// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2024 Inochi Amaoto <[email protected]>
*
* Sophgo power control mcu for SG2042
*/
#include <linux/cleanup.h>
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
/* fixed MCU registers */
#define REG_BOARD_TYPE 0x00
#define REG_MCU_FIRMWARE_VERSION 0x01
#define REG_PCB_VERSION 0x02
#define REG_PWR_CTRL 0x03
#define REG_SOC_TEMP 0x04
#define REG_BOARD_TEMP 0x05
#define REG_RST_COUNT 0x0a
#define REG_UPTIME 0x0b
#define REG_RESET_REASON 0x0d
#define REG_MCU_TYPE 0x18
#define REG_REPOWER_POLICY 0x65
#define REG_CRITICAL_TEMP 0x66
#define REG_REPOWER_TEMP 0x67
#define REPOWER_POLICY_REBOOT 1
#define REPOWER_POLICY_KEEP_OFF 2
#define MCU_POWER_MAX 0xff
#define DEFINE_MCU_DEBUG_ATTR(_name, _reg, _format) \
static int _name##_show(struct seq_file *seqf, \
void *unused) \
{ \
struct sg2042_mcu_data *mcu = seqf->private; \
int ret; \
ret = i2c_smbus_read_byte_data(mcu->client, (_reg)); \
if (ret < 0) \
return ret; \
seq_printf(seqf, _format "\n", ret); \
return 0; \
} \
DEFINE_SHOW_ATTRIBUTE(_name) \
struct sg2042_mcu_data {
struct i2c_client *client;
struct dentry *debugfs;
struct mutex mutex;
};
static struct dentry *sgmcu_debugfs;
static ssize_t reset_count_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
int ret;
ret = i2c_smbus_read_byte_data(mcu->client, REG_RST_COUNT);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", ret);
}
static ssize_t uptime_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
u8 time_val[2];
int ret;
ret = i2c_smbus_read_i2c_block_data(mcu->client, REG_UPTIME,
sizeof(time_val), time_val);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n",
(time_val[0]) | (time_val[1] << 8));
}
static ssize_t reset_reason_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
int ret;
ret = i2c_smbus_read_byte_data(mcu->client, REG_RESET_REASON);
if (ret < 0)
return ret;
return sprintf(buf, "0x%02x\n", ret);
}
static ssize_t repower_policy_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
int ret;
const char *action;
ret = i2c_smbus_read_byte_data(mcu->client, REG_REPOWER_POLICY);
if (ret < 0)
return ret;
if (ret == REPOWER_POLICY_REBOOT)
action = "repower";
else if (ret == REPOWER_POLICY_KEEP_OFF)
action = "keep";
else
action = "unknown";
return sprintf(buf, "%s\n", action);
}
static ssize_t repower_policy_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
u8 value;
int ret;
if (sysfs_streq("repower", buf))
value = REPOWER_POLICY_REBOOT;
else if (sysfs_streq("keep", buf))
value = REPOWER_POLICY_KEEP_OFF;
else
return -EINVAL;
ret = i2c_smbus_write_byte_data(mcu->client,
REG_REPOWER_POLICY, value);
if (ret < 0)
return ret;
return count;
}
static DEVICE_ATTR_RO(reset_count);
static DEVICE_ATTR_RO(uptime);
static DEVICE_ATTR_RO(reset_reason);
static DEVICE_ATTR_RW(repower_policy);
DEFINE_MCU_DEBUG_ATTR(firmware_version, REG_MCU_FIRMWARE_VERSION, "0x%02x");
DEFINE_MCU_DEBUG_ATTR(pcb_version, REG_PCB_VERSION, "0x%02x");
DEFINE_MCU_DEBUG_ATTR(board_type, REG_BOARD_TYPE, "0x%02x");
DEFINE_MCU_DEBUG_ATTR(mcu_type, REG_MCU_TYPE, "%d");
static struct attribute *sg2042_mcu_attrs[] = {
&dev_attr_reset_count.attr,
&dev_attr_uptime.attr,
&dev_attr_reset_reason.attr,
&dev_attr_repower_policy.attr,
NULL
};
static const struct attribute_group sg2042_mcu_attr_group = {
.attrs = sg2042_mcu_attrs,
};
static const struct attribute_group *sg2042_mcu_groups[] = {
&sg2042_mcu_attr_group,
NULL
};
static const struct hwmon_channel_info * const sg2042_mcu_info[] = {
HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_CRIT |
HWMON_T_CRIT_HYST,
HWMON_T_INPUT),
NULL
};
static int sg2042_mcu_read(struct device *dev,
enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
int tmp;
u8 reg;
switch (attr) {
case hwmon_temp_input:
reg = channel ? REG_BOARD_TEMP : REG_SOC_TEMP;
break;
case hwmon_temp_crit:
reg = REG_CRITICAL_TEMP;
break;
case hwmon_temp_crit_hyst:
reg = REG_REPOWER_TEMP;
break;
default:
return -EOPNOTSUPP;
}
tmp = i2c_smbus_read_byte_data(mcu->client, reg);
if (tmp < 0)
return tmp;
*val = tmp * 1000;
return 0;
}
static int sg2042_mcu_write(struct device *dev,
enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct sg2042_mcu_data *mcu = dev_get_drvdata(dev);
int temp = val / 1000;
int hyst_temp, crit_temp;
u8 reg;
temp = clamp_val(temp, 0, MCU_POWER_MAX);
guard(mutex)(&mcu->mutex);
switch (attr) {
case hwmon_temp_crit:
hyst_temp = i2c_smbus_read_byte_data(mcu->client,
REG_REPOWER_TEMP);
if (hyst_temp < 0)
return hyst_temp;
crit_temp = temp;
reg = REG_CRITICAL_TEMP;
break;
case hwmon_temp_crit_hyst:
crit_temp = i2c_smbus_read_byte_data(mcu->client,
REG_CRITICAL_TEMP);
if (crit_temp < 0)
return crit_temp;
hyst_temp = temp;
reg = REG_REPOWER_TEMP;
break;
default:
return -EOPNOTSUPP;
}
/*
* ensure hyst_temp is smaller to avoid MCU from
* keeping triggering repower event.
*/
if (crit_temp < hyst_temp)
return -EINVAL;
return i2c_smbus_write_byte_data(mcu->client, reg, temp);
}
static umode_t sg2042_mcu_is_visible(const void *_data,
enum hwmon_sensor_types type,
u32 attr, int channel)
{
switch (type) {
case hwmon_temp:
switch (attr) {
case hwmon_temp_input:
return 0444;
case hwmon_temp_crit:
case hwmon_temp_crit_hyst:
if (channel == 0)
return 0644;
break;
default:
break;
}
break;
default:
break;
}
return 0;
}
static const struct hwmon_ops sg2042_mcu_ops = {
.is_visible = sg2042_mcu_is_visible,
.read = sg2042_mcu_read,
.write = sg2042_mcu_write,
};
static const struct hwmon_chip_info sg2042_mcu_chip_info = {
.ops = &sg2042_mcu_ops,
.info = sg2042_mcu_info,
};
static void sg2042_mcu_debugfs_init(struct sg2042_mcu_data *mcu,
struct device *dev)
{
mcu->debugfs = debugfs_create_dir(dev_name(dev), sgmcu_debugfs);
debugfs_create_file("firmware_version", 0444, mcu->debugfs,
mcu, &firmware_version_fops);
debugfs_create_file("pcb_version", 0444, mcu->debugfs, mcu,
&pcb_version_fops);
debugfs_create_file("mcu_type", 0444, mcu->debugfs, mcu,
&mcu_type_fops);
debugfs_create_file("board_type", 0444, mcu->debugfs, mcu,
&board_type_fops);
}
static int sg2042_mcu_i2c_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct sg2042_mcu_data *mcu;
struct device *hwmon_dev;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA))
return -ENODEV;
mcu = devm_kmalloc(dev, sizeof(*mcu), GFP_KERNEL);
if (!mcu)
return -ENOMEM;
mutex_init(&mcu->mutex);
mcu->client = client;
i2c_set_clientdata(client, mcu);
hwmon_dev = devm_hwmon_device_register_with_info(dev, "sg2042_mcu",
mcu,
&sg2042_mcu_chip_info,
NULL);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
sg2042_mcu_debugfs_init(mcu, dev);
return 0;
}
static void sg2042_mcu_i2c_remove(struct i2c_client *client)
{
struct sg2042_mcu_data *mcu = i2c_get_clientdata(client);
debugfs_remove_recursive(mcu->debugfs);
}
static const struct i2c_device_id sg2042_mcu_id[] = {
{ "sg2042-hwmon-mcu", 0 },
{},
};
MODULE_DEVICE_TABLE(i2c, sg2042_mcu_id);
static const struct of_device_id sg2042_mcu_of_id[] = {
{ .compatible = "sophgo,sg2042-hwmon-mcu" },
{},
};
MODULE_DEVICE_TABLE(of, sg2042_mcu_of_id);
static struct i2c_driver sg2042_mcu_driver = {
.driver = {
.name = "sg2042-mcu",
.of_match_table = sg2042_mcu_of_id,
.dev_groups = sg2042_mcu_groups,
},
.probe = sg2042_mcu_i2c_probe,
.remove = sg2042_mcu_i2c_remove,
.id_table = sg2042_mcu_id,
};
static int __init sg2042_mcu_init(void)
{
sgmcu_debugfs = debugfs_create_dir("sg2042-mcu", NULL);
return i2c_add_driver(&sg2042_mcu_driver);
}
static void __exit sg2042_mcu_exit(void)
{
debugfs_remove_recursive(sgmcu_debugfs);
i2c_del_driver(&sg2042_mcu_driver);
}
module_init(sg2042_mcu_init);
module_exit(sg2042_mcu_exit);
MODULE_AUTHOR("Inochi Amaoto <[email protected]>");
MODULE_DESCRIPTION("MCU I2C driver for SG2042 soc platform");
MODULE_LICENSE("GPL");
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