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 thermal_zone_device *spear_thermal = dev_get_drvdata(dev);
60 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
61 	unsigned int actual_mask = 0;
62 
63 	/* Disable SPEAr Thermal Sensor */
64 	actual_mask = readl_relaxed(stdev->thermal_base);
65 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
66 
67 	clk_disable(stdev->clk);
68 	dev_info(dev, "Suspended.\n");
69 
70 	return 0;
71 }
72 
73 static int __maybe_unused spear_thermal_resume(struct device *dev)
74 {
75 	struct thermal_zone_device *spear_thermal = dev_get_drvdata(dev);
76 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
77 	unsigned int actual_mask = 0;
78 	int ret = 0;
79 
80 	ret = clk_enable(stdev->clk);
81 	if (ret) {
82 		dev_err(dev, "Can't enable clock\n");
83 		return ret;
84 	}
85 
86 	/* Enable SPEAr Thermal Sensor */
87 	actual_mask = readl_relaxed(stdev->thermal_base);
88 	writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
89 
90 	dev_info(dev, "Resumed.\n");
91 
92 	return 0;
93 }
94 
95 static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
96 		spear_thermal_resume);
97 
98 static int spear_thermal_probe(struct platform_device *pdev)
99 {
100 	struct thermal_zone_device *spear_thermal = NULL;
101 	struct spear_thermal_dev *stdev;
102 	struct device_node *np = pdev->dev.of_node;
103 	struct resource *res;
104 	int ret = 0, val;
105 
106 	if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
107 		dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
108 		return -EINVAL;
109 	}
110 
111 	stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
112 	if (!stdev)
113 		return -ENOMEM;
114 
115 	/* Enable thermal sensor */
116 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
117 	stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
118 	if (IS_ERR(stdev->thermal_base))
119 		return PTR_ERR(stdev->thermal_base);
120 
121 	stdev->clk = devm_clk_get(&pdev->dev, NULL);
122 	if (IS_ERR(stdev->clk)) {
123 		dev_err(&pdev->dev, "Can't get clock\n");
124 		return PTR_ERR(stdev->clk);
125 	}
126 
127 	ret = clk_enable(stdev->clk);
128 	if (ret) {
129 		dev_err(&pdev->dev, "Can't enable clock\n");
130 		return ret;
131 	}
132 
133 	stdev->flags = val;
134 	writel_relaxed(stdev->flags, stdev->thermal_base);
135 
136 	spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
137 				stdev, &ops, NULL, 0, 0);
138 	if (IS_ERR(spear_thermal)) {
139 		dev_err(&pdev->dev, "thermal zone device is NULL\n");
140 		ret = PTR_ERR(spear_thermal);
141 		goto disable_clk;
142 	}
143 
144 	platform_set_drvdata(pdev, spear_thermal);
145 
146 	dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
147 			stdev->thermal_base);
148 
149 	return 0;
150 
151 disable_clk:
152 	clk_disable(stdev->clk);
153 
154 	return ret;
155 }
156 
157 static int spear_thermal_exit(struct platform_device *pdev)
158 {
159 	unsigned int actual_mask = 0;
160 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
161 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
162 
163 	thermal_zone_device_unregister(spear_thermal);
164 
165 	/* Disable SPEAr Thermal Sensor */
166 	actual_mask = readl_relaxed(stdev->thermal_base);
167 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
168 
169 	clk_disable(stdev->clk);
170 
171 	return 0;
172 }
173 
174 static const struct of_device_id spear_thermal_id_table[] = {
175 	{ .compatible = "st,thermal-spear1340" },
176 	{}
177 };
178 MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
179 
180 static struct platform_driver spear_thermal_driver = {
181 	.probe = spear_thermal_probe,
182 	.remove = spear_thermal_exit,
183 	.driver = {
184 		.name = "spear_thermal",
185 		.pm = &spear_thermal_pm_ops,
186 		.of_match_table = spear_thermal_id_table,
187 	},
188 };
189 
190 module_platform_driver(spear_thermal_driver);
191 
192 MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
193 MODULE_DESCRIPTION("SPEAr thermal driver");
194 MODULE_LICENSE("GPL");
195