dt-bindings: thermal: Add support for Airoha EN7581 thermal sensor

Add support for Airoha EN7581 thermal sensor. This provide support for reading the CPU or SoC Package sensor and to setup trip points for hot and critical condition. An interrupt is fired to react on this and doesn't require passive poll to read the temperature.

The thermal regs provide a way to read the ADC value from an external register placed in the Chip SCU regs. Monitor will read this value and fire an interrupt if the trip condition configured is reached.

The Thermal Trip and Interrupt logic is conceptually similar to Mediatek LVTS Thermal but differ in register mapping and actual function/bug workaround. The implementation only share some register names but from functionality observation it's very different and used only for the basic function of periodically poll the temp and trip the interrupt.

Signed-off-by Christian Marangi <[email protected]>

---

drivers/thermal/airoha_thermal.c new file +18 -0

+#define   EN7581_HINTEN1			BIT(6)
+#define   EN7581_CINTEN1			BIT(5)
+#define   EN7581_NOHOTINTEN0			BIT(4)
+/* Similar to COLD and HOT also these seems to be swapped in documentation */
+#define   EN7581_LOFSINTEN0			BIT(3) /* In documentation: BIT(2) */
+#define   EN7581_HOFSINTEN0			BIT(2) /* In documentation: BIT(3) */
+/* It seems documentation have these swapped as the HW
+ * - Fire BIT(1) when lower than EN7581_COLD_THRE
+ * - Fire BIT(0) and BIT(5) when higher than EN7581_HOT2NORMAL_THRE or
+ *     EN7581_HOT_THRE
+ */
+#define   EN7581_CINTEN0			BIT(1) /* In documentation: BIT(0) */
+#define   EN7581_HINTEN0			BIT(0) /* In documentation: BIT(1) */
+#define EN7581_TEMPMONINTSTS			0x810
+#define   EN7581_STAGE3_INT_STAT		BIT(31)
+#define   EN7581_STAGE2_INT_STAT		BIT(30)
+#define   EN7581_STAGE1_INT_STAT		BIT(29)
+#define   EN7581_FILTER_INT_STAT_3		BIT(28)

drivers/thermal/airoha_thermal.c new file +33 -0

+#define   EN7581_NOHOTINTSTS0			BIT(4)
+/* Similar to COLD and HOT also these seems to be swapped in documentation */
+#define   EN7581_LOFSINTSTS0			BIT(3) /* In documentation: BIT(2) */
+#define   EN7581_HOFSINTSTS0			BIT(2) /* In documentation: BIT(3) */
+/* It seems documentation have these swapped as the HW
+ * - Fire BIT(1) when lower than EN7581_COLD_THRE
+ * - Fire BIT(0) and BIT(5) when higher than EN7581_HOT2NORMAL_THRE or
+ *     EN7581_HOT_THRE
+ *
+ * To clear things, we swap the define but we keep them documented here.
+ */
+#define   EN7581_CINTSTS0			BIT(1) /* In documentation: BIT(0) */
+#define   EN7581_HINTSTS0			BIT(0) /* In documentation: BIT(1)*/
+/* Monitor will take the bigger threshold between HOT2NORMAL and HOT
+ * and will fire both HOT2NORMAL and HOT interrupt when higher than the 2
+ *
+ * It has also been observed that not setting HOT2NORMAL makes the monitor
+ * treat COLD threshold as HOT2NORMAL.
+ */
+#define EN7581_TEMPH2NTHRE			0x824
+/* It seems HOT2NORMAL is actually NORMAL2HOT */
+#define   EN7581_HOT2NORMAL_THRE		GENMASK(11, 0)
+#define EN7581_TEMPHTHRE			0x828
+#define   EN7581_HOT_THRE			GENMASK(11, 0)
+/* Monitor will use this as HOT2NORMAL (fire interrupt when lower than...)*/
+#define EN7581_TEMPCTHRE			0x82c
+#define   EN7581_COLD_THRE			GENMASK(11, 0)
+/* Also LOW and HIGH offset register are swapped */
+#define EN7581_TEMPOFFSETL			0x830 /* In documentation: 0x834 */
+#define   EN7581_LOW_OFFSET			GENMASK(11, 0)
+#define EN7581_TEMPOFFSETH			0x834 /* In documentation: 0x830 */
+#define   EN7581_HIGH_OFFSET			GENMASK(11, 0)
+#define EN7581_TEMPMSRCTL0			0x838

Add support for Airoha EN7581 thermal sensor. This provide support for reading the CPU or SoC Package sensor and to setup trip points for hot and critical condition. An interrupt is fired to react on this and doesn't require passive poll to read the temperature.

The thermal regs provide a way to read the ADC value from an external register placed in the Chip SCU regs. Monitor will read this value and fire an interrupt if the trip condition configured is reached.

The Thermal Trip and Interrupt logic is conceptually similar to Mediatek LVTS Thermal but differ in register mapping and actual function/bug workaround. The implementation only share some register names but from functionality observation it's very different and used only for the basic function of periodically poll the temp and trip the interrupt.

Signed-off-by Christian Marangi <[email protected]>

---
Changes v5:
- Add additional info on difference from Mediatek LVTS driver

drivers/thermal/airoha_thermal.c new file +33 -0

+static void airoha_init_thermal_ADC_mode(struct airoha_thermal_priv *priv)
+{
+	u32 adc_mux, pllrg;
+
+	/* Save PLLRG current value */
+	regmap_read(priv->chip_scu, EN7581_PLLRG_PROTECT, &pllrg);
+
+	/* Give access to thermal regs */
+	regmap_write(priv->chip_scu, EN7581_PLLRG_PROTECT, EN7581_SCU_THERMAL_PROTECT_KEY);
+	adc_mux = FIELD_PREP(EN7581_MUX_TADC, EN7581_SCU_THERMAL_MUX_DIODE1);
+	regmap_write(priv->chip_scu, EN7581_PWD_TADC, adc_mux);
+
+	/* Restore PLLRG value on exit */
+	regmap_write(priv->chip_scu, EN7581_PLLRG_PROTECT, pllrg);
+}
+
+static int airoha_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct airoha_thermal_priv *priv = thermal_zone_device_priv(tz);
+	int min, max, avg_temp, temp_adc;
+	int i;
+
+	/* Get the starting temp */
+	temp_adc = airoha_get_thermal_ADC(priv);
+	min = temp_adc;
+	max = temp_adc;
+	avg_temp = temp_adc;
+
+	/* Make 5 more measurement and average the temp ADC difference */
+	for (i = 0; i < 5; i++) {
+		temp_adc = airoha_get_thermal_ADC(priv);
+		avg_temp += temp_adc;
+		if (temp_adc > max)

drivers/thermal/airoha_thermal.c new file +14 -0

+	return 0;
+}
+
+static const struct thermal_zone_device_ops thdev_ops = {
+	.get_temp = airoha_thermal_get_temp,
+	.set_trips = airoha_thermal_set_trips,
+};
+
+static irqreturn_t airoha_thermal_irq(int irq, void *data)
+{
+	struct airoha_thermal_priv *priv = data;
+	enum thermal_notify_event event;
+	u32 status;
+

drivers/thermal/airoha_thermal.c new file +3 -0

+	return IRQ_HANDLED;
+}
+

drivers/thermal/airoha_thermal.c new file +44 -0

+static void airoha_thermal_setup_monitor(struct airoha_thermal_priv *priv)
+{
+	/* Set measure mode */
+	writel(FIELD_PREP(EN7581_MSRCTL0, EN7581_MSRCTL_6SAMPLE_MAX_MIX_AVG4),
+	       priv->base + EN7581_TEMPMSRCTL0);
+
+	/*
+	 * Configure ADC valid reading addr
+	 * The AHB temp monitor system doesn't have direct access to the
+	 * thermal sensor. It does instead work by providing all kind of
+	 * address to configure how to access and setup an ADC for the
+	 * sensor. EN7581 supports only one sensor hence the
+	 * implementation is greatly simplified but the AHB supports
+	 * up to 4 different sensor from the same ADC that can be
+	 * switched by tuning the ADC mux or wiriting address.
+	 *
+	 * We set valid instead of volt as we don't enable valid/volt
+	 * split reading and AHB read valid addr in such case.
+	 */
+	writel(priv->scu_adc_res.start + EN7581_DOUT_TADC,
+	       priv->base + EN7581_TEMPADCVALIDADDR);
+
+	/*
+	 * Configure valid bit on a fake value of bit 16. The ADC outputs
+	 * max of 2 bytes for voltage.
+	 */
+	writel(FIELD_PREP(EN7581_ADV_RD_VALID_POS, 16),
+	       priv->base + EN7581_TEMPADCVALIDMASK);
+
+	/*
+	 * AHB supports max 12 bytes for ADC voltage. Shift the read
+	 * value 4 bit to the right. Precision lost by this is minimal
+	 * in the order of half a °C and is acceptable in the context
+	 * of triggering interrupt in critical condition.
+	 */
+	writel(FIELD_PREP(EN7581_ADC_VOLTAGE_SHIFT, 4),
+	       priv->base + EN7581_TEMPADCVOLTAGESHIFT);
+
+	/* BUS clock is 300MHz counting unit is 3 * 68.64 * 256 = 52.715us */
+	writel(FIELD_PREP(EN7581_PERIOD_UNIT, 3),
+	       priv->base + EN7581_TEMPMONCTL1);
+
+	/*
+	 * filt interval is 1 * 52.715us = 52.715us,

drivers/thermal/airoha_thermal.c new file +23 -0

+static int airoha_thermal_probe(struct platform_device *pdev)
+{
+	struct airoha_thermal_priv *priv;
+	struct device_node *chip_scu_np;
+	struct device *dev = &pdev->dev;
+	int irq, ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	chip_scu_np = of_parse_phandle(dev->of_node, "airoha,chip-scu", 0);
+	if (!chip_scu_np)
+		return -EINVAL;
+
+	priv->chip_scu = syscon_node_to_regmap(chip_scu_np);
+	if (IS_ERR(priv->chip_scu))
+		return PTR_ERR(priv->chip_scu);
+

drivers/thermal/airoha_thermal.c new file +43 -0

+	if (ret) {
+		dev_err(dev, "Can't get interrupt working.\n");
+		return ret;
+	}
+
+	airoha_thermal_setup_monitor(priv);
+	airoha_thermal_setup_adc_val(dev, priv);
+
+	/* register of thermal sensor and get info from DT */
+	priv->tz = devm_thermal_of_zone_register(dev, 0, priv, &thdev_ops);
+	if (IS_ERR(priv->tz)) {
+		dev_err(dev, "register thermal zone sensor failed\n");
+		return PTR_ERR(priv->tz);
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	/* Enable LOW and HIGH interrupt */
+	writel(EN7581_HOFSINTEN0 | EN7581_LOFSINTEN0,
+	       priv->base + EN7581_TEMPMONINT);
+
+	return 0;
+}
+
+static const struct of_device_id airoha_thermal_match[] = {
+	{ .compatible = "airoha,en7581-thermal" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, airoha_thermal_match);
+
+static struct platform_driver airoha_thermal_driver = {
+	.driver = {
+		.name = "airoha-thermal",
+		.of_match_table = airoha_thermal_match,
+	},
+	.probe = airoha_thermal_probe,
+};
+
+module_platform_driver(airoha_thermal_driver);
+
+MODULE_AUTHOR("Christian Marangi <[email protected]>");
+MODULE_DESCRIPTION("Airoha thermal driver");
+MODULE_LICENSE("GPL");

Quoted 19 lines · Christian Marangi

Add support for Airoha EN7581 thermal sensor. This provide support for reading the CPU or SoC Package sensor and to setup trip points for hot and critical condition. An interrupt is fired to react on this and doesn't require passive poll to read the temperature.

The thermal regs provide a way to read the ADC value from an external register placed in the Chip SCU regs. Monitor will read this value and fire an interrupt if the trip condition configured is reached.

The Thermal Trip and Interrupt logic is conceptually similar to Mediatek LVTS Thermal but differ in register mapping and actual function/bug workaround. The implementation only share some register names but from functionality observation it's very different and used only for the basic function of periodically poll the temp and trip the interrupt.

Signed-off-by Christian Marangi <[email protected]>

---
Changes v5:
- Add additional info on difference from Mediatek LVTS driver

[ ... ]

Quoted 38 lines

drivers/thermal/airoha_thermal.c new file +38 -0

+static void airoha_init_thermal_ADC_mode(struct airoha_thermal_priv *priv)
+{
+	u32 adc_mux, pllrg;
+
+	/* Save PLLRG current value */
+	regmap_read(priv->chip_scu, EN7581_PLLRG_PROTECT, &pllrg);
+
+	/* Give access to thermal regs */
+	regmap_write(priv->chip_scu, EN7581_PLLRG_PROTECT, EN7581_SCU_THERMAL_PROTECT_KEY);
+	adc_mux = FIELD_PREP(EN7581_MUX_TADC, EN7581_SCU_THERMAL_MUX_DIODE1);
+	regmap_write(priv->chip_scu, EN7581_PWD_TADC, adc_mux);
+
+	/* Restore PLLRG value on exit */
+	regmap_write(priv->chip_scu, EN7581_PLLRG_PROTECT, pllrg);
+}
+
+static int airoha_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct airoha_thermal_priv *priv = thermal_zone_device_priv(tz);
+	int min, max, avg_temp, temp_adc;
+	int i;
+
+	/* Get the starting temp */
+	temp_adc = airoha_get_thermal_ADC(priv);
+	min = temp_adc;
+	max = temp_adc;
+	avg_temp = temp_adc;
+
+	/* Make 5 more measurement and average the temp ADC difference */
+	for (i = 0; i < 5; i++) {
+		temp_adc = airoha_get_thermal_ADC(priv);
+		avg_temp += temp_adc;
+		if (temp_adc > max)
+			max = temp_adc;
+		if (temp_adc < min)
+			min = temp_adc;
+	}
+	avg_temp = avg_temp - max - min;

drivers/thermal/airoha_thermal.c line 255

Quoted 5 lines

drivers/thermal/airoha_thermal.c new file +5 -0

+	avg_temp /= 4;
+
+	*temp = RAW_TO_TEMP(priv, avg_temp);
+	return 0;
+}

Does this chip support the averaging with the filtered mode which prevent to do this expensive calls when getting the temperature ?

drivers/thermal/airoha_thermal.c line 265

Quoted 9 lines

drivers/thermal/airoha_thermal.c new file +9 -0

+static int airoha_thermal_set_trips(struct thermal_zone_device *tz, int low,
+				    int high)
+{
+	struct airoha_thermal_priv *priv = thermal_zone_device_priv(tz);
+
+	if (high != INT_MAX) {
+		/* Validate high and clamp them a sane value */
+		if (high > RAW_TO_TEMP(priv, FIELD_MAX(EN7581_DOUT_TADC_MASK)))
+			high = 110000;

There are helpers in minmax.h

drivers/thermal/airoha_thermal.c line 275

Quoted 9 lines

drivers/thermal/airoha_thermal.c new file +9 -0

+		/* We offset the high temp of 1°C to trigger correct event */
+		writel(TEMP_TO_RAW(priv, high) >> 4,
+		       priv->base + EN7581_TEMPOFFSETH);
+	}
+
+	if (low != -INT_MAX) {
+		/* Validate low and clamp them to a sane value */
+		if (low < RAW_TO_TEMP(priv, 0))
+			low = -33000;

Same.

drivers/thermal/airoha_thermal.c line 283

Quoted 7 lines

drivers/thermal/airoha_thermal.c new file +7 -0

+		/* We offset the low temp of 1°C to trigger correct event */
+		writel(TEMP_TO_RAW(priv, low) >> 4,
+		       priv->base + EN7581_TEMPOFFSETL);
+	}
+
+	/* Enable sensor 0 monitor */
+	writel(EN7581_SENSE0_EN, priv->base + EN7581_TEMPMONCTL0);

The sensor is enabled in this routine but disabled anywhere else. Should it be enabled in the init routine or in the set_mode callbacks ?

Quoted 18 lines

drivers/thermal/airoha_thermal.c new file +18 -0

+	return 0;
+}
+
+static const struct thermal_zone_device_ops thdev_ops = {
+	.get_temp = airoha_thermal_get_temp,
+	.set_trips = airoha_thermal_set_trips,
+};
+
+static irqreturn_t airoha_thermal_irq(int irq, void *data)
+{
+	struct airoha_thermal_priv *priv = data;
+	enum thermal_notify_event event;
+	u32 status;
+
+	status = readl(priv->base + EN7581_TEMPMONINTSTS);
+	switch (status & (EN7581_HOFSINTSTS0 | EN7581_LOFSINTSTS0)) {
+	case EN7581_HOFSINTSTS0:
+		event = THERMAL_TRIP_VIOLATED;

drivers/thermal/airoha_thermal.c line 308

Quoted 6 lines

drivers/thermal/airoha_thermal.c new file +6 -0

+		break;
+	case EN7581_LOFSINTSTS0:
+		event = THERMAL_EVENT_UNSPECIFIED;
+		break;
+	default:
+		goto exit;

Is the default case possible ?

drivers/thermal/airoha_thermal.c line 315

Quoted 6 lines

drivers/thermal/airoha_thermal.c new file +6 -0

+	}
+	thermal_zone_device_update(priv->tz, event);
+
+exit:
+	/* reset interrupt */
+	writel(status, priv->base + EN7581_TEMPMONINTSTS);

You may want to the ack the interrupt before calling thermal_zone_device_update() as the underlying code can interact with the driver like calling set_trips. I'm not sure if it has on impact or not but IMO it is a good practice.

Quoted 3 lines

drivers/thermal/airoha_thermal.c new file +3 -0

+	return IRQ_HANDLED;
+}
+

[ ... ]

Quoted 44 lines

drivers/thermal/airoha_thermal.c new file +44 -0

+static void airoha_thermal_setup_monitor(struct airoha_thermal_priv *priv)
+{
+	/* Set measure mode */
+	writel(FIELD_PREP(EN7581_MSRCTL0, EN7581_MSRCTL_6SAMPLE_MAX_MIX_AVG4),
+	       priv->base + EN7581_TEMPMSRCTL0);
+
+	/*
+	 * Configure ADC valid reading addr
+	 * The AHB temp monitor system doesn't have direct access to the
+	 * thermal sensor. It does instead work by providing all kind of
+	 * address to configure how to access and setup an ADC for the
+	 * sensor. EN7581 supports only one sensor hence the
+	 * implementation is greatly simplified but the AHB supports
+	 * up to 4 different sensor from the same ADC that can be
+	 * switched by tuning the ADC mux or wiriting address.
+	 *
+	 * We set valid instead of volt as we don't enable valid/volt
+	 * split reading and AHB read valid addr in such case.
+	 */
+	writel(priv->scu_adc_res.start + EN7581_DOUT_TADC,
+	       priv->base + EN7581_TEMPADCVALIDADDR);
+
+	/*
+	 * Configure valid bit on a fake value of bit 16. The ADC outputs
+	 * max of 2 bytes for voltage.
+	 */
+	writel(FIELD_PREP(EN7581_ADV_RD_VALID_POS, 16),
+	       priv->base + EN7581_TEMPADCVALIDMASK);
+
+	/*
+	 * AHB supports max 12 bytes for ADC voltage. Shift the read
+	 * value 4 bit to the right. Precision lost by this is minimal
+	 * in the order of half a °C and is acceptable in the context
+	 * of triggering interrupt in critical condition.
+	 */
+	writel(FIELD_PREP(EN7581_ADC_VOLTAGE_SHIFT, 4),
+	       priv->base + EN7581_TEMPADCVOLTAGESHIFT);
+
+	/* BUS clock is 300MHz counting unit is 3 * 68.64 * 256 = 52.715us */
+	writel(FIELD_PREP(EN7581_PERIOD_UNIT, 3),
+	       priv->base + EN7581_TEMPMONCTL1);
+
+	/*
+	 * filt interval is 1 * 52.715us = 52.715us,

drivers/thermal/airoha_thermal.c line 403

Quoted 10 lines

drivers/thermal/airoha_thermal.c new file +10 -0

+	 * sen interval is 379 * 52.715us = 19.97ms
+	 */
+	writel(FIELD_PREP(EN7581_FILT_INTERVAL, 1) |
+	       FIELD_PREP(EN7581_FILT_INTERVAL, 379),
+	       priv->base + EN7581_TEMPMONCTL2);
+
+	/* AHB poll is set to 146 * 68.64 = 10.02us */
+	writel(FIELD_PREP(EN7581_ADC_POLL_INTVL, 146),
+	       priv->base + EN7581_TEMPAHBPOLL);
+}

Thanks for documenting the different steps

Quoted 23 lines

drivers/thermal/airoha_thermal.c new file +23 -0

+static int airoha_thermal_probe(struct platform_device *pdev)
+{
+	struct airoha_thermal_priv *priv;
+	struct device_node *chip_scu_np;
+	struct device *dev = &pdev->dev;
+	int irq, ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	chip_scu_np = of_parse_phandle(dev->of_node, "airoha,chip-scu", 0);
+	if (!chip_scu_np)
+		return -EINVAL;
+
+	priv->chip_scu = syscon_node_to_regmap(chip_scu_np);
+	if (IS_ERR(priv->chip_scu))
+		return PTR_ERR(priv->chip_scu);
+

drivers/thermal/airoha_thermal.c line 437

Quoted 10 lines

drivers/thermal/airoha_thermal.c new file +10 -0

+	of_address_to_resource(chip_scu_np, 0, &priv->scu_adc_res);
+	of_node_put(chip_scu_np);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					airoha_thermal_irq, IRQF_ONESHOT,
+					pdev->name, (void *)priv);

(void *) cast is not needed

Quoted 43 lines

drivers/thermal/airoha_thermal.c new file +43 -0

+	if (ret) {
+		dev_err(dev, "Can't get interrupt working.\n");
+		return ret;
+	}
+
+	airoha_thermal_setup_monitor(priv);
+	airoha_thermal_setup_adc_val(dev, priv);
+
+	/* register of thermal sensor and get info from DT */
+	priv->tz = devm_thermal_of_zone_register(dev, 0, priv, &thdev_ops);
+	if (IS_ERR(priv->tz)) {
+		dev_err(dev, "register thermal zone sensor failed\n");
+		return PTR_ERR(priv->tz);
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	/* Enable LOW and HIGH interrupt */
+	writel(EN7581_HOFSINTEN0 | EN7581_LOFSINTEN0,
+	       priv->base + EN7581_TEMPMONINT);
+
+	return 0;
+}
+
+static const struct of_device_id airoha_thermal_match[] = {
+	{ .compatible = "airoha,en7581-thermal" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, airoha_thermal_match);
+
+static struct platform_driver airoha_thermal_driver = {
+	.driver = {
+		.name = "airoha-thermal",
+		.of_match_table = airoha_thermal_match,
+	},
+	.probe = airoha_thermal_probe,
+};
+
+module_platform_driver(airoha_thermal_driver);
+
+MODULE_AUTHOR("Christian Marangi <[email protected]>");
+MODULE_DESCRIPTION("Airoha thermal driver");
+MODULE_LICENSE("GPL");

Signature · 5 lines

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On Fri, May 02, 2025 at 03:30:56PM +0200, Daniel Lezcano wrote:

Quoted 15 lines

Quoted 15 lines

drivers/thermal/airoha_thermal.c new file +15 -0

+static int airoha_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct airoha_thermal_priv *priv = thermal_zone_device_priv(tz);
+	int min, max, avg_temp, temp_adc;
+	int i;
+
+	/* Get the starting temp */
+	temp_adc = airoha_get_thermal_ADC(priv);
+	min = temp_adc;
+	max = temp_adc;
+	avg_temp = temp_adc;
+
+	/* Make 5 more measurement and average the temp ADC difference */
+	for (i = 0; i < 5; i++) {
+		temp_adc = airoha_get_thermal_ADC(priv);

Quoted 8 lines

drivers/thermal/airoha_thermal.c line 251

Quoted 8 lines

drivers/thermal/airoha_thermal.c new file +8 -0

+		avg_temp += temp_adc;
+		if (temp_adc > max)
+			max = temp_adc;
+		if (temp_adc < min)
+			min = temp_adc;
+	}
+	avg_temp = avg_temp - max - min;
+	avg_temp /= 4;

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drivers/thermal/airoha_thermal.c line 253

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drivers/thermal/airoha_thermal.c new file +1 -0

+	*temp = RAW_TO_TEMP(priv, avg_temp);

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Review

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+	return 0;
+}

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Does this chip support the averaging with the filtered mode which prevent to do this expensive calls when getting the temperature ?

If you notice in this function we read directly from the ADC sensor to have a more precise and realtime temperature.

Yes the thermal module support averaging (and this is what is set for the critical temperature monitor) but since we base everything on interrupt the expensive call is called only when the user poll the temperature with sysfs.

Do you prefer to use the thermal module entirely?