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142 lines
3.2 KiB
142 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* sl28cpld hardware monitoring driver |
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* |
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* Copyright 2020 Kontron Europe GmbH |
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*/ |
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#include <linux/bitfield.h> |
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#include <linux/hwmon.h> |
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#include <linux/kernel.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/property.h> |
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#include <linux/regmap.h> |
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#define FAN_INPUT 0x00 |
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#define FAN_SCALE_X8 BIT(7) |
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#define FAN_VALUE_MASK GENMASK(6, 0) |
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struct sl28cpld_hwmon { |
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struct regmap *regmap; |
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u32 offset; |
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}; |
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static umode_t sl28cpld_hwmon_is_visible(const void *data, |
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enum hwmon_sensor_types type, |
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u32 attr, int channel) |
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{ |
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return 0444; |
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} |
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static int sl28cpld_hwmon_read(struct device *dev, |
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enum hwmon_sensor_types type, u32 attr, |
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int channel, long *input) |
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{ |
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struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev); |
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unsigned int value; |
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int ret; |
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switch (attr) { |
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case hwmon_fan_input: |
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ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT, |
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&value); |
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if (ret) |
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return ret; |
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/* |
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* The register has a 7 bit value and 1 bit which indicates the |
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* scale. If the MSB is set, then the lower 7 bit has to be |
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* multiplied by 8, to get the correct reading. |
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*/ |
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if (value & FAN_SCALE_X8) |
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value = FIELD_GET(FAN_VALUE_MASK, value) << 3; |
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/* |
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* The counter period is 1000ms and the sysfs specification |
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* says we should asssume 2 pulses per revolution. |
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*/ |
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value *= 60 / 2; |
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break; |
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default: |
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return -EOPNOTSUPP; |
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} |
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*input = value; |
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return 0; |
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} |
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static const u32 sl28cpld_hwmon_fan_config[] = { |
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HWMON_F_INPUT, |
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0 |
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}; |
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static const struct hwmon_channel_info sl28cpld_hwmon_fan = { |
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.type = hwmon_fan, |
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.config = sl28cpld_hwmon_fan_config, |
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}; |
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static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = { |
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&sl28cpld_hwmon_fan, |
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NULL |
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}; |
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static const struct hwmon_ops sl28cpld_hwmon_ops = { |
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.is_visible = sl28cpld_hwmon_is_visible, |
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.read = sl28cpld_hwmon_read, |
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}; |
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static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = { |
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.ops = &sl28cpld_hwmon_ops, |
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.info = sl28cpld_hwmon_info, |
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}; |
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static int sl28cpld_hwmon_probe(struct platform_device *pdev) |
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{ |
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struct sl28cpld_hwmon *hwmon; |
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struct device *hwmon_dev; |
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int ret; |
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if (!pdev->dev.parent) |
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return -ENODEV; |
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hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL); |
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if (!hwmon) |
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return -ENOMEM; |
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hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL); |
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if (!hwmon->regmap) |
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return -ENODEV; |
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ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset); |
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if (ret) |
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return -EINVAL; |
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hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, |
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"sl28cpld_hwmon", hwmon, |
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&sl28cpld_hwmon_chip_info, NULL); |
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if (IS_ERR(hwmon_dev)) |
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dev_err(&pdev->dev, "failed to register as hwmon device"); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct of_device_id sl28cpld_hwmon_of_match[] = { |
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{ .compatible = "kontron,sl28cpld-fan" }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, sl28cpld_hwmon_of_match); |
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static struct platform_driver sl28cpld_hwmon_driver = { |
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.probe = sl28cpld_hwmon_probe, |
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.driver = { |
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.name = "sl28cpld-fan", |
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.of_match_table = sl28cpld_hwmon_of_match, |
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}, |
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}; |
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module_platform_driver(sl28cpld_hwmon_driver); |
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MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver"); |
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MODULE_AUTHOR("Michael Walle <[email protected]>"); |
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MODULE_LICENSE("GPL");
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