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

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