hwmon: (pmbus) Add driver for Infineon IR36021

The IR36021 is a dual‐loop digital multi‐phase buck controller.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20210301035954.16713-3-chris.packham@alliedtelesis.co.nzSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -77,6 +77,7 @@ Hardware Monitoring Kernel Drivers
    intel-m10-bmc-hwmon
    ir35221
    ir38064
+   ir36021
    isl68137
    it87
    jc42

Documentation/hwmon/ir36021.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver ir36021
+=====================
+
+Supported chips:
+
+  * Infineon IR36021
+
+    Prefix: ir36021
+    Addresses scanned: -
+
+    Datasheet: Publicly available at the Infineon website
+      https://www.infineon.com/dgdl/ir36021.pdf?fileId=5546d462533600a4015355d0aa2d1775
+
+Authors:
+      - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+Description
+-----------
+
+The IR36021 is a dual‐loop digital multi‐phase buck controller designed for
+point of load applications.
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Sysfs attributes
+----------------
+
+======================= ===========================
+curr1_label             "iin"
+curr1_input             Measured input current
+curr1_alarm             Input fault alarm
+
+curr2_label             "iout1"
+curr2_input             Measured output current
+curr2_alarm             Output over-current alarm
+
+in1_label               "vin"
+in1_input               Measured input voltage
+in1_alarm               Input under-voltage alarm
+
+in2_label               "vout1"
+in2_input               Measured output voltage
+in2_alarm               Output over-voltage alarm
+
+power1_label            "pin"
+power1_input            Measured input power
+power1_alarm            Input under-voltage alarm
+
+power2_label            "pout1"
+power2_input            Measured output power
+
+temp1_input             Measured temperature
+temp1_alarm             Temperature alarm
+
+temp2_input             Measured other loop temperature
+temp2_alarm             Temperature alarm
+======================= ===========================

drivers/hwmon/pmbus/Kconfig

@@ -84,6 +84,15 @@ config SENSORS_IR35221
 	  This driver can also be built as a module. If so, the module will
 	  be called ir35221.
 
+config SENSORS_IR36021
+	tristate "Infineon IR36021"
+	help
+	  If you say yes here you get hardware monitoring support for Infineon
+	  IR36021.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ir36021.
+
 config SENSORS_IR38064
 	tristate "Infineon IR38064"
 	help

drivers/hwmon/pmbus/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_SENSORS_BEL_PFE)	+= bel-pfe.o
 obj-$(CONFIG_SENSORS_IBM_CFFPS)	+= ibm-cffps.o
 obj-$(CONFIG_SENSORS_INSPUR_IPSPS) += inspur-ipsps.o
 obj-$(CONFIG_SENSORS_IR35221)	+= ir35221.o
+obj-$(CONFIG_SENSORS_IR36021)	+= ir36021.o
 obj-$(CONFIG_SENSORS_IR38064)	+= ir38064.o
 obj-$(CONFIG_SENSORS_IRPS5401)	+= irps5401.o
 obj-$(CONFIG_SENSORS_ISL68137)	+= isl68137.o

drivers/hwmon/pmbus/ir36021.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for Infineon IR36021
+ *
+ * Copyright (c) 2021 Allied Telesis
+ */
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+static struct pmbus_driver_info ir36021_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.format[PSC_CURRENT_IN] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_POWER] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT
+		| PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT
+		| PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
+		| PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
+		| PMBUS_HAVE_STATUS_TEMP,
+};
+
+static int ir36021_probe(struct i2c_client *client)
+{
+	u8 buf[I2C_SMBUS_BLOCK_MAX];
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_BYTE_DATA
+				     | I2C_FUNC_SMBUS_READ_WORD_DATA
+				     | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
+		return -ENODEV;
+
+	ret = i2c_smbus_read_i2c_block_data(client, PMBUS_MFR_MODEL, 2, buf);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read PMBUS_MFR_MODEL\n");
+		return ret;
+	}
+	if (ret != 2 || buf[0] != 0x01 || buf[1] != 0x2d) {
+		dev_err(&client->dev, "MFR_MODEL unrecognised\n");
+		return -ENODEV;
+	}
+
+	return pmbus_do_probe(client, &ir36021_info);
+}
+
+static const struct i2c_device_id ir36021_id[] = {
+	{ "ir36021", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, ir36021_id);
+
+static const struct of_device_id __maybe_unused ir36021_of_id[] = {
+	{ .compatible = "infineon,ir36021" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ir36021_of_id);
+
+static struct i2c_driver ir36021_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name = "ir36021",
+		.of_match_table = of_match_ptr(ir36021_of_id),
+	},
+	.probe_new = ir36021_probe,
+	.id_table = ir36021_id,
+};
+
+module_i2c_driver(ir36021_driver);
+
+MODULE_AUTHOR("Chris Packham <chris.packham@alliedtelesis.co.nz>");
+MODULE_DESCRIPTION("PMBus driver for Infineon IR36021");
+MODULE_LICENSE("GPL");