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

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