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// SPDX-License-Identifier: GPL-2.0
/*
* AMD Versal SysMon I2C driver
*
* Copyright (C) 2023 - 2026, Advanced Micro Devices, Inc.
*/
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/types.h>
#include <linux/unaligned.h>
#include "versal-sysmon.h"
#define SYSMON_I2C_INSTR_READ BIT(2)
#define SYSMON_I2C_INSTR_WRITE BIT(3)
/*
* I2C command frame layout (8 bytes):
* [0..3] data payload (little-endian u32)
* [4..5] register offset >> 2 (little-endian u16)
* [6] instruction (read/write)
* [7] reserved
*/
#define SYSMON_I2C_DATA_OFS 0
#define SYSMON_I2C_REG_OFS 4
#define SYSMON_I2C_INSTR_OFS 6
static int sysmon_i2c_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct i2c_client *client = context;
u8 write_buf[8] = { };
u8 read_buf[4];
int ret;
put_unaligned_le16(reg >> 2, &write_buf[SYSMON_I2C_REG_OFS]);
write_buf[SYSMON_I2C_INSTR_OFS] = SYSMON_I2C_INSTR_READ;
ret = i2c_master_send(client, write_buf, sizeof(write_buf));
if (ret < 0)
return ret;
if (ret != sizeof(write_buf))
return -EIO;
ret = i2c_master_recv(client, read_buf, sizeof(read_buf));
if (ret < 0)
return ret;
if (ret != sizeof(read_buf))
return -EIO;
*val = get_unaligned_le32(read_buf);
return 0;
}
static int sysmon_i2c_reg_write(void *context, unsigned int reg,
unsigned int val)
{
struct i2c_client *client = context;
u8 write_buf[8] = { };
int ret;
put_unaligned_le32(val, &write_buf[SYSMON_I2C_DATA_OFS]);
put_unaligned_le16(reg >> 2, &write_buf[SYSMON_I2C_REG_OFS]);
write_buf[SYSMON_I2C_INSTR_OFS] = SYSMON_I2C_INSTR_WRITE;
ret = i2c_master_send(client, write_buf, sizeof(write_buf));
if (ret < 0)
return ret;
if (ret != sizeof(write_buf))
return -EIO;
return 0;
}
/*
* Almost all registers are volatile (live ADC readings, interrupt
* status). The rest are not accessed often enough to benefit from
* caching.
*/
static const struct regmap_config sysmon_i2c_regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = SYSMON_REG_STRIDE,
.max_register = SYSMON_MAX_REG,
.reg_read = sysmon_i2c_reg_read,
.reg_write = sysmon_i2c_reg_write,
};
static int sysmon_i2c_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct regmap *regmap;
regmap = devm_regmap_init(dev, NULL, client, &sysmon_i2c_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
/* I2C has no IRQ connection; events are not supported */
return devm_versal_sysmon_core_probe(dev, regmap);
}
static const struct of_device_id sysmon_i2c_of_match_table[] = {
{ .compatible = "xlnx,versal-sysmon" },
{ }
};
MODULE_DEVICE_TABLE(of, sysmon_i2c_of_match_table);
static const struct i2c_device_id sysmon_i2c_id_table[] = {
{ .name = "versal-sysmon" },
{ }
};
MODULE_DEVICE_TABLE(i2c, sysmon_i2c_id_table);
static struct i2c_driver sysmon_i2c_driver = {
.probe = sysmon_i2c_probe,
.driver = {
.name = "versal-sysmon-i2c",
.of_match_table = sysmon_i2c_of_match_table,
},
.id_table = sysmon_i2c_id_table,
};
module_i2c_driver(sysmon_i2c_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AMD Versal SysMon I2C Driver");
MODULE_IMPORT_NS("VERSAL_SYSMON");
MODULE_AUTHOR("Conall O'Griofa <conall.ogriofa@amd.com>");
MODULE_AUTHOR("Salih Erim <salih.erim@amd.com>");
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