4 files changed, 228 insertions, 0 deletions

diff --git a/Documentation/hwmon/scpi-hwmon b/Documentation/hwmon/scpi-hwmon
new file mode 100644
index 000000000000..4cfcdf2d5eab
--- /dev/null
+++ b/Documentation/hwmon/scpi-hwmon
@@ -0,0 +1,33 @@
+Kernel driver scpi-hwmon
+========================
+
+Supported chips:
+ * Chips based on ARM System Control Processor Interface
+   Addresses scanned: -
+   Datasheet: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0922b/index.html
+
+Author: Punit Agrawal <punit.agrawal@arm.com>
+
+Description
+-----------
+
+This driver supports hardware monitoring for SoC's based on the ARM
+System Control Processor (SCP) implementing the System Control
+Processor Interface (SCPI). The following sensor types are supported
+by the SCP -
+
+  * temperature
+  * voltage
+  * current
+  * power
+
+The SCP interface provides an API to query the available sensors and
+their values which are then exported to userspace by this driver.
+
+Usage Notes
+-----------
+
+The driver relies on device tree node to indicate the presence of SCPI
+support in the kernel. See
+Documentation/devicetree/bindings/arm/arm,scpi.txt for details of the
+devicetree node.
\ No newline at end of file
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 500b262b89bb..4663693b58f6 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -321,6 +321,14 @@ config SENSORS_APPLESMC
           Say Y here if you have an applicable laptop and want to experience
           the awesome power of applesmc.
 
+config SENSORS_ARM_SCPI
+        tristate "ARM SCPI Sensors"
+        depends on ARM_SCPI_PROTOCOL
+        help
+          This driver provides support for temperature, voltage, current
+          and power sensors available on ARM Ltd's SCP based platforms. The
+          actual number and type of sensors exported depend on the platform.
+
 config SENSORS_ASB100
         tristate "Asus ASB100 Bach"
         depends on X86 && I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 9e0f3dd2841d..66e7a4715da7 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_SENSORS_ADT7462)	+= adt7462.o
 obj-$(CONFIG_SENSORS_ADT7470)   += adt7470.o
 obj-$(CONFIG_SENSORS_ADT7475)   += adt7475.o
 obj-$(CONFIG_SENSORS_APPLESMC)  += applesmc.o
+obj-$(CONFIG_SENSORS_ARM_SCPI)  += scpi-hwmon.o
 obj-$(CONFIG_SENSORS_ASC7621)   += asc7621.o
 obj-$(CONFIG_SENSORS_ATXP1)     += atxp1.o
 obj-$(CONFIG_SENSORS_CORETEMP)  += coretemp.o
diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
new file mode 100644
index 000000000000..c7d1d1423427
--- /dev/null
+++ b/drivers/hwmon/scpi-hwmon.c
@@ -0,0 +1,186 @@
+/*
+ * System Control and Power Interface(SCPI) based hwmon sensor driver
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ * Punit Agrawal <punit.agrawal@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/scpi_protocol.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+struct sensor_data {
+        struct scpi_sensor_info info;
+        struct device_attribute dev_attr_input;
+        struct device_attribute dev_attr_label;
+        char input[20];
+        char label[20];
+};
+
+struct scpi_sensors {
+        struct scpi_ops *scpi_ops;
+        struct sensor_data *data;
+        struct attribute **attrs;
+        struct attribute_group group;
+        const struct attribute_group *groups[2];
+};
+
+/* hwmon callback functions */
+static ssize_t
+scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
+        struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
+        struct sensor_data *sensor;
+        u32 value;
+        int ret;
+
+        sensor = container_of(attr, struct sensor_data, dev_attr_input);
+
+        ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
+        if (ret)
+                return ret;
+
+        return sprintf(buf, "%u\n", value);
+}
+
+static ssize_t
+scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct sensor_data *sensor;
+
+        sensor = container_of(attr, struct sensor_data, dev_attr_label);
+
+        return sprintf(buf, "%s\n", sensor->info.name);
+}
+
+static int scpi_hwmon_probe(struct platform_device *pdev)
+{
+        u16 nr_sensors, i;
+        int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
+        struct scpi_ops *scpi_ops;
+        struct device *hwdev, *dev = &pdev->dev;
+        struct scpi_sensors *scpi_sensors;
+        int ret;
+
+        scpi_ops = get_scpi_ops();
+        if (!scpi_ops)
+                return -EPROBE_DEFER;
+
+        ret = scpi_ops->sensor_get_capability(&nr_sensors);
+        if (ret)
+                return ret;
+
+        if (!nr_sensors)
+                return -ENODEV;
+
+        scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
+        if (!scpi_sensors)
+                return -ENOMEM;
+
+        scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
+                                   sizeof(*scpi_sensors->data), GFP_KERNEL);
+        if (!scpi_sensors->data)
+                return -ENOMEM;
+
+        scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
+                                   sizeof(*scpi_sensors->attrs), GFP_KERNEL);
+        if (!scpi_sensors->attrs)
+                return -ENOMEM;
+
+        scpi_sensors->scpi_ops = scpi_ops;
+
+        for (i = 0; i < nr_sensors; i++) {
+                struct sensor_data *sensor = &scpi_sensors->data[i];
+
+                ret = scpi_ops->sensor_get_info(i, &sensor->info);
+                if (ret)
+                        return ret;
+
+                switch (sensor->info.class) {
+                case TEMPERATURE:
+                        snprintf(sensor->input, sizeof(sensor->input),
+                                 "temp%d_input", num_temp + 1);
+                        snprintf(sensor->label, sizeof(sensor->input),
+                                 "temp%d_label", num_temp + 1);
+                        num_temp++;
+                        break;
+                case VOLTAGE:
+                        snprintf(sensor->input, sizeof(sensor->input),
+                                 "in%d_input", num_volt);
+                        snprintf(sensor->label, sizeof(sensor->input),
+                                 "in%d_label", num_volt);
+                        num_volt++;
+                        break;
+                case CURRENT:
+                        snprintf(sensor->input, sizeof(sensor->input),
+                                 "curr%d_input", num_current + 1);
+                        snprintf(sensor->label, sizeof(sensor->input),
+                                 "curr%d_label", num_current + 1);
+                        num_current++;
+                        break;
+                case POWER:
+                        snprintf(sensor->input, sizeof(sensor->input),
+                                 "power%d_input", num_power + 1);
+                        snprintf(sensor->label, sizeof(sensor->input),
+                                 "power%d_label", num_power + 1);
+                        num_power++;
+                        break;
+                default:
+                        break;
+                }
+
+                sensor->dev_attr_input.attr.mode = S_IRUGO;
+                sensor->dev_attr_input.show = scpi_show_sensor;
+                sensor->dev_attr_input.attr.name = sensor->input;
+
+                sensor->dev_attr_label.attr.mode = S_IRUGO;
+                sensor->dev_attr_label.show = scpi_show_label;
+                sensor->dev_attr_label.attr.name = sensor->label;
+
+                scpi_sensors->attrs[i << 1] = &sensor->dev_attr_input.attr;
+                scpi_sensors->attrs[(i << 1) + 1] = &sensor->dev_attr_label.attr;
+
+                sysfs_attr_init(scpi_sensors->attrs[i << 1]);
+                sysfs_attr_init(scpi_sensors->attrs[(i << 1) + 1]);
+        }
+
+        scpi_sensors->group.attrs = scpi_sensors->attrs;
+        scpi_sensors->groups[0] = &scpi_sensors->group;
+
+        hwdev = devm_hwmon_device_register_with_groups(dev,
+                        "scpi_sensors", scpi_sensors, scpi_sensors->groups);
+
+        return PTR_ERR_OR_ZERO(hwdev);
+}
+
+static const struct of_device_id scpi_of_match[] = {
+        {.compatible = "arm,scpi-sensors"},
+        {},
+};
+
+static struct platform_driver scpi_hwmon_platdrv = {
+        .driver = {
+                .name   = "scpi-hwmon",
+                .owner  = THIS_MODULE,
+                .of_match_table = scpi_of_match,
+        },
+        .probe          = scpi_hwmon_probe,
+};
+module_platform_driver(scpi_hwmon_platdrv);
+
+MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
+MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
+MODULE_LICENSE("GPL v2");