=============
- Generic use of devm_* functions in hwmon like using devm_kzalloc() for dynamic
  memory request, avoiding the need to explicit free of memory.
  Adding 'struct attribute_group' as member of platform data structure to be
  populated and then passed to devm_hwmon_device_register_with_groups().

  Note: Having an array of pointers of 'attribute_group' and each group
  corresponds to 'enum sensors' type. Not completely sure, if it's ideal or
  could have just one group populated with attributes of sensor types?

- 'ibmpowernv' is not hot-pluggable device so moving 'platform_driver' callback
  function (probe) as part of __init code.
- Fixed issues related to coding style.
- Other general comments in v1.

 drivers/hwmon/Kconfig      |    8 +
 drivers/hwmon/Makefile     |    1 
 drivers/hwmon/ibmpowernv.c |  368 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 377 insertions(+)
 create mode 100644 drivers/hwmon/ibmpowernv.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index bc196f4..3e308fa 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -554,6 +554,14 @@ config SENSORS_IBMPEX
 	  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 platform.
+
 config SENSORS_IIO_HWMON
 	tristate "Hwmon driver that uses channels specified via iio maps"
 	depends on IIO
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index c48f987..199c401 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o
 obj-$(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
diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c
new file mode 100644
index 0000000..afce620
--- /dev/null
+++ b/drivers/hwmon/ibmpowernv.c
@@ -0,0 +1,368 @@
+/*
+ * IBM PowerNV platform sensors for temperature/fan/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.
+ */
+
+#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 DRVNAME		"ibmpowernv"
+#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", {0}, 0},
+	{"temp", "ibm,opal-sensor-amb-temp", {0}, 0},
+	{"in", "ibm,opal-sensor-power-supply", {0}, 0},
+	{"power", "ibm,opal-sensor-power", {0}, 0}
+};
+
+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) {
+		pr_err("%s: Failed to get opal sensor data\n", __func__);
+		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, "%d\n", x);
+}
+
+static void __init get_sensor_index_attr(const char *name, u32 *index, char *attr)
+{
+	char *hash_pos = strchr(name, '#');
+	char *dash_pos;
+	u32 copy_len;
+	char buf[8];
+
+	memset(buf, 0, sizeof(buf));
+	*index = 0;
+	*attr = '\0';
+
+	if (hash_pos) {
+		dash_pos = strchr(hash_pos, '-');
+		if (dash_pos) {
+			copy_len = dash_pos - hash_pos - 1;
+			if (copy_len < sizeof(buf)) {
+				strncpy(buf, hash_pos + 1, copy_len);
+				sscanf(buf, "%d", index);
+			}
+
+			strncpy(attr, dash_pos + 1, MAX_ATTR_LEN);
+		}
+	}
+}
+
+/*
+ * 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(enum sensors type, const char *node_name,
+				  char *hwmon_attr_name)
+{
+	char attr_suffix[MAX_ATTR_LEN];
+	char *attr_name;
+	u32 index;
+
+	get_sensor_index_attr(node_name, &index, attr_suffix);
+	if (!index || !strlen(attr_suffix)) {
+		pr_info("%s: Sensor device node name is invalid, name: %s\n",
+				__func__, node_name);
+		return -EINVAL;
+	}
+
+	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;
+	int err = 0;
+
+	opal = of_find_node_by_path("/ibm,opal/sensors");
+        if (!opal) {
+		pr_err("%s: Opal 'sensors' node not found\n", __func__);
+		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;
+			}
+	}
+
+	for (type = 0; type < MAX_SENSOR_TYPE; type++) {
+		if (!sensor_groups[type].attr_count)
+			continue;
+
+		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) {
+			pr_err("%s: Failed to allocate memory for attribute"
+					"array\n", __func__);
+			err = -ENOMEM;
+			goto exit_put_node;
+		}
+
+		pgroups[type] = &sensor_groups[type].group;
+		pdata->sensors_count += sensor_groups[type].attr_count;
+		sensor_groups[type].attr_count = 0;
+	}
+
+exit_put_node:
+	of_node_put(opal);
+	return err;
+}
+
+/*
+ * Iterate through the device tree for each child of sensor 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 u32 *sensor_id;
+	enum sensors type;
+	u32 count = 0;
+	int err = 0;
+
+	opal = of_find_node_by_path("/ibm,opal/sensors");
+        if (!opal) {
+		pr_err("%s: Opal 'sensors' node not found\n", __func__);
+		return -ENODEV;
+        }
+
+	sdata = devm_kzalloc(&pdev->dev, (pdata->sensors_count) *
+			     sizeof(*sdata), GFP_KERNEL);
+	if (!sdata) {
+		pr_err("%s: Failed to allocate memory for the sensor_data",
+				__func__);
+		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) {
+			pr_info("%s: %s doesn't have sensor-id\n", __func__,
+				np->name);
+			continue;
+		}
+
+		sdata[count].id = *sensor_id;
+		sdata[count].type = type;
+		err = create_hwmon_attr_name(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 file 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("%s: Device allocation failed\n", __func__);
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	err = platform_device_add(pdevice);
+	if (err) {
+		pr_err("%s: Device addition failed (%d)\n", __func__, err);
+		goto exit_device_put;
+	}
+
+	err = platform_driver_probe(&ibmpowernv_driver, ibmpowernv_probe);
+	if (err) {
+		pr_err("%s: Platfrom driver probe failed\n", __func__);
+		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);
