linux/drivers/thermal/spear_thermal.c
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   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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