--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver max20830
+======================
+
+Supported chips:
+
+ * Analog Devices MAX20830
+
+ Prefix: 'max20830'
+
+ Addresses scanned: -
+
+ Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/max20830.pdf
+
+Author:
+
+ - Alexis Czezar Torreno <alexisczezar.torreno@analog.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices MAX20830
+Step-Down Switching Regulator with PMBus Interface.
+
+The MAX20830 is a 2.7V to 16V, 30A fully integrated step-down DC-DC switching
+regulator. Through the PMBus interface, the device can monitor input/output
+voltages, output current and temperature.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+Sysfs entries
+-------------
+
+================= ========================================
+in1_label "vin"
+in1_input Measured input voltage
+in1_alarm Input voltage alarm
+in2_label "vout1"
+in2_input Measured output voltage
+in2_alarm Output voltage alarm
+curr1_label "iout1"
+curr1_input Measured output current
+curr1_alarm Output current alarm
+temp1_input Measured temperature
+temp1_alarm Chip temperature alarm
+================= ========================================
--- /dev/null
+// 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/mod_devicetable.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");
projects / thirdparty / linux.git / commitdiff
