1 /*
2  * SPEAr thermal driver.
3  *
4  * Copyright (C) 2011-2012 ST Microelectronics
5  * Author: Vincenzo Frascino <vincenzo.frascino@st.com>
6  *
7  * This software is licensed under the terms of the GNU General Public
8  * License version 2, as published by the Free Software Foundation, and
9  * may be copied, distributed, and modified under those terms.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  */
17 
18 #include <linux/clk.h>
19 #include <linux/device.h>
20 #include <linux/err.h>
21 #include <linux/io.h>
22 #include <linux/kernel.h>
23 #include <linux/of.h>
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 #include <linux/thermal.h>
27 
28 #define MD_FACTOR	1000
29 
30 /* SPEAr Thermal Sensor Dev Structure */
31 struct spear_thermal_dev {
32 	/* pointer to base address of the thermal sensor */
33 	void __iomem *thermal_base;
34 	/* clk structure */
35 	struct clk *clk;
36 	/* pointer to thermal flags */
37 	unsigned int flags;
38 };
39 
40 static inline int thermal_get_temp(struct thermal_zone_device *thermal,
41 				int *temp)
42 {
43 	struct spear_thermal_dev *stdev = thermal->devdata;
44 
45 	/*
46 	 * Data are ready to be read after 628 usec from POWERDOWN signal
47 	 * (PDN) = 1
48 	 */
49 	*temp = (readl_relaxed(stdev->thermal_base) & 0x7F) * MD_FACTOR;
50 	return 0;
51 }
52 
53 static struct thermal_zone_device_ops ops = {
54 	.get_temp = thermal_get_temp,
55 };
56 
57 static int __maybe_unused spear_thermal_suspend(struct device *dev)
58 {
59 	struct platform_device *pdev = to_platform_device(dev);
60 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
61 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
62 	unsigned int actual_mask = 0;
63 
64 	/* Disable SPEAr Thermal Sensor */
65 	actual_mask = readl_relaxed(stdev->thermal_base);
66 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
67 
68 	clk_disable(stdev->clk);
69 	dev_info(dev, "Suspended.\n");
70 
71 	return 0;
72 }
73 
74 static int __maybe_unused spear_thermal_resume(struct device *dev)
75 {
76 	struct platform_device *pdev = to_platform_device(dev);
77 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
78 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
79 	unsigned int actual_mask = 0;
80 	int ret = 0;
81 
82 	ret = clk_enable(stdev->clk);
83 	if (ret) {
84 		dev_err(&pdev->dev, "Can't enable clock\n");
85 		return ret;
86 	}
87 
88 	/* Enable SPEAr Thermal Sensor */
89 	actual_mask = readl_relaxed(stdev->thermal_base);
90 	writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
91 
92 	dev_info(dev, "Resumed.\n");
93 
94 	return 0;
95 }
96 
97 static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
98 		spear_thermal_resume);
99 
100 static int spear_thermal_probe(struct platform_device *pdev)
101 {
102 	struct thermal_zone_device *spear_thermal = NULL;
103 	struct spear_thermal_dev *stdev;
104 	struct device_node *np = pdev->dev.of_node;
105 	struct resource *res;
106 	int ret = 0, val;
107 
108 	if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
109 		dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
110 		return -EINVAL;
111 	}
112 
113 	stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
114 	if (!stdev)
115 		return -ENOMEM;
116 
117 	/* Enable thermal sensor */
118 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
119 	stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
120 	if (IS_ERR(stdev->thermal_base))
121 		return PTR_ERR(stdev->thermal_base);
122 
123 	stdev->clk = devm_clk_get(&pdev->dev, NULL);
124 	if (IS_ERR(stdev->clk)) {
125 		dev_err(&pdev->dev, "Can't get clock\n");
126 		return PTR_ERR(stdev->clk);
127 	}
128 
129 	ret = clk_enable(stdev->clk);
130 	if (ret) {
131 		dev_err(&pdev->dev, "Can't enable clock\n");
132 		return ret;
133 	}
134 
135 	stdev->flags = val;
136 	writel_relaxed(stdev->flags, stdev->thermal_base);
137 
138 	spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
139 				stdev, &ops, NULL, 0, 0);
140 	if (IS_ERR(spear_thermal)) {
141 		dev_err(&pdev->dev, "thermal zone device is NULL\n");
142 		ret = PTR_ERR(spear_thermal);
143 		goto disable_clk;
144 	}
145 
146 	platform_set_drvdata(pdev, spear_thermal);
147 
148 	dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
149 			stdev->thermal_base);
150 
151 	return 0;
152 
153 disable_clk:
154 	clk_disable(stdev->clk);
155 
156 	return ret;
157 }
158 
159 static int spear_thermal_exit(struct platform_device *pdev)
160 {
161 	unsigned int actual_mask = 0;
162 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
163 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
164 
165 	thermal_zone_device_unregister(spear_thermal);
166 
167 	/* Disable SPEAr Thermal Sensor */
168 	actual_mask = readl_relaxed(stdev->thermal_base);
169 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
170 
171 	clk_disable(stdev->clk);
172 
173 	return 0;
174 }
175 
176 static const struct of_device_id spear_thermal_id_table[] = {
177 	{ .compatible = "st,thermal-spear1340" },
178 	{}
179 };
180 MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
181 
182 static struct platform_driver spear_thermal_driver = {
183 	.probe = spear_thermal_probe,
184 	.remove = spear_thermal_exit,
185 	.driver = {
186 		.name = "spear_thermal",
187 		.pm = &spear_thermal_pm_ops,
188 		.of_match_table = spear_thermal_id_table,
189 	},
190 };
191 
192 module_platform_driver(spear_thermal_driver);
193 
194 MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
195 MODULE_DESCRIPTION("SPEAr thermal driver");
196 MODULE_LICENSE("GPL");
197