pmbus: Add driver for Maxim MAX31785 Intelligent Fan Controller

The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel
fan management with temperature and remote voltage sensing. It supports
various fan control features, including PWM frequency control, temperature
hysteresis, dual tachometer measurements, and fan health monitoring.

This patch presents a basic driver using only the existing features of the
PMBus subsystem.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
[groeck: Modified description to clarify that fan control is not yet provided]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/Documentation/hwmon/max31785 b/Documentation/hwmon/max31785
new file mode 100644 (file)
index 0000000..45fb609
--- /dev/null
+++ b/Documentation/hwmon/max31785
@@ -0,0 +1,51 @@
+Kernel driver max31785
+======================
+
+Supported chips:
+  * Maxim MAX31785, MAX31785A
+    Prefix: 'max31785' or 'max31785a'
+    Addresses scanned: -
+    Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
+
+Author: Andrew Jeffery <andrew@aj.id.au>
+
+Description
+-----------
+
+The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
+management with temperature and remote voltage sensing. Various fan control
+features are provided, including PWM frequency control, temperature hysteresis,
+dual tachometer measurements, and fan health monitoring.
+
+For dual rotor fan configuration, the MAX31785 exposes the slowest rotor of the
+two in the fan[1-4]_input attributes.
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Sysfs attributes
+----------------
+
+fan[1-4]_alarm         Fan alarm.
+fan[1-4]_fault         Fan fault.
+fan[1-4]_input         Fan RPM.
+
+in[1-6]_crit           Critical maximum output voltage
+in[1-6]_crit_alarm     Output voltage critical high alarm
+in[1-6]_input          Measured output voltage
+in[1-6]_label          "vout[18-23]"
+in[1-6]_lcrit          Critical minimum output voltage
+in[1-6]_lcrit_alarm    Output voltage critical low alarm
+in[1-6]_max            Maximum output voltage
+in[1-6]_max_alarm      Output voltage high alarm
+in[1-6]_min            Minimum output voltage
+in[1-6]_min_alarm      Output voltage low alarm
+
+temp[1-11]_crit                Critical high temperature
+temp[1-11]_crit_alarm  Chip temperature critical high alarm
+temp[1-11]_input       Measured temperature
+temp[1-11]_max         Maximum temperature
+temp[1-11]_max_alarm   Chip temperature high alarm

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 40019325b517f413bf3fae5bf9561ebfb993bfd5..08479006c7f9e9f65e6deaebb6031e5e9e5d3ef5 100644 (file)
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -114,6 +114,16 @@ config SENSORS_MAX20751
          This driver can also be built as a module. If so, the module will
          be called max20751.
 
+config SENSORS_MAX31785
+       tristate "Maxim MAX31785 and compatibles"
+       default n
+       help
+         If you say yes here you get hardware monitoring support for Maxim
+         MAX31785.
+
+         This driver can also be built as a module. If so, the module will
+         be called max31785.
+
 config SENSORS_MAX34440
        tristate "Maxim MAX34440 and compatibles"
        default n

diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 459a6be3390e842bc7018b20e261b9c45fd43816..a8bf0e490db9a65dec24de6bd180bc064085a24a 100644 (file)
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SENSORS_LTC2978) += ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)  += ltc3815.o
 obj-$(CONFIG_SENSORS_MAX16064) += max16064.o
 obj-$(CONFIG_SENSORS_MAX20751) += max20751.o
+obj-$(CONFIG_SENSORS_MAX31785) += max31785.o
 obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)  += max8688.o
 obj-$(CONFIG_SENSORS_TPS40422) += tps40422.o

diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
new file mode 100644 (file)
index 0000000..9313849
--- /dev/null
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2017 IBM Corp.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+enum max31785_regs {
+       MFR_REVISION            = 0x9b,
+};
+
+#define MAX31785_NR_PAGES              23
+
+#define MAX31785_FAN_FUNCS \
+       (PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12)
+
+#define MAX31785_TEMP_FUNCS \
+       (PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP)
+
+#define MAX31785_VOUT_FUNCS \
+       (PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
+
+static const struct pmbus_driver_info max31785_info = {
+       .pages = MAX31785_NR_PAGES,
+
+       /* RPM */
+       .format[PSC_FAN] = direct,
+       .m[PSC_FAN] = 1,
+       .b[PSC_FAN] = 0,
+       .R[PSC_FAN] = 0,
+       .func[0] = MAX31785_FAN_FUNCS,
+       .func[1] = MAX31785_FAN_FUNCS,
+       .func[2] = MAX31785_FAN_FUNCS,
+       .func[3] = MAX31785_FAN_FUNCS,
+       .func[4] = MAX31785_FAN_FUNCS,
+       .func[5] = MAX31785_FAN_FUNCS,
+
+       .format[PSC_TEMPERATURE] = direct,
+       .m[PSC_TEMPERATURE] = 1,
+       .b[PSC_TEMPERATURE] = 0,
+       .R[PSC_TEMPERATURE] = 2,
+       .func[6]  = MAX31785_TEMP_FUNCS,
+       .func[7]  = MAX31785_TEMP_FUNCS,
+       .func[8]  = MAX31785_TEMP_FUNCS,
+       .func[9]  = MAX31785_TEMP_FUNCS,
+       .func[10] = MAX31785_TEMP_FUNCS,
+       .func[11] = MAX31785_TEMP_FUNCS,
+       .func[12] = MAX31785_TEMP_FUNCS,
+       .func[13] = MAX31785_TEMP_FUNCS,
+       .func[14] = MAX31785_TEMP_FUNCS,
+       .func[15] = MAX31785_TEMP_FUNCS,
+       .func[16] = MAX31785_TEMP_FUNCS,
+
+       .format[PSC_VOLTAGE_OUT] = direct,
+       .m[PSC_VOLTAGE_OUT] = 1,
+       .b[PSC_VOLTAGE_OUT] = 0,
+       .R[PSC_VOLTAGE_OUT] = 0,
+       .func[17] = MAX31785_VOUT_FUNCS,
+       .func[18] = MAX31785_VOUT_FUNCS,
+       .func[19] = MAX31785_VOUT_FUNCS,
+       .func[20] = MAX31785_VOUT_FUNCS,
+       .func[21] = MAX31785_VOUT_FUNCS,
+       .func[22] = MAX31785_VOUT_FUNCS,
+};
+
+static int max31785_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+       struct device *dev = &client->dev;
+       struct pmbus_driver_info *info;
+       s64 ret;
+
+       info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
+
+       *info = max31785_info;
+
+       ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 255);
+       if (ret < 0)
+               return ret;
+
+       return pmbus_do_probe(client, id, info);
+}
+
+static const struct i2c_device_id max31785_id[] = {
+       { "max31785", 0 },
+       { "max31785a", 0 },
+       { },
+};
+
+MODULE_DEVICE_TABLE(i2c, max31785_id);
+
+static struct i2c_driver max31785_driver = {
+       .driver = {
+               .name = "max31785",
+       },
+       .probe = max31785_probe,
+       .remove = pmbus_do_remove,
+       .id_table = max31785_id,
+};
+
+module_i2c_driver(max31785_driver);
+
+MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
+MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785");
+MODULE_LICENSE("GPL");