thermal/drivers/spacemit/k1: Add thermal sensor support

The thermal sensor on K1 supports monitoring five temperature zones.
The driver registers these sensors with the thermal framework
and supports standard operations:
- Reading temperature (millidegree Celsius)
- Setting high/low thresholds for interrupts

Signed-off-by: Shuwei Wu <shuwei.wu@mailbox.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
Reviewed-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Reviewed-by: Yao Zi <me@ziyao.cc>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Tested-by: Vincent Legoll <legoll@online.fr> # OrangePi-RV2
Tested-by: Gong Shuai <gsh517025@gmail.com>
Link: https://patch.msgid.link/20260427-k1-thermal-v5-2-df39187480ed@mailbox.org

drivers/thermal/Kconfig

@@ -473,6 +473,8 @@ endmenu
 
 source "drivers/thermal/renesas/Kconfig"
 
+source "drivers/thermal/spacemit/Kconfig"
+
 source "drivers/thermal/tegra/Kconfig"
 
 config GENERIC_ADC_THERMAL

drivers/thermal/Makefile

@@ -65,6 +65,7 @@ obj-y				+= mediatek/
 obj-$(CONFIG_GENERIC_ADC_THERMAL)	+= thermal-generic-adc.o
 obj-$(CONFIG_UNIPHIER_THERMAL)	+= uniphier_thermal.o
 obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
+obj-y				+= spacemit/
 obj-$(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/spacemit/Kconfig

@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "SpacemiT thermal drivers"
+depends on ARCH_SPACEMIT || COMPILE_TEST
+
+config SPACEMIT_K1_TSENSOR
+	tristate "SpacemiT K1 thermal sensor driver"
+	depends on THERMAL_OF
+	help
+	  This driver provides support for the thermal sensor
+	  integrated in the SpacemiT K1 SoC.
+
+	  The thermal sensor monitors temperatures for five thermal zones:
+	  soc, package, gpu, cluster0, and cluster1. It supports reporting
+	  temperature values and handling high/low threshold interrupts.
+
+	  Say Y here if you want to enable thermal monitoring on SpacemiT K1.
+	  If compiled as a module, it will be called k1_tsensor.
+
+endmenu

drivers/thermal/spacemit/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_SPACEMIT_K1_TSENSOR)	+= k1_tsensor.o

drivers/thermal/spacemit/k1_tsensor.c

@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thermal sensor driver for SpacemiT K1 SoC
+ *
+ * Copyright (C) 2026 Shuwei Wu <shuwei.wu@mailbox.org>
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#include "../thermal_hwmon.h"
+
+#define K1_TSENSOR_PCTRL_REG		0x00
+#define K1_TSENSOR_PCTRL_ENABLE		BIT(0)
+#define K1_TSENSOR_PCTRL_TEMP_MODE	BIT(3)
+#define K1_TSENSOR_PCTRL_RAW_SEL	BIT(7)
+
+#define K1_TSENSOR_PCTRL_CTUNE		GENMASK(11, 8)
+#define K1_TSENSOR_PCTRL_SW_CTRL	GENMASK(21, 18)
+#define K1_TSENSOR_PCTRL_HW_AUTO_MODE	BIT(23)
+
+#define K1_TSENSOR_EN_REG		0x08
+#define K1_TSENSOR_EN_ALL		GENMASK(MAX_SENSOR_NUMBER - 1, 0)
+
+#define K1_TSENSOR_TIME_REG		0x0C
+#define K1_TSENSOR_TIME_WAIT_REF_CNT	GENMASK(3, 0)
+#define K1_TSENSOR_TIME_ADC_CNT_RST	GENMASK(7, 4)
+#define K1_TSENSOR_TIME_FILTER_PERIOD	GENMASK(21, 20)
+#define K1_TSENSOR_TIME_MASK		GENMASK(23, 0)
+
+#define K1_TSENSOR_INT_CLR_REG		0x10
+#define K1_TSENSOR_INT_EN_REG		0x14
+#define K1_TSENSOR_INT_STA_REG		0x18
+
+#define K1_TSENSOR_INT_EN_MASK		BIT(0)
+#define K1_TSENSOR_INT_MASK(x)		(GENMASK(2, 1) << ((x) * 2))
+
+#define K1_TSENSOR_DATA_BASE_REG	0x20
+#define K1_TSENSOR_DATA_REG(x)		(K1_TSENSOR_DATA_BASE_REG + ((x) / 2) * 4)
+#define K1_TSENSOR_DATA_LOW_MASK	GENMASK(15, 0)
+#define K1_TSENSOR_DATA_HIGH_MASK	GENMASK(31, 16)
+
+#define K1_TSENSOR_THRSH_BASE_REG	0x40
+#define K1_TSENSOR_THRSH_REG(x)		(K1_TSENSOR_THRSH_BASE_REG + ((x) * 4))
+#define K1_TSENSOR_THRSH_LOW_MASK	GENMASK(15, 0)
+#define K1_TSENSOR_THRSH_HIGH_MASK	GENMASK(31, 16)
+
+#define MAX_SENSOR_NUMBER		5
+
+/* Hardware offset value required for temperature calculation */
+#define TEMPERATURE_OFFSET		278
+
+struct k1_tsensor_channel {
+	struct k1_tsensor *ts;
+	struct thermal_zone_device *tzd;
+	int id;
+};
+
+struct k1_tsensor {
+	void __iomem *base;
+	struct k1_tsensor_channel ch[MAX_SENSOR_NUMBER];
+};
+
+static void k1_tsensor_init(struct k1_tsensor *ts)
+{
+	u32 val;
+
+	/* Disable all the interrupts */
+	writel(0xffffffff, ts->base + K1_TSENSOR_INT_EN_REG);
+
+	/* Configure ADC sampling time and filter period */
+	val = readl(ts->base + K1_TSENSOR_TIME_REG);
+	val &= ~K1_TSENSOR_TIME_MASK;
+	val |= K1_TSENSOR_TIME_FILTER_PERIOD |
+	       K1_TSENSOR_TIME_ADC_CNT_RST |
+	       K1_TSENSOR_TIME_WAIT_REF_CNT;
+	writel(val, ts->base + K1_TSENSOR_TIME_REG);
+
+	/*
+	 * Enable all sensors' auto mode, enable dither control,
+	 * consecutive mode, and power up sensor.
+	 */
+	val = readl(ts->base + K1_TSENSOR_PCTRL_REG);
+	val &= ~K1_TSENSOR_PCTRL_SW_CTRL;
+	val &= ~K1_TSENSOR_PCTRL_CTUNE;
+	val |= K1_TSENSOR_PCTRL_RAW_SEL |
+	       K1_TSENSOR_PCTRL_TEMP_MODE |
+	       K1_TSENSOR_PCTRL_HW_AUTO_MODE |
+	       K1_TSENSOR_PCTRL_ENABLE;
+	writel(val, ts->base + K1_TSENSOR_PCTRL_REG);
+
+	/* Enable each sensor */
+	val = readl(ts->base + K1_TSENSOR_EN_REG);
+	val |= K1_TSENSOR_EN_ALL;
+	writel(val, ts->base + K1_TSENSOR_EN_REG);
+}
+
+static void k1_tsensor_enable_irq(struct k1_tsensor_channel *ch)
+{
+	struct k1_tsensor *ts = ch->ts;
+	u32 val;
+
+	val = readl(ts->base + K1_TSENSOR_INT_CLR_REG);
+	val |= K1_TSENSOR_INT_MASK(ch->id);
+	writel(val, ts->base + K1_TSENSOR_INT_CLR_REG);
+
+	val = readl(ts->base + K1_TSENSOR_INT_EN_REG);
+	val &= ~K1_TSENSOR_INT_MASK(ch->id);
+	writel(val, ts->base + K1_TSENSOR_INT_EN_REG);
+
+	/* Enable thermal interrupt */
+	val = readl(ts->base + K1_TSENSOR_INT_EN_REG);
+	val |= K1_TSENSOR_INT_EN_MASK;
+	writel(val, ts->base + K1_TSENSOR_INT_EN_REG);
+}
+
+/*
+ * The conversion formula used is:
+ * T(m°C) = (((raw_value & mask) >> shift) - TEMPERATURE_OFFSET) * 1000
+ */
+static int k1_tsensor_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct k1_tsensor_channel *ch = thermal_zone_device_priv(tz);
+	struct k1_tsensor *ts = ch->ts;
+	u32 val;
+
+	val = readl(ts->base + K1_TSENSOR_DATA_REG(ch->id));
+	if (ch->id % 2)
+		*temp = FIELD_GET(K1_TSENSOR_DATA_HIGH_MASK, val);
+	else
+		*temp = FIELD_GET(K1_TSENSOR_DATA_LOW_MASK, val);
+
+	*temp -= TEMPERATURE_OFFSET;
+	*temp *= 1000;
+
+	return 0;
+}
+
+/*
+ * For each sensor, the hardware threshold register is 32 bits:
+ * - Lower 16 bits [15:0] configure the low threshold temperature.
+ * - Upper 16 bits [31:16] configure the high threshold temperature.
+ */
+static int k1_tsensor_set_trips(struct thermal_zone_device *tz, int low, int high)
+{
+	struct k1_tsensor_channel *ch = thermal_zone_device_priv(tz);
+	struct k1_tsensor *ts = ch->ts;
+	u32 val;
+
+	if (low >= high)
+		return -EINVAL;
+
+	low = clamp_val(low / 1000 + TEMPERATURE_OFFSET, TEMPERATURE_OFFSET,
+			FIELD_MAX(K1_TSENSOR_THRSH_LOW_MASK));
+	high = clamp_val(high / 1000 + TEMPERATURE_OFFSET, TEMPERATURE_OFFSET,
+			 FIELD_MAX(K1_TSENSOR_THRSH_HIGH_MASK));
+
+	val = readl(ts->base + K1_TSENSOR_THRSH_REG(ch->id));
+
+	val &= ~(K1_TSENSOR_THRSH_LOW_MASK | K1_TSENSOR_THRSH_HIGH_MASK);
+	val |= FIELD_PREP(K1_TSENSOR_THRSH_LOW_MASK, low);
+	val |= FIELD_PREP(K1_TSENSOR_THRSH_HIGH_MASK, high);
+
+	writel(val, ts->base + K1_TSENSOR_THRSH_REG(ch->id));
+
+	return 0;
+}
+
+static const struct thermal_zone_device_ops k1_tsensor_ops = {
+	.get_temp = k1_tsensor_get_temp,
+	.set_trips = k1_tsensor_set_trips,
+};
+
+static irqreturn_t k1_tsensor_irq_thread(int irq, void *data)
+{
+	struct k1_tsensor *ts = (struct k1_tsensor *)data;
+	int mask, status, i;
+
+	status = readl(ts->base + K1_TSENSOR_INT_STA_REG);
+
+	for (i = 0; i < MAX_SENSOR_NUMBER; i++) {
+		if (status & K1_TSENSOR_INT_MASK(i)) {
+			mask = readl(ts->base + K1_TSENSOR_INT_CLR_REG);
+			mask |= K1_TSENSOR_INT_MASK(i);
+			writel(mask, ts->base + K1_TSENSOR_INT_CLR_REG);
+			thermal_zone_device_update(ts->ch[i].tzd, THERMAL_EVENT_UNSPECIFIED);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int k1_tsensor_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct k1_tsensor *ts;
+	struct reset_control *reset;
+	struct clk *clk;
+	int i, irq, ret;
+
+	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ts->base))
+		return dev_err_probe(dev, PTR_ERR(ts->base), "Failed to get reg\n");
+
+	reset = devm_reset_control_get_exclusive_deasserted(dev, NULL);
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset), "Failed to get/deassert reset control\n");
+
+	clk = devm_clk_get_enabled(dev, "core");
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "Failed to get core clock\n");
+
+	clk = devm_clk_get_enabled(dev, "bus");
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "Failed to get bus clock\n");
+
+	k1_tsensor_init(ts);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_threaded_irq(dev, irq, NULL,
+					k1_tsensor_irq_thread,
+					IRQF_ONESHOT, "k1_tsensor", ts);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < MAX_SENSOR_NUMBER; ++i) {
+		ts->ch[i].id = i;
+		ts->ch[i].ts = ts;
+		ts->ch[i].tzd = devm_thermal_of_zone_register(dev, i, ts->ch + i, &k1_tsensor_ops);
+		if (IS_ERR(ts->ch[i].tzd))
+			return PTR_ERR(ts->ch[i].tzd);
+
+		/* Attach sysfs hwmon attributes for userspace monitoring */
+		ret = devm_thermal_add_hwmon_sysfs(dev, ts->ch[i].tzd);
+		if (ret)
+			dev_warn(dev, "Failed to add hwmon sysfs attributes\n");
+
+		k1_tsensor_enable_irq(ts->ch + i);
+	}
+
+	platform_set_drvdata(pdev, ts);
+
+	return 0;
+}
+
+static const struct of_device_id k1_tsensor_dt_ids[] = {
+	{ .compatible = "spacemit,k1-tsensor" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, k1_tsensor_dt_ids);
+
+static struct platform_driver k1_tsensor_driver = {
+	.driver = {
+		.name		= "k1_tsensor",
+		.of_match_table = k1_tsensor_dt_ids,
+	},
+	.probe	= k1_tsensor_probe,
+};
+module_platform_driver(k1_tsensor_driver);
+
+MODULE_DESCRIPTION("SpacemiT K1 Thermal Sensor Driver");
+MODULE_AUTHOR("Shuwei Wu <shuwei.wu@mailbox.org>");
+MODULE_LICENSE("GPL");