diff options
Diffstat (limited to 'drivers/hwmon/scpi-hwmon.c')
| -rw-r--r-- | drivers/hwmon/scpi-hwmon.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c new file mode 100644 index 000000000..562f3e287 --- /dev/null +++ b/drivers/hwmon/scpi-hwmon.c @@ -0,0 +1,318 @@ +/* + * System Control and Power Interface(SCPI) based hwmon sensor driver + * + * Copyright (C) 2015 ARM Ltd. + * Punit Agrawal <punit.agrawal@arm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#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(void *dev, int *temp) +{ + struct scpi_thermal_zone *zone = dev; + 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_of_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; + const struct of_device_id *of_id; + 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; + + of_id = of_match_device(scpi_of_match, &pdev->dev); + if (!of_id) { + dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n"); + return -ENODEV; + } + scale = of_id->data; + + 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 = S_IRUGO; + sensor->dev_attr_input.show = scpi_show_sensor; + sensor->dev_attr_input.attr.name = sensor->input; + + sensor->dev_attr_label.attr.mode = S_IRUGO; + 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_zone_of_sensor_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); + continue; + } + } + + 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 <punit.agrawal@arm.com>"); +MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); +MODULE_LICENSE("GPL v2"); |