_OUT] = linear;
data->info.format[PSC_TEMPERATURE] = linear;
data->info.format[PSC_POWER] = linear;
ret = i2c_smbus_read_word_data(client, PMBUS_READ_VOUT);
if (ret < 0)
return dev_err_probe(&client->dev, ret, "Can't get vout exponent.");
data->vout_linear_exponent = (u8)((ret >> 11) & 0x1f);
} else {
data->vout_mode = direct;
ret = i2c_smbus_read_word_data(client, I_SCALE_SEL);
if (ret < 0)
return ret;
if (ret & BIT(6))
data->info.m[PSC_CURRENT_IN] = 4;
}
return pmbus_do_probe(client, info);
}
static const struct i2c_device_id mp5926_id[] = {
{ "mp5926", 0 },
{}
};
MODULE_DEVICE_TABLE(i2c, mp5926_id);
static const struct of_device_id mp5926_of_match[] = {
{ .compatible = "mps,mp5926" },
{}
};
MODULE_DEVICE_TABLE(of, mp5926_of_match);
static struct i2c_driver mp5926_driver = {
.probe = mp5926_probe,
.driver = {
.name = "mp5926",
.of_match_table = mp5926_of_match,
},
.id_table = mp5926_id,
};
module_i2c_driver(mp5926_driver);
MODULE_AUTHOR("Yuxi Wang <Yuxi.Wang@monolithicpower.com>");
MODULE_DESCRIPTION("MPS MP5926 pmbus driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");
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