xref: /openbmc/linux/drivers/hwmon/as370-hwmon.c (revision 39f03438)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Synaptics AS370 SoC Hardware Monitoring Driver
4  *
5  * Copyright (C) 2018 Synaptics Incorporated
6  * Author: Jisheng Zhang <jszhang@kernel.org>
7  */
8 
9 #include <linux/bitops.h>
10 #include <linux/hwmon.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/platform_device.h>
16 
17 #define CTRL		0x0
18 #define  PD		BIT(0)
19 #define  EN		BIT(1)
20 #define  T_SEL		BIT(2)
21 #define  V_SEL		BIT(3)
22 #define  NMOS_SEL	BIT(8)
23 #define  PMOS_SEL	BIT(9)
24 #define STS		0x4
25 #define  BN_MASK	GENMASK(11, 0)
26 #define  EOC		BIT(12)
27 
28 struct as370_hwmon {
29 	void __iomem *base;
30 };
31 
init_pvt(struct as370_hwmon * hwmon)32 static void init_pvt(struct as370_hwmon *hwmon)
33 {
34 	u32 val;
35 	void __iomem *addr = hwmon->base + CTRL;
36 
37 	val = PD;
38 	writel_relaxed(val, addr);
39 	val |= T_SEL;
40 	writel_relaxed(val, addr);
41 	val |= EN;
42 	writel_relaxed(val, addr);
43 	val &= ~PD;
44 	writel_relaxed(val, addr);
45 }
46 
as370_hwmon_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * temp)47 static int as370_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
48 			    u32 attr, int channel, long *temp)
49 {
50 	int val;
51 	struct as370_hwmon *hwmon = dev_get_drvdata(dev);
52 
53 	switch (attr) {
54 	case hwmon_temp_input:
55 		val = readl_relaxed(hwmon->base + STS) & BN_MASK;
56 		*temp = DIV_ROUND_CLOSEST(val * 251802, 4096) - 85525;
57 		break;
58 	default:
59 		return -EOPNOTSUPP;
60 	}
61 
62 	return 0;
63 }
64 
65 static umode_t
as370_hwmon_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)66 as370_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
67 		       u32 attr, int channel)
68 {
69 	if (type != hwmon_temp)
70 		return 0;
71 
72 	switch (attr) {
73 	case hwmon_temp_input:
74 		return 0444;
75 	default:
76 		return 0;
77 	}
78 }
79 
80 static const struct hwmon_channel_info * const as370_hwmon_info[] = {
81 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
82 	NULL
83 };
84 
85 static const struct hwmon_ops as370_hwmon_ops = {
86 	.is_visible = as370_hwmon_is_visible,
87 	.read = as370_hwmon_read,
88 };
89 
90 static const struct hwmon_chip_info as370_chip_info = {
91 	.ops = &as370_hwmon_ops,
92 	.info = as370_hwmon_info,
93 };
94 
as370_hwmon_probe(struct platform_device * pdev)95 static int as370_hwmon_probe(struct platform_device *pdev)
96 {
97 	struct device *hwmon_dev;
98 	struct as370_hwmon *hwmon;
99 	struct device *dev = &pdev->dev;
100 
101 	hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
102 	if (!hwmon)
103 		return -ENOMEM;
104 
105 	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
106 	if (IS_ERR(hwmon->base))
107 		return PTR_ERR(hwmon->base);
108 
109 	init_pvt(hwmon);
110 
111 	hwmon_dev = devm_hwmon_device_register_with_info(dev,
112 							 "as370",
113 							 hwmon,
114 							 &as370_chip_info,
115 							 NULL);
116 	return PTR_ERR_OR_ZERO(hwmon_dev);
117 }
118 
119 static const struct of_device_id as370_hwmon_match[] = {
120 	{ .compatible = "syna,as370-hwmon" },
121 	{},
122 };
123 MODULE_DEVICE_TABLE(of, as370_hwmon_match);
124 
125 static struct platform_driver as370_hwmon_driver = {
126 	.probe = as370_hwmon_probe,
127 	.driver = {
128 		.name = "as370-hwmon",
129 		.of_match_table = as370_hwmon_match,
130 	},
131 };
132 module_platform_driver(as370_hwmon_driver);
133 
134 MODULE_AUTHOR("Jisheng Zhang<jszhang@kernel.org>");
135 MODULE_DESCRIPTION("Synaptics AS370 SoC hardware monitor");
136 MODULE_LICENSE("GPL v2");
137