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 
24 struct s5_hwmon {
25 	void __iomem *base;
26 	struct clk *clk;
27 };
28 
s5_temp_clk_disable(void * data)29 static void s5_temp_clk_disable(void *data)
30 {
31 	struct clk *clk = data;
32 
33 	clk_disable_unprepare(clk);
34 }
35 
s5_temp_enable(struct s5_hwmon * hwmon)36 static void s5_temp_enable(struct s5_hwmon *hwmon)
37 {
38 	u32 val = readl(hwmon->base + TEMP_CFG);
39 	u32 clk = clk_get_rate(hwmon->clk) / USEC_PER_SEC;
40 
41 	val &= ~TEMP_CFG_CYCLES;
42 	val |= FIELD_PREP(TEMP_CFG_CYCLES, clk);
43 	val |= TEMP_CFG_ENA;
44 
45 	writel(val, hwmon->base + TEMP_CFG);
46 }
47 
s5_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * temp)48 static int s5_read(struct device *dev, enum hwmon_sensor_types type,
49 		   u32 attr, int channel, long *temp)
50 {
51 	struct s5_hwmon *hwmon = dev_get_drvdata(dev);
52 	int rc = 0, value;
53 	u32 stat;
54 
55 	switch (attr) {
56 	case hwmon_temp_input:
57 		stat = readl_relaxed(hwmon->base + TEMP_STAT);
58 		if (!(stat & TEMP_STAT_VALID))
59 			return -EAGAIN;
60 		value = stat & TEMP_STAT_TEMP;
61 		/*
62 		 * From register documentation:
63 		 * Temp(C) = TEMP_SENSOR_STAT.TEMP / 4096 * 352.2 - 109.4
64 		 */
65 		value = DIV_ROUND_CLOSEST(value * 3522, 4096) - 1094;
66 		/*
67 		 * Scale down by 10 from above and multiply by 1000 to
68 		 * have millidegrees as specified by the hwmon sysfs
69 		 * interface.
70 		 */
71 		value *= 100;
72 		*temp = value;
73 		break;
74 	default:
75 		rc = -EOPNOTSUPP;
76 		break;
77 	}
78 
79 	return rc;
80 }
81 
s5_is_visible(const void * _data,enum hwmon_sensor_types type,u32 attr,int channel)82 static umode_t s5_is_visible(const void *_data, enum hwmon_sensor_types type,
83 			     u32 attr, int channel)
84 {
85 	if (type != hwmon_temp)
86 		return 0;
87 
88 	switch (attr) {
89 	case hwmon_temp_input:
90 		return 0444;
91 	default:
92 		return 0;
93 	}
94 }
95 
96 static const struct hwmon_channel_info *s5_info[] = {
97 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
98 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
99 	NULL
100 };
101 
102 static const struct hwmon_ops s5_hwmon_ops = {
103 	.is_visible = s5_is_visible,
104 	.read = s5_read,
105 };
106 
107 static const struct hwmon_chip_info s5_chip_info = {
108 	.ops = &s5_hwmon_ops,
109 	.info = s5_info,
110 };
111 
s5_temp_probe(struct platform_device * pdev)112 static int s5_temp_probe(struct platform_device *pdev)
113 {
114 	struct device *hwmon_dev;
115 	struct s5_hwmon *hwmon;
116 	int ret;
117 
118 	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
119 	if (!hwmon)
120 		return -ENOMEM;
121 
122 	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
123 	if (IS_ERR(hwmon->base))
124 		return PTR_ERR(hwmon->base);
125 
126 	hwmon->clk = devm_clk_get(&pdev->dev, NULL);
127 	if (IS_ERR(hwmon->clk))
128 		return PTR_ERR(hwmon->clk);
129 
130 	ret = clk_prepare_enable(hwmon->clk);
131 	if (ret)
132 		return ret;
133 
134 	ret = devm_add_action_or_reset(&pdev->dev, s5_temp_clk_disable,
135 				       hwmon->clk);
136 	if (ret)
137 		return ret;
138 
139 	s5_temp_enable(hwmon);
140 
141 	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
142 							 "s5_temp",
143 							 hwmon,
144 							 &s5_chip_info,
145 							 NULL);
146 
147 	return PTR_ERR_OR_ZERO(hwmon_dev);
148 }
149 
150 static const struct of_device_id s5_temp_match[] = {
151 	{ .compatible = "microchip,sparx5-temp" },
152 	{},
153 };
154 MODULE_DEVICE_TABLE(of, s5_temp_match);
155 
156 static struct platform_driver s5_temp_driver = {
157 	.probe = s5_temp_probe,
158 	.driver = {
159 		.name = "sparx5-temp",
160 		.of_match_table = s5_temp_match,
161 	},
162 };
163 
164 module_platform_driver(s5_temp_driver);
165 
166 MODULE_AUTHOR("Lars Povlsen <lars.povlsen@microchip.com>");
167 MODULE_DESCRIPTION("Sparx5 SoC temperature sensor driver");
168 MODULE_LICENSE("GPL");
169