1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
new file mode 100644
index 000000000..e192f0c67
--- /dev/null
+++ b/drivers/hwmon/scmi-hwmon.c
@@ -0,0 +1,374 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface(SCMI) based hwmon sensor driver
+ *
+ * Copyright (C) 2018-2021 ARM Ltd.
+ * Sudeep Holla <sudeep.holla@arm.com>
+ */
+
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/scmi_protocol.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/thermal.h>
+
+static const struct scmi_sensor_proto_ops *sensor_ops;
+
+struct scmi_sensors {
+	const struct scmi_protocol_handle *ph;
+	const struct scmi_sensor_info **info[hwmon_max];
+};
+
+struct scmi_thermal_sensor {
+	const struct scmi_protocol_handle *ph;
+	const struct scmi_sensor_info *info;
+};
+
+static inline u64 __pow10(u8 x)
+{
+	u64 r = 1;
+
+	while (x--)
+		r *= 10;
+
+	return r;
+}
+
+static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
+{
+	int scale = sensor->scale;
+	u64 f;
+
+	switch (sensor->type) {
+	case TEMPERATURE_C:
+	case VOLTAGE:
+	case CURRENT:
+		scale += 3;
+		break;
+	case POWER:
+	case ENERGY:
+		scale += 6;
+		break;
+	default:
+		break;
+	}
+
+	if (scale == 0)
+		return 0;
+
+	if (abs(scale) > 19)
+		return -E2BIG;
+
+	f = __pow10(abs(scale));
+	if (scale > 0)
+		*value *= f;
+	else
+		*value = div64_u64(*value, f);
+
+	return 0;
+}
+
+static int scmi_hwmon_read_scaled_value(const struct scmi_protocol_handle *ph,
+					const struct scmi_sensor_info *sensor,
+					long *val)
+{
+	int ret;
+	u64 value;
+
+	ret = sensor_ops->reading_get(ph, sensor->id, &value);
+	if (ret)
+		return ret;
+
+	ret = scmi_hwmon_scale(sensor, &value);
+	if (!ret)
+		*val = value;
+
+	return ret;
+}
+
+static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, long *val)
+{
+	const struct scmi_sensor_info *sensor;
+	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
+
+	sensor = *(scmi_sensors->info[type] + channel);
+
+	return scmi_hwmon_read_scaled_value(scmi_sensors->ph, sensor, val);
+}
+
+static int
+scmi_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, const char **str)
+{
+	const struct scmi_sensor_info *sensor;
+	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
+
+	sensor = *(scmi_sensors->info[type] + channel);
+	*str = sensor->name;
+
+	return 0;
+}
+
+static umode_t
+scmi_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
+		      u32 attr, int channel)
+{
+	const struct scmi_sensor_info *sensor;
+	const struct scmi_sensors *scmi_sensors = drvdata;
+
+	sensor = *(scmi_sensors->info[type] + channel);
+	if (sensor)
+		return 0444;
+
+	return 0;
+}
+
+static const struct hwmon_ops scmi_hwmon_ops = {
+	.is_visible = scmi_hwmon_is_visible,
+	.read = scmi_hwmon_read,
+	.read_string = scmi_hwmon_read_string,
+};
+
+static struct hwmon_chip_info scmi_chip_info = {
+	.ops = &scmi_hwmon_ops,
+	.info = NULL,
+};
+
+static int scmi_hwmon_thermal_get_temp(struct thermal_zone_device *tz,
+				       int *temp)
+{
+	int ret;
+	long value;
+	struct scmi_thermal_sensor *th_sensor = tz->devdata;
+
+	ret = scmi_hwmon_read_scaled_value(th_sensor->ph, th_sensor->info,
+					   &value);
+	if (!ret)
+		*temp = value;
+
+	return ret;
+}
+
+static const struct thermal_zone_device_ops scmi_hwmon_thermal_ops = {
+	.get_temp = scmi_hwmon_thermal_get_temp,
+};
+
+static int scmi_hwmon_add_chan_info(struct hwmon_channel_info *scmi_hwmon_chan,
+				    struct device *dev, int num,
+				    enum hwmon_sensor_types type, u32 config)
+{
+	int i;
+	u32 *cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
+
+	if (!cfg)
+		return -ENOMEM;
+
+	scmi_hwmon_chan->type = type;
+	scmi_hwmon_chan->config = cfg;
+	for (i = 0; i < num; i++, cfg++)
+		*cfg = config;
+
+	return 0;
+}
+
+static enum hwmon_sensor_types scmi_types[] = {
+	[TEMPERATURE_C] = hwmon_temp,
+	[VOLTAGE] = hwmon_in,
+	[CURRENT] = hwmon_curr,
+	[POWER] = hwmon_power,
+	[ENERGY] = hwmon_energy,
+};
+
+static u32 hwmon_attributes[hwmon_max] = {
+	[hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
+	[hwmon_in] = HWMON_I_INPUT | HWMON_I_LABEL,
+	[hwmon_curr] = HWMON_C_INPUT | HWMON_C_LABEL,
+	[hwmon_power] = HWMON_P_INPUT | HWMON_P_LABEL,
+	[hwmon_energy] = HWMON_E_INPUT | HWMON_E_LABEL,
+};
+
+static int scmi_thermal_sensor_register(struct device *dev,
+					const struct scmi_protocol_handle *ph,
+					const struct scmi_sensor_info *sensor)
+{
+	struct scmi_thermal_sensor *th_sensor;
+	struct thermal_zone_device *tzd;
+
+	th_sensor = devm_kzalloc(dev, sizeof(*th_sensor), GFP_KERNEL);
+	if (!th_sensor)
+		return -ENOMEM;
+
+	th_sensor->ph = ph;
+	th_sensor->info = sensor;
+
+	/*
+	 * Try to register a temperature sensor with the Thermal Framework:
+	 * skip sensors not defined as part of any thermal zone (-ENODEV) but
+	 * report any other errors related to misconfigured zones/sensors.
+	 */
+	tzd = devm_thermal_of_zone_register(dev, th_sensor->info->id, th_sensor,
+					    &scmi_hwmon_thermal_ops);
+	if (IS_ERR(tzd)) {
+		devm_kfree(dev, th_sensor);
+
+		if (PTR_ERR(tzd) != -ENODEV)
+			return PTR_ERR(tzd);
+
+		dev_dbg(dev, "Sensor '%s' not attached to any thermal zone.\n",
+			sensor->name);
+	} else {
+		dev_dbg(dev, "Sensor '%s' attached to thermal zone ID:%d\n",
+			sensor->name, tzd->id);
+	}
+
+	return 0;
+}
+
+static int scmi_hwmon_probe(struct scmi_device *sdev)
+{
+	int i, idx;
+	u16 nr_sensors;
+	enum hwmon_sensor_types type;
+	struct scmi_sensors *scmi_sensors;
+	const struct scmi_sensor_info *sensor;
+	int nr_count[hwmon_max] = {0}, nr_types = 0, nr_count_temp = 0;
+	const struct hwmon_chip_info *chip_info;
+	struct device *hwdev, *dev = &sdev->dev;
+	struct hwmon_channel_info *scmi_hwmon_chan;
+	const struct hwmon_channel_info **ptr_scmi_ci;
+	const struct scmi_handle *handle = sdev->handle;
+	struct scmi_protocol_handle *ph;
+
+	if (!handle)
+		return -ENODEV;
+
+	sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
+	if (IS_ERR(sensor_ops))
+		return PTR_ERR(sensor_ops);
+
+	nr_sensors = sensor_ops->count_get(ph);
+	if (!nr_sensors)
+		return -EIO;
+
+	scmi_sensors = devm_kzalloc(dev, sizeof(*scmi_sensors), GFP_KERNEL);
+	if (!scmi_sensors)
+		return -ENOMEM;
+
+	scmi_sensors->ph = ph;
+
+	for (i = 0; i < nr_sensors; i++) {
+		sensor = sensor_ops->info_get(ph, i);
+		if (!sensor)
+			return -EINVAL;
+
+		switch (sensor->type) {
+		case TEMPERATURE_C:
+		case VOLTAGE:
+		case CURRENT:
+		case POWER:
+		case ENERGY:
+			type = scmi_types[sensor->type];
+			if (!nr_count[type])
+				nr_types++;
+			nr_count[type]++;
+			break;
+		}
+	}
+
+	if (nr_count[hwmon_temp])
+		nr_count_temp = nr_count[hwmon_temp];
+
+	scmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*scmi_hwmon_chan),
+				       GFP_KERNEL);
+	if (!scmi_hwmon_chan)
+		return -ENOMEM;
+
+	ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*ptr_scmi_ci),
+				   GFP_KERNEL);
+	if (!ptr_scmi_ci)
+		return -ENOMEM;
+
+	scmi_chip_info.info = ptr_scmi_ci;
+	chip_info = &scmi_chip_info;
+
+	for (type = 0; type < hwmon_max; type++) {
+		if (!nr_count[type])
+			continue;
+
+		scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, nr_count[type],
+					 type, hwmon_attributes[type]);
+		*ptr_scmi_ci++ = scmi_hwmon_chan++;
+
+		scmi_sensors->info[type] =
+			devm_kcalloc(dev, nr_count[type],
+				     sizeof(*scmi_sensors->info), GFP_KERNEL);
+		if (!scmi_sensors->info[type])
+			return -ENOMEM;
+	}
+
+	for (i = nr_sensors - 1; i >= 0 ; i--) {
+		sensor = sensor_ops->info_get(ph, i);
+		if (!sensor)
+			continue;
+
+		switch (sensor->type) {
+		case TEMPERATURE_C:
+		case VOLTAGE:
+		case CURRENT:
+		case POWER:
+		case ENERGY:
+			type = scmi_types[sensor->type];
+			idx = --nr_count[type];
+			*(scmi_sensors->info[type] + idx) = sensor;
+			break;
+		}
+	}
+
+	hwdev = devm_hwmon_device_register_with_info(dev, "scmi_sensors",
+						     scmi_sensors, chip_info,
+						     NULL);
+	if (IS_ERR(hwdev))
+		return PTR_ERR(hwdev);
+
+	for (i = 0; i < nr_count_temp; i++) {
+		int ret;
+
+		sensor = *(scmi_sensors->info[hwmon_temp] + i);
+		if (!sensor)
+			continue;
+
+		/*
+		 * Warn on any misconfiguration related to thermal zones but
+		 * bail out of probing only on memory errors.
+		 */
+		ret = scmi_thermal_sensor_register(dev, ph, sensor);
+		if (ret) {
+			if (ret == -ENOMEM)
+				return ret;
+			dev_warn(dev,
+				 "Thermal zone misconfigured for %s. err=%d\n",
+				 sensor->name, ret);
+		}
+	}
+
+	return 0;
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+	{ SCMI_PROTOCOL_SENSOR, "hwmon" },
+	{ },
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static struct scmi_driver scmi_hwmon_drv = {
+	.name		= "scmi-hwmon",
+	.probe		= scmi_hwmon_probe,
+	.id_table	= scmi_id_table,
+};
+module_scmi_driver(scmi_hwmon_drv);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
+MODULE_LICENSE("GPL v2");