drivers/thermal/rcar_thermal.c

   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
  39 struct 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  */
  52 static 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 */
  67 static 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
  80 static 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  */
  99 static 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
 179 static struct thermal_zone_device_ops rcar_thermal_zone_ops = {
 180         .get_temp = rcar_thermal_get_temp,
 181 };
 182
 183 /*
 184  *              platform functions
 185  */
 186 static 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
 228 static 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
 238 static struct platform_driver rcar_thermal_driver = {
 239         .driver = {
 240                 .name   = "rcar_thermal",
 241         },
 242         .probe          = rcar_thermal_probe,
 243         .remove         = rcar_thermal_remove,
 244 };
 245 module_platform_driver(rcar_thermal_driver);
 246
 247 MODULE_LICENSE("GPL");
 248 MODULE_DESCRIPTION("R-Car THS/TSC thermal sensor driver");
 249 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");