// SPDX-License-Identifier: GPL-2.0-only /* * sl28cpld hardware monitoring driver * * Copyright 2020 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 FAN_INPUT 0x00 #define FAN_SCALE_X8 BIT(7) #define FAN_VALUE_MASK GENMASK(6, 0) struct sl28cpld_hwmon { struct regmap *regmap; u32 offset; }; static umode_t sl28cpld_hwmon_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) { return 0444; } static int sl28cpld_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *input) { struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev); unsigned int value; int ret; switch (attr) { case hwmon_fan_input: ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT, &value); if (ret) return ret; /* * The register has a 7 bit value and 1 bit which indicates the * scale. If the MSB is set, then the lower 7 bit has to be * multiplied by 8, to get the correct reading. */ if (value & FAN_SCALE_X8) value = FIELD_GET(FAN_VALUE_MASK, value) << 3; /* * The counter period is 1000ms and the sysfs specification * says we should assume 2 pulses per revolution. */ value *= 60 / 2; break; default: return -EOPNOTSUPP; } *input = value; return 0; } static const struct hwmon_channel_info * const sl28cpld_hwmon_info[] = { HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT), NULL }; static const struct hwmon_ops sl28cpld_hwmon_ops = { .is_visible = sl28cpld_hwmon_is_visible, .read = sl28cpld_hwmon_read, }; static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = { .ops = &sl28cpld_hwmon_ops, .info = sl28cpld_hwmon_info, }; static int sl28cpld_hwmon_probe(struct platform_device *pdev) { struct sl28cpld_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, "sl28cpld_hwmon", hwmon, &sl28cpld_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 sl28cpld_hwmon_of_match[] = { { .compatible = "kontron,sl28cpld-fan" }, {} }; MODULE_DEVICE_TABLE(of, sl28cpld_hwmon_of_match); static struct platform_driver sl28cpld_hwmon_driver = { .probe = sl28cpld_hwmon_probe, .driver = { .name = "sl28cpld-fan", .of_match_table = sl28cpld_hwmon_of_match, }, }; module_platform_driver(sl28cpld_hwmon_driver); MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver"); MODULE_AUTHOR("Michael Walle <michael@walle.cc>"); MODULE_LICENSE("GPL");