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// SPDX-License-Identifier: GPL-2.0
/*
* Hardware monitoring driver for Analog Devices MAX20830
*
* Copyright (C) 2026 Analog Devices, Inc.
*/
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/string.h>
#include "pmbus.h"
#define MAX20830_IC_DEVICE_ID_LENGTH 9
static struct pmbus_driver_info max20830_info = {
.pages = 1,
.format[PSC_VOLTAGE_IN] = linear,
.format[PSC_VOLTAGE_OUT] = linear,
.format[PSC_CURRENT_OUT] = linear,
.format[PSC_TEMPERATURE] = linear,
.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
PMBUS_HAVE_TEMP |
PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
};
static int max20830_probe(struct i2c_client *client)
{
u8 buf[I2C_SMBUS_BLOCK_MAX + 1] = {};
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA) &&
!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -ENODEV;
/*
* Use i2c_smbus_read_block_data() if supported, otherwise fall back
* to i2c_smbus_read_i2c_block_data() to support I2C controllers
* which do not support SMBus block reads.
*/
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
/* Reads 9 Data bytes from MAX20830 */
ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to read IC_DEVICE_ID\n");
} else {
/* Reads 1 length byte + 9 Data bytes from MAX20830 */
ret = i2c_smbus_read_i2c_block_data(client, PMBUS_IC_DEVICE_ID,
MAX20830_IC_DEVICE_ID_LENGTH + 1,
buf);
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to read IC_DEVICE_ID\n");
/*
* Moves data forward, removing the length byte, this is to
* match the format of i2c_smbus_read_block_data().
* Also adjust return value to reflect length byte removal.
*/
memmove(buf, buf + 1, MAX20830_IC_DEVICE_ID_LENGTH);
ret = ret - 1;
}
/*
* MAX20830 IC_DEVICE_ID sends string data "MAX20830\0".
* Return value should at least be 9 bytes of data.
*/
if (ret < MAX20830_IC_DEVICE_ID_LENGTH)
return dev_err_probe(&client->dev, -ENODEV,
"IC_DEVICE_ID too short: expected at least 9 bytes, got %d\n",
ret);
/* 9 bytes of data, buf[0]-buf[7] = "MAX20830", buf[8] = '\0' */
buf[MAX20830_IC_DEVICE_ID_LENGTH - 1] = '\0';
if (strncmp(buf, "MAX20830", MAX20830_IC_DEVICE_ID_LENGTH - 1))
return dev_err_probe(&client->dev, -ENODEV,
"Unsupported device: '%s'\n", buf);
return pmbus_do_probe(client, &max20830_info);
}
static const struct i2c_device_id max20830_id[] = {
{"max20830"},
{ }
};
MODULE_DEVICE_TABLE(i2c, max20830_id);
static const struct of_device_id max20830_of_match[] = {
{ .compatible = "adi,max20830" },
{ }
};
MODULE_DEVICE_TABLE(of, max20830_of_match);
static struct i2c_driver max20830_driver = {
.driver = {
.name = "max20830",
.of_match_table = max20830_of_match,
},
.probe = max20830_probe,
.id_table = max20830_id,
};
module_i2c_driver(max20830_driver);
MODULE_AUTHOR("Alexis Czezar Torreno <alexisczezar.torreno@analog.com>");
MODULE_DESCRIPTION("PMBus driver for Analog Devices MAX20830");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");
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