From: "Edward A. James" <eaja...@us.ibm.com>

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

Signed-off-by: Edward A. James <eaja...@us.ibm.com>
Signed-off-by: Andrew Jeffery <and...@aj.id.au>
---
 Documentation/hwmon/occ       |  62 +++++++++++
 drivers/hwmon/occ/Makefile    |   2 +-
 drivers/hwmon/occ/occ_sysfs.c | 251 ++++++++++++++++++++++++++++++++++++++++++
 drivers/hwmon/occ/occ_sysfs.h |  30 +++++
 4 files changed, 344 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..9598f78
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.c
@@ -0,0 +1,251 @@
+/*
+ * 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/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include "occ.h"
+#include "occ_sysfs.h"
+
+#define OCC_HWMON_NAME_LENGTH  32
+
+struct occ_sysfs {
+       struct device *dev;
+       struct occ *occ;
+
+       char hwmon_name[OCC_HWMON_NAME_LENGTH + 1];
+       const u32 *sensor_hwmon_configs;
+       struct hwmon_channel_info **occ_sensors;
+       struct hwmon_chip_info occ_info;
+       u16 user_powercap;
+};
+
+static int occ_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+                         u32 attr, int channel, long *val)
+{
+       int rc;
+       struct occ_sysfs *driver = dev_get_drvdata(dev);
+       struct occ *occ = driver->occ;
+
+       switch (type) {
+       case hwmon_in:
+               rc = occ_get_sensor_field(occ, FREQ, channel, attr, val);
+               break;
+       case hwmon_temp:
+               rc = occ_get_sensor_field(occ, TEMP, channel, attr, val);
+               break;
+       case hwmon_power:
+               rc = occ_get_sensor_field(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;
+
+       /* will fetch the "label", the sensor_id */
+       rc = occ_hwmon_read(dev, type, attr, channel, &val);
+       if (rc < 0)
+               return rc;
+
+       rc = snprintf(*str, PAGE_SIZE - 1, "%lu", 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;
+       struct occ_sysfs *driver = dev_get_drvdata(dev);
+
+       if (type == hwmon_power && attr == hwmon_power_alarm) {
+               rc = occ_set_user_powercap(driver->occ, val);
+               if (rc) {
+                       dev_err(dev, "set user powercap failed:%d\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 00644;
+               break;
+       case hwmon_in:
+               if (BIT(attr) & driver->sensor_hwmon_configs[0])
+                       return 00444;
+               break;
+       case hwmon_temp:
+               if (BIT(attr) & driver->sensor_hwmon_configs[1])
+                       return 00444;
+               break;
+       case hwmon_power:
+               /* user power limit */
+               if (attr == hwmon_power_alarm)
+                       return 00644;
+               else if ((BIT(attr) & driver->sensor_hwmon_configs[2]) ||
+                        (BIT(attr) & driver->sensor_hwmon_configs[3]))
+                       return 00444;
+               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 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)
+{
+       int rc, i, j, num_sensors, 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 */
+       hwmon->occ_sensors =
+               devm_kzalloc(dev, sizeof(struct hwmon_channel_info *) *
+                            (MAX_OCC_SENSOR_TYPE + 1), GFP_KERNEL);
+       if (!hwmon->occ_sensors)
+               return ERR_PTR(-ENOMEM);
+
+       hwmon->occ = occ;
+       hwmon->sensor_hwmon_configs = sensor_hwmon_configs;
+       hwmon->occ_info.ops = &occ_hwmon_ops;
+       hwmon->occ_info.info =
+               (const struct hwmon_channel_info **)hwmon->occ_sensors;
+
+       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)
+               return ERR_PTR(rc);
+
+       for (i = 0; i < MAX_OCC_SENSOR_TYPE; i++) {
+               id = resp->sensor_block_id[i];
+               if (id < 0)
+                       continue;
+
+               num_sensors = resp->blocks[id].header.num_sensors;
+               /* need null-termination */
+               sensor_config = devm_kzalloc(dev,
+                                            sizeof(u32) * (num_sensors + 1),
+                                            GFP_KERNEL);
+               if (!sensor_config)
+                       return ERR_PTR(-ENOMEM);
+
+               for (j = 0; j < num_sensors; 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++;
+       }
+
+       /* 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_CAST(hwmon->dev);
+       }
+
+       return hwmon;
+}
+EXPORT_SYMBOL(occ_sysfs_start);
+
+MODULE_AUTHOR("Eddie James <eaja...@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..462f9d2
--- /dev/null
+++ b/drivers/hwmon/occ/occ_sysfs.h
@@ -0,0 +1,30 @@
+/*
+ * 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__
+
+struct occ;
+struct device;
+struct occ_sysfs;
+
+struct occ_sysfs *occ_sysfs_start(struct device *dev, struct occ *occ,
+                                 const u32 *sensor_hwmon_configs,
+                                 const char *name);
+#endif /* __OCC_SYSFS_H__ */
-- 
1.8.3.1

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