1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/hwmon/sa67mcu-hwmon.c b/drivers/hwmon/sa67mcu-hwmon.c
new file mode 100644
index 000000000000..22f703b7b256
--- /dev/null
+++ b/drivers/hwmon/sa67mcu-hwmon.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sl67mcu hardware monitoring driver
+ *
+ * Copyright 2025 Kontron Europe GmbH
+ */
+
+#include <linux/bitfield.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define SA67MCU_VOLTAGE(n)	(0x00 + ((n) * 2))
+#define SA67MCU_TEMP(n)		(0x04 + ((n) * 2))
+
+struct sa67mcu_hwmon {
+	struct regmap *regmap;
+	u32 offset;
+};
+
+static int sa67mcu_hwmon_read(struct device *dev,
+			      enum hwmon_sensor_types type, u32 attr,
+			      int channel, long *input)
+{
+	struct sa67mcu_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int offset;
+	u8 reg[2];
+	int ret;
+
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			offset = hwmon->offset + SA67MCU_VOLTAGE(channel);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			offset = hwmon->offset + SA67MCU_TEMP(channel);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	/* Reading the low byte will capture the value */
+	ret = regmap_bulk_read(hwmon->regmap, offset, reg, ARRAY_SIZE(reg));
+	if (ret)
+		return ret;
+
+	*input = reg[1] << 8 | reg[0];
+
+	/* Temperatures are s16 and in 0.1degC steps. */
+	if (type == hwmon_temp)
+		*input = sign_extend32(*input, 15) * 100;
+
+	return 0;
+}
+
+static const struct hwmon_channel_info * const sa67mcu_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static const char *const sa67mcu_hwmon_in_labels[] = {
+	"VDDIN",
+	"VDD_RTC",
+};
+
+static int sa67mcu_hwmon_read_string(struct device *dev,
+				     enum hwmon_sensor_types type, u32 attr,
+				     int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_label:
+			*str = sa67mcu_hwmon_in_labels[channel];
+			return 0;
+		default:
+			return -EOPNOTSUPP;
+		}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const struct hwmon_ops sa67mcu_hwmon_ops = {
+	.visible = 0444,
+	.read = sa67mcu_hwmon_read,
+	.read_string = sa67mcu_hwmon_read_string,
+};
+
+static const struct hwmon_chip_info sa67mcu_hwmon_chip_info = {
+	.ops = &sa67mcu_hwmon_ops,
+	.info = sa67mcu_hwmon_info,
+};
+
+static int sa67mcu_hwmon_probe(struct platform_device *pdev)
+{
+	struct sa67mcu_hwmon *hwmon;
+	struct device *hwmon_dev;
+	int ret;
+
+	if (!pdev->dev.parent)
+		return -ENODEV;
+
+	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!hwmon->regmap)
+		return -ENODEV;
+
+	ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
+	if (ret)
+		return -EINVAL;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+							 "sa67mcu_hwmon", hwmon,
+							 &sa67mcu_hwmon_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		dev_err(&pdev->dev, "failed to register as hwmon device");
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct of_device_id sa67mcu_hwmon_of_match[] = {
+	{ .compatible = "kontron,sa67mcu-hwmon", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sa67mcu_hwmon_of_match);
+
+static struct platform_driver sa67mcu_hwmon_driver = {
+	.probe = sa67mcu_hwmon_probe,
+	.driver = {
+		.name = "sa67mcu-hwmon",
+		.of_match_table = sa67mcu_hwmon_of_match,
+	},
+};
+module_platform_driver(sa67mcu_hwmon_driver);
+
+MODULE_DESCRIPTION("sa67mcu Hardware Monitoring Driver");
+MODULE_AUTHOR("Michael Walle <mwalle@kernel.org>");
+MODULE_LICENSE("GPL");