hwmon: Add driver for Astera Labs PT5161L retimer

This driver implements support for temperature monitoring of Astera Labs
PT5161L series PCIe retimer chips.

This driver implementation originates from the CSDK available at
Link: https://github.com/facebook/openbmc/tree/helium/common/recipes-lib/retimer-v2.14
The communication protocol utilized is based on the I2C/SMBus standard.

Signed-off-by: Cosmo Chou <chou.cosmo@gmail.com>
Link: https://lore.kernel.org/r/20240206125420.3884300-2-chou.cosmo@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -190,6 +190,7 @@ Hardware Monitoring Kernel Drivers
    pmbus
    powerz
    powr1220
+   pt5161l
    pxe1610
    pwm-fan
    q54sj108a2

Documentation/hwmon/pt5161l.rst

@@ -0,0 +1,42 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver pt5161l
+=====================
+
+Supported chips:
+
+  * Astera Labs PT5161L
+
+    Prefix: 'pt5161l'
+
+    Addresses scanned: I2C 0x20 - 0x27
+
+    Datasheet: Not publicly available.
+
+Authors: Cosmo Chou <cosmo.chou@quantatw.com>
+
+Description
+-----------
+
+This driver implements support for temperature monitoring of Astera Labs
+PT5161L series PCIe retimer chips.
+
+This driver implementation originates from the CSDK available at
+https://github.com/facebook/openbmc/tree/helium/common/recipes-lib/retimer-v2.14
+The communication protocol utilized is based on the I2C/SMBus standard.
+
+Sysfs entries
+----------------
+
+================ ==============================================
+temp1_input      Measured temperature (in millidegrees Celsius)
+================ ==============================================
+
+Debugfs entries
+----------------
+
+================ ===============================
+fw_load_status   Firmware load status
+fw_ver           Firmware version of the retimer
+heartbeat_status Heartbeat status
+================ ===============================

MAINTAINERS

@@ -17698,6 +17698,13 @@ F:	fs/pstore/
 F:	include/linux/pstore*
 K:	\b(pstore|ramoops)
 
+PT5161L HARDWARE MONITOR DRIVER
+M:	Cosmo Chou <cosmo.chou@quantatw.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/pt5161l.rst
+F:	drivers/hwmon/pt5161l.c
+
 PTP HARDWARE CLOCK SUPPORT
 M:	Richard Cochran <richardcochran@gmail.com>
 L:	netdev@vger.kernel.org

drivers/hwmon/Kconfig

@@ -1755,6 +1755,16 @@ source "drivers/hwmon/peci/Kconfig"
 
 source "drivers/hwmon/pmbus/Kconfig"
 
+config SENSORS_PT5161L
+	tristate "Astera Labs PT5161L PCIe retimer hardware monitoring"
+	depends on I2C
+	help
+	  If you say yes here you get support for temperature monitoring
+	  on the Astera Labs PT5161L PCIe retimer.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called pt5161l.
+
 config SENSORS_PWM_FAN
 	tristate "PWM fan"
 	depends on (PWM && OF) || COMPILE_TEST

drivers/hwmon/Makefile

@@ -184,6 +184,7 @@ obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
 obj-$(CONFIG_SENSORS_POWERZ)	+= powerz.o
 obj-$(CONFIG_SENSORS_POWR1220)  += powr1220.o
+obj-$(CONFIG_SENSORS_PT5161L)	+= pt5161l.o
 obj-$(CONFIG_SENSORS_PWM_FAN)	+= pwm-fan.o
 obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON)	+= raspberrypi-hwmon.o
 obj-$(CONFIG_SENSORS_SBTSI)	+= sbtsi_temp.o

drivers/hwmon/pt5161l.c

@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+/* Aries current average temp ADC code CSR */
+#define ARIES_CURRENT_AVG_TEMP_ADC_CSR	0x42c
+
+/* Device Load check register */
+#define ARIES_CODE_LOAD_REG	0x605
+/* Value indicating FW was loaded properly, [3:1] = 3'b111 */
+#define ARIES_LOAD_CODE	0xe
+
+/* Main Micro Heartbeat register */
+#define ARIES_MM_HEARTBEAT_ADDR	0x923
+
+/* Reg offset to specify Address for MM assisted accesses */
+#define ARIES_MM_ASSIST_REG_ADDR_OFFSET	0xd99
+/* Reg offset to specify Command for MM assisted accesses */
+#define ARIES_MM_ASSIST_CMD_OFFSET	0xd9d
+/* Reg offset to MM SPARE 0 used specify Address[7:0] */
+#define ARIES_MM_ASSIST_SPARE_0_OFFSET	0xd9f
+/* Reg offset to MM SPARE 3 used specify Data Byte 0 */
+#define ARIES_MM_ASSIST_SPARE_3_OFFSET	0xda2
+/* Wide register reads */
+#define ARIES_MM_RD_WIDE_REG_2B	0x1d
+#define ARIES_MM_RD_WIDE_REG_3B	0x1e
+#define ARIES_MM_RD_WIDE_REG_4B	0x1f
+#define ARIES_MM_RD_WIDE_REG_5B	0x20
+
+/* Time delay between checking MM status of EEPROM write (microseconds) */
+#define ARIES_MM_STATUS_TIME	5000
+
+/* AL Main SRAM DMEM offset (A0) */
+#define AL_MAIN_SRAM_DMEM_OFFSET	(64 * 1024)
+/* SRAM read command */
+#define AL_TG_RD_LOC_IND_SRAM	0x16
+
+/* Offset for main micro FW info */
+#define ARIES_MAIN_MICRO_FW_INFO	(96 * 1024 - 128)
+/* FW Info (Major) offset location in struct */
+#define ARIES_MM_FW_VERSION_MAJOR	0
+/* FW Info (Minor) offset location in struct */
+#define ARIES_MM_FW_VERSION_MINOR	1
+/* FW Info (Build no.) offset location in struct */
+#define ARIES_MM_FW_VERSION_BUILD	2
+
+#define ARIES_TEMP_CAL_CODE_DEFAULT	84
+
+/* Struct defining FW version loaded on an Aries device */
+struct pt5161l_fw_ver {
+	u8 major;
+	u8 minor;
+	u16 build;
+};
+
+/* Each client has this additional data */
+struct pt5161l_data {
+	struct i2c_client *client;
+	struct dentry *debugfs;
+	struct pt5161l_fw_ver fw_ver;
+	struct mutex lock; /* for atomic I2C transactions */
+	bool init_done;
+	bool code_load_okay; /* indicate if code load reg value is expected */
+	bool mm_heartbeat_okay; /* indicate if Main Micro heartbeat is good */
+	bool mm_wide_reg_access; /* MM assisted wide register access */
+};
+
+static struct dentry *pt5161l_debugfs_dir;
+
+/*
+ * Write multiple data bytes to Aries over I2C
+ */
+static int pt5161l_write_block_data(struct pt5161l_data *data, u32 address,
+				    u8 len, u8 *val)
+{
+	struct i2c_client *client = data->client;
+	int ret;
+	u8 remain_len = len;
+	u8 xfer_len, curr_len;
+	u8 buf[16];
+	u8 cmd = 0x0F; /* [7]:pec_en, [4:2]:func, [1]:start, [0]:end */
+	u8 config = 0x40; /* [6]:cfg_type, [4:1]:burst_len, [0]:address bit16 */
+
+	while (remain_len > 0) {
+		if (remain_len > 4) {
+			curr_len = 4;
+			remain_len -= 4;
+		} else {
+			curr_len = remain_len;
+			remain_len = 0;
+		}
+
+		buf[0] = config | (curr_len - 1) << 1 | ((address >> 16) & 0x1);
+		buf[1] = (address >> 8) & 0xff;
+		buf[2] = address & 0xff;
+		memcpy(&buf[3], val, curr_len);
+
+		xfer_len = 3 + curr_len;
+		ret = i2c_smbus_write_block_data(client, cmd, xfer_len, buf);
+		if (ret)
+			return ret;
+
+		val += curr_len;
+		address += curr_len;
+	}
+
+	return 0;
+}
+
+/*
+ * Read multiple data bytes from Aries over I2C
+ */
+static int pt5161l_read_block_data(struct pt5161l_data *data, u32 address,
+				   u8 len, u8 *val)
+{
+	struct i2c_client *client = data->client;
+	int ret, tries;
+	u8 remain_len = len;
+	u8 curr_len;
+	u8 wbuf[16], rbuf[24];
+	u8 cmd = 0x08; /* [7]:pec_en, [4:2]:func, [1]:start, [0]:end */
+	u8 config = 0x00; /* [6]:cfg_type, [4:1]:burst_len, [0]:address bit16 */
+
+	while (remain_len > 0) {
+		if (remain_len > 16) {
+			curr_len = 16;
+			remain_len -= 16;
+		} else {
+			curr_len = remain_len;
+			remain_len = 0;
+		}
+
+		wbuf[0] = config | (curr_len - 1) << 1 |
+			  ((address >> 16) & 0x1);
+		wbuf[1] = (address >> 8) & 0xff;
+		wbuf[2] = address & 0xff;
+
+		for (tries = 0; tries < 3; tries++) {
+			ret = i2c_smbus_write_block_data(client, (cmd | 0x2), 3,
+							 wbuf);
+			if (ret)
+				return ret;
+
+			ret = i2c_smbus_read_block_data(client, (cmd | 0x1),
+							rbuf);
+			if (ret == curr_len)
+				break;
+		}
+		if (tries >= 3)
+			return ret;
+
+		memcpy(val, rbuf, curr_len);
+		val += curr_len;
+		address += curr_len;
+	}
+
+	return 0;
+}
+
+static int pt5161l_read_wide_reg(struct pt5161l_data *data, u32 address,
+				 u8 width, u8 *val)
+{
+	int ret, tries;
+	u8 buf[8];
+	u8 status;
+
+	/*
+	 * Safely access wide registers using mailbox method to prevent
+	 * risking conflict with Aries firmware; otherwise fallback to
+	 * legacy, less secure method.
+	 */
+	if (data->mm_wide_reg_access) {
+		buf[0] = address & 0xff;
+		buf[1] = (address >> 8) & 0xff;
+		buf[2] = (address >> 16) & 0x1;
+		ret = pt5161l_write_block_data(data,
+					       ARIES_MM_ASSIST_SPARE_0_OFFSET,
+					       3, buf);
+		if (ret)
+			return ret;
+
+		/* Set command based on width */
+		switch (width) {
+		case 2:
+			buf[0] = ARIES_MM_RD_WIDE_REG_2B;
+			break;
+		case 3:
+			buf[0] = ARIES_MM_RD_WIDE_REG_3B;
+			break;
+		case 4:
+			buf[0] = ARIES_MM_RD_WIDE_REG_4B;
+			break;
+		case 5:
+			buf[0] = ARIES_MM_RD_WIDE_REG_5B;
+			break;
+		default:
+			return -EINVAL;
+		}
+		ret = pt5161l_write_block_data(data, ARIES_MM_ASSIST_CMD_OFFSET,
+					       1, buf);
+		if (ret)
+			return ret;
+
+		status = 0xff;
+		for (tries = 0; tries < 100; tries++) {
+			ret = pt5161l_read_block_data(data,
+						      ARIES_MM_ASSIST_CMD_OFFSET,
+						      1, &status);
+			if (ret)
+				return ret;
+
+			if (status == 0)
+				break;
+
+			usleep_range(ARIES_MM_STATUS_TIME,
+				     ARIES_MM_STATUS_TIME + 1000);
+		}
+		if (status != 0)
+			return -ETIMEDOUT;
+
+		ret = pt5161l_read_block_data(data,
+					      ARIES_MM_ASSIST_SPARE_3_OFFSET,
+					      width, val);
+		if (ret)
+			return ret;
+	} else {
+		return pt5161l_read_block_data(data, address, width, val);
+	}
+
+	return 0;
+}
+
+/*
+ * Read multiple (up to eight) data bytes from micro SRAM over I2C
+ */
+static int
+pt5161l_read_block_data_main_micro_indirect(struct pt5161l_data *data,
+					    u32 address, u8 len, u8 *val)
+{
+	int ret, tries;
+	u8 buf[8];
+	u8 i, status;
+	u32 uind_offs = ARIES_MM_ASSIST_REG_ADDR_OFFSET;
+	u32 eeprom_base, eeprom_addr;
+
+	/* No multi-byte indirect support here. Hence read a byte at a time */
+	eeprom_base = address - AL_MAIN_SRAM_DMEM_OFFSET;
+	for (i = 0; i < len; i++) {
+		eeprom_addr = eeprom_base + i;
+		buf[0] = eeprom_addr & 0xff;
+		buf[1] = (eeprom_addr >> 8) & 0xff;
+		buf[2] = (eeprom_addr >> 16) & 0xff;
+		ret = pt5161l_write_block_data(data, uind_offs, 3, buf);
+		if (ret)
+			return ret;
+
+		buf[0] = AL_TG_RD_LOC_IND_SRAM;
+		ret = pt5161l_write_block_data(data, uind_offs + 4, 1, buf);
+		if (ret)
+			return ret;
+
+		status = 0xff;
+		for (tries = 0; tries < 255; tries++) {
+			ret = pt5161l_read_block_data(data, uind_offs + 4, 1,
+						      &status);
+			if (ret)
+				return ret;
+
+			if (status == 0)
+				break;
+		}
+		if (status != 0)
+			return -ETIMEDOUT;
+
+		ret = pt5161l_read_block_data(data, uind_offs + 3, 1, buf);
+		if (ret)
+			return ret;
+
+		val[i] = buf[0];
+	}
+
+	return 0;
+}
+
+/*
+ * Check firmware load status
+ */
+static int pt5161l_fw_load_check(struct pt5161l_data *data)
+{
+	int ret;
+	u8 buf[8];
+
+	ret = pt5161l_read_block_data(data, ARIES_CODE_LOAD_REG, 1, buf);
+	if (ret)
+		return ret;
+
+	if (buf[0] < ARIES_LOAD_CODE) {
+		dev_dbg(&data->client->dev,
+			"Code Load reg unexpected. Not all modules are loaded %x\n",
+			buf[0]);
+		data->code_load_okay = false;
+	} else {
+		data->code_load_okay = true;
+	}
+
+	return 0;
+}
+
+/*
+ * Check main micro heartbeat
+ */
+static int pt5161l_heartbeat_check(struct pt5161l_data *data)
+{
+	int ret, tries;
+	u8 buf[8];
+	u8 heartbeat;
+	bool hb_changed = false;
+
+	ret = pt5161l_read_block_data(data, ARIES_MM_HEARTBEAT_ADDR, 1, buf);
+	if (ret)
+		return ret;
+
+	heartbeat = buf[0];
+	for (tries = 0; tries < 100; tries++) {
+		ret = pt5161l_read_block_data(data, ARIES_MM_HEARTBEAT_ADDR, 1,
+					      buf);
+		if (ret)
+			return ret;
+
+		if (buf[0] != heartbeat) {
+			hb_changed = true;
+			break;
+		}
+	}
+	data->mm_heartbeat_okay = hb_changed;
+
+	return 0;
+}
+
+/*
+ * Check the status of firmware
+ */
+static int pt5161l_fwsts_check(struct pt5161l_data *data)
+{
+	int ret;
+	u8 buf[8];
+	u8 major = 0, minor = 0;
+	u16 build = 0;
+
+	ret = pt5161l_fw_load_check(data);
+	if (ret)
+		return ret;
+
+	ret = pt5161l_heartbeat_check(data);
+	if (ret)
+		return ret;
+
+	if (data->code_load_okay && data->mm_heartbeat_okay) {
+		ret = pt5161l_read_block_data_main_micro_indirect(data, ARIES_MAIN_MICRO_FW_INFO +
+								  ARIES_MM_FW_VERSION_MAJOR,
+								  1, &major);
+		if (ret)
+			return ret;
+
+		ret = pt5161l_read_block_data_main_micro_indirect(data, ARIES_MAIN_MICRO_FW_INFO +
+								  ARIES_MM_FW_VERSION_MINOR,
+								  1, &minor);
+		if (ret)
+			return ret;
+
+		ret = pt5161l_read_block_data_main_micro_indirect(data, ARIES_MAIN_MICRO_FW_INFO +
+								  ARIES_MM_FW_VERSION_BUILD,
+								  2, buf);
+		if (ret)
+			return ret;
+		build = buf[1] << 8 | buf[0];
+	}
+	data->fw_ver.major = major;
+	data->fw_ver.minor = minor;
+	data->fw_ver.build = build;
+
+	return 0;
+}
+
+static int pt5161l_fw_is_at_least(struct pt5161l_data *data, u8 major, u8 minor,
+				  u16 build)
+{
+	u32 ver = major << 24 | minor << 16 | build;
+	u32 curr_ver = data->fw_ver.major << 24 | data->fw_ver.minor << 16 |
+		       data->fw_ver.build;
+
+	if (curr_ver >= ver)
+		return true;
+
+	return false;
+}
+
+static int pt5161l_init_dev(struct pt5161l_data *data)
+{
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = pt5161l_fwsts_check(data);
+	mutex_unlock(&data->lock);
+	if (ret)
+		return ret;
+
+	/* Firmware 2.2.0 enables safe access to wide registers */
+	if (pt5161l_fw_is_at_least(data, 2, 2, 0))
+		data->mm_wide_reg_access = true;
+
+	data->init_done = true;
+
+	return 0;
+}
+
+static int pt5161l_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	struct pt5161l_data *data = dev_get_drvdata(dev);
+	int ret;
+	u8 buf[8];
+	long adc_code;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		if (!data->init_done) {
+			ret = pt5161l_init_dev(data);
+			if (ret)
+				return ret;
+		}
+
+		mutex_lock(&data->lock);
+		ret = pt5161l_read_wide_reg(data,
+					    ARIES_CURRENT_AVG_TEMP_ADC_CSR, 4,
+					    buf);
+		mutex_unlock(&data->lock);
+		if (ret) {
+			dev_dbg(dev, "Read adc_code failed %d\n", ret);
+			return ret;
+		}
+
+		adc_code = buf[3] << 24 | buf[2] << 16 | buf[1] << 8 | buf[0];
+		if (adc_code == 0 || adc_code >= 0x3ff) {
+			dev_dbg(dev, "Invalid adc_code %lx\n", adc_code);
+			return -EIO;
+		}
+
+		*val = 110000 +
+		       ((adc_code - (ARIES_TEMP_CAL_CODE_DEFAULT + 250)) *
+			-320);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t pt5161l_is_visible(const void *data,
+				  enum hwmon_sensor_types type, u32 attr,
+				  int channel)
+{
+	switch (attr) {
+	case hwmon_temp_input:
+		return 0444;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_channel_info *pt5161l_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops pt5161l_hwmon_ops = {
+	.is_visible = pt5161l_is_visible,
+	.read = pt5161l_read,
+};
+
+static const struct hwmon_chip_info pt5161l_chip_info = {
+	.ops = &pt5161l_hwmon_ops,
+	.info = pt5161l_info,
+};
+
+static ssize_t pt5161l_debugfs_read_fw_ver(struct file *file, char __user *buf,
+					   size_t count, loff_t *ppos)
+{
+	struct pt5161l_data *data = file->private_data;
+	int ret;
+	char ver[32];
+
+	mutex_lock(&data->lock);
+	ret = pt5161l_fwsts_check(data);
+	mutex_unlock(&data->lock);
+	if (ret)
+		return ret;
+
+	ret = snprintf(ver, sizeof(ver), "%u.%u.%u\n", data->fw_ver.major,
+		       data->fw_ver.minor, data->fw_ver.build);
+
+	return simple_read_from_buffer(buf, count, ppos, ver, ret);
+}
+
+static const struct file_operations pt5161l_debugfs_ops_fw_ver = {
+	.read = pt5161l_debugfs_read_fw_ver,
+	.open = simple_open,
+};
+
+static ssize_t pt5161l_debugfs_read_fw_load_sts(struct file *file,
+						char __user *buf, size_t count,
+						loff_t *ppos)
+{
+	struct pt5161l_data *data = file->private_data;
+	int ret;
+	bool status = false;
+	char health[16];
+
+	mutex_lock(&data->lock);
+	ret = pt5161l_fw_load_check(data);
+	mutex_unlock(&data->lock);
+	if (ret == 0)
+		status = data->code_load_okay;
+
+	ret = snprintf(health, sizeof(health), "%s\n",
+		       status ? "normal" : "abnormal");
+
+	return simple_read_from_buffer(buf, count, ppos, health, ret);
+}
+
+static const struct file_operations pt5161l_debugfs_ops_fw_load_sts = {
+	.read = pt5161l_debugfs_read_fw_load_sts,
+	.open = simple_open,
+};
+
+static ssize_t pt5161l_debugfs_read_hb_sts(struct file *file, char __user *buf,
+					   size_t count, loff_t *ppos)
+{
+	struct pt5161l_data *data = file->private_data;
+	int ret;
+	bool status = false;
+	char health[16];
+
+	mutex_lock(&data->lock);
+	ret = pt5161l_heartbeat_check(data);
+	mutex_unlock(&data->lock);
+	if (ret == 0)
+		status = data->mm_heartbeat_okay;
+
+	ret = snprintf(health, sizeof(health), "%s\n",
+		       status ? "normal" : "abnormal");
+
+	return simple_read_from_buffer(buf, count, ppos, health, ret);
+}
+
+static const struct file_operations pt5161l_debugfs_ops_hb_sts = {
+	.read = pt5161l_debugfs_read_hb_sts,
+	.open = simple_open,
+};
+
+static int pt5161l_init_debugfs(struct pt5161l_data *data)
+{
+	data->debugfs = debugfs_create_dir(dev_name(&data->client->dev),
+					   pt5161l_debugfs_dir);
+
+	debugfs_create_file("fw_ver", 0444, data->debugfs, data,
+			    &pt5161l_debugfs_ops_fw_ver);
+
+	debugfs_create_file("fw_load_status", 0444, data->debugfs, data,
+			    &pt5161l_debugfs_ops_fw_load_sts);
+
+	debugfs_create_file("heartbeat_status", 0444, data->debugfs, data,
+			    &pt5161l_debugfs_ops_hb_sts);
+
+	return 0;
+}
+
+static int pt5161l_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct pt5161l_data *data;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->lock);
+	pt5161l_init_dev(data);
+	dev_set_drvdata(dev, data);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data,
+							 &pt5161l_chip_info,
+							 NULL);
+
+	pt5161l_init_debugfs(data);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static void pt5161l_remove(struct i2c_client *client)
+{
+	struct pt5161l_data *data = i2c_get_clientdata(client);
+
+	debugfs_remove_recursive(data->debugfs);
+}
+
+static const struct of_device_id __maybe_unused pt5161l_of_match[] = {
+	{ .compatible = "asteralabs,pt5161l" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pt5161l_of_match);
+
+static const struct acpi_device_id __maybe_unused pt5161l_acpi_match[] = {
+	{ "PT5161L", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, pt5161l_acpi_match);
+
+static const struct i2c_device_id pt5161l_id[] = {
+	{ "pt5161l", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, pt5161l_id);
+
+static struct i2c_driver pt5161l_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name = "pt5161l",
+		.of_match_table = of_match_ptr(pt5161l_of_match),
+		.acpi_match_table = ACPI_PTR(pt5161l_acpi_match),
+	},
+	.probe = pt5161l_probe,
+	.remove = pt5161l_remove,
+	.id_table = pt5161l_id,
+};
+
+static int __init pt5161l_init(void)
+{
+	pt5161l_debugfs_dir = debugfs_create_dir("pt5161l", NULL);
+	return i2c_add_driver(&pt5161l_driver);
+}
+
+static void __exit pt5161l_exit(void)
+{
+	i2c_del_driver(&pt5161l_driver);
+	debugfs_remove_recursive(pt5161l_debugfs_dir);
+}
+
+module_init(pt5161l_init);
+module_exit(pt5161l_exit);
+
+MODULE_AUTHOR("Cosmo Chou <cosmo.chou@quantatw.com>");
+MODULE_DESCRIPTION("Hwmon driver for Astera Labs Aries PCIe retimer");
+MODULE_LICENSE("GPL");