--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver sg2042-mcu
+========================
+
+Supported chips:
+
+ * Onboard MCU for sg2042
+
+ Addresses scanned: -
+
+ Prefix: 'sg2042-mcu'
+
+Authors:
+
+ - Inochi Amaoto <inochiama@outlook.com>
+
+Description
+-----------
+
+This driver supprts hardware monitoring for onboard MCU with
+i2c interface.
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate
+the devices explicitly.
+Please see Documentation/i2c/instantiating-devices.rst for details.
+
+Sysfs Attributes
+----------------
+
+The following table shows the standard entries support by the driver:
+
+================= =====================================================
+Name Description
+================= =====================================================
+temp1_input Measured temperature of SoC
+temp1_crit Critical high temperature
+temp1_crit_hyst hysteresis temperature restore from Critical
+temp2_input Measured temperature of the base board
+================= =====================================================
+
+The following table shows the extra entries support by the driver
+(the MCU device is in i2c subsystem):
+
+================= ======= =============================================
+Name Perm Description
+================= ======= =============================================
+reset_count RO Reset count of the SoC
+uptime RO Seconds after the MCU is powered
+reset_reason RO Reset reason for the last reset
+repower_policy RW Execution policy when triggering repower
+================= ======= =============================================
+
+``repower_policy``
+ The repower is triggered when the temperature of the SoC falls below
+ the hysteresis temperature after triggering a shutdown due to
+ reaching the critical temperature.
+ The valid values for this entry are "repower" and "keep". "keep" will
+ leave the SoC down when the triggering repower, and "repower" will
+ boot the SoC.
+
+Debugfs Interfaces
+------------------
+
+If debugfs is available, this driver exposes some hardware specific
+data in ``/sys/kernel/debug/sg2042-mcu/*/``.
+
+================= ======= =============================================
+Name Format Description
+================= ======= =============================================
+firmware_version 0x%02x firmware version of the MCU
+pcb_version 0x%02x version number of the base board
+board_type 0x%02x identifiers for the base board
+mcu_type %d type of the MCU: 0 is STM32, 1 is GD32
+================= ======= =============================================
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024 Inochi Amaoto <inochiama@outlook.com>
+ *
+ * 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 <inochiama@outlook.com>");
+MODULE_DESCRIPTION("MCU I2C driver for SG2042 soc platform");
+MODULE_LICENSE("GPL");
projects / thirdparty / linux.git / commitdiff
