diff mbox

[linux,v2,2/6] hwmon: occ: Add sysfs interface

Message ID 1484158237-10014-3-git-send-email-eajames.ibm@gmail.com (mailing list archive)
State Changes Requested
Headers show

Commit Message

eajames.ibm@gmail.com Jan. 11, 2017, 6:10 p.m. UTC 
From: "Edward A. James" <eajames@us.ibm.com>

Add a generic mechanism to expose the sensors provided by the OCC in
sysfs.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 Documentation/hwmon/occ       |  62 ++++++++++
 drivers/hwmon/occ/Makefile    |   2 +-
 drivers/hwmon/occ/occ_sysfs.c | 274 ++++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ_sysfs.h |  44 +++++++
 4 files changed, 381 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/occ/occ_sysfs.c
 create mode 100644 drivers/hwmon/occ/occ_sysfs.h

Comments

kernel test robot Jan. 12, 2017, 7:39 a.m. UTC | #1 
Hi Edward,

[auto build test WARNING on hwmon/hwmon-next]
[also build test WARNING on v4.10-rc3 next-20170111]
[cannot apply to linux/master]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/eajames-ibm-gmail-com/hwmon-Add-core-On-Chip-Controller-support-for-POWER-CPUs/20170112-150440
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next


coccinelle warnings: (new ones prefixed by >>)

>> drivers/hwmon/occ/occ_sysfs.c:265:9-16: WARNING: ERR_CAST can be used with hwmon -> dev

Please review and possibly fold the followup patch.

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Guenter Roeck Jan. 15, 2017, 6:18 p.m. UTC | #2 
On 01/11/2017 10:10 AM, eajames.ibm@gmail.com wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
>
> Add a generic mechanism to expose the sensors provided by the OCC in
> sysfs.
>
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
>  Documentation/hwmon/occ       |  62 ++++++++++
>  drivers/hwmon/occ/Makefile    |   2 +-
>  drivers/hwmon/occ/occ_sysfs.c | 274 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/occ/occ_sysfs.h |  44 +++++++
>  4 files changed, 381 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/hwmon/occ/occ_sysfs.c
>  create mode 100644 drivers/hwmon/occ/occ_sysfs.h
>
> diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
> index 79d1642..d0bdf06 100644
> --- a/Documentation/hwmon/occ
> +++ b/Documentation/hwmon/occ
> @@ -25,6 +25,68 @@ Currently, all versions of the OCC support four types of sensor data: power,
>  temperature, frequency, and "caps," which indicate limits and thresholds used
>  internally on the OCC.
>
> +sysfs Entries
> +-------------
> +
> +The OCC driver uses the hwmon sysfs framework to provide data to userspace.
> +
> +The driver exports a number of sysfs files for each type of sensor. The
> +sensor-specific files vary depending on the processor type, though many of the
> +attributes are common for both the POWER8 and POWER9.
> +
> +The hwmon interface cannot define every type of sensor that may be used.
> +Therefore, the frequency sensor on the OCC uses the "input" type sensor defined
> +by the hwmon interface, rather than defining a new type of custom sensor.
> +
> +Below are detailed the names and meaning of each sensor file for both types of
> +processors. All sensors are read-only unless otherwise specified. <x> indicates
> +the hwmon index. sensor id indicates the unique internal OCC identifer. Please
> +see the POWER OCC specification for details on all these sensor values.
> +
> +frequency:
> +	all processors:
> +		in<x>_input - frequency value
> +		in<x>_label - sensor id
> +temperature:
> +	POWER8:
> +		temp<x>_input - temperature value
> +		temp<x>_label - sensor id
> +	POWER9 (in addition to above):
> +		temp<x>_type - FRU type
> +
> +power:
> +	POWER8:
> +		power<x>_input - power value
> +		power<x>_label - sensor id
> +		power<x>_average - accumulator
> +		power<x>_average_interval - update tag (number of samples in
> +			accumulator)
> +	POWER9:
> +		power<x>_input - power value
> +		power<x>_label - sensor id
> +		power<x>_average_min - accumulator[0]
> +		power<x>_average_max - accumulator[1] (64 bits total)
> +		power<x>_average_interval - update tag
> +		power<x>_reset_history - (function_id | (apss_channel << 8)
> +
> +caps:
> +	POWER8:
> +		power<x>_cap - current powercap
> +		power<x>_cap_max - max powercap
> +		power<x>_cap_min - min powercap
> +		power<x>_max - normal powercap
> +		power<x>_alarm - user powercap, r/w
> +	POWER9:
> +		power<x>_cap_alarm - user powercap source
> +
> +The driver also provides two sysfs entries through hwmon to better
> +control the driver and monitor the master OCC. Though there may be multiple
> +OCCs present on the system, these two files are only present for the "master"
> +OCC.
> +	name - read the name of the driver
> +	update_interval - read or write the minimum interval for polling the
> +		OCC.
> +
>  BMC - Host Communications
>  -------------------------
>
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> index 93cb52f..a6881f9 100644
> --- a/drivers/hwmon/occ/Makefile
> +++ b/drivers/hwmon/occ/Makefile
> @@ -1 +1 @@
> -obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o
> +obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o
> diff --git a/drivers/hwmon/occ/occ_sysfs.c b/drivers/hwmon/occ/occ_sysfs.c
> new file mode 100644
> index 0000000..e846b0c
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_sysfs.c
> @@ -0,0 +1,274 @@
> +/*
> + * occ_sysfs.c - OCC sysfs interface
> + *
> + * This file contains the methods and data structures for implementing the OCC
> + * hwmon sysfs entries.
> + *
> + * Copyright 2016 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.
> + *
> + * 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/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/jiffies.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/err.h>
> +#include <linux/mutex.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +
Again, for all patches: alphabetic order, please.

> +#include "occ.h"
> +#include "occ_sysfs.h"
> +
> +#define RESP_RETURN_CMD_INVAL	0x13
> +
> +static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> +			  u32 attr, int channel, long *val)
> +{
> +	int rc = 0;
> +	struct occ_sysfs *driver = dev_get_drvdata(dev);
> +	struct occ *occ = driver->occ;
> +
> +	switch (type) {
> +	case hwmon_in:
> +		rc = occ_get_sensor_value(occ, FREQ, channel, attr, val);
> +		break;
> +	case hwmon_temp:
> +		rc = occ_get_sensor_value(occ, TEMP, channel, attr, val);
> +		break;
> +	case hwmon_power:
> +		rc = occ_get_sensor_value(occ, POWER, channel, attr, val);
> +		break;
> +	default:
> +		rc = -EOPNOTSUPP;
> +	}
> +
> +	return rc;
> +}
> +
> +static int occ_hwmon_read_string(struct device *dev,
> +				 enum hwmon_sensor_types type, u32 attr,
> +				 int channel, char **str)
> +{
> +	int rc;
> +	unsigned long val = 0;
> +
> +	if (!((type == hwmon_in && attr == hwmon_in_label) ||
> +	    (type == hwmon_temp && attr == hwmon_temp_label) ||
> +	    (type == hwmon_power && attr == hwmon_power_label)))
> +		return -EOPNOTSUPP;
> +
> +	rc = occ_hwmon_read(dev, type, attr, channel, &val);
> +	if (rc < 0)
> +		return rc;
> +
> +	rc = snprintf(*str, PAGE_SIZE - 1, "%ld", val);
> +	if (rc > 0)
> +		rc = 0;
> +
> +	return rc;
> +}
> +
> +static int occ_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
> +			   u32 attr, int channel, long val)
> +{
> +	int rc = 0;
> +	struct occ_sysfs *driver = dev_get_drvdata(dev);
> +
> +	if (type == hwmon_chip && attr == hwmon_chip_update_interval) {
> +		occ_set_update_interval(driver->occ, val);
> +		return 0;
> +	} else if (type == hwmon_power && attr == hwmon_power_alarm) {
> +		rc = occ_set_user_powercap(driver->occ, val);
> +		if (rc) {
> +			if (rc == RESP_RETURN_CMD_INVAL) {
> +				dev_err(dev,
> +					"set invalid powercap value: %ld\n",
> +					val);
> +				return -EINVAL;
> +			}
> +
> +			dev_err(dev, "set user powercap failed: 0x:%x\n", rc);
> +			return rc;
> +		}
> +
> +		driver->user_powercap = val;
> +
> +		return rc;
> +	}
> +
> +	return -EOPNOTSUPP;
> +}
> +
> +static umode_t occ_is_visible(const void *data, enum hwmon_sensor_types type,
> +			      u32 attr, int channel)
> +{
> +	const struct occ_sysfs *driver = data;
> +
> +	switch (type) {
> +	case hwmon_chip:
> +		if (attr == hwmon_chip_update_interval)
> +			return S_IRUGO | S_IWUSR;
> +		break;
> +	case hwmon_in:
> +		if (BIT(attr) & driver->sensor_hwmon_configs[0])
> +			return S_IRUGO;
> +		break;
> +	case hwmon_temp:
> +		if (BIT(attr) & driver->sensor_hwmon_configs[1])
> +			return S_IRUGO;
> +		break;
> +	case hwmon_power:
> +		/* user power limit */
> +		if (attr == hwmon_power_alarm)
> +			return S_IRUGO | S_IWUSR;
> +		else if ((BIT(attr) & driver->sensor_hwmon_configs[2]) ||
> +			 (BIT(attr) & driver->sensor_hwmon_configs[3]))
> +			return S_IRUGO;
> +		break;
> +	default:
> +		return 0;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct hwmon_ops occ_hwmon_ops = {
> +	.is_visible = occ_is_visible,
> +	.read = occ_hwmon_read,
> +	.read_string = occ_hwmon_read_string,
> +	.write = occ_hwmon_write,
> +};
> +
> +static const u32 occ_chip_config[] = {
> +	HWMON_C_UPDATE_INTERVAL,
> +	0
> +};
> +
> +static const struct hwmon_channel_info occ_chip = {
> +	.type = hwmon_chip,
> +	.config = occ_chip_config
> +};
> +
> +static const enum hwmon_sensor_types occ_sensor_types[MAX_OCC_SENSOR_TYPE] = {
> +	hwmon_in,
> +	hwmon_temp,
> +	hwmon_power,
> +	hwmon_power
> +};
> +
> +struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
> +				  const u32 *sensor_hwmon_configs,
> +				  const char *name)
> +{
> +	bool master_occ = false;
> +	int rc, i, j, sensor_num, index = 0, id;
> +	char *brk;
> +	struct occ_blocks *resp = NULL;
> +	u32 *sensor_config;
> +	struct occ_sysfs *hwmon = devm_kzalloc(dev, sizeof(struct occ_sysfs),
> +					       GFP_KERNEL);
> +	if (!hwmon)
> +		return ERR_PTR(-ENOMEM);
> +
> +	/* need space for null-termination and occ chip */
> +	hwmon->occ_sensors =
> +		devm_kzalloc(dev, sizeof(struct hwmon_channel_info *) *
> +			     (MAX_OCC_SENSOR_TYPE + 2), GFP_KERNEL);
> +	if (!hwmon->occ_sensors)
> +		return ERR_PTR(-ENOMEM);
> +
> +	hwmon->occ = occ;
> +	hwmon->sensor_hwmon_configs = (u32 *)sensor_hwmon_configs;
> +	hwmon->occ_info.ops = &occ_hwmon_ops;
> +	hwmon->occ_info.info =
> +		(const struct hwmon_channel_info **)hwmon->occ_sensors;
> +
> +	dev_set_drvdata(dev, hwmon);
> +
Overwritten in the calling code. It is actually not needed here because dev_get_drvdata()
in the access functions gets the value from the hwmon device, and that is set with
the 3rd parameter of devm_hwmon_device_register_with_info().

> +	occ_get_response_blocks(occ, &resp);
> +
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; ++i)
> +		resp->sensor_block_id[i] = -1;
> +
> +	/* read sensor data from occ */
> +	rc = occ_update_device(occ);
> +	if (rc) {
> +		dev_err(dev, "cannot get occ sensor data: %d\n", rc);
> +		return ERR_PTR(rc);
> +	}
> +	if (!resp->blocks)
> +		return ERR_PTR(-ENOMEM);
> +
> +	master_occ = resp->sensor_block_id[CAPS] >= 0;
> +
> +	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
> +		id = resp->sensor_block_id[i];
> +		if (id < 0)
> +			continue;
> +
> +		sensor_num = resp->blocks[id].header.sensor_num;
> +		/* need null-termination */
> +		sensor_config = devm_kzalloc(dev,
> +					     sizeof(u32) * (sensor_num + 1),
> +					     GFP_KERNEL);
> +		if (!sensor_config)
> +			return ERR_PTR(-ENOMEM);
> +
> +		for (j = 0; j < sensor_num; j++)
> +			sensor_config[j] = sensor_hwmon_configs[i];
> +
> +		hwmon->occ_sensors[index] =
> +			devm_kzalloc(dev, sizeof(struct hwmon_channel_info),
> +				     GFP_KERNEL);
> +		if (!hwmon->occ_sensors[index])
> +			return ERR_PTR(-ENOMEM);
> +
> +		hwmon->occ_sensors[index]->type = occ_sensor_types[i];
> +		hwmon->occ_sensors[index]->config = sensor_config;
> +		index++;
> +	}
> +
> +	/* only need one of these for any number of occs */
> +	if (master_occ)
> +		hwmon->occ_sensors[index] =
> +			(struct hwmon_channel_info *)&occ_chip;
> +
> +	/* search for bad chars */
> +	strncpy(hwmon->hwmon_name, name, OCC_HWMON_NAME_LENGTH);
> +	brk = strpbrk(hwmon->hwmon_name, "-* \t\n");
> +	while (brk) {
> +		*brk = '_';
> +		brk = strpbrk(brk,  "-* \t\n");
> +	}
> +
> +	hwmon->dev = devm_hwmon_device_register_with_info(dev,
> +							  hwmon->hwmon_name,
> +							  hwmon,
> +							  &hwmon->occ_info,
> +							  NULL);
> +	if (IS_ERR(hwmon->dev)) {
> +		dev_err(dev, "cannot register hwmon device %s: %ld\n",
> +			hwmon->hwmon_name, PTR_ERR(hwmon->dev));
> +		return ERR_PTR(PTR_ERR(hwmon->dev));
> +	}
> +
> +	return hwmon;
> +}
> +EXPORT_SYMBOL(occ_sysfs_start);
> +
> +MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
> +MODULE_DESCRIPTION("OCC sysfs driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hwmon/occ/occ_sysfs.h b/drivers/hwmon/occ/occ_sysfs.h
> new file mode 100644
> index 0000000..7de92e7
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_sysfs.h
> @@ -0,0 +1,44 @@
> +/*
> + * occ_sysfs.h - OCC sysfs interface
> + *
> + * This file contains the data structures and function prototypes for the OCC
> + * hwmon sysfs entries.
> + *
> + * Copyright 2016 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.
> + *
> + * 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.
> + */
> +
> +#ifndef __OCC_SYSFS_H__
> +#define __OCC_SYSFS_H__
> +
> +#include <linux/hwmon.h>
> +
> +struct occ;
> +struct device;
> +
> +#define OCC_HWMON_NAME_LENGTH	32
> +
> +struct occ_sysfs {
> +	struct device *dev;
> +	struct occ *occ;
> +
> +	char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
> +	u32 *sensor_hwmon_configs;
> +	struct hwmon_channel_info **occ_sensors;
> +	struct hwmon_chip_info occ_info;
> +	u16 user_powercap;
> +};
> +
> +struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
> +				  const u32 *sensor_hwmon_configs,
> +				  const char *name);
> +#endif /* __OCC_SYSFS_H__ */
>

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diff mbox

Patch

diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ
index 79d1642..d0bdf06 100644
--- a/Documentation/hwmon/occ
+++ b/Documentation/hwmon/occ
@@ -25,6 +25,68 @@  Currently, all versions of the OCC support four types of sensor data: power,
 temperature, frequency, and "caps," which indicate limits and thresholds used
 internally on the OCC.
 
+sysfs Entries
+-------------
+
+The OCC driver uses the hwmon sysfs framework to provide data to userspace.
+
+The driver exports a number of sysfs files for each type of sensor. The
+sensor-specific files vary depending on the processor type, though many of the
+attributes are common for both the POWER8 and POWER9.
+
+The hwmon interface cannot define every type of sensor that may be used.
+Therefore, the frequency sensor on the OCC uses the "input" type sensor defined
+by the hwmon interface, rather than defining a new type of custom sensor.
+
+Below are detailed the names and meaning of each sensor file for both types of
+processors. All sensors are read-only unless otherwise specified. <x> indicates
+the hwmon index. sensor id indicates the unique internal OCC identifer. Please
+see the POWER OCC specification for details on all these sensor values.
+
+frequency:
+	all processors:
+		in<x>_input - frequency value
+		in<x>_label - sensor id
+temperature:
+	POWER8:
+		temp<x>_input - temperature value
+		temp<x>_label - sensor id
+	POWER9 (in addition to above):
+		temp<x>_type - FRU type
+
+power:
+	POWER8:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average - accumulator
+		power<x>_average_interval - update tag (number of samples in
+			accumulator)
+	POWER9:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average_min - accumulator[0]
+		power<x>_average_max - accumulator[1] (64 bits total)
+		power<x>_average_interval - update tag
+		power<x>_reset_history - (function_id | (apss_channel << 8)
+
+caps:
+	POWER8:
+		power<x>_cap - current powercap
+		power<x>_cap_max - max powercap
+		power<x>_cap_min - min powercap
+		power<x>_max - normal powercap
+		power<x>_alarm - user powercap, r/w
+	POWER9:
+		power<x>_cap_alarm - user powercap source
+
+The driver also provides two sysfs entries through hwmon to better
+control the driver and monitor the master OCC. Though there may be multiple
+OCCs present on the system, these two files are only present for the "master"
+OCC.
+	name - read the name of the driver
+	update_interval - read or write the minimum interval for polling the
+		OCC.
+
 BMC - Host Communications
 -------------------------
 
diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
index 93cb52f..a6881f9 100644
--- a/drivers/hwmon/occ/Makefile
+++ b/drivers/hwmon/occ/Makefile
@@ -1 +1 @@ 
-obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o
+obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o
diff --git a/drivers/hwmon/occ/occ_sysfs.c b/drivers/hwmon/occ/occ_sysfs.c
new file mode 100644
index 0000000..e846b0c
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.c
@@ -0,0 +1,274 @@ 
+/*
+ * occ_sysfs.c - OCC sysfs interface
+ *
+ * This file contains the methods and data structures for implementing the OCC
+ * hwmon sysfs entries.
+ *
+ * Copyright 2016 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.
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+
+#include "occ.h"
+#include "occ_sysfs.h"
+
+#define RESP_RETURN_CMD_INVAL	0x13
+
+static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			  u32 attr, int channel, long *val)
+{
+	int rc = 0;
+	struct occ_sysfs *driver = dev_get_drvdata(dev);
+	struct occ *occ = driver->occ;
+
+	switch (type) {
+	case hwmon_in:
+		rc = occ_get_sensor_value(occ, FREQ, channel, attr, val);
+		break;
+	case hwmon_temp:
+		rc = occ_get_sensor_value(occ, TEMP, channel, attr, val);
+		break;
+	case hwmon_power:
+		rc = occ_get_sensor_value(occ, POWER, channel, attr, val);
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+	}
+
+	return rc;
+}
+
+static int occ_hwmon_read_string(struct device *dev,
+				 enum hwmon_sensor_types type, u32 attr,
+				 int channel, char **str)
+{
+	int rc;
+	unsigned long val = 0;
+
+	if (!((type == hwmon_in && attr == hwmon_in_label) ||
+	    (type == hwmon_temp && attr == hwmon_temp_label) ||
+	    (type == hwmon_power && attr == hwmon_power_label)))
+		return -EOPNOTSUPP;
+
+	rc = occ_hwmon_read(dev, type, attr, channel, &val);
+	if (rc < 0)
+		return rc;
+
+	rc = snprintf(*str, PAGE_SIZE - 1, "%ld", val);
+	if (rc > 0)
+		rc = 0;
+
+	return rc;
+}
+
+static int occ_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, long val)
+{
+	int rc = 0;
+	struct occ_sysfs *driver = dev_get_drvdata(dev);
+
+	if (type == hwmon_chip && attr == hwmon_chip_update_interval) {
+		occ_set_update_interval(driver->occ, val);
+		return 0;
+	} else if (type == hwmon_power && attr == hwmon_power_alarm) {
+		rc = occ_set_user_powercap(driver->occ, val);
+		if (rc) {
+			if (rc == RESP_RETURN_CMD_INVAL) {
+				dev_err(dev,
+					"set invalid powercap value: %ld\n",
+					val);
+				return -EINVAL;
+			}
+
+			dev_err(dev, "set user powercap failed: 0x:%x\n", rc);
+			return rc;
+		}
+
+		driver->user_powercap = val;
+
+		return rc;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static umode_t occ_is_visible(const void *data, enum hwmon_sensor_types type,
+			      u32 attr, int channel)
+{
+	const struct occ_sysfs *driver = data;
+
+	switch (type) {
+	case hwmon_chip:
+		if (attr == hwmon_chip_update_interval)
+			return S_IRUGO | S_IWUSR;
+		break;
+	case hwmon_in:
+		if (BIT(attr) & driver->sensor_hwmon_configs[0])
+			return S_IRUGO;
+		break;
+	case hwmon_temp:
+		if (BIT(attr) & driver->sensor_hwmon_configs[1])
+			return S_IRUGO;
+		break;
+	case hwmon_power:
+		/* user power limit */
+		if (attr == hwmon_power_alarm)
+			return S_IRUGO | S_IWUSR;
+		else if ((BIT(attr) & driver->sensor_hwmon_configs[2]) ||
+			 (BIT(attr) & driver->sensor_hwmon_configs[3]))
+			return S_IRUGO;
+		break;
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops occ_hwmon_ops = {
+	.is_visible = occ_is_visible,
+	.read = occ_hwmon_read,
+	.read_string = occ_hwmon_read_string,
+	.write = occ_hwmon_write,
+};
+
+static const u32 occ_chip_config[] = {
+	HWMON_C_UPDATE_INTERVAL,
+	0
+};
+
+static const struct hwmon_channel_info occ_chip = {
+	.type = hwmon_chip,
+	.config = occ_chip_config
+};
+
+static const enum hwmon_sensor_types occ_sensor_types[MAX_OCC_SENSOR_TYPE] = {
+	hwmon_in,
+	hwmon_temp,
+	hwmon_power,
+	hwmon_power
+};
+
+struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
+				  const u32 *sensor_hwmon_configs,
+				  const char *name)
+{
+	bool master_occ = false;
+	int rc, i, j, sensor_num, index = 0, id;
+	char *brk;
+	struct occ_blocks *resp = NULL;
+	u32 *sensor_config;
+	struct occ_sysfs *hwmon = devm_kzalloc(dev, sizeof(struct occ_sysfs),
+					       GFP_KERNEL);
+	if (!hwmon)
+		return ERR_PTR(-ENOMEM);
+
+	/* need space for null-termination and occ chip */
+	hwmon->occ_sensors =
+		devm_kzalloc(dev, sizeof(struct hwmon_channel_info *) *
+			     (MAX_OCC_SENSOR_TYPE + 2), GFP_KERNEL);
+	if (!hwmon->occ_sensors)
+		return ERR_PTR(-ENOMEM);
+
+	hwmon->occ = occ;
+	hwmon->sensor_hwmon_configs = (u32 *)sensor_hwmon_configs;
+	hwmon->occ_info.ops = &occ_hwmon_ops;
+	hwmon->occ_info.info =
+		(const struct hwmon_channel_info **)hwmon->occ_sensors;
+
+	dev_set_drvdata(dev, hwmon);
+
+	occ_get_response_blocks(occ, &resp);
+
+	for (i = 0; i < MAX_OCC_SENSOR_TYPE; ++i)
+		resp->sensor_block_id[i] = -1;
+
+	/* read sensor data from occ */
+	rc = occ_update_device(occ);
+	if (rc) {
+		dev_err(dev, "cannot get occ sensor data: %d\n", rc);
+		return ERR_PTR(rc);
+	}
+	if (!resp->blocks)
+		return ERR_PTR(-ENOMEM);
+
+	master_occ = resp->sensor_block_id[CAPS] >= 0;
+
+	for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
+		id = resp->sensor_block_id[i];
+		if (id < 0)
+			continue;
+
+		sensor_num = resp->blocks[id].header.sensor_num;
+		/* need null-termination */
+		sensor_config = devm_kzalloc(dev,
+					     sizeof(u32) * (sensor_num + 1),
+					     GFP_KERNEL);
+		if (!sensor_config)
+			return ERR_PTR(-ENOMEM);
+
+		for (j = 0; j < sensor_num; j++)
+			sensor_config[j] = sensor_hwmon_configs[i];
+
+		hwmon->occ_sensors[index] =
+			devm_kzalloc(dev, sizeof(struct hwmon_channel_info),
+				     GFP_KERNEL);
+		if (!hwmon->occ_sensors[index])
+			return ERR_PTR(-ENOMEM);
+
+		hwmon->occ_sensors[index]->type = occ_sensor_types[i];
+		hwmon->occ_sensors[index]->config = sensor_config;
+		index++;
+	}
+
+	/* only need one of these for any number of occs */
+	if (master_occ)
+		hwmon->occ_sensors[index] =
+			(struct hwmon_channel_info *)&occ_chip;
+
+	/* search for bad chars */
+	strncpy(hwmon->hwmon_name, name, OCC_HWMON_NAME_LENGTH);
+	brk = strpbrk(hwmon->hwmon_name, "-* \t\n");
+	while (brk) {
+		*brk = '_';
+		brk = strpbrk(brk,  "-* \t\n");
+	}
+
+	hwmon->dev = devm_hwmon_device_register_with_info(dev,
+							  hwmon->hwmon_name,
+							  hwmon,
+							  &hwmon->occ_info,
+							  NULL);
+	if (IS_ERR(hwmon->dev)) {
+		dev_err(dev, "cannot register hwmon device %s: %ld\n",
+			hwmon->hwmon_name, PTR_ERR(hwmon->dev));
+		return ERR_PTR(PTR_ERR(hwmon->dev));
+	}
+
+	return hwmon;
+}
+EXPORT_SYMBOL(occ_sysfs_start);
+
+MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>");
+MODULE_DESCRIPTION("OCC sysfs driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hwmon/occ/occ_sysfs.h b/drivers/hwmon/occ/occ_sysfs.h
new file mode 100644
index 0000000..7de92e7
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.h
@@ -0,0 +1,44 @@ 
+/*
+ * occ_sysfs.h - OCC sysfs interface
+ *
+ * This file contains the data structures and function prototypes for the OCC
+ * hwmon sysfs entries.
+ *
+ * Copyright 2016 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.
+ *
+ * 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.
+ */
+
+#ifndef __OCC_SYSFS_H__
+#define __OCC_SYSFS_H__
+
+#include <linux/hwmon.h>
+
+struct occ;
+struct device;
+
+#define OCC_HWMON_NAME_LENGTH	32
+
+struct occ_sysfs {
+	struct device *dev;
+	struct occ *occ;
+
+	char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
+	u32 *sensor_hwmon_configs;
+	struct hwmon_channel_info **occ_sensors;
+	struct hwmon_chip_info occ_info;
+	u16 user_powercap;
+};
+
+struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
+				  const u32 *sensor_hwmon_configs,
+				  const char *name);
+#endif /* __OCC_SYSFS_H__ */