Re: [RFC 2/2] hwmon: powernv: Hwmon driver for OCC inband power and temperature sensors

Signed-off-by: Shilpasri G Bhat <redacted>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Jean Delvare <jdelvare@suse.com>
CC: Guenter Roeck <linux@roeck-us.net>
CC: Jonathan Corbet <corbet@lwn.net>
CC: devicetree@vger.kernel.org
CC: linux-hwmon@vger.kernel.org
CC: linux-doc@vger.kernel.org
---
 .../devicetree/bindings/hwmon/ibmpowernv-occ.txt   |   4 +
 Documentation/hwmon/ibmpowernv-occ                 |  24 ++
 drivers/hwmon/Kconfig                              |  11 +
 drivers/hwmon/Makefile                             |   1 +
 drivers/hwmon/ibmpowernv-occ.c                     | 302 +++++++++++++++++++++
 5 files changed, 342 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/ibmpowernv-occ.txt
 create mode 100644 Documentation/hwmon/ibmpowernv-occ
 create mode 100644 drivers/hwmon/ibmpowernv-occ.c

diff --git a/Documentation/devicetree/bindings/hwmon/ibmpowernv-occ.txt b/Documentation/devicetree/bindings/hwmon/ibmpowernv-occ.txt
new file mode 100644
index 0000000..d03f744
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ibmpowernv-occ.txt

@@ -0,0 +1,4 @@
+IBM POWERNV OCC inband platform sensors
+
+Required device-tree property:
+- compatible: "ibm,p9-occ-inband-sensor"

diff --git a/Documentation/hwmon/ibmpowernv-occ b/Documentation/hwmon/ibmpowernv-occ
new file mode 100644
index 0000000..151028b
--- /dev/null
+++ b/Documentation/hwmon/ibmpowernv-occ

@@ -0,0 +1,24 @@
+Kernel driver ibmpowernv-occ
+=============================
+
+Supported systems:
+ * P9 server based on POWERNV platform
+
+Description
+------------
+
+This driver exports the power and temperature sensors from OCC inband
+sensors on P9 POWERNV platforms.
+
+Sysfs attributes
+----------------
+
+powerX_input		Latest power reading
+powerX_input_highest	Minimum power
+powerX_input_lowest	Maximum power
+powerX_label		Sensor name
+
+tempX_input		Latest temperature reading
+tempX_max		Minimum temperature
+tempX_min		Maximum temperature
+tempX_label		Sensor name

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 0649d53f3..3b1dbb9 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig

@@ -598,6 +598,17 @@ config SENSORS_IBMPOWERNV
 	  This driver can also be built as a module. If so, the module
 	  will be called ibmpowernv.
 
+config SENSORS_IBMPOWERNV_OCC
+	tristate "IBM POWERNV OCC Inband platform sensors"
+	depends on PPC_POWERNV
+	default y
+	help
+	  If you say yes here you get support for the temperature/power
+	  OCC inband sensors on your PowerNV platform.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called ibmpowernv-occ.
+
 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 5509edf..0da2207 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile

@@ -75,6 +75,7 @@ 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-$(CONFIG_SENSORS_IBMPOWERNV_OCC)+= ibmpowernv-occ.o
 obj-$(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-occ.c b/drivers/hwmon/ibmpowernv-occ.c
new file mode 100644
index 0000000..97b1bbe
--- /dev/null
+++ b/drivers/hwmon/ibmpowernv-occ.c

@@ -0,0 +1,302 @@
+/*
+ * IBM PowerNV platform OCC inband sensors for temperature/power
+ * Copyright (C) 2017 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_occ"
+#define pr_fmt(fmt)	DRVNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/hwmon.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+#include <asm/opal.h>
+
+#define MAX_HWMON_ATTR_LEN	32
+#define MAX_HWMON_LABEL_LEN	(MAX_OCC_SENSOR_NAME_LEN * 2)
+#define HWMON_ATTRS_PER_SENSOR	16
+#define TO_MILLI_UNITS(x)	((x) * 1000)
+#define TO_MICRO_UNITS(x)	((x) * 1000000)
+
+enum sensors {
+	TEMP,
+	POWER,
+	MAX_SENSOR_TYPE,
+};
+
+static struct sensor_type {
+	const char *name;
+	int hwmon_id;
+} sensor_types[] = {
+	{ "temp"},
+	{ "power"},
+};
+
+static struct sensor_data {
+	u32 occ_id;
+	u64 offset;  /* Offset to ping/pong reading buffer */
+	enum sensors type;
+	char label[MAX_HWMON_LABEL_LEN];
+	char name[MAX_HWMON_ATTR_LEN];
+	struct device_attribute attr;
+} *sdata;
+
+static struct attribute_group sensor_attrs_group;
+__ATTRIBUTE_GROUPS(sensor_attrs);
+
+#define show(file_name)							\
+static ssize_t ibmpowernv_occ_show_##file_name				\
+(struct device *dev, struct device_attribute *dattr, char *buf)		\
+{									\
+	struct sensor_data *sdata = container_of(dattr,			\
+						 struct sensor_data,	\
+						 attr);			\
+	u64 val;							\
+	int ret;							\
+	ret = opal_occ_sensor_get_##file_name(sdata->occ_id,		\
+					      sdata->offset,		\
+					      &val);			\
+	if (ret)							\
+		return ret;						\
+	if (sdata->type == TEMP)					\
+		val = TO_MILLI_UNITS(val);				\
+	else if (sdata->type == POWER)					\
+		val = TO_MICRO_UNITS(val);				\
+	return sprintf(buf, "%llu\n", val);				\
+}
+
+show(sample);
+show(max);
+show(min);
+show(js_min);
+show(js_max);
+show(csm_min);
+show(csm_max);
+show(prof_min);
+show(prof_max);
+
+static struct sensor_view_groups {
+	const char *name;
+	ssize_t (*show_sample)(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf);
+	ssize_t (*show_min)(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf);
+	ssize_t (*show_max)(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf);
+} sensor_views[] = {
+	{
+		.name		= "",
+		.show_sample	= ibmpowernv_occ_show_sample,
+		.show_min	= ibmpowernv_occ_show_min,
+		.show_max	= ibmpowernv_occ_show_max
+	},
+	{
+		.name		= "_JS",
+		.show_sample	= ibmpowernv_occ_show_sample,
+		.show_min	= ibmpowernv_occ_show_js_min,
+		.show_max	= ibmpowernv_occ_show_js_max
+	},
+	{	.name		= "_CSM",
+		.show_sample	= ibmpowernv_occ_show_sample,
+		.show_min	= ibmpowernv_occ_show_csm_min,
+		.show_max	= ibmpowernv_occ_show_csm_max
+	},
+	{	.name		= "_Prof",
+		.show_sample	= ibmpowernv_occ_show_sample,
+		.show_min	= ibmpowernv_occ_show_prof_min,
+		.show_max	= ibmpowernv_occ_show_prof_max
+	},
+};
+
+static ssize_t ibmpowernv_occ_show_label(struct device *dev,
+					 struct device_attribute *dattr,
+					 char *buf)
+{
+	struct sensor_data *sdata = container_of(dattr, struct sensor_data,
+						 attr);
+
+	return sprintf(buf, "%s\n", sdata->label);
+}
+
+static int ibmpowernv_occ_get_sensor_type(enum occ_sensor_type type)
+{
+	switch (type) {
+	case OCC_SENSOR_TYPE_POWER:
+		return POWER;
+	case OCC_SENSOR_TYPE_TEMPERATURE:
+		return TEMP;
+	default:
+		return MAX_SENSOR_TYPE;
+	}
+
+	return MAX_SENSOR_TYPE;
+}
+
+static void ibmpowernv_occ_add_sdata(struct occ_hwmon_sensor sensor,
+				     struct sensor_data *sdata, char *name,
+				     int hwmon_id, enum sensors type,
+				     ssize_t (*show)(struct device *dev,
+						struct device_attribute *attr,
+						char *buf))
+{
+	sdata->type = type;
+	sdata->occ_id = sensor.occ_id;
+	sdata->offset = sensor.offset;
+	snprintf(sdata->name, MAX_HWMON_ATTR_LEN, "%s%d_%s",
+		 sensor_types[type].name, hwmon_id, name);
+	sysfs_attr_init(&sdata->attr.attr);
+	sdata->attr.attr.name = sdata->name;
+	sdata->attr.attr.mode = 0444;
+	sdata->attr.show = show;
+}
+
+static void ibmpowernv_occ_add_sensor_attrs(struct occ_hwmon_sensor sensor,
+					    int index)
+{
+	struct attribute **attrs = sensor_attrs_group.attrs;
+	char attr_str[MAX_HWMON_ATTR_LEN];
+	enum sensors type = ibmpowernv_occ_get_sensor_type(sensor.type);
+	int i;
+
+	index *= HWMON_ATTRS_PER_SENSOR;
+	for (i = 0; i < ARRAY_SIZE(sensor_views); i++) {
+		int hid = ++sensor_types[type].hwmon_id;
+
+		/* input */
+		ibmpowernv_occ_add_sdata(sensor, &sdata[index], "input", hid,
+					 type, sensor_views[i].show_sample);
+		attrs[index] = &sdata[index].attr.attr;
+		index++;
+
+		/* min */
+		if (type == POWER)
+			snprintf(attr_str, MAX_HWMON_ATTR_LEN, "%s",
+				 "input_lowest");
+		else
+			snprintf(attr_str, MAX_HWMON_ATTR_LEN, "%s", "min");
+
+		ibmpowernv_occ_add_sdata(sensor, &sdata[index], attr_str, hid,
+					 type, sensor_views[i].show_min);
+		attrs[index] = &sdata[index].attr.attr;
+		index++;
+
+		/* max */
+		if (type == POWER)
+			snprintf(attr_str, MAX_HWMON_ATTR_LEN, "%s",
+				 "input_highest");
+		else
+			snprintf(attr_str, MAX_HWMON_ATTR_LEN, "%s", "max");
+
+		ibmpowernv_occ_add_sdata(sensor, &sdata[index], attr_str, hid,
+					 type, sensor_views[i].show_max);
+		attrs[index] = &sdata[index].attr.attr;
+		index++;
+
+		/* label */
+		snprintf(sdata[index].label, MAX_HWMON_LABEL_LEN, "%s%s",
+			 sensor.name, sensor_views[i].name);
+		ibmpowernv_occ_add_sdata(sensor, &sdata[index], "label", hid,
+					 type, ibmpowernv_occ_show_label);
+		attrs[index] = &sdata[index].attr.attr;
+		index++;
+	}
+}
+
+static int ibmpowernv_occ_add_device_attrs(struct platform_device *pdev)
+{
+	struct attribute **attrs;
+	struct occ_hwmon_sensor *slist = NULL;
+	int nr_sensors = 0, i;
+	int ret = -ENOMEM;
+
+	slist = opal_occ_sensor_get_hwmon_list(&nr_sensors);
+	if (!nr_sensors)
+		return -ENODEV;
+
+	if (!slist)
+		return ret;
+
+	sdata = devm_kzalloc(&pdev->dev, nr_sensors * sizeof(*sdata) *
+			     HWMON_ATTRS_PER_SENSOR, GFP_KERNEL);
+	if (!sdata)
+		goto out;
+
+	attrs = devm_kzalloc(&pdev->dev, nr_sensors * sizeof(*attrs) *
+			     HWMON_ATTRS_PER_SENSOR, GFP_KERNEL);
+	if (!attrs)
+		goto out;
+
+	sensor_attrs_group.attrs = attrs;
+	for (i = 0; i < nr_sensors; i++)
+		ibmpowernv_occ_add_sensor_attrs(slist[i], i);
+
+	ret = 0;
+out:
+	kfree(slist);
+	return ret;
+}
+
+static int ibmpowernv_occ_probe(struct platform_device *pdev)
+{
+	struct device *hwmon_dev;
+	int err;
+
+	err = ibmpowernv_occ_add_device_attrs(pdev);
+	if (err)
+		goto out;
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev, DRVNAME,
+							   NULL,
+							   sensor_attrs_groups);
+
+	err = PTR_ERR_OR_ZERO(hwmon_dev);
+out:
+	if (err)
+		pr_warn("Failed to initialize Hwmon OCC inband sensors\n");
+
+	return err;
+}
+
+static const struct platform_device_id occ_sensor_ids[] = {
+	{ .name = "occ-inband-sensor" },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, occ_sensor_ids);
+
+static const struct of_device_id occ_sensor_of_ids[] = {
+	{ .compatible	= "ibm,p9-occ-inband-sensor" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, occ_sensor_of_ids);
+
+static struct platform_driver ibmpowernv_occ_driver = {
+	.probe		= ibmpowernv_occ_probe,
+	.id_table	= occ_sensor_ids,
+	.driver		= {
+		.name	= DRVNAME,
+		.of_match_table	= occ_sensor_of_ids,
+	},
+};
+
+module_platform_driver(ibmpowernv_occ_driver);
+
+MODULE_AUTHOR("Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM POWERNV platform OCC inband sensors");
+MODULE_LICENSE("GPL");

-- 
1.8.3.1