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 */
31struct 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
40static 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
53static struct thermal_zone_device_ops ops = {
54	.get_temp = thermal_get_temp,
55};
56
57#ifdef CONFIG_PM
58static 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
75static 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
99static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
100		spear_thermal_resume);
101
102static 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
155disable_clk:
156	clk_disable(stdev->clk);
157
158	return ret;
159}
160
161static 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
178static const struct of_device_id spear_thermal_id_table[] = {
179	{ .compatible = "st,thermal-spear1340" },
180	{}
181};
182MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
183
184static 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
194module_platform_driver(spear_thermal_driver);
195
196MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
197MODULE_DESCRIPTION("SPEAr thermal driver");
198MODULE_LICENSE("GPL");
199