[v2,2/2] hwmon: (pmbus) Add support for MPS Multi-phase mp5990

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 042e1cf9501b..8c70e10fc795 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -157,6 +157,7 @@  Hardware Monitoring Kernel Drivers
    mp2888
    mp2975
    mp5023
+   mp5990
    nct6683
    nct6775
    nct7802
diff --git a/Documentation/hwmon/mp5990.rst b/Documentation/hwmon/mp5990.rst
new file mode 100644
index 000000000000..d2da0f767530
--- /dev/null
+++ b/Documentation/hwmon/mp5990.rst
@@ -0,0 +1,84 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp5990
+====================
+
+Supported chips:
+
+  * MPS MP5990
+
+    Prefix: 'mp5990'
+
+  * Datasheet
+
+    Publicly available at the MPS website : https://www.monolithicpower.com/en/mp5990.html
+
+Author:
+
+	Peter Yin <peteryin.openbmc@gmail.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MP5990 Hot-Swap Controller.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+Device supports direct format for reading input voltage, output voltage,
+output current, input power and temperature.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_max**
+
+**in1_max_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_alarm**
+
+**curr1_max**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+**power1_alarm**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_max**
+
+**temp1_max_alarm**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 270b6336b76d..65a116f7744d 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -326,6 +326,15 @@  config SENSORS_MP5023
 	  This driver can also be built as a module. If so, the module will
 	  be called mp5023.
 
+config SENSORS_MP5990
+	tristate "MPS MP5990"
+	help
+	  If you say yes here you get hardware monitoring support for MPS
+	  MP5990.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called mp5990.
+
 config SENSORS_MPQ7932_REGULATOR
 	bool "Regulator support for MPQ7932"
 	depends on SENSORS_MPQ7932 && REGULATOR
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 84ee960a6c2d..212d9ca0acc9 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -35,6 +35,7 @@  obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
 obj-$(CONFIG_SENSORS_MP2888)	+= mp2888.o
 obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
 obj-$(CONFIG_SENSORS_MP5023)	+= mp5023.o
+obj-$(CONFIG_SENSORS_MP5990)	+= mp5990.o
 obj-$(CONFIG_SENSORS_MPQ7932)	+= mpq7932.o
 obj-$(CONFIG_SENSORS_PLI1209BC)	+= pli1209bc.o
 obj-$(CONFIG_SENSORS_PM6764TR)	+= pm6764tr.o
diff --git a/drivers/hwmon/pmbus/mp5990.c b/drivers/hwmon/pmbus/mp5990.c
new file mode 100644
index 000000000000..fb3ac9c5d44e
--- /dev/null
+++ b/drivers/hwmon/pmbus/mp5990.c
@@ -0,0 +1,86 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MPS MP5990 Hot-Swap Controller
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+static int mp5990_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+	switch (reg) {
+	case PMBUS_VOUT_MODE:
+		/* The datasheet does not support the VOUT command,
+		 * but the device responds with a default value of 0x17.
+		 * In the standard, 0x17 represents linear mode. However,
+		 * for the MP5990, the VOUT linear mode is linear11, not linear16.
+		 * Therefore, we should enforce the VOUT in the direct format.
+		 */
+		return PB_VOUT_MODE_DIRECT;
+	default:
+		return -ENODATA;
+	}
+}
+
+static struct pmbus_driver_info mp5990_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = direct,
+	.format[PSC_VOLTAGE_OUT] = direct,
+	.format[PSC_CURRENT_OUT] = direct,
+	.format[PSC_POWER] = direct,
+	.format[PSC_TEMPERATURE] = direct,
+	.m[PSC_VOLTAGE_IN] = 32,
+	.b[PSC_VOLTAGE_IN] = 0,
+	.R[PSC_VOLTAGE_IN] = 0,
+	.m[PSC_VOLTAGE_OUT] = 32,
+	.b[PSC_VOLTAGE_OUT] = 0,
+	.R[PSC_VOLTAGE_OUT] = 0,
+	.m[PSC_CURRENT_OUT] = 16,
+	.b[PSC_CURRENT_OUT] = 0,
+	.R[PSC_CURRENT_OUT] = 0,
+	.m[PSC_POWER] = 1,
+	.b[PSC_POWER] = 0,
+	.R[PSC_POWER] = 0,
+	.m[PSC_TEMPERATURE] = 1,
+	.b[PSC_TEMPERATURE] = 0,
+	.R[PSC_TEMPERATURE] = 0,
+	.func[0] =
+		PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_PIN |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_IOUT |
+		PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
+	.read_byte_data = mp5990_read_byte_data,
+};
+
+static int mp5990_probe(struct i2c_client *client)
+{
+	return pmbus_do_probe(client, &mp5990_info);
+}
+
+static const struct of_device_id mp5990_of_match[] = {
+	{ .compatible = "mps,mp5990" },
+	{}
+};
+
+static const struct i2c_device_id mp5990_id[] = {
+	{"mp5990", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mp5990_id);
+
+static struct i2c_driver mp5990_driver = {
+	.driver = {
+		   .name = "mp5990",
+		   .of_match_table = mp5990_of_match,
+	},
+	.probe = mp5990_probe,
+	.id_table = mp5990_id,
+};
+module_i2c_driver(mp5990_driver);
+
+MODULE_AUTHOR("Peter Yin <peter.yin@quantatw.com>");
+MODULE_DESCRIPTION("PMBus driver for MP5990 HSC");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);