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 				unsigned long *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 #ifdef CONFIG_PM
58 static int spear_thermal_suspend(struct device *dev)
59 {
60 	struct platform_device *pdev = to_platform_device(dev);
61 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
62 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
63 	unsigned int actual_mask = 0;
64 
65 	/* Disable SPEAr Thermal Sensor */
66 	actual_mask = readl_relaxed(stdev->thermal_base);
67 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
68 
69 	clk_disable(stdev->clk);
70 	dev_info(dev, "Suspended.\n");
71 
72 	return 0;
73 }
74 
75 static int spear_thermal_resume(struct device *dev)
76 {
77 	struct platform_device *pdev = to_platform_device(dev);
78 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
79 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
80 	unsigned int actual_mask = 0;
81 	int ret = 0;
82 
83 	ret = clk_enable(stdev->clk);
84 	if (ret) {
85 		dev_err(&pdev->dev, "Can't enable clock\n");
86 		return ret;
87 	}
88 
89 	/* Enable SPEAr Thermal Sensor */
90 	actual_mask = readl_relaxed(stdev->thermal_base);
91 	writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
92 
93 	dev_info(dev, "Resumed.\n");
94 
95 	return 0;
96 }
97 #endif
98 
99 static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
100 		spear_thermal_resume);
101 
102 static int spear_thermal_probe(struct platform_device *pdev)
103 {
104 	struct thermal_zone_device *spear_thermal = NULL;
105 	struct spear_thermal_dev *stdev;
106 	struct device_node *np = pdev->dev.of_node;
107 	struct resource *res;
108 	int ret = 0, val;
109 
110 	if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
111 		dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
112 		return -EINVAL;
113 	}
114 
115 	stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
116 	if (!stdev)
117 		return -ENOMEM;
118 
119 	/* Enable thermal sensor */
120 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
121 	stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
122 	if (IS_ERR(stdev->thermal_base))
123 		return PTR_ERR(stdev->thermal_base);
124 
125 	stdev->clk = devm_clk_get(&pdev->dev, NULL);
126 	if (IS_ERR(stdev->clk)) {
127 		dev_err(&pdev->dev, "Can't get clock\n");
128 		return PTR_ERR(stdev->clk);
129 	}
130 
131 	ret = clk_enable(stdev->clk);
132 	if (ret) {
133 		dev_err(&pdev->dev, "Can't enable clock\n");
134 		return ret;
135 	}
136 
137 	stdev->flags = val;
138 	writel_relaxed(stdev->flags, stdev->thermal_base);
139 
140 	spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
141 				stdev, &ops, NULL, 0, 0);
142 	if (IS_ERR(spear_thermal)) {
143 		dev_err(&pdev->dev, "thermal zone device is NULL\n");
144 		ret = PTR_ERR(spear_thermal);
145 		goto disable_clk;
146 	}
147 
148 	platform_set_drvdata(pdev, spear_thermal);
149 
150 	dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
151 			stdev->thermal_base);
152 
153 	return 0;
154 
155 disable_clk:
156 	clk_disable(stdev->clk);
157 
158 	return ret;
159 }
160 
161 static int spear_thermal_exit(struct platform_device *pdev)
162 {
163 	unsigned int actual_mask = 0;
164 	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
165 	struct spear_thermal_dev *stdev = spear_thermal->devdata;
166 
167 	thermal_zone_device_unregister(spear_thermal);
168 
169 	/* Disable SPEAr Thermal Sensor */
170 	actual_mask = readl_relaxed(stdev->thermal_base);
171 	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
172 
173 	clk_disable(stdev->clk);
174 
175 	return 0;
176 }
177 
178 static const struct of_device_id spear_thermal_id_table[] = {
179 	{ .compatible = "st,thermal-spear1340" },
180 	{}
181 };
182 MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
183 
184 static struct platform_driver spear_thermal_driver = {
185 	.probe = spear_thermal_probe,
186 	.remove = spear_thermal_exit,
187 	.driver = {
188 		.name = "spear_thermal",
189 		.pm = &spear_thermal_pm_ops,
190 		.of_match_table = spear_thermal_id_table,
191 	},
192 };
193 
194 module_platform_driver(spear_thermal_driver);
195 
196 MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
197 MODULE_DESCRIPTION("SPEAr thermal driver");
198 MODULE_LICENSE("GPL");
199