hwmon: add support for MC33XS2410 hardware monitoring

The device is able to monitor temperature, voltage and current of each of
the four outputs. Add basic support for monitoring the temperature of the
four outputs and the die temperature.

Signed-off-by: Dimitri Fedrau <[e-mail]>
Acked-by: Guenter Roeck <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

Documentation/hwmon/index.rst

···
    max77705
    max8688
    mc13783-adc
+   mc33xs2410_hwmon
    mc34vr500
    mcp3021
    menf21bmc

Documentation/hwmon/mc33xs2410_hwmon.rst

···
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mc33xs2410_hwmon
+==============================
+
+Supported devices:
+
+  * NXPs MC33XS2410
+
+    Datasheet: https://www.nxp.com/docs/en/data-sheet/MC33XS2410.pdf
+
+Authors:
+
+	Dimitri Fedrau <[e-mail]>
+
+Description
+-----------
+
+The MC33XS2410 is a four channel self-protected high-side switch featuring
+hardware monitoring functions such as temperature, current and voltages for each
+of the four channels.
+
+Sysfs entries
+-------------
+
+======================= ======================================================
+temp1_label		"Central die temperature"
+temp1_input		Measured temperature of central die
+
+temp[2-5]_label		"Channel [1-4] temperature"
+temp[2-5]_input		Measured temperature of a single channel
+temp[2-5]_alarm		Temperature alarm
+temp[2-5]_max		Maximal temperature
+======================= ======================================================

drivers/hwmon/Kconfig

···
         help
           Support for the A/D converter on MC13783 and MC13892 PMIC.
 
+config SENSORS_MC33XS2410
+	tristate "MC33XS2410 HWMON support"
+	depends on PWM_MC33XS2410
+	help
+	  If you say yes here you get hardware monitoring support for
+	  MC33XS2410.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mc33xs2410_hwmon.
+
 config SENSORS_FSCHMD
 	tristate "Fujitsu Siemens Computers sensor chips"
 	depends on (X86 || COMPILE_TEST) && I2C

drivers/hwmon/Makefile

···
 obj-$(CONFIG_MAX31827) += max31827.o
 obj-$(CONFIG_SENSORS_MAX77705) += max77705-hwmon.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
+obj-$(CONFIG_SENSORS_MC33XS2410) += mc33xs2410_hwmon.o
 obj-$(CONFIG_SENSORS_MC34VR500)	+= mc34vr500.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
 obj-$(CONFIG_SENSORS_TC654)	+= tc654.o

drivers/hwmon/mc33xs2410_hwmon.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 Liebherr-Electronics and Drives GmbH
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/hwmon.h>
+#include <linux/mc33xs2410.h>
+#include <linux/module.h>
+
+/* ctrl registers */
+
+#define MC33XS2410_TEMP_WT			0x29
+#define MC33XS2410_TEMP_WT_MASK			GENMASK(7, 0)
+
+/* diag registers */
+
+/* chan in { 1 ... 4 } */
+#define MC33XS2410_OUT_STA(chan)		(0x02 + (chan) - 1)
+#define MC33XS2410_OUT_STA_OTW			BIT(8)
+
+#define MC33XS2410_TS_TEMP_DIE			0x26
+#define MC33XS2410_TS_TEMP_MASK			GENMASK(9, 0)
+
+/* chan in { 1 ... 4 } */
+#define MC33XS2410_TS_TEMP(chan)		(0x2f + (chan) - 1)
+
+static const struct hwmon_channel_info * const mc33xs2410_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_LABEL | HWMON_T_INPUT,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX |
+			   HWMON_T_ALARM,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX |
+			   HWMON_T_ALARM,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX |
+			   HWMON_T_ALARM,
+			   HWMON_T_LABEL | HWMON_T_INPUT | HWMON_T_MAX |
+			   HWMON_T_ALARM),
+	NULL,
+};
+
+static umode_t mc33xs2410_hwmon_is_visible(const void *data,
+					   enum hwmon_sensor_types type,
+					   u32 attr, int channel)
+{
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_alarm:
+	case hwmon_temp_label:
+		return 0444;
+	case hwmon_temp_max:
+		return 0644;
+	default:
+		return 0;
+	}
+}
+
+static int mc33xs2410_hwmon_read(struct device *dev,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel, long *val)
+{
+	struct spi_device *spi = dev_get_drvdata(dev);
+	u16 reg_val;
+	int ret;
+	u8 reg;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		reg = (channel == 0) ? MC33XS2410_TS_TEMP_DIE :
+				       MC33XS2410_TS_TEMP(channel);
+		ret = mc33xs2410_read_reg_diag(spi, reg, &reg_val);
+		if (ret < 0)
+			return ret;
+
+		/* LSB is 0.25 degree celsius */
+		*val = FIELD_GET(MC33XS2410_TS_TEMP_MASK, reg_val) * 250 - 40000;
+		return 0;
+	case hwmon_temp_alarm:
+		ret = mc33xs2410_read_reg_diag(spi, MC33XS2410_OUT_STA(channel),
+					       &reg_val);
+		if (ret < 0)
+			return ret;
+
+		*val = FIELD_GET(MC33XS2410_OUT_STA_OTW, reg_val);
+		return 0;
+	case hwmon_temp_max:
+		ret = mc33xs2410_read_reg_ctrl(spi, MC33XS2410_TEMP_WT, &reg_val);
+		if (ret < 0)
+			return ret;
+
+		/* LSB is 1 degree celsius */
+		*val = FIELD_GET(MC33XS2410_TEMP_WT_MASK, reg_val) * 1000 - 40000;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int mc33xs2410_hwmon_write(struct device *dev,
+				  enum hwmon_sensor_types type, u32 attr,
+				  int channel, long val)
+{
+	struct spi_device *spi = dev_get_drvdata(dev);
+
+	switch (attr) {
+	case hwmon_temp_max:
+		val = clamp_val(val, -40000, 215000);
+
+		/* LSB is 1 degree celsius */
+		val = (val / 1000) + 40;
+		return mc33xs2410_modify_reg(spi, MC33XS2410_TEMP_WT,
+					     MC33XS2410_TEMP_WT_MASK, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const char *const mc33xs2410_temp_label[] = {
+	"Central die temperature",
+	"Channel 1 temperature",
+	"Channel 2 temperature",
+	"Channel 3 temperature",
+	"Channel 4 temperature",
+};
+
+static int mc33xs2410_read_string(struct device *dev,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel, const char **str)
+{
+	*str = mc33xs2410_temp_label[channel];
+
+	return 0;
+}
+
+static const struct hwmon_ops mc33xs2410_hwmon_hwmon_ops = {
+	.is_visible = mc33xs2410_hwmon_is_visible,
+	.read = mc33xs2410_hwmon_read,
+	.read_string = mc33xs2410_read_string,
+	.write = mc33xs2410_hwmon_write,
+};
+
+static const struct hwmon_chip_info mc33xs2410_hwmon_chip_info = {
+	.ops = &mc33xs2410_hwmon_hwmon_ops,
+	.info = mc33xs2410_hwmon_info,
+};
+
+static int mc33xs2410_hwmon_probe(struct auxiliary_device *adev,
+				  const struct auxiliary_device_id *id)
+{
+	struct device *dev = &adev->dev;
+	struct spi_device *spi = container_of(dev->parent, struct spi_device, dev);
+	struct device *hwmon;
+
+	hwmon = devm_hwmon_device_register_with_info(dev, NULL, spi,
+						     &mc33xs2410_hwmon_chip_info,
+						     NULL);
+	return PTR_ERR_OR_ZERO(hwmon);
+}
+
+static const struct auxiliary_device_id mc33xs2410_hwmon_ids[] = {
+	{
+		.name = "pwm_mc33xs2410.hwmon",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(auxiliary, mc33xs2410_hwmon_ids);
+
+static struct auxiliary_driver mc33xs2410_hwmon_driver = {
+	.probe = mc33xs2410_hwmon_probe,
+	.id_table = mc33xs2410_hwmon_ids,
+};
+module_auxiliary_driver(mc33xs2410_hwmon_driver);
+
+MODULE_DESCRIPTION("NXP MC33XS2410 hwmon driver");
+MODULE_AUTHOR("Dimitri Fedrau <[e-mail]>");
+MODULE_LICENSE("GPL");