This is a generic thermal driver for simple MMIO sensors, of which
amazon,al-thermal is one.
This device uses a single MMIO transaction to read the temperature and
report it to the thermal subsystem.
Signed-off-by: Talel Shenhar <talel@xxxxxxxxxx>
Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
MAINTAINERS | 6 ++
drivers/thermal/Kconfig | 10 ++++
drivers/thermal/Makefile | 1 +
drivers/thermal/thermal_mmio.c | 129 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 146 insertions(+)
create mode 100644 drivers/thermal/thermal_mmio.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 955463f..262cb2c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -727,6 +727,12 @@ S: Supported
F: Documentation/networking/ena.txt
F: drivers/net/ethernet/amazon/
+AMAZON ANNAPURNA LABS THERMAL MMIO DRIVER
+M: Talel Shenhar <talel@xxxxxxxxxx>
+S: Maintained
+F: Documentation/devicetree/bindings/thermal/amazon,al-thermal.txt
+F: drivers/thermal/thermal_mmio.c
+
AMD CRYPTOGRAPHIC COPROCESSOR (CCP) DRIVER
M: Tom Lendacky <thomas.lendacky@xxxxxxx>
M: Gary Hook <gary.hook@xxxxxxx>
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 1775d44..96d9236 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -199,6 +199,16 @@ config THERMAL_EMULATION
because userland can easily disable the thermal policy by simply
flooding this sysfs node with low temperature values.
+config THERMAL_MMIO
+ tristate "Generic Thermal MMIO driver"
+ depends on OF || COMPILE_TEST
+ help
+ This option enables the generic thermal MMIO driver that will use
+ memory-mapped reads to get the temperature. Any HW/System that
+ allows temperature reading by a single memory-mapped reading, be it
+ register or shared memory, is a potential candidate to work with this
+ driver.
+
config HISI_THERMAL
tristate "Hisilicon thermal driver"
depends on ARCH_HISI || COMPILE_TEST
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 82bb50d..d4c9ae7 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -29,6 +29,7 @@ thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
# platform thermal drivers
obj-y += broadcom/
+obj-$(CONFIG_THERMAL_MMIO) += thermal_mmio.o
obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM) += qcom-spmi-temp-alarm.o
obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
obj-$(CONFIG_ROCKCHIP_THERMAL) += rockchip_thermal.o
diff --git a/drivers/thermal/thermal_mmio.c b/drivers/thermal/thermal_mmio.c
new file mode 100644
index 0000000..de3ccee
--- /dev/null
+++ b/drivers/thermal/thermal_mmio.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/thermal.h>
+
+struct thermal_mmio {
+ void __iomem *mmio_base;
+ u32 (*read_mmio)(void __iomem *mmio_base);
+ u32 mask;
+ int factor;
+};
+
+static u32 thermal_mmio_readb(void __iomem *mmio_base)
+{
+ return readb(mmio_base);
+}
+
+static int thermal_mmio_get_temperature(void *private, int *temp)
+{
+ int t;
+ struct thermal_mmio *sensor =
+ (struct thermal_mmio *)private;
+
+ t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
+ t *= sensor->factor;
+
+ *temp = t;
+
+ return 0;
+}
+
+static struct thermal_zone_of_device_ops thermal_mmio_ops = {
+ .get_temp = thermal_mmio_get_temperature,
+};
+
+static int thermal_mmio_probe(struct platform_device *pdev)
+{
+ struct resource *resource;
+ struct thermal_mmio *sensor;
+ int (*sensor_init_func)(struct platform_device *pdev,
+ struct thermal_mmio *sensor);
+ struct thermal_zone_device *thermal_zone;
+ int ret;
+ int temperature;
+
+ sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
+ if (!sensor)
+ return -ENOMEM;
+
+ resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (IS_ERR(resource)) {
+ dev_err(&pdev->dev,
+ "fail to get platform memory resource (%ld)\n",
+ PTR_ERR(resource));
+ return PTR_ERR(resource);
+ }
+
+ sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource);
+ if (IS_ERR(sensor->mmio_base)) {
+ dev_err(&pdev->dev, "failed to ioremap memory (%ld)\n",
+ PTR_ERR(sensor->mmio_base));
+ return PTR_ERR(sensor->mmio_base);
+ }
+
+ sensor_init_func = device_get_match_data(&pdev->dev);
+ if (sensor_init_func) {
+ ret = sensor_init_func(pdev, sensor);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to initialize sensor (%d)\n",
+ ret);
+ return ret;
+ }
+ }
+
+ thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev,
+ 0,
+ sensor,
+ &thermal_mmio_ops);
+ if (IS_ERR(thermal_zone)) {
+ dev_err(&pdev->dev,
+ "failed to register sensor (%ld)\n",
+ PTR_ERR(thermal_zone));
+ return PTR_ERR(thermal_zone);
+ }
+
+ thermal_mmio_get_temperature(sensor, &temperature);
+ dev_info(&pdev->dev,
+ "thermal mmio sensor %s registered, current temperature: %d\n",
+ pdev->name, temperature);
+
+ return 0;
+}
+
+static int al_thermal_init(struct platform_device *pdev,
+ struct thermal_mmio *sensor)
+{
+ sensor->read_mmio = thermal_mmio_readb;
+ sensor->mask = 0xff;
+ sensor->factor = 1000;
+
+ return 0;
+}
+
+static const struct of_device_id thermal_mmio_id_table[] = {
+ { .compatible = "amazon,al-thermal", .data = al_thermal_init},
+ {}
+};
+MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
+
+static struct platform_driver thermal_mmio_driver = {
+ .probe = thermal_mmio_probe,
+ .driver = {
+ .name = "thermal-mmio",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(thermal_mmio_id_table),
+ },
+};
+
+module_platform_driver(thermal_mmio_driver);
+
+MODULE_AUTHOR("Talel Shenhar <talel@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Thermal MMIO Driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
