hwmon: (pmbus) Add support for MAX20751

MAX20751 is a multiphase power controller with internal buck converter.
It uses VR12.0 to report the output voltage. This requires an explicit
driver, since the VR version can not be auto-detected.

The chip supports a manufacturer specific command to fine-tune the output
voltage.  This command is not currently supported.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

5 files changed, 159 insertions, 0 deletions

diff --git a/Documentation/hwmon/max20751 b/Documentation/hwmon/max20751
new file mode 100644
index 000000000000..f9fa25ebb521
--- /dev/null
+++ b/Documentation/hwmon/max20751
@@ -0,0 +1,77 @@
+Kernel driver max20751
+======================
+
+Supported chips:
+  * maxim MAX20751
+    Prefix: 'max20751'
+    Addresses scanned: -
+    Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX20751.pdf
+    Application note: http://pdfserv.maximintegrated.com/en/an/AN5941.pdf
+
+Author: Guenter Roeck <linux@roeck-us.net>
+
+
+Description
+-----------
+
+This driver supports MAX20751 Multiphase Master with PMBus Interface
+and Internal Buck Converter.
+
+The driver is a client driver to the core PMBus driver.
+Please see Documentation/hwmon/pmbus for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices for
+details.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported.
+
+in1_label               "vin1"
+in1_input               Measured voltage.
+in1_min                 Minimum input voltage.
+in1_max                 Maximum input voltage.
+in1_lcrit               Critical minimum input voltage.
+in1_crit                Critical maximum input voltage.
+in1_min_alarm           Input voltage low alarm.
+in1_lcrit_alarm         Input voltage critical low alarm.
+in1_min_alarm           Input voltage low alarm.
+in1_max_alarm           Input voltage high alarm.
+
+in2_label               "vout1"
+in2_input               Measured voltage.
+in2_min                 Minimum output voltage.
+in2_max                 Maximum output voltage.
+in2_lcrit               Critical minimum output voltage.
+in2_crit                Critical maximum output voltage.
+in2_min_alarm           Output voltage low alarm.
+in2_lcrit_alarm         Output voltage critical low alarm.
+in2_min_alarm           Output voltage low alarm.
+in2_max_alarm           Output voltage high alarm.
+
+curr1_input             Measured output current.
+curr1_label             "iout1"
+curr1_max               Maximum output current.
+curr1_alarm             Current high alarm.
+
+temp1_input             Measured temperature.
+temp1_max               Maximum temperature.
+temp1_crit              Critical high temperature.
+temp1_max_alarm         Chip temperature high alarm.
+temp1_crit_alarm        Chip temperature critical high alarm.
+
+power1_input            Output power.
+power1_label            "pout1"
diff --git a/MAINTAINERS b/MAINTAINERS
index a9ae6c105520..6a406b607eeb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6539,6 +6539,13 @@ S:	Maintained
 F:      Documentation/hwmon/max16065
 F:      drivers/hwmon/max16065.c
 
+MAX20751 HARDWARE MONITOR DRIVER
+M:      Guenter Roeck <linux@roeck-us.net>
+L:      lm-sensors@lm-sensors.org
+S:      Maintained
+F:      Documentation/hwmon/max20751
+F:      drivers/hwmon/max20751.c
+
 MAX6650 HARDWARE MONITOR AND FAN CONTROLLER DRIVER
 M:      "Hans J. Koch" <hjk@hansjkoch.de>
 L:      lm-sensors@lm-sensors.org
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 67901cb08f77..6e1e6fe434f7 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -73,6 +73,16 @@ config SENSORS_MAX16064
           This driver can also be built as a module. If so, the module will
           be called max16064.
 
+config SENSORS_MAX20751
+        tristate "Maxim MAX20751"
+        default n
+        help
+          If you say yes here you get hardware monitoring support for Maxim
+          MAX20751.
+
+          This driver can also be built as a module. If so, the module will
+          be called max20751.
+
 config SENSORS_MAX34440
         tristate "Maxim MAX34440 and compatibles"
         default n
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 1454293e985c..bce046d37f02 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_SENSORS_ADM1275)	+= adm1275.o
 obj-$(CONFIG_SENSORS_LM25066)   += lm25066.o
 obj-$(CONFIG_SENSORS_LTC2978)   += ltc2978.o
 obj-$(CONFIG_SENSORS_MAX16064)  += max16064.o
+obj-$(CONFIG_SENSORS_MAX20751)  += max20751.o
 obj-$(CONFIG_SENSORS_MAX34440)  += max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)   += max8688.o
 obj-$(CONFIG_SENSORS_TPS40422)  += tps40422.o
diff --git a/drivers/hwmon/pmbus/max20751.c b/drivers/hwmon/pmbus/max20751.c
new file mode 100644
index 000000000000..ab74aeae8cf2
--- /dev/null
+++ b/drivers/hwmon/pmbus/max20751.c
@@ -0,0 +1,64 @@
+/*
+ * Hardware monitoring driver for Maxim MAX20751
+ *
+ * Copyright (c) 2015 Guenter Roeck
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+static struct pmbus_driver_info max20751_info = {
+        .pages = 1,
+        .format[PSC_VOLTAGE_IN] = linear,
+        .format[PSC_VOLTAGE_OUT] = vid,
+        .vrm_version = vr12,
+        .format[PSC_TEMPERATURE] = linear,
+        .format[PSC_CURRENT_OUT] = linear,
+        .format[PSC_POWER] = linear,
+        .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+                PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+                PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
+                PMBUS_HAVE_POUT,
+};
+
+static int max20751_probe(struct i2c_client *client,
+                          const struct i2c_device_id *id)
+{
+        return pmbus_do_probe(client, id, &max20751_info);
+}
+
+static const struct i2c_device_id max20751_id[] = {
+        {"max20751", 0},
+        {}
+};
+
+MODULE_DEVICE_TABLE(i2c, max20751_id);
+
+static struct i2c_driver max20751_driver = {
+        .driver = {
+                   .name = "max20751",
+                   },
+        .probe = max20751_probe,
+        .remove = pmbus_do_remove,
+        .id_table = max20751_id,
+};
+
+module_i2c_driver(max20751_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("PMBus driver for Maxim MAX20751");
+MODULE_LICENSE("GPL");