hwmon: (powerpc/powernv) hwmon driver for power, fan rpm, voltage and temperature

IBM POWERNV platform sensors

----------------------------

Required node properties:

- compatible: must be one of

		"ibm,opal-sensor-cooling-fan"

		"ibm,opal-sensor-amb-temp"

		"ibm,opal-sensor-power-supply"

		"ibm,opal-sensor-power"

- sensor-id: an opaque id provided by the firmware to the kernel, identifies a

	     given sensor and its attribute data

Example sensors node:

cooling-fan#8-data {

	sensor-id = <0x7052107>;

	compatible = "ibm,opal-sensor-cooling-fan";

};

amb-temp#1-thrs {

	sensor-id = <0x5096000>;

	compatible = "ibm,opal-sensor-amb-temp";

};

Kernel Driver IBMPOWERNV

========================

Supported systems:

  * Any recent IBM P servers based on POWERNV platform

Author: Neelesh Gupta

Description

-----------

This driver implements reading the platform sensors data like temperature/fan/

voltage/power for 'POWERNV' platform.

The driver uses the platform device infrastructure. It probes the device tree

for sensor devices during the __init phase and registers them with the 'hwmon'.

'hwmon' populates the 'sysfs' tree having attribute files, each for a given

sensor type and its attribute data.

All the nodes in the DT appear under "/ibm,opal/sensors" and each valid node in

the DT maps to an attribute file in 'sysfs'. The node exports unique 'sensor-id'

which the driver uses to make an OPAL call to the firmware.

Usage notes

-----------

The driver is built statically with the kernel by enabling the config

CONFIG_SENSORS_IBMPOWERNV. It can also be built as module 'ibmpowernv'.

Sysfs attributes

----------------

fanX_input		Measured RPM value.

fanX_min		Threshold RPM for alert generation.

fanX_fault		0: No fail condition

			1: Failing fan

tempX_input		Measured ambient temperature.

tempX_max		Threshold ambient temperature for alert generation.

inX_input		Measured power supply voltage

inX_fault		0: No fail condition.

			1: Failing power supply.

power1_input		System power consumption (microWatt)

	  This driver can also be built as a module.  If so, the module

	  will be called ibmpex.

config SENSORS_IBMPOWERNV

	tristate "IBM POWERNV platform sensors"

	depends on PPC_POWERNV

	default y

	help

	  If you say yes here you get support for the temperature/fan/power

	  sensors on your PowerNV platform.

	  This driver can also be built as a module. If so, the module

	  will be called ibmpowernv.

config SENSORS_IIO_HWMON

	tristate "Hwmon driver that uses channels specified via iio maps"

	depends on IIO

obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o

obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o

obj-$(CONFIG_SENSORS_IBMPEX)	+= ibmpex.o

obj-$(CONFIG_SENSORS_IBMPOWERNV)+= ibmpowernv.o

obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o

obj-$(CONFIG_SENSORS_INA209)	+= ina209.o

obj-$(CONFIG_SENSORS_INA2XX)	+= ina2xx.o

/*

 * IBM PowerNV platform sensors for temperature/fan/voltage/power

 * Copyright (C) 2014 IBM

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.

 */

#define DRVNAME		"ibmpowernv"

#define pr_fmt(fmt)	DRVNAME ": " fmt

#include <linux/init.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/of.h>

#include <linux/slab.h>

#include <linux/platform_device.h>

#include <asm/opal.h>

#include <linux/err.h>

#define MAX_ATTR_LEN	32

/* Sensor suffix name from DT */

#define DT_FAULT_ATTR_SUFFIX		"faulted"

#define DT_DATA_ATTR_SUFFIX		"data"

#define DT_THRESHOLD_ATTR_SUFFIX	"thrs"

/*

 * Enumerates all the types of sensors in the POWERNV platform and does index

 * into 'struct sensor_group'

 */

enum sensors {

	FAN,

	AMBIENT_TEMP,

	POWER_SUPPLY,

	POWER_INPUT,

	MAX_SENSOR_TYPE,

};

static struct sensor_group {

	const char *name;

	const char *compatible;

	struct attribute_group group;

	u32 attr_count;

} sensor_groups[] = {

	{"fan", "ibm,opal-sensor-cooling-fan"},

	{"temp", "ibm,opal-sensor-amb-temp"},

	{"in", "ibm,opal-sensor-power-supply"},

	{"power", "ibm,opal-sensor-power"}

};

struct sensor_data {

	u32 id; /* An opaque id of the firmware for each sensor */

	enum sensors type;

	char name[MAX_ATTR_LEN];

	struct device_attribute dev_attr;

};

struct platform_data {

	const struct attribute_group *attr_groups[MAX_SENSOR_TYPE + 1];

	u32 sensors_count; /* Total count of sensors from each group */

};

/* Platform device representing all the ibmpowernv sensors */

static struct platform_device *pdevice;

static ssize_t show_sensor(struct device *dev, struct device_attribute *devattr,

			   char *buf)

{

	struct sensor_data *sdata = container_of(devattr, struct sensor_data,

						 dev_attr);

	ssize_t ret;

	u32 x;

	ret = opal_get_sensor_data(sdata->id, &x);

	if (ret)

		return ret;

	/* Convert temperature to milli-degrees */

	if (sdata->type == AMBIENT_TEMP)

		x *= 1000;

	/* Convert power to micro-watts */

	else if (sdata->type == POWER_INPUT)

		x *= 1000000;

	return sprintf(buf, "%u\n", x);

}

static int __init get_sensor_index_attr(const char *name, u32 *index,

					char *attr)

{

	char *hash_pos = strchr(name, '#');

	char buf[8] = { 0 };

	char *dash_pos;

	u32 copy_len;

	int err;

	if (!hash_pos)

		return -EINVAL;

	dash_pos = strchr(hash_pos, '-');

	if (!dash_pos)

		return -EINVAL;

	copy_len = dash_pos - hash_pos - 1;

	if (copy_len >= sizeof(buf))

		return -EINVAL;

	strncpy(buf, hash_pos + 1, copy_len);

	err = kstrtou32(buf, 10, index);

	if (err)

		return err;

	strncpy(attr, dash_pos + 1, MAX_ATTR_LEN);

	return 0;

}

/*

 * This function translates the DT node name into the 'hwmon' attribute name.

 * IBMPOWERNV device node appear like cooling-fan#2-data, amb-temp#1-thrs etc.

 * which need to be mapped as fan2_input, temp1_max respectively before

 * populating them inside hwmon device class.

 */

static int __init create_hwmon_attr_name(struct device *dev, enum sensors type,

					 const char *node_name,

					 char *hwmon_attr_name)

{

	char attr_suffix[MAX_ATTR_LEN];

	char *attr_name;

	u32 index;

	int err;

	err = get_sensor_index_attr(node_name, &index, attr_suffix);

	if (err) {

		dev_err(dev, "Sensor device node name '%s' is invalid\n",

			node_name);

		return err;

	}

	if (!strcmp(attr_suffix, DT_FAULT_ATTR_SUFFIX)) {

		attr_name = "fault";

	} else if (!strcmp(attr_suffix, DT_DATA_ATTR_SUFFIX)) {

		attr_name = "input";

	} else if (!strcmp(attr_suffix, DT_THRESHOLD_ATTR_SUFFIX)) {

		if (type == AMBIENT_TEMP)

			attr_name = "max";

		else if (type == FAN)

			attr_name = "min";

		else

			return -ENOENT;

	} else {

		return -ENOENT;

	}

	snprintf(hwmon_attr_name, MAX_ATTR_LEN, "%s%d_%s",

		 sensor_groups[type].name, index, attr_name);

	return 0;

}

static int __init populate_attr_groups(struct platform_device *pdev)

{

	struct platform_data *pdata = platform_get_drvdata(pdev);

	const struct attribute_group **pgroups = pdata->attr_groups;

	struct device_node *opal, *np;

	enum sensors type;

	opal = of_find_node_by_path("/ibm,opal/sensors");

	if (!opal) {

		dev_err(&pdev->dev, "Opal node 'sensors' not found\n");

		return -ENODEV;

	}

	for_each_child_of_node(opal, np) {

		if (np->name == NULL)

			continue;

		for (type = 0; type < MAX_SENSOR_TYPE; type++)

			if (of_device_is_compatible(np,

					sensor_groups[type].compatible)) {

				sensor_groups[type].attr_count++;

				break;

			}

	}

	of_node_put(opal);

	for (type = 0; type < MAX_SENSOR_TYPE; type++) {

		sensor_groups[type].group.attrs = devm_kzalloc(&pdev->dev,

					sizeof(struct attribute *) *

					(sensor_groups[type].attr_count + 1),

					GFP_KERNEL);

		if (!sensor_groups[type].group.attrs)

			return -ENOMEM;

		pgroups[type] = &sensor_groups[type].group;

		pdata->sensors_count += sensor_groups[type].attr_count;

		sensor_groups[type].attr_count = 0;

	}

	return 0;

}

/*

 * Iterate through the device tree for each child of 'sensors' node, create

 * a sysfs attribute file, the file is named by translating the DT node name

 * to the name required by the higher 'hwmon' driver like fan1_input, temp1_max

 * etc..

 */

static int __init create_device_attrs(struct platform_device *pdev)

{

	struct platform_data *pdata = platform_get_drvdata(pdev);

	const struct attribute_group **pgroups = pdata->attr_groups;

	struct device_node *opal, *np;

	struct sensor_data *sdata;

	const __be32 *sensor_id;

	enum sensors type;

	u32 count = 0;

	int err = 0;

	opal = of_find_node_by_path("/ibm,opal/sensors");

	sdata = devm_kzalloc(&pdev->dev, pdata->sensors_count * sizeof(*sdata),

			     GFP_KERNEL);

	if (!sdata) {

		err = -ENOMEM;

		goto exit_put_node;

	}

	for_each_child_of_node(opal, np) {

		if (np->name == NULL)

			continue;

		for (type = 0; type < MAX_SENSOR_TYPE; type++)

			if (of_device_is_compatible(np,

					sensor_groups[type].compatible))

				break;

		if (type == MAX_SENSOR_TYPE)

			continue;

		sensor_id = of_get_property(np, "sensor-id", NULL);

		if (!sensor_id) {

			dev_info(&pdev->dev,

				 "'sensor-id' missing in the node '%s'\n",

				 np->name);

			continue;

		}

		sdata[count].id = be32_to_cpup(sensor_id);

		sdata[count].type = type;

		err = create_hwmon_attr_name(&pdev->dev, type, np->name,

					     sdata[count].name);

		if (err)

			goto exit_put_node;

		sysfs_attr_init(&sdata[count].dev_attr.attr);

		sdata[count].dev_attr.attr.name = sdata[count].name;

		sdata[count].dev_attr.attr.mode = S_IRUGO;

		sdata[count].dev_attr.show = show_sensor;

		pgroups[type]->attrs[sensor_groups[type].attr_count++] =

				&sdata[count++].dev_attr.attr;

	}

exit_put_node:

	of_node_put(opal);

	return err;

}

static int __init ibmpowernv_probe(struct platform_device *pdev)

{

	struct platform_data *pdata;

	struct device *hwmon_dev;

	int err;

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);

	if (!pdata)

		return -ENOMEM;

	platform_set_drvdata(pdev, pdata);

	pdata->sensors_count = 0;

	err = populate_attr_groups(pdev);

	if (err)

		return err;

	/* Create sysfs attribute data for each sensor found in the DT */

	err = create_device_attrs(pdev);

	if (err)

		return err;

	/* Finally, register with hwmon */

	hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev, DRVNAME,

							   pdata,

							   pdata->attr_groups);

	return PTR_ERR_OR_ZERO(hwmon_dev);

}

static struct platform_driver ibmpowernv_driver = {

	.driver = {

		.owner = THIS_MODULE,

		.name = DRVNAME,

	},

};

static int __init ibmpowernv_init(void)

{

	int err;

	pdevice = platform_device_alloc(DRVNAME, 0);

	if (!pdevice) {

		pr_err("Device allocation failed\n");

		err = -ENOMEM;

		goto exit;

	}

	err = platform_device_add(pdevice);

	if (err) {

		pr_err("Device addition failed (%d)\n", err);

		goto exit_device_put;

	}

	err = platform_driver_probe(&ibmpowernv_driver, ibmpowernv_probe);

	if (err) {

		pr_err("Platfrom driver probe failed\n");

		goto exit_device_del;

	}

	return 0;

exit_device_del:

	platform_device_del(pdevice);

exit_device_put:

	platform_device_put(pdevice);

exit:

	return err;

}

static void __exit ibmpowernv_exit(void)

{

	platform_driver_unregister(&ibmpowernv_driver);

	platform_device_unregister(pdevice);

}

MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");

MODULE_DESCRIPTION("IBM POWERNV platform sensors");

MODULE_LICENSE("GPL");

module_init(ibmpowernv_init);

module_exit(ibmpowernv_exit);