[RFC,v2,3/5] thermal: qcom: Add support for MBG thermal monitoring

diff --git a/drivers/thermal/qcom/Kconfig b/drivers/thermal/qcom/Kconfig
index f9876fb8606dd05022bd5ace56a0804f5a8cbfce..2ddfb6228edc7369355d9091fba3b1c130cad459 100644
--- a/drivers/thermal/qcom/Kconfig
+++ b/drivers/thermal/qcom/Kconfig
@@ -32,6 +32,17 @@  config QCOM_SPMI_ADC_TM5_GEN3
 	  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 Technologies, Inc. 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 828d9e7bc797094453566f310b1aea558294162b..937ba0fe2801325592ba8e4354ba1f0ec3109c32 100644
--- a/drivers/thermal/qcom/Makefile
+++ b/drivers/thermal/qcom/Makefile
@@ -5,5 +5,6 @@  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_ADC_TM5_GEN3)	+= qcom-spmi-adc-tm5-gen3.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 0000000000000000000000000000000000000000..22ca331a6de355af22f270d6e047167ce1bcb55a
--- /dev/null
+++ b/drivers/thermal/qcom/qcom-spmi-mbg-tm.c
@@ -0,0 +1,245 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+//Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/thermal.h>
+#include <linux/iio/consumer.h>
+
+#include "../thermal_core.h"
+
+#define MBG_TEMP_MON2_FAULT_STATUS	0x50
+
+#define MON_FAULT_STATUS_MASK		GENMASK(7, 6)
+#define MON_POLARITY_STATUS_MASK	GENMASK(5, 4)
+
+#define MON_FAULT_STATUS_LVL1		BIT(6)
+#define MON_POLARITY_STATUS_UPR		BIT(4)
+
+#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 {
+	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 {
+	int min_temp;
+	int vtemp0;
+	int tc;
+};
+
+static const struct mbg_map_table map_table[] = {
+	/* minT	vtemp0	tc */
+	{ -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;
+
+	if (!temp)
+		return -EINVAL;
+
+	if (chip->last_thres_crossed) {
+		pr_debug("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 %d\n", ret);
+		return ret;
+	}
+
+	*temp = milli_celsius;
+
+	return 0;
+}
+
+static int temp_to_vtemp(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;
+
+	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) {
+		regmap_set_bits(chip->map,
+			chip->base + MBG_TEMP_MON2_MISC_CFG, MON2_UP_THRESH_EN);
+		ret = regmap_write(chip->map, chip->base + MON2_LVL1_UP_THRESH,
+						temp_to_vtemp(temp));
+		if (ret < 0)
+			return ret;
+	} else {
+		dev_dbg(chip->dev, "Set trip b/w 25C and 160C\n");
+		regmap_clear_bits(chip->map,
+			chip->base + MBG_TEMP_MON2_MISC_CFG, MON2_UP_THRESH_EN);
+	}
+
+	/*
+	 * 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 ((val & MON_FAULT_STATUS_MASK) & MON_FAULT_STATUS_LVL1) {
+		if ((val & MON_POLARITY_STATUS_MASK) & MON_POLARITY_STATUS_UPR) {
+			chip->last_thres_crossed = true;
+			thermal_zone_device_update(chip->tz_dev,
+						THERMAL_TRIP_VIOLATED);
+			dev_dbg(chip->dev, "Notifying Thermal, fault status=%d\n", val);
+		} else {
+			dev_dbg(chip->dev, "Lvl1 upr 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 ret;
+
+	chip->base = res;
+
+	chip->irq = platform_get_irq(pdev, 0);
+	if (chip->irq < 0)
+		return chip->irq;
+
+	chip->adc = devm_iio_channel_get(&pdev->dev, "thermal");
+	if (IS_ERR(chip->adc))
+		return dev_err_probe(&pdev->dev, PTR_ERR(chip->adc),
+			       "failed to get adc channel\n");
+
+	chip->tz_dev = devm_thermal_of_zone_register(&pdev->dev, 0,
+						chip, &mbg_tm_ops);
+	if (IS_ERR(chip->tz_dev))
+		return dev_err_probe(&pdev->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,spmi-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");