1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Sparx5 SoC temperature sensor driver
3 *
4 * Copyright (C) 2020 Lars Povlsen <lars.povlsen@microchip.com>
5 */
6
7#include <linux/bitfield.h>
8#include <linux/clk.h>
9#include <linux/hwmon.h>
10#include <linux/init.h>
11#include <linux/io.h>
12#include <linux/mod_devicetable.h>
13#include <linux/module.h>
14#include <linux/platform_device.h>
15
16#define TEMP_CTRL		0
17#define TEMP_CFG		4
18#define  TEMP_CFG_CYCLES	GENMASK(24, 15)
19#define  TEMP_CFG_ENA		BIT(0)
20#define TEMP_STAT		8
21#define  TEMP_STAT_VALID	BIT(12)
22#define  TEMP_STAT_TEMP		GENMASK(11, 0)
23
24struct s5_hwmon {
25	void __iomem *base;
26	struct clk *clk;
27};
28
29static void s5_temp_enable(struct s5_hwmon *hwmon)
30{
31	u32 val = readl(hwmon->base + TEMP_CFG);
32	u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;
33
34	val &= ~TEMP_CFG_CYCLES;
35	val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);
36	val |= TEMP_CFG_ENA;
37
38	writel(val, hwmon->base + TEMP_CFG);
39}
40
41static int s5_read(struct device *dev, enum hwmon_sensor_types type,
42		   u32 attr, int channel, long *temp)
43{
44	struct s5_hwmon *hwmon = dev_get_drvdata(dev);
45	int rc = 0, value;
46	u32 stat;
47
48	switch (attr) {
49	case hwmon_temp_input:
50		stat = readl_relaxed(hwmon->base + TEMP_STAT);
51		if (!(stat & TEMP_STAT_VALID))
52			return -EAGAIN;
53		value = stat & TEMP_STAT_TEMP;
54		/*
55		 * From register documentation:
56		 * Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.4
57		 */
58		value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
59		/*
60		 * Scale down by 10 from above and multiply by 1000 to
61		 * have millidegrees as specified by the hwmon sysfs
62		 * interface.
63		 */
64		value *= 100;
65		*temp = value;
66		break;
67	default:
68		rc = -EOPNOTSUPP;
69		break;
70	}
71
72	return rc;
73}
74
75static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,
76			     u32 attr, int channel)
77{
78	if (type != hwmon_temp)
79		return 0;
80
81	switch (attr) {
82	case hwmon_temp_input:
83		return 0444;
84	default:
85		return 0;
86	}
87}
88
89static const struct hwmon_channel_info * const s5_info[] = {
90	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
91	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
92	NULL
93};
94
95static const struct hwmon_ops s5_hwmon_ops = {
96	.is_visible = s5_is_visible,
97	.read = s5_read,
98};
99
100static const struct hwmon_chip_info s5_chip_info = {
101	.ops = &s5_hwmon_ops,
102	.info = s5_info,
103};
104
105static int s5_temp_probe(struct platform_device *pdev)
106{
107	struct device *hwmon_dev;
108	struct s5_hwmon *hwmon;
109
110	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
111	if (!hwmon)
112		return -ENOMEM;
113
114	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
115	if (IS_ERR(hwmon->base))
116		return PTR_ERR(hwmon->base);
117
118	hwmon->clk = devm_clk_get_enabled(&pdev->dev, NULL);
119	if (IS_ERR(hwmon->clk))
120		return PTR_ERR(hwmon->clk);
121
122	s5_temp_enable(hwmon);
123
124	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
125							 "s5_temp",
126							 hwmon,
127							 &s5_chip_info,
128							 NULL);
129
130	return PTR_ERR_OR_ZERO(hwmon_dev);
131}
132
133static const struct of_device_id s5_temp_match[] = {
134	{ .compatible = "microchip,sparx5-temp" },
135	{},
136};
137MODULE_DEVICE_TABLE(of, s5_temp_match);
138
139static struct platform_driver s5_temp_driver = {
140	.probe = s5_temp_probe,
141	.driver = {
142		.name = "sparx5-temp",
143		.of_match_table = s5_temp_match,
144	},
145};
146
147module_platform_driver(s5_temp_driver);
148
149MODULE_AUTHOR("Lars Povlsen <lars.povlsen@microchip.com>");
150MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
151MODULE_LICENSE("GPL");
152