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- // SPDX-License-Identifier: GPL-2.0
- /*
- * System Control and Power Interface(SCPI) based hwmon sensor driver
- *
- * Copyright (C) 2015 ARM Ltd.
- * Punit Agrawal <[email protected]>
- */
- #include <linux/hwmon.h>
- #include <linux/module.h>
- #include <linux/of_device.h>
- #include <linux/platform_device.h>
- #include <linux/scpi_protocol.h>
- #include <linux/slab.h>
- #include <linux/sysfs.h>
- #include <linux/thermal.h>
- struct sensor_data {
- unsigned int scale;
- struct scpi_sensor_info info;
- struct device_attribute dev_attr_input;
- struct device_attribute dev_attr_label;
- char input[20];
- char label[20];
- };
- struct scpi_thermal_zone {
- int sensor_id;
- struct scpi_sensors *scpi_sensors;
- };
- struct scpi_sensors {
- struct scpi_ops *scpi_ops;
- struct sensor_data *data;
- struct list_head thermal_zones;
- struct attribute **attrs;
- struct attribute_group group;
- const struct attribute_group *groups[2];
- };
- static const u32 gxbb_scpi_scale[] = {
- [TEMPERATURE] = 1, /* (celsius) */
- [VOLTAGE] = 1000, /* (millivolts) */
- [CURRENT] = 1000, /* (milliamperes) */
- [POWER] = 1000000, /* (microwatts) */
- [ENERGY] = 1000000, /* (microjoules) */
- };
- static const u32 scpi_scale[] = {
- [TEMPERATURE] = 1000, /* (millicelsius) */
- [VOLTAGE] = 1000, /* (millivolts) */
- [CURRENT] = 1000, /* (milliamperes) */
- [POWER] = 1000000, /* (microwatts) */
- [ENERGY] = 1000000, /* (microjoules) */
- };
- static void scpi_scale_reading(u64 *value, struct sensor_data *sensor)
- {
- if (scpi_scale[sensor->info.class] != sensor->scale) {
- *value *= scpi_scale[sensor->info.class];
- do_div(*value, sensor->scale);
- }
- }
- static int scpi_read_temp(struct thermal_zone_device *tz, int *temp)
- {
- struct scpi_thermal_zone *zone = tz->devdata;
- struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
- struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
- struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
- u64 value;
- int ret;
- ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
- if (ret)
- return ret;
- scpi_scale_reading(&value, sensor);
- *temp = value;
- return 0;
- }
- /* hwmon callback functions */
- static ssize_t
- scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
- {
- struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
- struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
- struct sensor_data *sensor;
- u64 value;
- int ret;
- sensor = container_of(attr, struct sensor_data, dev_attr_input);
- ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
- if (ret)
- return ret;
- scpi_scale_reading(&value, sensor);
- /*
- * Temperature sensor values are treated as signed values based on
- * observation even though that is not explicitly specified, and
- * because an unsigned u64 temperature does not really make practical
- * sense especially when the temperature is below zero degrees Celsius.
- */
- if (sensor->info.class == TEMPERATURE)
- return sprintf(buf, "%lld\n", (s64)value);
- return sprintf(buf, "%llu\n", value);
- }
- static ssize_t
- scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
- {
- struct sensor_data *sensor;
- sensor = container_of(attr, struct sensor_data, dev_attr_label);
- return sprintf(buf, "%s\n", sensor->info.name);
- }
- static const struct thermal_zone_device_ops scpi_sensor_ops = {
- .get_temp = scpi_read_temp,
- };
- static const struct of_device_id scpi_of_match[] = {
- {.compatible = "arm,scpi-sensors", .data = &scpi_scale},
- {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},
- {},
- };
- MODULE_DEVICE_TABLE(of, scpi_of_match);
- static int scpi_hwmon_probe(struct platform_device *pdev)
- {
- u16 nr_sensors, i;
- const u32 *scale;
- int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
- int num_energy = 0;
- struct scpi_ops *scpi_ops;
- struct device *hwdev, *dev = &pdev->dev;
- struct scpi_sensors *scpi_sensors;
- int idx, ret;
- scpi_ops = get_scpi_ops();
- if (!scpi_ops)
- return -EPROBE_DEFER;
- ret = scpi_ops->sensor_get_capability(&nr_sensors);
- if (ret)
- return ret;
- if (!nr_sensors)
- return -ENODEV;
- scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
- if (!scpi_sensors)
- return -ENOMEM;
- scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
- sizeof(*scpi_sensors->data), GFP_KERNEL);
- if (!scpi_sensors->data)
- return -ENOMEM;
- scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
- sizeof(*scpi_sensors->attrs), GFP_KERNEL);
- if (!scpi_sensors->attrs)
- return -ENOMEM;
- scpi_sensors->scpi_ops = scpi_ops;
- scale = of_device_get_match_data(&pdev->dev);
- if (!scale) {
- dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");
- return -ENODEV;
- }
- for (i = 0, idx = 0; i < nr_sensors; i++) {
- struct sensor_data *sensor = &scpi_sensors->data[idx];
- ret = scpi_ops->sensor_get_info(i, &sensor->info);
- if (ret)
- return ret;
- switch (sensor->info.class) {
- case TEMPERATURE:
- snprintf(sensor->input, sizeof(sensor->input),
- "temp%d_input", num_temp + 1);
- snprintf(sensor->label, sizeof(sensor->input),
- "temp%d_label", num_temp + 1);
- num_temp++;
- break;
- case VOLTAGE:
- snprintf(sensor->input, sizeof(sensor->input),
- "in%d_input", num_volt);
- snprintf(sensor->label, sizeof(sensor->input),
- "in%d_label", num_volt);
- num_volt++;
- break;
- case CURRENT:
- snprintf(sensor->input, sizeof(sensor->input),
- "curr%d_input", num_current + 1);
- snprintf(sensor->label, sizeof(sensor->input),
- "curr%d_label", num_current + 1);
- num_current++;
- break;
- case POWER:
- snprintf(sensor->input, sizeof(sensor->input),
- "power%d_input", num_power + 1);
- snprintf(sensor->label, sizeof(sensor->input),
- "power%d_label", num_power + 1);
- num_power++;
- break;
- case ENERGY:
- snprintf(sensor->input, sizeof(sensor->input),
- "energy%d_input", num_energy + 1);
- snprintf(sensor->label, sizeof(sensor->input),
- "energy%d_label", num_energy + 1);
- num_energy++;
- break;
- default:
- continue;
- }
- sensor->scale = scale[sensor->info.class];
- sensor->dev_attr_input.attr.mode = 0444;
- sensor->dev_attr_input.show = scpi_show_sensor;
- sensor->dev_attr_input.attr.name = sensor->input;
- sensor->dev_attr_label.attr.mode = 0444;
- sensor->dev_attr_label.show = scpi_show_label;
- sensor->dev_attr_label.attr.name = sensor->label;
- scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
- scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
- sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
- sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
- idx++;
- }
- scpi_sensors->group.attrs = scpi_sensors->attrs;
- scpi_sensors->groups[0] = &scpi_sensors->group;
- platform_set_drvdata(pdev, scpi_sensors);
- hwdev = devm_hwmon_device_register_with_groups(dev,
- "scpi_sensors", scpi_sensors, scpi_sensors->groups);
- if (IS_ERR(hwdev))
- return PTR_ERR(hwdev);
- /*
- * Register the temperature sensors with the thermal framework
- * to allow their usage in setting up the thermal zones from
- * device tree.
- *
- * NOTE: Not all temperature sensors maybe used for thermal
- * control
- */
- INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
- for (i = 0; i < nr_sensors; i++) {
- struct sensor_data *sensor = &scpi_sensors->data[i];
- struct thermal_zone_device *z;
- struct scpi_thermal_zone *zone;
- if (sensor->info.class != TEMPERATURE)
- continue;
- zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
- if (!zone)
- return -ENOMEM;
- zone->sensor_id = i;
- zone->scpi_sensors = scpi_sensors;
- z = devm_thermal_of_zone_register(dev,
- sensor->info.sensor_id,
- zone,
- &scpi_sensor_ops);
- /*
- * The call to thermal_zone_of_sensor_register returns
- * an error for sensors that are not associated with
- * any thermal zones or if the thermal subsystem is
- * not configured.
- */
- if (IS_ERR(z))
- devm_kfree(dev, zone);
- }
- return 0;
- }
- static struct platform_driver scpi_hwmon_platdrv = {
- .driver = {
- .name = "scpi-hwmon",
- .of_match_table = scpi_of_match,
- },
- .probe = scpi_hwmon_probe,
- };
- module_platform_driver(scpi_hwmon_platdrv);
- MODULE_AUTHOR("Punit Agrawal <[email protected]>");
- MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
- MODULE_LICENSE("GPL v2");
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