1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * sl28cpld hardware monitoring driver
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright 2020 Kontron Europe GmbH
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/bitfield.h>
9*4882a593Smuzhiyun #include <linux/hwmon.h>
10*4882a593Smuzhiyun #include <linux/kernel.h>
11*4882a593Smuzhiyun #include <linux/mod_devicetable.h>
12*4882a593Smuzhiyun #include <linux/module.h>
13*4882a593Smuzhiyun #include <linux/platform_device.h>
14*4882a593Smuzhiyun #include <linux/property.h>
15*4882a593Smuzhiyun #include <linux/regmap.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #define FAN_INPUT 0x00
18*4882a593Smuzhiyun #define FAN_SCALE_X8 BIT(7)
19*4882a593Smuzhiyun #define FAN_VALUE_MASK GENMASK(6, 0)
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun struct sl28cpld_hwmon {
22*4882a593Smuzhiyun struct regmap *regmap;
23*4882a593Smuzhiyun u32 offset;
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
sl28cpld_hwmon_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)26*4882a593Smuzhiyun static umode_t sl28cpld_hwmon_is_visible(const void *data,
27*4882a593Smuzhiyun enum hwmon_sensor_types type,
28*4882a593Smuzhiyun u32 attr, int channel)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun return 0444;
31*4882a593Smuzhiyun }
32*4882a593Smuzhiyun
sl28cpld_hwmon_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * input)33*4882a593Smuzhiyun static int sl28cpld_hwmon_read(struct device *dev,
34*4882a593Smuzhiyun enum hwmon_sensor_types type, u32 attr,
35*4882a593Smuzhiyun int channel, long *input)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
38*4882a593Smuzhiyun unsigned int value;
39*4882a593Smuzhiyun int ret;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun switch (attr) {
42*4882a593Smuzhiyun case hwmon_fan_input:
43*4882a593Smuzhiyun ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
44*4882a593Smuzhiyun &value);
45*4882a593Smuzhiyun if (ret)
46*4882a593Smuzhiyun return ret;
47*4882a593Smuzhiyun /*
48*4882a593Smuzhiyun * The register has a 7 bit value and 1 bit which indicates the
49*4882a593Smuzhiyun * scale. If the MSB is set, then the lower 7 bit has to be
50*4882a593Smuzhiyun * multiplied by 8, to get the correct reading.
51*4882a593Smuzhiyun */
52*4882a593Smuzhiyun if (value & FAN_SCALE_X8)
53*4882a593Smuzhiyun value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun /*
56*4882a593Smuzhiyun * The counter period is 1000ms and the sysfs specification
57*4882a593Smuzhiyun * says we should asssume 2 pulses per revolution.
58*4882a593Smuzhiyun */
59*4882a593Smuzhiyun value *= 60 / 2;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun break;
62*4882a593Smuzhiyun default:
63*4882a593Smuzhiyun return -EOPNOTSUPP;
64*4882a593Smuzhiyun }
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun *input = value;
67*4882a593Smuzhiyun return 0;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun static const u32 sl28cpld_hwmon_fan_config[] = {
71*4882a593Smuzhiyun HWMON_F_INPUT,
72*4882a593Smuzhiyun 0
73*4882a593Smuzhiyun };
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
76*4882a593Smuzhiyun .type = hwmon_fan,
77*4882a593Smuzhiyun .config = sl28cpld_hwmon_fan_config,
78*4882a593Smuzhiyun };
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
81*4882a593Smuzhiyun &sl28cpld_hwmon_fan,
82*4882a593Smuzhiyun NULL
83*4882a593Smuzhiyun };
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun static const struct hwmon_ops sl28cpld_hwmon_ops = {
86*4882a593Smuzhiyun .is_visible = sl28cpld_hwmon_is_visible,
87*4882a593Smuzhiyun .read = sl28cpld_hwmon_read,
88*4882a593Smuzhiyun };
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
91*4882a593Smuzhiyun .ops = &sl28cpld_hwmon_ops,
92*4882a593Smuzhiyun .info = sl28cpld_hwmon_info,
93*4882a593Smuzhiyun };
94*4882a593Smuzhiyun
sl28cpld_hwmon_probe(struct platform_device * pdev)95*4882a593Smuzhiyun static int sl28cpld_hwmon_probe(struct platform_device *pdev)
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun struct sl28cpld_hwmon *hwmon;
98*4882a593Smuzhiyun struct device *hwmon_dev;
99*4882a593Smuzhiyun int ret;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun if (!pdev->dev.parent)
102*4882a593Smuzhiyun return -ENODEV;
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
105*4882a593Smuzhiyun if (!hwmon)
106*4882a593Smuzhiyun return -ENOMEM;
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
109*4882a593Smuzhiyun if (!hwmon->regmap)
110*4882a593Smuzhiyun return -ENODEV;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
113*4882a593Smuzhiyun if (ret)
114*4882a593Smuzhiyun return -EINVAL;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
117*4882a593Smuzhiyun "sl28cpld_hwmon", hwmon,
118*4882a593Smuzhiyun &sl28cpld_hwmon_chip_info, NULL);
119*4882a593Smuzhiyun if (IS_ERR(hwmon_dev))
120*4882a593Smuzhiyun dev_err(&pdev->dev, "failed to register as hwmon device");
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun return PTR_ERR_OR_ZERO(hwmon_dev);
123*4882a593Smuzhiyun }
124*4882a593Smuzhiyun
125*4882a593Smuzhiyun static const struct of_device_id sl28cpld_hwmon_of_match[] = {
126*4882a593Smuzhiyun { .compatible = "kontron,sl28cpld-fan" },
127*4882a593Smuzhiyun {}
128*4882a593Smuzhiyun };
129*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, sl28cpld_hwmon_of_match);
130*4882a593Smuzhiyun
131*4882a593Smuzhiyun static struct platform_driver sl28cpld_hwmon_driver = {
132*4882a593Smuzhiyun .probe = sl28cpld_hwmon_probe,
133*4882a593Smuzhiyun .driver = {
134*4882a593Smuzhiyun .name = "sl28cpld-fan",
135*4882a593Smuzhiyun .of_match_table = sl28cpld_hwmon_of_match,
136*4882a593Smuzhiyun },
137*4882a593Smuzhiyun };
138*4882a593Smuzhiyun module_platform_driver(sl28cpld_hwmon_driver);
139*4882a593Smuzhiyun
140*4882a593Smuzhiyun MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
141*4882a593Smuzhiyun MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
142*4882a593Smuzhiyun MODULE_LICENSE("GPL");
143