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[PATCH v4 0/5] SCPI sensors support

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  [PATCH v4 0/5] SCPI sensors support Punit Agrawal <punit.agrawal@arm.com> - 2015-09-15 19:00 +0200
    [PATCH v4 5/5] arm64: dts: Add sensor node to Juno dt Punit Agrawal <punit.agrawal@arm.com> - 2015-09-15 19:00 +0200
    [PATCH v4 4/5] hwmon: Support thermal zones registration for SCP temperature sensors Punit Agrawal <punit.agrawal@arm.com> - 2015-09-15 19:00 +0200
    [PATCH v4 1/5] Documentation: add DT bindings for ARM SCPI sensors Punit Agrawal <punit.agrawal@arm.com> - 2015-09-15 19:00 +0200

#1225432 — [PATCH v4 0/5] SCPI sensors support

Hi,

This series adds support for SCPI based sensors for ARM development
platform. In addition to supporting sensors, when a temperature sensor
is discovered the driver registers the sensor with the thermal
framework.

The sensor patches here have been split out from a longer series
adding support for registering power model based cooling devices for
the CPU via device tree. Earliers postings can be seen at [0], [1], [2].

Patches 1-3 create a hwmon sensor driver for sensors provided by SCPI
firmware. Patch 4 adds support for the temperature sensors to register
with the thermal framework. This allows setting up platform thermals
using OF thermal bindings.

The last patch adds support for the sensors in the Juno r0 device
tree.

The patches depend on SCPI and mailbox patches[3] from Sudeep. The
SCPI protocol document with details of the sensor interface can be
found at [4].

I'd like to aim for merging the patches with the SCPI changes if
possible. The hwmon patches have been acked by Guenter. If there
aren't any objections, I would like to request acks for the binding
updates in Patch 1.

Thanks,
Punit

Changes v3 -> v4
  - clarified binding regarding use of sensor identifier

Changes v2 -> v3
  - split out the sensor patches (posted here)
  - rebase onto v4.3-rc1
  
Changes v1 -> v2
  - added documentation for the scpi-hwmon driver
  - replaced static allocation of platform structure in scpi-hwmon.c
    with dynamic allocation
  - re-structured registering of thermal zones to better handle
    error conditions
  - reduced chattiness in scpi-hwmon.c
  - corrected sensor numbering to align with hwmon documentation
  - dynamic allocation of attributes and attribute groups

[0] http://thread.gmane.org/gmane.linux.kernel/2002152
[1] http://thread.gmane.org/gmane.linux.kernel/2011466
[2] http://thread.gmane.org/gmane.linux.power-management.general/65475
[3] http://thread.gmane.org/gmane.linux.kernel/2009735
[4] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922b/index.html

Punit Agrawal (5):
  Documentation: add DT bindings for ARM SCPI sensors
  firmware: arm_scpi: Extend to support sensors
  hwmon: Support sensors exported via ARM SCP interface
  hwmon: Support thermal zones registration for SCP temperature sensors
  arm64: dts: Add sensor node to Juno dt

 Documentation/devicetree/bindings/arm/arm,scpi.txt |  38 +++
 Documentation/hwmon/scpi-hwmon                     |  33 +++
 arch/arm64/boot/dts/arm/juno-base.dtsi             |   5 +
 drivers/firmware/arm_scpi.c                        |  60 +++++
 drivers/hwmon/Kconfig                              |   8 +
 drivers/hwmon/Makefile                             |   1 +
 drivers/hwmon/scpi-hwmon.c                         | 288 +++++++++++++++++++++
 include/linux/scpi_protocol.h                      |  17 ++
 8 files changed, 450 insertions(+)
 create mode 100644 Documentation/hwmon/scpi-hwmon
 create mode 100644 drivers/hwmon/scpi-hwmon.c

-- 
2.5.1

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#1225433 — [PATCH v4 5/5] arm64: dts: Add sensor node to Juno dt

The SCP firmware on Juno provides access to SoC sensors via the
SCPI. Add the sensor nodes to the device tree to enable this support.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
---
 arch/arm64/boot/dts/arm/juno-base.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi
index c624208..dd5158e 100644
--- a/arch/arm64/boot/dts/arm/juno-base.dtsi
+++ b/arch/arm64/boot/dts/arm/juno-base.dtsi
@@ -96,6 +96,11 @@
 				clock-output-names = "pxlclk0", "pxlclk1";
 			};
 		};
+
+		scpi_sensors0: sensors {
+			compatible = "arm,scpi-sensors";
+			#thermal-sensor-cells = <1>;
+		};
 	};
 
 	/include/ "juno-clocks.dtsi"
-- 
2.5.1

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#1225441 — [PATCH v4 4/5] hwmon: Support thermal zones registration for SCP temperature sensors

Add support to create thermal zones based on the temperature sensors
provided by the SCP. The thermal zones can be defined using the
thermal DT bindings and should refer to the SCP sensor id to select
the sensor.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: Eduardo Valentin <edubezval@gmail.com>
---
 drivers/hwmon/scpi-hwmon.c | 104 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 103 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
index c7d1d14..2c1241b 100644
--- a/drivers/hwmon/scpi-hwmon.c
+++ b/drivers/hwmon/scpi-hwmon.c
@@ -20,6 +20,7 @@
 #include <linux/scpi_protocol.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
+#include <linux/thermal.h>
 
 struct sensor_data {
 	struct scpi_sensor_info info;
@@ -29,14 +30,39 @@ struct sensor_data {
 	char label[20];
 };
 
+struct scpi_thermal_zone {
+	struct list_head list;
+	int sensor_id;
+	struct scpi_sensors *scpi_sensors;
+	struct thermal_zone_device *tzd;
+};
+
 struct scpi_sensors {
 	struct scpi_ops *scpi_ops;
 	struct sensor_data *data;
+	struct list_head thermal_zones;
 	struct attribute **attrs;
 	struct attribute_group group;
 	const struct attribute_group *groups[2];
 };
 
+static int scpi_read_temp(void *dev, int *temp)
+{
+	struct scpi_thermal_zone *zone = dev;
+	struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
+	struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
+	struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
+	u32 value;
+	int ret;
+
+	ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
+	if (ret)
+		return ret;
+
+	*temp = value;
+	return 0;
+}
+
 /* hwmon callback functions */
 static ssize_t
 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
@@ -66,6 +92,24 @@ scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
 	return sprintf(buf, "%s\n", sensor->info.name);
 }
 
+static void
+unregister_thermal_zones(struct platform_device *pdev,
+			 struct scpi_sensors *scpi_sensors)
+{
+	struct list_head *pos;
+
+	list_for_each(pos, &scpi_sensors->thermal_zones) {
+		struct scpi_thermal_zone *zone;
+
+		zone = list_entry(pos, struct scpi_thermal_zone, list);
+		thermal_zone_of_sensor_unregister(&pdev->dev, zone->tzd);
+	}
+}
+
+static struct thermal_zone_of_device_ops scpi_sensor_ops = {
+	.get_temp = scpi_read_temp,
+};
+
 static int scpi_hwmon_probe(struct platform_device *pdev)
 {
 	u16 nr_sensors, i;
@@ -160,10 +204,67 @@ static int scpi_hwmon_probe(struct platform_device *pdev)
 	scpi_sensors->group.attrs = scpi_sensors->attrs;
 	scpi_sensors->groups[0] = &scpi_sensors->group;
 
+	platform_set_drvdata(pdev, scpi_sensors);
+
 	hwdev = devm_hwmon_device_register_with_groups(dev,
 			"scpi_sensors", scpi_sensors, scpi_sensors->groups);
 
-	return PTR_ERR_OR_ZERO(hwdev);
+	if (IS_ERR(hwdev))
+		return PTR_ERR(hwdev);
+
+	/*
+	 * Register the temperature sensors with the thermal framework
+	 * to allow their usage in setting up the thermal zones from
+	 * device tree.
+	 *
+	 * NOTE: Not all temperature sensors maybe used for thermal
+	 * control
+	 */
+	INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
+	for (i = 0; i < nr_sensors; i++) {
+		struct sensor_data *sensor = &scpi_sensors->data[i];
+		struct scpi_thermal_zone *zone;
+
+		if (sensor->info.class != TEMPERATURE)
+			continue;
+
+		zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
+		if (!zone) {
+			ret = -ENOMEM;
+			goto unregister_tzd;
+		}
+
+		zone->sensor_id = i;
+		zone->scpi_sensors = scpi_sensors;
+		zone->tzd = thermal_zone_of_sensor_register(dev, i, zone,
+							    &scpi_sensor_ops);
+		/*
+		 * The call to thermal_zone_of_sensor_register returns
+		 * an error for sensors that are not associated with
+		 * any thermal zones or if the thermal subsystem is
+		 * not configured.
+		 */
+		if (IS_ERR(zone->tzd)) {
+			devm_kfree(dev, zone);
+			continue;
+		}
+		list_add(&zone->list, &scpi_sensors->thermal_zones);
+	}
+
+	return 0;
+
+unregister_tzd:
+	unregister_thermal_zones(pdev, scpi_sensors);
+	return ret;
+}
+
+static int scpi_hwmon_remove(struct platform_device *pdev)
+{
+	struct scpi_sensors *scpi_sensors = platform_get_drvdata(pdev);
+
+	unregister_thermal_zones(pdev, scpi_sensors);
+
+	return 0;
 }
 
 static const struct of_device_id scpi_of_match[] = {
@@ -178,6 +279,7 @@ static struct platform_driver scpi_hwmon_platdrv = {
 		.of_match_table = scpi_of_match,
 	},
 	.probe		= scpi_hwmon_probe,
+	.remove		= scpi_hwmon_remove,
 };
 module_platform_driver(scpi_hwmon_platdrv);
 
-- 
2.5.1

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#1225448 — [PATCH v4 1/5] Documentation: add DT bindings for ARM SCPI sensors

The System Control Processor (SCP) provides access to SoC sensors via
the System Control and Power Interface (SCPI) Message Protocol. Add
bindings to allow probing of these sensors. Also support referencing
of the sensors for setting up thermal zones via the thermal DT
bindings.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
---
 Documentation/devicetree/bindings/arm/arm,scpi.txt | 38 ++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt b/Documentation/devicetree/bindings/arm/arm,scpi.txt
index f002460..86302de 100644
--- a/Documentation/devicetree/bindings/arm/arm,scpi.txt
+++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt
@@ -72,8 +72,25 @@ Required sub-node properties:
 - compatible : should be "arm,juno-scp-shmem" for Non-secure SRAM based
 	       shared memory on Juno platforms
 
+Sensor bindings for the sensors based on SCPI Message Protocol
+--------------------------------------------------------------
+SCPI provides an API to access the various sensors on the SoC.
+
+Required properties:
+- compatible : should be "arm,scpi-sensors".
+- #thermal-sensor-cells: should be set to 1. This property follows the
+			 thermal device tree bindings[2].
+
+			 Valid cell values are raw identifiers (Sensor
+			 ID) as used by the firmware. Refer to
+			 platform documentation for your
+			 implementation for the IDs to use. For Juno
+			 R0 and Juno R1 refer to [3].
+
 [0] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922b/index.html
 [1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/thermal/thermal.txt
+[3] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0922b/apas03s22.html
 
 Example:
 
@@ -122,6 +139,11 @@ scpi_protocol: scpi@2e000000 {
 			clock-output-names = "pxlclk0", "pxlclk1";
 		};
 	};
+
+	scpi_sensors0: sensors {
+		compatible = "arm,scpi-sensors";
+		#thermal-sensor-cells = <1>;
+	};
 };
 
 cpu@0 {
@@ -136,6 +158,17 @@ hdlcd@7ff60000 {
 	clocks = <&scpi_clk 4>;
 };
 
+thermal-zones {
+	soc_thermal {
+		polling-delay-passive = <100>;
+		polling-delay = <1000>;
+
+				/* sensor         ID */
+		thermal-sensors = <&scpi_sensors0 3>;
+		...
+	};
+};
+
 In the above example, the #clock-cells is set to 1 as required.
 scpi_dvfs has 3 output clocks namely: atlclk, aplclk, and gpuclk with 0,
 1 and 2 as clock-indices. scpi_clk has 2 output clocks namely: pxlclk0
@@ -148,3 +181,8 @@ scpi_dvfs i.e. "atlclk".
 Similarly the second example is hdlcd@7ff60000 and it has pxlclk1 as input
 clock. '4' in the clock specifier here points to the second entry
 in the output clocks of scpi_clocks  i.e. "pxlclk1"
+
+The thermal-sensors property in the soc_thermal node uses the
+temperature sensor provided by SCP firmware to setup a thermal
+zone. The ID "3" is the sensor identifier for the temperature sensor
+as used by the firmware.
-- 
2.5.1

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