projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 3f697027 MW |
1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* | |
| 3 | * sl28cpld hardware monitoring driver | |
| 4 | * | |
| 5 | * Copyright 2020 Kontron Europe GmbH | |
| 6 | */ | |
| 7 | ||
| 8 | #include <linux/bitfield.h> | |
| 9 | #include <linux/hwmon.h> | |
| 10 | #include <linux/kernel.h> | |
| 11 | #include <linux/mod_devicetable.h> | |
| 12 | #include <linux/module.h> | |
| 13 | #include <linux/platform_device.h> | |
| 14 | #include <linux/property.h> | |
| 15 | #include <linux/regmap.h> | |
| 16 | ||
| 17 | #define FAN_INPUT 0x00 | |
| 18 | #define FAN_SCALE_X8 BIT(7) | |
| 19 | #define FAN_VALUE_MASK GENMASK(6, 0) | |
| 20 | ||
| 21 | struct sl28cpld_hwmon { | |
| 22 | struct regmap *regmap; | |
| 23 | u32 offset; | |
| 24 | }; | |
| 25 | ||
| 26 | static umode_t sl28cpld_hwmon_is_visible(const void *data, | |
| 27 | enum hwmon_sensor_types type, | |
| 28 | u32 attr, int channel) | |
| 29 | { | |
| 30 | return 0444; | |
| 31 | } | |
| 32 | ||
| 33 | static int sl28cpld_hwmon_read(struct device *dev, | |
| 34 | enum hwmon_sensor_types type, u32 attr, | |
| 35 | int channel, long *input) | |
| 36 | { | |
| 37 | struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev); | |
| 38 | unsigned int value; | |
| 39 | int ret; | |
| 40 | ||
| 41 | switch (attr) { | |
| 42 | case hwmon_fan_input: | |
| 43 | ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT, | |
| 44 | &value); | |
| 45 | if (ret) | |
| 46 | return ret; | |
| 47 | /* | |
| 48 | * The register has a 7 bit value and 1 bit which indicates the | |
| 49 | * scale. If the MSB is set, then the lower 7 bit has to be | |
| 50 | * multiplied by 8, to get the correct reading. | |
| 51 | */ | |
| 52 | if (value & FAN_SCALE_X8) | |
| 53 | value = FIELD_GET(FAN_VALUE_MASK, value) << 3; | |
| 54 | ||
| 55 | /* | |
| 56 | * The counter period is 1000ms and the sysfs specification | |
| 57 | * says we should asssume 2 pulses per revolution. | |
| 58 | */ | |
| 59 | value *= 60 / 2; | |
| 60 | ||
| 61 | break; | |
| 62 | default: | |
| 63 | return -EOPNOTSUPP; | |
| 64 | } | |
| 65 | ||
| 66 | *input = value; | |
| 67 | return 0; | |
| 68 | } | |
| 69 | ||
| 70 | static const u32 sl28cpld_hwmon_fan_config[] = { | |
| 71 | HWMON_F_INPUT, | |
| 72 | 0 | |
| 73 | }; | |
| 74 | ||
| 75 | static const struct hwmon_channel_info sl28cpld_hwmon_fan = { | |
| 76 | .type = hwmon_fan, | |
| 77 | .config = sl28cpld_hwmon_fan_config, | |
| 78 | }; | |
| 79 | ||
| 80 | static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = { | |
| 81 | &sl28cpld_hwmon_fan, | |
| 82 | NULL | |
| 83 | }; | |
| 84 | ||
| 85 | static const struct hwmon_ops sl28cpld_hwmon_ops = { | |
| 86 | .is_visible = sl28cpld_hwmon_is_visible, | |
| 87 | .read = sl28cpld_hwmon_read, | |
| 88 | }; | |
| 89 | ||
| 90 | static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = { | |
| 91 | .ops = &sl28cpld_hwmon_ops, | |
| 92 | .info = sl28cpld_hwmon_info, | |
| 93 | }; | |
| 94 | ||
| 95 | static int sl28cpld_hwmon_probe(struct platform_device *pdev) | |
| 96 | { | |
| 97 | struct sl28cpld_hwmon *hwmon; | |
| 98 | struct device *hwmon_dev; | |
| 99 | int ret; | |
| 100 | ||
| 101 | if (!pdev->dev.parent) | |
| 102 | return -ENODEV; | |
| 103 | ||
| 104 | hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL); | |
| 105 | if (!hwmon) | |
| 106 | return -ENOMEM; | |
| 107 | ||
| 108 | hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL); | |
| 109 | if (!hwmon->regmap) | |
| 110 | return -ENODEV; | |
| 111 | ||
| 112 | ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset); | |
| 113 | if (ret) | |
| 114 | return -EINVAL; | |
| 115 | ||
| 116 | hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, | |
| 117 | "sl28cpld_hwmon", hwmon, | |
| 118 | &sl28cpld_hwmon_chip_info, NULL); | |
| 119 | if (IS_ERR(hwmon_dev)) | |
| 120 | dev_err(&pdev->dev, "failed to register as hwmon device"); | |
| 121 | ||
| 122 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
| 123 | } | |
| 124 | ||
| 125 | static const struct of_device_id sl28cpld_hwmon_of_match[] = { | |
| 126 | { .compatible = "kontron,sl28cpld-fan" }, | |
| 127 | {} | |
| 128 | }; | |
| 129 | MODULE_DEVICE_TABLE(of, sl28cpld_hwmon_of_match); | |
| 130 | ||
| 131 | static struct platform_driver sl28cpld_hwmon_driver = { | |
| 132 | .probe = sl28cpld_hwmon_probe, | |
| 133 | .driver = { | |
| 134 | .name = "sl28cpld-fan", | |
| 135 | .of_match_table = sl28cpld_hwmon_of_match, | |
| 136 | }, | |
| 137 | }; | |
| 138 | module_platform_driver(sl28cpld_hwmon_driver); | |
| 139 | ||
| 140 | MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver"); | |
| 141 | MODULE_AUTHOR("Michael Walle <[email protected]>"); | |
| 142 | MODULE_LICENSE("GPL"); |