hwmon: (pmbus/ir38064) Add driver for Infineon IR38064 Voltage Regulator

Add the pmbus driver for the Infineon ir38064 voltage regulator.

VOUT_MODE is not supported by the device. The driver fakes linear16
mode with exponent value -8.

The device supports VOUT_PEAK, IOUT_PEAK, and TEMPERATURE_PEAK, however
this driver does not enable them.

Signed-off-by: Maxim Sloyko <[e-mail]>
Signed-off-by: Patrick Venture <[e-mail]>
Signed-off-by: Guenter Roeck <[e-mail]>

Documentation/hwmon/ir38064

···
+Kernel driver ir38064
+=====================
+
+Supported chips:
+  * Infineon IR38064
+    Prefix: 'ir38064'
+    Addresses scanned: -
+    Datasheet: Publicly available at the Infineon webiste
+      https://www.infineon.com/dgdl/Infineon-IR38064MTRPBF-DS-v03_07-EN.pdf?fileId=5546d462584d1d4a0158db0d9efb67ca
+
+Datasheet is not publicly available.
+
+
+Authors:
+        Maxim Sloyko <[e-mail]>
+        Patrick Venture <[e-mail]>
+
+Description
+-----------
+
+IR38064 is a Single-input Voltage, Synchronous Buck Regulator, DC-DC Converter.
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Sysfs attributes
+----------------
+
+curr1_label		"iout1"
+curr1_input		Measured output current
+curr1_crit		Critical maximum current
+curr1_crit_alarm	Current critical high alarm
+curr1_max		Maximum current
+curr1_max_alarm	Current high alarm
+
+in1_label		"vin"
+in1_input		Measured input voltage
+in1_crit		Critical maximum input voltage
+in1_crit_alarm		Input voltage critical high alarm
+in1_min		Minimum input voltage
+in1_min_alarm		Input voltage low alarm
+
+in2_label		"vout1"
+in2_input		Measured output voltage
+in2_lcrit		Critical minimum output voltage
+in2_lcrit_alarm	Output voltage critical low alarm
+in2_crit		Critical maximum output voltage
+in2_crit_alarm		Output voltage critical high alarm
+in2_max		Maximum output voltage
+in2_max_alarm		Output voltage high alarm
+in2_min		Minimum output voltage
+in2_min_alarm		Output voltage low alarm
+
+power1_label		"pout1"
+power1_input		Measured output power
+
+temp1_input		Measured temperature
+temp1_crit		Critical high temperature
+temp1_crit_alarm	Chip temperature critical high alarm
+temp1_max		Maximum temperature
+temp1_max_alarm	Chip temperature high alarm

drivers/hwmon/pmbus/Kconfig

···
 	  This driver can also be built as a module. If so, the module will
 	  be called ir35521.
 
+config SENSORS_IR38064
+	tristate "Infineon IR38064"
+	help
+	  If you say yes here you get hardware monitoring support for Infineon
+	  IR38064.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ir38064.
+
 config SENSORS_LM25066
 	tristate "National Semiconductor LM25066 and compatibles"
 	help

drivers/hwmon/pmbus/Makefile

···
 obj-$(CONFIG_SENSORS_ADM1275)	+= adm1275.o
 obj-$(CONFIG_SENSORS_IBM_CFFPS)	+= ibm-cffps.o
 obj-$(CONFIG_SENSORS_IR35221)	+= ir35221.o
+obj-$(CONFIG_SENSORS_IR38064)	+= ir38064.o
 obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
 obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o

drivers/hwmon/pmbus/ir38064.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for Infineon IR38064
+ *
+ * Copyright (c) 2017 Google Inc
+ *
+ * VOUT_MODE is not supported by the device. The driver fakes VOUT linear16
+ * mode with exponent value -8 as direct mode with m=256/b=0/R=0.
+ *          
+ * The device supports VOUT_PEAK, IOUT_PEAK, and TEMPERATURE_PEAK, however
+ * this driver does not currently support them.
+ */
+
+#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 ir38064_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = direct,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_POWER] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.m[PSC_VOLTAGE_OUT] = 256,
+	.b[PSC_VOLTAGE_OUT] = 0,
+	.R[PSC_VOLTAGE_OUT] = 0,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+	    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
+	    | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+	    | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+	    | PMBUS_HAVE_POUT,
+};
+
+static int ir38064_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	return pmbus_do_probe(client, id, &ir38064_info);
+}
+
+static const struct i2c_device_id ir38064_id[] = {
+	{"ir38064", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, ir38064_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ir38064_driver = {
+	.driver = {
+		   .name = "ir38064",
+		   },
+	.probe = ir38064_probe,
+	.remove = pmbus_do_remove,
+	.id_table = ir38064_id,
+};
+
+module_i2c_driver(ir38064_driver);
+
+MODULE_AUTHOR("Maxim Sloyko <[e-mail]>");
+MODULE_DESCRIPTION("PMBus driver for Infineon IR38064");
+MODULE_LICENSE("GPL");