[PATCH] thermal: Add Raspberry Pi BCM2835 thermal driver

[lkundrak@v3.sk (Lubomir Rintel)]

BCM2835 thermal sensor accessible via Raspberry Pi VideoCore 4 firmware
interface.

Based on work by Craig McGeachie, ported to the Raspberry Pi firmware
interface (from the original mailbox client version).

Signed-off-by: Craig McGeachie <slapdau@yahoo.com.au>
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Lee Jones <lee@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: linux-rpi-kernel at lists.infradead.org
Cc: linux-arm-kernel at lists.infradead.org
---
Needs the RPi firmware patchset from branch 'rpi-firmware' of 
https://github.com/anholt/linux

 drivers/thermal/Kconfig           |   8 ++
 drivers/thermal/Makefile          |   1 +
 drivers/thermal/bcm2835-thermal.c | 161 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 170 insertions(+)
 create mode 100644 drivers/thermal/bcm2835-thermal.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 5aabc4b..5305a95 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -222,6 +222,14 @@ config DOVE_THERMAL
 	  Support for the Dove thermal sensor driver in the Linux thermal
 	  framework.
 
+config BCM2835_THERMAL
+	tristate "BCM2835 Temperature sensor on Raspberry Pi"
+	depends on RASPBERRYPI_FIRMWARE
+	help
+	  Support for the Broadcom BCM2835 thermal sensor driver on Raspberry Pi
+	  devices in the Linux thermal framework. The BCM2835 has one sensor on
+	  chip, with one trip point and no cooling devices.
+
 config DB8500_THERMAL
 	bool "DB8500 thermal management"
 	depends on ARCH_U8500
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 26f1608..e71182b 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -45,3 +45,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
 obj-$(CONFIG_ST_THERMAL)	+= st/
 obj-$(CONFIG_TEGRA_SOCTHERM)	+= tegra_soctherm.o
 obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
+obj-$(CONFIG_BCM2835_THERMAL)	+= bcm2835-thermal.o
diff --git a/drivers/thermal/bcm2835-thermal.c b/drivers/thermal/bcm2835-thermal.c
new file mode 100644
index 0000000..7989c60
--- /dev/null
+++ b/drivers/thermal/bcm2835-thermal.c
@@ -0,0 +1,161 @@
+/*
+ *  Copyright (C) 2013 Craig McGeachie
+ *  Copyright (C) 2014,2015 Lubomir Rintel
+ *
+ * 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 device presents the BCM2835 SoC temperature sensor as a thermal
+ * device.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/dma-mapping.h>
+#include <linux/mailbox_client.h>
+#include <linux/mutex.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define VC_TAG_GET_TEMP 0x00030006
+#define VC_TAG_GET_MAX_TEMP 0x0003000A
+#define VC_SUCCESS 0x80000000
+
+struct prop {
+	u32 id;
+	u32 val;
+} __packed;
+
+struct bcm2835_therm {
+	struct device *dev;
+	struct thermal_zone_device *thermal_dev;
+	struct rpi_firmware *fw;
+};
+
+static int bcm2835_get_temp_common(struct thermal_zone_device *thermal_dev,
+						int *temp, u32 temp_type)
+{
+	struct bcm2835_therm *therm = thermal_dev->devdata;
+	struct device *dev = therm->dev;
+	struct prop msg = {
+		.id = 0,
+		.val = 0
+	};
+	int ret;
+
+	ret = rpi_firmware_property(therm->fw, temp_type, &msg, sizeof(msg));
+	if (ret) {
+		dev_err(dev, "VC temperature request failed\n");
+		goto exit;
+	}
+
+	*temp = msg.val;
+
+exit:
+	return ret;
+}
+
+static int bcm2835_get_temp(struct thermal_zone_device *thermal_dev, int *temp)
+{
+	return bcm2835_get_temp_common(thermal_dev, temp, VC_TAG_GET_TEMP);
+}
+
+static int bcm2835_get_max_temp(struct thermal_zone_device *thermal_dev,
+						int trip_num, int *temp)
+{
+	return bcm2835_get_temp_common(thermal_dev, temp, VC_TAG_GET_MAX_TEMP);
+}
+
+static int bcm2835_get_trip_type(struct thermal_zone_device *thermal_dev,
+			int trip_num, enum thermal_trip_type *trip_type)
+{
+	*trip_type = THERMAL_TRIP_HOT;
+
+	return 0;
+}
+
+static int bcm2835_get_mode(struct thermal_zone_device *thermal_dev,
+		enum thermal_device_mode *dev_mode)
+{
+	*dev_mode = THERMAL_DEVICE_ENABLED;
+
+	return 0;
+}
+
+static struct thermal_zone_device_ops ops  = {
+	.get_temp = bcm2835_get_temp,
+	.get_trip_temp = bcm2835_get_max_temp,
+	.get_trip_type = bcm2835_get_trip_type,
+	.get_mode = bcm2835_get_mode,
+};
+
+static int bcm2835_thermal_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bcm2835_therm *therm;
+	struct device_node *fw;
+
+	therm = devm_kzalloc(dev, sizeof(*therm), GFP_KERNEL);
+	if (!therm)
+		return -ENOMEM;
+
+	therm->dev = dev;
+	dev_set_drvdata(dev, therm);
+
+	fw = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
+	if (!fw) {
+		dev_err(dev, "no firmware node");
+		return -ENODEV;
+	}
+	therm->fw = rpi_firmware_get(fw);
+	if (!therm->fw)
+		return -EPROBE_DEFER;
+
+	therm->thermal_dev = thermal_zone_device_register("bcm2835_thermal",
+					1, 0, therm, &ops, NULL, 0, 0);
+	if (IS_ERR(therm->thermal_dev)) {
+		dev_err(dev, "Unable to register the thermal device");
+		return PTR_ERR(therm->thermal_dev);
+	}
+
+	dev_info(dev, "Broadcom BCM2835 thermal sensor\n");
+
+	return 0;
+}
+
+static int bcm2835_thermal_remove(struct platform_device *pdev)
+{
+	struct bcm2835_therm *therm = dev_get_drvdata(&pdev->dev);
+
+	thermal_zone_device_unregister(therm->thermal_dev);
+
+	return 0;
+}
+
+static const struct of_device_id bcm2835_thermal_of_match[] = {
+	{ .compatible = "raspberrypi,bcm2835-thermal", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match);
+
+static struct platform_driver bcm2835_thermal_driver = {
+	.driver = {
+		.name = "bcm2835_thermal",
+		.owner = THIS_MODULE,
+		.of_match_table = bcm2835_thermal_of_match,
+	},
+	.probe = bcm2835_thermal_probe,
+	.remove = bcm2835_thermal_remove,
+};
+
+module_platform_driver(bcm2835_thermal_driver);
+
+MODULE_AUTHOR("Craig McGeachie");
+MODULE_AUTHOR("Lubomir Rintel");
+MODULE_DESCRIPTION("Raspberry Pi BCM2835 thermal driver");
+MODULE_LICENSE("GPL v2");
-- 
2.4.3