This patch introduces a generic thermal driver, which enables easy
connectivity between "simple" thermal HW devices and the thermal
subsystem.
"simple" may be any system that allows temperature reading via a single
memory-mapped read, be it register or shared memory, and that doesn't
require any HW configuration to be done by the driver.
Such "simple" HW is a candidate to work with this driver.
Signed-off-by: Talel Shenhar <talel@xxxxxxxxxx>
---
drivers/thermal/Kconfig | 11 +++
drivers/thermal/Makefile | 3 +
drivers/thermal/thermal_mmio.c | 214 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 228 insertions(+)
create mode 100644 drivers/thermal/thermal_mmio.c
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 1775d44..0033ba2 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -199,6 +199,17 @@ config THERMAL_EMULATION
because userland can easily disable the thermal policy by simply
flooding this sysfs node with low temperature values.
+config THERMAL_MMIO
+ bool
+ depends on OF || COMPILE_TEST
+ prompt "mmio thermal driver"
+ 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..beec616 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -27,6 +27,9 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o
# devfreq cooling
thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
+# generic memory mapped thermal driver
+thermal_sys-$(CONFIG_THERMAL_MMIO) += thermal_mmio.o
+
# platform thermal drivers
obj-y += broadcom/
obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM) += qcom-spmi-temp-alarm.o
diff --git a/drivers/thermal/thermal_mmio.c b/drivers/thermal/thermal_mmio.c
new file mode 100644
index 0000000..1119e71
--- /dev/null
+++ b/drivers/thermal/thermal_mmio.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 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>
+
+#define THERMAL_MMIO_DEFAULT_SENSOR_WIDTH sizeof(u32)
+#define THERMAL_MMIO_DEFAULT_SENSOR_FACTOR 1
+#define THERMAL_MMIO_DEFAULT_SENSOR_BIAS 0
+#define THERMAL_MMIO_DEFAULT_SENSOR_DIVIDER 1
+
+struct thermal_mmio {
+ void __iomem *mmio_base;
+ u32 (*read_mmio)(void __iomem *mmio_base);
+ int width;
+ u32 mask;
+ int factor;
+ int bias;
+ int divider;
+};
+
+static u32 thermal_mmio_readb(void __iomem *mmio_base)
+{
+ return readb(mmio_base);
+}
+
+static u32 thermal_mmio_readw(void __iomem *mmio_base)
+{
+ return readw(mmio_base);
+}
+
+static u32 thermal_mmio_readl(void __iomem *mmio_base)
+{
+ return readl(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;
+ t += sensor->bias;
+ t /= sensor->divider;
+
+ *temp = t;
+
+ return 0;
+}
+
+static struct thermal_zone_of_device_ops thermal_mmio_ops = {
+ .get_temp = thermal_mmio_get_temperature,
+};
+
+static int thermal_mmio_parse_dt(struct platform_device *pdev,
+ struct thermal_mmio *sensor)
+{
+ struct resource *resource;
+ int ret;
+
+ 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);
+ }
+
+ ret = of_property_read_u32(pdev->dev.of_node, "sensor-width",
+ &sensor->width);
+ if (ret < 0) {
+ sensor->width = THERMAL_MMIO_DEFAULT_SENSOR_WIDTH;
+ dev_dbg(&pdev->dev,
+ "sensor-width undefined (%d) - using default: %d\n",
+ ret, sensor->width);
+ }
+
+ ret = of_property_read_u32(pdev->dev.of_node, "sensor-mask",
+ &sensor->mask);
+ if (ret < 0) {
+ sensor->mask = GENMASK(sizeof(u32) * BITS_PER_BYTE - 1, 0);
+ dev_dbg(&pdev->dev,
+ "sensor-mask undefined (%d) - using default: 0x%x\n",
+ ret, sensor->mask);
+ }
+
+ ret = of_property_read_s32(pdev->dev.of_node, "sensor-factor",
+ &sensor->factor);
+ if (ret < 0) {
+ sensor->factor = THERMAL_MMIO_DEFAULT_SENSOR_FACTOR;
+ dev_dbg(&pdev->dev,
+ "sensor-factor undefined (%d) - using default: %d\n",
+ ret, sensor->factor);
+ }
+
+ ret = of_property_read_s32(pdev->dev.of_node, "sensor-bias",
+ &sensor->bias);
+ if (ret < 0) {
+ sensor->bias = THERMAL_MMIO_DEFAULT_SENSOR_BIAS;
+ dev_dbg(&pdev->dev,
+ "sensor-bias undefined (%d) - using default: %d\n",
+ ret, sensor->bias);
+ }
+
+ ret = of_property_read_u32(pdev->dev.of_node, "sensor-divider",
+ &sensor->divider);
+ if (ret < 0) {
+ sensor->divider = THERMAL_MMIO_DEFAULT_SENSOR_DIVIDER;
+ dev_dbg(&pdev->dev,
+ "sensor-divider undefined (%d) - using default: %d\n",
+ ret, sensor->divider);
+ }
+
+ /* configuration value sanity */
+ if (sensor->width > resource_size(resource)) {
+ dev_err(&pdev->dev,
+ "too small MMIO size, expected (%d) < supplied (%d)\n",
+ sensor->width, (int)resource_size(resource));
+ return -EINVAL;
+ }
+
+ dev_dbg(&pdev->dev,
+ "width=%d, mask=0x%x factor=%d bias=%d divider=%d\n",
+ sensor->width, sensor->mask, sensor->factor, sensor->bias,
+ sensor->divider);
+
+ return 0;
+}
+
+static int thermal_mmio_probe(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;
+
+ ret = thermal_mmio_parse_dt(pdev, sensor);
+ if (ret) {
+ dev_err(&pdev->dev, "fail to parse dt\n");
+ return ret;
+ }
+
+ switch (sensor->width) {
+ case sizeof(u8):
+ sensor->read_mmio = thermal_mmio_readb;
+ break;
+ case sizeof(u16):
+ sensor->read_mmio = thermal_mmio_readw;
+ break;
+ case sizeof(u32):
+ sensor->read_mmio = thermal_mmio_readl;
+ break;
+ default:
+ dev_err(&pdev->dev, "bad sensor-width property supplied: %d\n",
+ sensor->width);
+ return -EINVAL;
+ }
+
+ 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 const struct of_device_id thermal_mmio_id_table[] = {
+ { .compatible = "thermal-mmio" },
+ {}
+};
+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
