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