thermal/drivers/loongson-2: Add thermal management support

This patch adds the support for Loongson-2 thermal sensor controller,
which can support maximum four sensor selectors that corresponding to four
sets of thermal control registers and one set of sampling register. The
sensor selector can selector a speific thermal sensor as temperature input.
The sampling register is used to obtain the temperature in real time, the
control register GATE field is used to set the threshold of high or low
temperature, when the input temperature is higher than the high temperature
threshold or lower than the low temperature threshold, an interrupt will
occur.

Signed-off-by: zhanghongchen <zhanghongchen@loongson.cn>
Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230817021007.10350-1-zhuyinbo@loongson.cn

MAINTAINERS

@@ -12285,6 +12285,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/pinctrl/loongson,ls2k-pinctrl.yaml
 F:	drivers/pinctrl/pinctrl-loongson2.c
 
+LOONGSON-2 SOC SERIES THERMAL DRIVER
+M:	zhanghongchen <zhanghongchen@loongson.cn>
+M:	Yinbo Zhu <zhuyinbo@loongson.cn>
+L:	linux-pm@vger.kernel.org
+S:	Maintained
+F:	drivers/thermal/loongson2_thermal.c
+
 LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
 M:	Sathya Prakash <sathya.prakash@broadcom.com>
 M:	Sreekanth Reddy <sreekanth.reddy@broadcom.com>

drivers/thermal/Kconfig

@@ -510,4 +510,16 @@ config KHADAS_MCU_FAN_THERMAL
 	  If you say yes here you get support for the FAN controlled
 	  by the Microcontroller found on the Khadas VIM boards.
 
+config LOONGSON2_THERMAL
+	tristate "Loongson-2 SoC series thermal driver"
+	depends on LOONGARCH || COMPILE_TEST
+	depends on OF
+	help
+	  Support for Thermal driver found on Loongson-2 SoC series platforms.
+	  The thermal driver realizes get_temp and set_trips function, which
+	  are used to obtain the temperature of the current node and set the
+	  temperature range to trigger the interrupt. When the input temperature
+	  is higher than the high temperature threshold or lower than the low
+	  temperature threshold, the interrupt will occur.
+
 endif

drivers/thermal/Makefile

@@ -63,3 +63,4 @@ obj-$(CONFIG_UNIPHIER_THERMAL)	+= uniphier_thermal.o
 obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
 obj-$(CONFIG_SPRD_THERMAL)	+= sprd_thermal.o
 obj-$(CONFIG_KHADAS_MCU_FAN_THERMAL)	+= khadas_mcu_fan.o
+obj-$(CONFIG_LOONGSON2_THERMAL)	+= loongson2_thermal.o

drivers/thermal/loongson2_thermal.c

@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Author: zhanghongchen <zhanghongchen@loongson.cn>
+ *         Yinbo Zhu <zhuyinbo@loongson.cn>
+ * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/thermal.h>
+#include <linux/units.h>
+#include "thermal_hwmon.h"
+
+#define LOONGSON2_MAX_SENSOR_SEL_NUM			3
+
+#define LOONGSON2_THSENS_CTRL_HI_REG			0x0
+#define LOONGSON2_THSENS_CTRL_LOW_REG			0x8
+#define LOONGSON2_THSENS_STATUS_REG			0x10
+#define LOONGSON2_THSENS_OUT_REG			0x14
+
+#define LOONGSON2_THSENS_INT_LO				BIT(0)
+#define LOONGSON2_THSENS_INT_HIGH			BIT(1)
+#define LOONGSON2_THSENS_OUT_MASK			0xFF
+
+struct loongson2_thermal_chip_data {
+	unsigned int	thermal_sensor_sel;
+};
+
+struct loongson2_thermal_data {
+	void __iomem	*regs;
+	const struct loongson2_thermal_chip_data *chip_data;
+};
+
+static int loongson2_thermal_set(struct loongson2_thermal_data *data,
+					int low, int high, bool enable)
+{
+	u64 reg_ctrl = 0;
+	int reg_off = data->chip_data->thermal_sensor_sel * 2;
+
+	low = clamp(-40, low, high);
+	high = clamp(125, low, high);
+
+	low += HECTO;
+	high += HECTO;
+
+	reg_ctrl = low;
+	reg_ctrl |= enable ? 0x100 : 0;
+	writew(reg_ctrl, data->regs + LOONGSON2_THSENS_CTRL_LOW_REG + reg_off);
+
+	reg_ctrl = high;
+	reg_ctrl |= enable ? 0x100 : 0;
+	writew(reg_ctrl, data->regs + LOONGSON2_THSENS_CTRL_HI_REG + reg_off);
+
+	return 0;
+}
+
+static int loongson2_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	u32 reg_val;
+	struct loongson2_thermal_data *data = thermal_zone_device_priv(tz);
+
+	reg_val = readl(data->regs + LOONGSON2_THSENS_OUT_REG);
+	*temp = ((reg_val & LOONGSON2_THSENS_OUT_MASK) - HECTO) * KILO;
+
+	return 0;
+}
+
+static irqreturn_t loongson2_thermal_irq_thread(int irq, void *dev)
+{
+	struct thermal_zone_device *tzd = dev;
+	struct loongson2_thermal_data *data = thermal_zone_device_priv(tzd);
+
+	writeb(LOONGSON2_THSENS_INT_LO | LOONGSON2_THSENS_INT_HIGH, data->regs +
+		LOONGSON2_THSENS_STATUS_REG);
+
+	thermal_zone_device_update(tzd, THERMAL_EVENT_UNSPECIFIED);
+
+	return IRQ_HANDLED;
+}
+
+static int loongson2_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
+{
+	struct loongson2_thermal_data *data = thermal_zone_device_priv(tz);
+
+	return loongson2_thermal_set(data, low/MILLI, high/MILLI, true);
+}
+
+static const struct thermal_zone_device_ops loongson2_of_thermal_ops = {
+	.get_temp = loongson2_thermal_get_temp,
+	.set_trips = loongson2_thermal_set_trips,
+};
+
+static int loongson2_thermal_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct loongson2_thermal_data *data;
+	struct thermal_zone_device *tzd;
+	int ret, irq, i;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->chip_data = device_get_match_data(dev);
+
+	data->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->regs))
+		return PTR_ERR(data->regs);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	writeb(LOONGSON2_THSENS_INT_LO | LOONGSON2_THSENS_INT_HIGH, data->regs +
+		LOONGSON2_THSENS_STATUS_REG);
+
+	loongson2_thermal_set(data, 0, 0, false);
+
+	for (i = 0; i <= LOONGSON2_MAX_SENSOR_SEL_NUM; i++) {
+		tzd = devm_thermal_of_zone_register(dev, i, data,
+			&loongson2_of_thermal_ops);
+
+		if (!IS_ERR(tzd))
+			break;
+
+		if (PTR_ERR(tzd) != ENODEV)
+			continue;
+
+		return dev_err_probe(dev, PTR_ERR(tzd), "failed to register");
+	}
+
+	ret = devm_request_threaded_irq(dev, irq, NULL, loongson2_thermal_irq_thread,
+			IRQF_ONESHOT, "loongson2_thermal", tzd);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to request alarm irq\n");
+
+	devm_thermal_add_hwmon_sysfs(dev, tzd);
+
+	return 0;
+}
+
+static const struct loongson2_thermal_chip_data loongson2_thermal_ls2k1000_data = {
+	.thermal_sensor_sel = 0,
+};
+
+static const struct of_device_id of_loongson2_thermal_match[] = {
+	{
+		.compatible = "loongson,ls2k1000-thermal",
+		.data = &loongson2_thermal_ls2k1000_data,
+	},
+	{ /* end */ }
+};
+MODULE_DEVICE_TABLE(of, of_loongson2_thermal_match);
+
+static struct platform_driver loongson2_thermal_driver = {
+	.driver = {
+		.name		= "loongson2_thermal",
+		.of_match_table = of_loongson2_thermal_match,
+	},
+	.probe	= loongson2_thermal_probe,
+};
+module_platform_driver(loongson2_thermal_driver);
+
+MODULE_DESCRIPTION("Loongson2 thermal driver");
+MODULE_LICENSE("GPL");