linux/drivers/thermal/rcar_thermal.c
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   1/*
   2 *  R-Car THS/TSC thermal sensor driver
   3 *
   4 * Copyright (C) 2012 Renesas Solutions Corp.
   5 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
   6 *
   7 *  This program is free software; you can redistribute it and/or modify
   8 *  it under the terms of the GNU General Public License as published by
   9 *  the Free Software Foundation; version 2 of the License.
  10 *
  11 *  This program is distributed in the hope that it will be useful, but
  12 *  WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 *  General Public License for more details.
  15 *
  16 *  You should have received a copy of the GNU General Public License along
  17 *  with this program; if not, write to the Free Software Foundation, Inc.,
  18 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  19 */
  20#include <linux/delay.h>
  21#include <linux/err.h>
  22#include <linux/io.h>
  23#include <linux/module.h>
  24#include <linux/platform_device.h>
  25#include <linux/slab.h>
  26#include <linux/spinlock.h>
  27#include <linux/thermal.h>
  28
  29#define THSCR   0x2c
  30#define THSSR   0x30
  31
  32/* THSCR */
  33#define CPTAP   0xf
  34
  35/* THSSR */
  36#define CTEMP   0x3f
  37
  38
  39struct rcar_thermal_priv {
  40        void __iomem *base;
  41        struct device *dev;
  42        spinlock_t lock;
  43        u32 comp;
  44};
  45
  46#define MCELSIUS(temp)                  ((temp) * 1000)
  47#define rcar_zone_to_priv(zone)         (zone->devdata)
  48
  49/*
  50 *              basic functions
  51 */
  52static u32 rcar_thermal_read(struct rcar_thermal_priv *priv, u32 reg)
  53{
  54        unsigned long flags;
  55        u32 ret;
  56
  57        spin_lock_irqsave(&priv->lock, flags);
  58
  59        ret = ioread32(priv->base + reg);
  60
  61        spin_unlock_irqrestore(&priv->lock, flags);
  62
  63        return ret;
  64}
  65
  66#if 0 /* no user at this point */
  67static void rcar_thermal_write(struct rcar_thermal_priv *priv,
  68                               u32 reg, u32 data)
  69{
  70        unsigned long flags;
  71
  72        spin_lock_irqsave(&priv->lock, flags);
  73
  74        iowrite32(data, priv->base + reg);
  75
  76        spin_unlock_irqrestore(&priv->lock, flags);
  77}
  78#endif
  79
  80static void rcar_thermal_bset(struct rcar_thermal_priv *priv, u32 reg,
  81                              u32 mask, u32 data)
  82{
  83        unsigned long flags;
  84        u32 val;
  85
  86        spin_lock_irqsave(&priv->lock, flags);
  87
  88        val = ioread32(priv->base + reg);
  89        val &= ~mask;
  90        val |= (data & mask);
  91        iowrite32(val, priv->base + reg);
  92
  93        spin_unlock_irqrestore(&priv->lock, flags);
  94}
  95
  96/*
  97 *              zone device functions
  98 */
  99static int rcar_thermal_get_temp(struct thermal_zone_device *zone,
 100                           unsigned long *temp)
 101{
 102        struct rcar_thermal_priv *priv = rcar_zone_to_priv(zone);
 103        int val, min, max, tmp;
 104
 105        tmp = -200; /* default */
 106        while (1) {
 107                if (priv->comp < 1 || priv->comp > 12) {
 108                        dev_err(priv->dev,
 109                                "THSSR invalid data (%d)\n", priv->comp);
 110                        priv->comp = 4; /* for next thermal */
 111                        return -EINVAL;
 112                }
 113
 114                /*
 115                 * THS comparator offset and the reference temperature
 116                 *
 117                 * Comparator   | reference     | Temperature field
 118                 * offset       | temperature   | measurement
 119                 *              | (degrees C)   | (degrees C)
 120                 * -------------+---------------+-------------------
 121                 *  1           |  -45          |  -45 to  -30
 122                 *  2           |  -30          |  -30 to  -15
 123                 *  3           |  -15          |  -15 to    0
 124                 *  4           |    0          |    0 to  +15
 125                 *  5           |  +15          |  +15 to  +30
 126                 *  6           |  +30          |  +30 to  +45
 127                 *  7           |  +45          |  +45 to  +60
 128                 *  8           |  +60          |  +60 to  +75
 129                 *  9           |  +75          |  +75 to  +90
 130                 * 10           |  +90          |  +90 to +105
 131                 * 11           | +105          | +105 to +120
 132                 * 12           | +120          | +120 to +135
 133                 */
 134
 135                /* calculate thermal limitation */
 136                min = (priv->comp * 15) - 60;
 137                max = min + 15;
 138
 139                /*
 140                 * we need to wait 300us after changing comparator offset
 141                 * to get stable temperature.
 142                 * see "Usage Notes" on datasheet
 143                 */
 144                rcar_thermal_bset(priv, THSCR, CPTAP, priv->comp);
 145                udelay(300);
 146
 147                /* calculate current temperature */
 148                val = rcar_thermal_read(priv, THSSR) & CTEMP;
 149                val = (val * 5) - 65;
 150
 151                dev_dbg(priv->dev, "comp/min/max/val = %d/%d/%d/%d\n",
 152                        priv->comp, min, max, val);
 153
 154                /*
 155                 * If val is same as min/max, then,
 156                 * it should try again on next comparator.
 157                 * But the val might be correct temperature.
 158                 * Keep it on "tmp" and compare with next val.
 159                 */
 160                if (tmp == val)
 161                        break;
 162
 163                if (val <= min) {
 164                        tmp = min;
 165                        priv->comp--; /* try again */
 166                } else if (val >= max) {
 167                        tmp = max;
 168                        priv->comp++; /* try again */
 169                } else {
 170                        tmp = val;
 171                        break;
 172                }
 173        }
 174
 175        *temp = MCELSIUS(tmp);
 176        return 0;
 177}
 178
 179static struct thermal_zone_device_ops rcar_thermal_zone_ops = {
 180        .get_temp = rcar_thermal_get_temp,
 181};
 182
 183/*
 184 *              platform functions
 185 */
 186static int rcar_thermal_probe(struct platform_device *pdev)
 187{
 188        struct thermal_zone_device *zone;
 189        struct rcar_thermal_priv *priv;
 190        struct resource *res;
 191
 192        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 193        if (!res) {
 194                dev_err(&pdev->dev, "Could not get platform resource\n");
 195                return -ENODEV;
 196        }
 197
 198        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 199        if (!priv) {
 200                dev_err(&pdev->dev, "Could not allocate priv\n");
 201                return -ENOMEM;
 202        }
 203
 204        priv->comp = 4; /* basic setup */
 205        priv->dev = &pdev->dev;
 206        spin_lock_init(&priv->lock);
 207        priv->base = devm_ioremap_nocache(&pdev->dev,
 208                                          res->start, resource_size(res));
 209        if (!priv->base) {
 210                dev_err(&pdev->dev, "Unable to ioremap thermal register\n");
 211                return -ENOMEM;
 212        }
 213
 214        zone = thermal_zone_device_register("rcar_thermal", 0, 0, priv,
 215                                    &rcar_thermal_zone_ops, NULL, 0, 0);
 216        if (IS_ERR(zone)) {
 217                dev_err(&pdev->dev, "thermal zone device is NULL\n");
 218                return PTR_ERR(zone);
 219        }
 220
 221        platform_set_drvdata(pdev, zone);
 222
 223        dev_info(&pdev->dev, "proved\n");
 224
 225        return 0;
 226}
 227
 228static int rcar_thermal_remove(struct platform_device *pdev)
 229{
 230        struct thermal_zone_device *zone = platform_get_drvdata(pdev);
 231
 232        thermal_zone_device_unregister(zone);
 233        platform_set_drvdata(pdev, NULL);
 234
 235        return 0;
 236}
 237
 238static struct platform_driver rcar_thermal_driver = {
 239        .driver = {
 240                .name   = "rcar_thermal",
 241        },
 242        .probe          = rcar_thermal_probe,
 243        .remove         = rcar_thermal_remove,
 244};
 245module_platform_driver(rcar_thermal_driver);
 246
 247MODULE_LICENSE("GPL");
 248MODULE_DESCRIPTION("R-Car THS/TSC thermal sensor driver");
 249MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
 250
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