Root/drivers/thermal/spear_thermal.c

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                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
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 *stres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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    if (!stres) {
116        dev_err(&pdev->dev, "memory resource missing\n");
117        return -ENODEV;
118    }
119
120    stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
121    if (!stdev) {
122        dev_err(&pdev->dev, "kzalloc fail\n");
123        return -ENOMEM;
124    }
125
126    /* Enable thermal sensor */
127    stdev->thermal_base = devm_ioremap(&pdev->dev, stres->start,
128            resource_size(stres));
129    if (!stdev->thermal_base) {
130        dev_err(&pdev->dev, "ioremap failed\n");
131        return -ENOMEM;
132    }
133
134    stdev->clk = devm_clk_get(&pdev->dev, NULL);
135    if (IS_ERR(stdev->clk)) {
136        dev_err(&pdev->dev, "Can't get clock\n");
137        return PTR_ERR(stdev->clk);
138    }
139
140    ret = clk_enable(stdev->clk);
141    if (ret) {
142        dev_err(&pdev->dev, "Can't enable clock\n");
143        return ret;
144    }
145
146    stdev->flags = val;
147    writel_relaxed(stdev->flags, stdev->thermal_base);
148
149    spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
150                stdev, &ops, NULL, 0, 0);
151    if (IS_ERR(spear_thermal)) {
152        dev_err(&pdev->dev, "thermal zone device is NULL\n");
153        ret = PTR_ERR(spear_thermal);
154        goto disable_clk;
155    }
156
157    platform_set_drvdata(pdev, spear_thermal);
158
159    dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
160            stdev->thermal_base);
161
162    return 0;
163
164disable_clk:
165    clk_disable(stdev->clk);
166
167    return ret;
168}
169
170static int spear_thermal_exit(struct platform_device *pdev)
171{
172    unsigned int actual_mask = 0;
173    struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
174    struct spear_thermal_dev *stdev = spear_thermal->devdata;
175
176    thermal_zone_device_unregister(spear_thermal);
177    platform_set_drvdata(pdev, NULL);
178
179    /* Disable SPEAr Thermal Sensor */
180    actual_mask = readl_relaxed(stdev->thermal_base);
181    writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
182
183    clk_disable(stdev->clk);
184
185    return 0;
186}
187
188static const struct of_device_id spear_thermal_id_table[] = {
189    { .compatible = "st,thermal-spear1340" },
190    {}
191};
192MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
193
194static struct platform_driver spear_thermal_driver = {
195    .probe = spear_thermal_probe,
196    .remove = spear_thermal_exit,
197    .driver = {
198        .name = "spear_thermal",
199        .owner = THIS_MODULE,
200        .pm = &spear_thermal_pm_ops,
201        .of_match_table = of_match_ptr(spear_thermal_id_table),
202    },
203};
204
205module_platform_driver(spear_thermal_driver);
206
207MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
208MODULE_DESCRIPTION("SPEAr thermal driver");
209MODULE_LICENSE("GPL");
210

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