--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver sa67mcu
+=====================
+
+Supported chips:
+
+ * Kontron sa67mcu
+
+ Prefix: 'sa67mcu'
+
+ Datasheet: not available
+
+Authors: Michael Walle <mwalle@kernel.org>
+
+Description
+-----------
+
+The sa67mcu is a board management controller which also exposes a hardware
+monitoring controller.
+
+The controller has two voltage and one temperature sensor. The values are
+hold in two 8 bit registers to form one 16 bit value. Reading the lower byte
+will also capture the high byte to make the access atomic. The unit of the
+volatge sensors are 1mV and the unit of the temperature sensor is 0.1degC.
+
+Sysfs entries
+-------------
+
+The following attributes are supported.
+
+======================= ========================================================
+in0_label "VDDIN"
+in0_input Measured VDDIN voltage.
+
+in1_label "VDD_RTC"
+in1_input Measured VDD_RTC voltage.
+
+temp1_input MCU temperature. Roughly the board temperature.
+======================= ========================================================
+
--- /dev/null
+// 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");
projects / thirdparty / kernel / stable.git / commitdiff
