* [PATCH v2 1/2] dt-bindings: thermal: Add Qualcomm MBG thermal monitor support
2026-07-06 8:14 [PATCH v2 0/2] thermal: qcom: Add Qualcomm SPMI MBG thermal monitor support Sachin Gupta
@ 2026-07-06 8:14 ` Sachin Gupta
2026-07-06 8:14 ` [PATCH v2 2/2] thermal: qcom: Add support for Qualcomm MBG thermal monitoring Sachin Gupta
1 sibling, 0 replies; 5+ messages in thread
From: Sachin Gupta @ 2026-07-06 8:14 UTC (permalink / raw)
To: Lee Jones, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Rafael J. Wysocki, Daniel Lezcano, Zhang Rui, Lukasz Luba,
Stephen Boyd, Jishnu Prakash, Kamal Wadhwa, Amit Kucheria,
Thara Gopinath
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pm,
Satya Priya Kakitapalli, Sachin Gupta, Ajit Pandey, Imran Shaik,
Taniya Das, Jagadeesh Kona
From: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
Add bindings for the Qualcomm MBG (Master Bandgap) temperature alarm
peripheral found on the PM8775 PMIC. Unlike the existing SPMI temp alarm
peripheral, the MBG peripheral supports both hot and cold threshold
monitoring across two programmable levels (LVL1 and LVL2), with interrupt
status reported via a fault status register over SPMI.
Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
Co-developed-by: Sachin Gupta <sachin.gupta@oss.qualcomm.com>
Signed-off-by: Sachin Gupta <sachin.gupta@oss.qualcomm.com>
---
.../devicetree/bindings/mfd/qcom,spmi-pmic.yaml | 4 ++
.../bindings/thermal/qcom,pm8775-mbg-tm.yaml | 72 ++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/Documentation/devicetree/bindings/mfd/qcom,spmi-pmic.yaml b/Documentation/devicetree/bindings/mfd/qcom,spmi-pmic.yaml
index 809be2756a0c..bd77cb7173e2 100644
--- a/Documentation/devicetree/bindings/mfd/qcom,spmi-pmic.yaml
+++ b/Documentation/devicetree/bindings/mfd/qcom,spmi-pmic.yaml
@@ -194,6 +194,10 @@ patternProperties:
type: object
$ref: /schemas/thermal/qcom,spmi-temp-alarm.yaml#
+ "^temperature-sensor@[0-9a-f]+$":
+ type: object
+ $ref: /schemas/thermal/qcom,pm8775-mbg-tm.yaml#
+
"^typec@[0-9a-f]+$":
type: object
$ref: /schemas/usb/qcom,pmic-typec.yaml#
diff --git a/Documentation/devicetree/bindings/thermal/qcom,pm8775-mbg-tm.yaml b/Documentation/devicetree/bindings/thermal/qcom,pm8775-mbg-tm.yaml
new file mode 100644
index 000000000000..2e084d040625
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/qcom,pm8775-mbg-tm.yaml
@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/qcom,pm8775-mbg-tm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm's SPMI PMIC MBG Thermal Monitoring
+
+maintainers:
+ - Jishnu Prakash <jishnu.prakash@oss.qualcomm.com>
+ - Kamal Wadhwa <kamal.wadhwa@oss.qualcomm.com>
+
+description:
+ Qualcomm's MBG(Master Bandgap) temperature alarm monitors the die
+ temperature and generates an interrupt if the PMIC die temperature is
+ over a set of programmable temperature thresholds. It allows monitoring
+ for both hot and cold, LVL1 and LVL2 thresholds, which makes it different
+ from the existing temp alarm peripheral. The interrupt comes over SPMI
+ and the MBG's fault status register gives details to understand whether
+ it is a hot/cold and LVL1/LVL2 violation.
+
+properties:
+ compatible:
+ const: qcom,pm8775-mbg-tm
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ io-channels:
+ items:
+ - description: ADC channel, which reports chip die temperature.
+
+ io-channel-names:
+ items:
+ - const: thermal
+
+ '#thermal-sensor-cells':
+ const: 0
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - io-channels
+ - io-channel-names
+
+allOf:
+ - $ref: thermal-sensor.yaml#
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+
+ pmic {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ temperature-sensor@d700 {
+ compatible = "qcom,pm8775-mbg-tm";
+ reg = <0xd700>;
+ interrupts = <0x1 0xd7 0x0 IRQ_TYPE_EDGE_RISING>;
+ io-channels = <&pm8775_adc 0x3>;
+ io-channel-names = "thermal";
+ #thermal-sensor-cells = <0>;
+ };
+ };
+...
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/2] thermal: qcom: Add support for Qualcomm MBG thermal monitoring
2026-07-06 8:14 [PATCH v2 0/2] thermal: qcom: Add Qualcomm SPMI MBG thermal monitor support Sachin Gupta
2026-07-06 8:14 ` [PATCH v2 1/2] dt-bindings: thermal: Add Qualcomm " Sachin Gupta
@ 2026-07-06 8:14 ` Sachin Gupta
2026-07-06 8:26 ` sashiko-bot
2026-07-06 10:33 ` Konrad Dybcio
1 sibling, 2 replies; 5+ messages in thread
From: Sachin Gupta @ 2026-07-06 8:14 UTC (permalink / raw)
To: Lee Jones, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Rafael J. Wysocki, Daniel Lezcano, Zhang Rui, Lukasz Luba,
Stephen Boyd, Jishnu Prakash, Kamal Wadhwa, Amit Kucheria,
Thara Gopinath
Cc: linux-arm-msm, devicetree, linux-kernel, linux-pm,
Satya Priya Kakitapalli, Sachin Gupta, Ajit Pandey, Imran Shaik,
Taniya Das, Jagadeesh Kona
From: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
Add driver for the Qualcomm MBG thermal monitoring device. It monitors the
die temperature, and when there is a level 1 upper threshold violation, it
receives an interrupt over spmi. The driver reads the fault status
register and notifies thermal accordingly.
Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@quicinc.com>
Co-developed-by: Sachin Gupta <sachin.gupta@oss.qualcomm.com>
Signed-off-by: Sachin Gupta <sachin.gupta@oss.qualcomm.com>
---
drivers/thermal/qcom/Kconfig | 11 ++
drivers/thermal/qcom/Makefile | 1 +
drivers/thermal/qcom/qcom-spmi-mbg-tm.c | 256 ++++++++++++++++++++++++++++++++
3 files changed, 268 insertions(+)
diff --git a/drivers/thermal/qcom/Kconfig b/drivers/thermal/qcom/Kconfig
index a6bb01082ec6..f2fc24a3096f 100644
--- a/drivers/thermal/qcom/Kconfig
+++ b/drivers/thermal/qcom/Kconfig
@@ -21,6 +21,17 @@ config QCOM_SPMI_ADC_TM5
Thermal client sets threshold temperature for both warm and cool and
gets updated when a threshold is reached.
+config QCOM_SPMI_MBG_TM
+ tristate "Qualcomm SPMI PMIC MBG Temperature monitor"
+ depends on QCOM_SPMI_ADC5_GEN3
+ select REGMAP_SPMI
+ help
+ This enables a thermal driver for the MBG thermal monitoring device.
+ It shows up in sysfs as a thermal sensor with single trip point.
+ It notifies the thermal framework when this trip is violated. The
+ temperature reported by the thermal sensor reflects the real
+ time die temperature through ADC channel.
+
config QCOM_SPMI_TEMP_ALARM
tristate "Qualcomm SPMI PMIC Temperature Alarm"
depends on OF && SPMI && IIO
diff --git a/drivers/thermal/qcom/Makefile b/drivers/thermal/qcom/Makefile
index 0fa2512042e7..1bec2746b98d 100644
--- a/drivers/thermal/qcom/Makefile
+++ b/drivers/thermal/qcom/Makefile
@@ -4,5 +4,6 @@ obj-$(CONFIG_QCOM_TSENS) += qcom_tsens.o
qcom_tsens-y += tsens.o tsens-v2.o tsens-v1.o tsens-v0_1.o \
tsens-8960.o
obj-$(CONFIG_QCOM_SPMI_ADC_TM5) += qcom-spmi-adc-tm5.o
+obj-$(CONFIG_QCOM_SPMI_MBG_TM) += qcom-spmi-mbg-tm.o
obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM) += qcom-spmi-temp-alarm.o
obj-$(CONFIG_QCOM_LMH) += lmh.o
diff --git a/drivers/thermal/qcom/qcom-spmi-mbg-tm.c b/drivers/thermal/qcom/qcom-spmi-mbg-tm.c
new file mode 100644
index 000000000000..fa2f10002253
--- /dev/null
+++ b/drivers/thermal/qcom/qcom-spmi-mbg-tm.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/thermal.h>
+#include <linux/iio/consumer.h>
+
+#define MBG_TEMP_MON2_FAULT_STATUS 0x50
+
+#define MON_FAULT_STATUS_MASK GENMASK(7, 4)
+#define MON_FAULT_LVL1_UPR 0x5
+
+#define MON2_LVL1_UP_THRESH 0x59
+
+#define MBG_TEMP_MON2_MISC_CFG 0x5f
+#define MON2_UP_THRESH_EN BIT(1)
+
+#define MBG_TEMP_STEP_MV 8
+#define MBG_TEMP_DEFAULT_TEMP_MV 600
+#define MBG_TEMP_CONSTANT 1000
+#define MBG_MIN_TRIP_TEMP 25000
+#define MBG_MAX_SUPPORTED_TEMP 160000
+
+/**
+ * struct mbg_tm_chip - MBG thermal monitor device data.
+ * @map: regmap for accessing MBG thermal registers.
+ * @dev: mbg_tm_chip device.
+ * @tz_dev: thermal zone device registered with the thermal framework.
+ * @lock: mbg_tm_chip lock for set trip temperature.
+ * @base: base register offset for this MBG instance
+ * @irq: interrupt line used to signal threshold events
+ * @last_temp: last measured temperature.
+ * @last_thres_crossed: indicates whether the last interrupt crossed a threshold
+ * @adc: IIO ADC channel used for temperature sensing
+ */
+struct mbg_tm_chip {
+ struct regmap *map;
+ struct device *dev;
+ struct thermal_zone_device *tz_dev;
+ struct mutex lock;
+ unsigned int base;
+ int irq;
+ int last_temp;
+ bool last_thres_crossed;
+ struct iio_channel *adc;
+};
+
+/**
+ * struct mbg_map_table - temperature to voltage mapping entry
+ * @min_temp: minimum temperature supported by this mapping entry
+ * @vtemp0: reference voltage or ADC code corresponding to the temperature
+ * @tc: temperature coefficient used for conversion calculations
+ */
+struct mbg_map_table {
+ int min_temp;
+ int vtemp0;
+ int tc;
+};
+
+static const struct mbg_map_table map_table[] = {
+ { -60000, 4337, 1967 },
+ { -40000, 4731, 1964 },
+ { -20000, 5124, 1957 },
+ { 0, 5515, 1949 },
+ { 20000, 5905, 1940 },
+ { 40000, 6293, 1930 },
+ { 60000, 6679, 1921 },
+ { 80000, 7064, 1910 },
+ { 100000, 7446, 1896 },
+ { 120000, 7825, 1878 },
+ { 140000, 8201, 1859 },
+};
+
+static int mbg_tm_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+ struct mbg_tm_chip *chip = thermal_zone_device_priv(tz);
+ int ret, milli_celsius;
+
+ scoped_guard(mutex, &chip->lock) {
+ if (chip->last_thres_crossed) {
+ dev_dbg(chip->dev, "last_temp: %d\n", chip->last_temp);
+ chip->last_thres_crossed = false;
+ *temp = chip->last_temp;
+ return 0;
+ }
+ }
+
+ ret = iio_read_channel_processed(chip->adc, &milli_celsius);
+ if (ret < 0) {
+ dev_err(chip->dev, "Failed to read iio channel with %d\n", ret);
+ return ret;
+ }
+
+ *temp = milli_celsius;
+
+ return 0;
+}
+
+static int temp_to_vtemp_mv(int temp)
+{
+ int idx, vtemp, tc = 0, t0 = 0, vtemp0 = 0;
+
+ for (idx = 0; idx < ARRAY_SIZE(map_table); idx++)
+ if (temp >= map_table[idx].min_temp &&
+ temp < (map_table[idx].min_temp + 20000)) {
+ tc = map_table[idx].tc;
+ t0 = map_table[idx].min_temp;
+ vtemp0 = map_table[idx].vtemp0;
+ break;
+ }
+
+ /*
+ * Formula to calculate vtemp(mV) from a given temp
+ * vtemp = (temp - minT) * tc + vtemp0
+ * tc, t0 and vtemp0 values are mentioned in the map_table array.
+ */
+ vtemp = ((temp - t0) * tc + vtemp0 * 100000) / 1000000;
+
+ /* step size is 8mV */
+ return abs(vtemp - MBG_TEMP_DEFAULT_TEMP_MV) / MBG_TEMP_STEP_MV;
+}
+
+static int mbg_tm_set_trip_temp(struct thermal_zone_device *tz, int low_temp,
+ int temp)
+{
+ struct mbg_tm_chip *chip = thermal_zone_device_priv(tz);
+ int ret = 0;
+
+ guard(mutex)(&chip->lock);
+
+ /* The HW has a limitation that the trip set must be above 25C */
+ if (temp > MBG_MIN_TRIP_TEMP && temp < MBG_MAX_SUPPORTED_TEMP) {
+ ret = regmap_write(chip->map, chip->base + MON2_LVL1_UP_THRESH,
+ temp_to_vtemp_mv(temp));
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_set_bits(chip->map, chip->base + MBG_TEMP_MON2_MISC_CFG,
+ MON2_UP_THRESH_EN);
+ if (ret < 0)
+ return ret;
+ } else {
+ dev_err(chip->dev, "Set trip b/w 25C and 160C\n");
+ ret = regmap_clear_bits(chip->map, chip->base + MBG_TEMP_MON2_MISC_CFG,
+ MON2_UP_THRESH_EN);
+ return -ERANGE;
+ }
+
+ /*
+ * Configure the last_temp one degree higher, to ensure the
+ * violated temp is returned to thermal framework when it reads
+ * temperature for the first time after the violation happens.
+ * This is needed to account for the inaccuracy in the conversion
+ * formula used which leads to the thermal framework setting back
+ * the same thresholds in case the temperature it reads does not
+ * show violation.
+ */
+ chip->last_temp = temp + MBG_TEMP_CONSTANT;
+
+ return ret;
+}
+
+static const struct thermal_zone_device_ops mbg_tm_ops = {
+ .get_temp = mbg_tm_get_temp,
+ .set_trips = mbg_tm_set_trip_temp,
+};
+
+static irqreturn_t mbg_tm_isr(int irq, void *data)
+{
+ struct mbg_tm_chip *chip = data;
+ int ret, val;
+
+ scoped_guard(mutex, &chip->lock) {
+ ret = regmap_read(chip->map, chip->base + MBG_TEMP_MON2_FAULT_STATUS, &val);
+ if (ret < 0)
+ return IRQ_HANDLED;
+ if (FIELD_GET(MON_FAULT_STATUS_MASK, val) == MON_FAULT_LVL1_UPR)
+ chip->last_thres_crossed = true;
+ }
+
+ if (FIELD_GET(MON_FAULT_STATUS_MASK, val) == MON_FAULT_LVL1_UPR) {
+ dev_dbg(chip->dev, "Notifying Thermal, fault status=%d\n", val);
+ thermal_zone_device_update(chip->tz_dev, THERMAL_TRIP_VIOLATED);
+ } else {
+ dev_dbg(chip->dev, "Lvl1 upper threshold not violated, ignoring interrupt\n");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int mbg_tm_probe(struct platform_device *pdev)
+{
+ struct mbg_tm_chip *chip;
+ struct device_node *node = pdev->dev.of_node;
+ u32 res;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->dev = &pdev->dev;
+
+ mutex_init(&chip->lock);
+
+ chip->map = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!chip->map)
+ return -ENXIO;
+
+ ret = device_property_read_u32(chip->dev, "reg", &res);
+ if (ret < 0)
+ return dev_err_probe(chip->dev, ret, "Couldn't read reg property\n");
+
+ chip->base = res;
+
+ chip->irq = platform_get_irq(pdev, 0);
+ if (chip->irq < 0)
+ return dev_err_probe(chip->dev, chip->irq, "Failed to get irq\n");
+
+ chip->adc = devm_iio_channel_get(&pdev->dev, "thermal");
+ if (IS_ERR(chip->adc))
+ return dev_err_probe(chip->dev, PTR_ERR(chip->adc), "Failed to get adc channel\n");
+
+ chip->tz_dev = devm_thermal_of_zone_register(chip->dev, 0, chip, &mbg_tm_ops);
+ if (IS_ERR(chip->tz_dev))
+ return dev_err_probe(chip->dev, PTR_ERR(chip->tz_dev),
+ "Failed to register sensor\n");
+
+ return devm_request_threaded_irq(&pdev->dev, chip->irq, NULL, mbg_tm_isr, IRQF_ONESHOT,
+ node->name, chip);
+}
+
+static const struct of_device_id mbg_tm_match_table[] = {
+ { .compatible = "qcom,pm8775-mbg-tm" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mbg_tm_match_table);
+
+static struct platform_driver mbg_tm_driver = {
+ .driver = {
+ .name = "qcom-spmi-mbg-tm",
+ .of_match_table = mbg_tm_match_table,
+ },
+ .probe = mbg_tm_probe,
+};
+module_platform_driver(mbg_tm_driver);
+
+MODULE_DESCRIPTION("PMIC MBG Temperature monitor driver");
+MODULE_LICENSE("GPL");
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread