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 /*
  47  *              basic functions
  48  */
  49 static u32 rcar_thermal_read(struct rcar_thermal_priv *priv, u32 reg)
  50 {
  51         unsigned long flags;
  52         u32 ret;
  53
  54         spin_lock_irqsave(&priv->lock, flags);
  55
  56         ret = ioread32(priv->base + reg);
  57
  58         spin_unlock_irqrestore(&priv->lock, flags);
  59
  60         return ret;
  61 }
  62
  63 #if 0 /* no user at this point */
  64 static void rcar_thermal_write(struct rcar_thermal_priv *priv,
  65                                u32 reg, u32 data)
  66 {
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(&priv->lock, flags);
  70
  71         iowrite32(data, priv->base + reg);
  72
  73         spin_unlock_irqrestore(&priv->lock, flags);
  74 }
  75 #endif
  76
  77 static void rcar_thermal_bset(struct rcar_thermal_priv *priv, u32 reg,
  78                               u32 mask, u32 data)
  79 {
  80         unsigned long flags;
  81         u32 val;
  82
  83         spin_lock_irqsave(&priv->lock, flags);
  84
  85         val = ioread32(priv->base + reg);
  86         val &= ~mask;
  87         val |= (data & mask);
  88         iowrite32(val, priv->base + reg);
  89
  90         spin_unlock_irqrestore(&priv->lock, flags);
  91 }
  92
  93 /*
  94  *              zone device functions
  95  */
  96 static int rcar_thermal_get_temp(struct thermal_zone_device *zone,
  97                            unsigned long *temp)
  98 {
  99         struct rcar_thermal_priv *priv = zone->devdata;
 100         int val, min, max, tmp;
 101
 102         tmp = -200; /* default */
 103         while (1) {
 104                 if (priv->comp < 1 || priv->comp > 12) {
 105                         dev_err(priv->dev,
 106                                 "THSSR invalid data (%d)\n", priv->comp);
 107                         priv->comp = 4; /* for next thermal */
 108                         return -EINVAL;
 109                 }
 110
 111                 /*
 112                  * THS comparator offset and the reference temperature
 113                  *
 114                  * Comparator   | reference     | Temperature field
 115                  * offset       | temperature   | measurement
 116                  *              | (degrees C)   | (degrees C)
 117                  * -------------+---------------+-------------------
 118                  *  1           |  -45          |  -45 to  -30
 119                  *  2           |  -30          |  -30 to  -15
 120                  *  3           |  -15          |  -15 to    0
 121                  *  4           |    0          |    0 to  +15
 122                  *  5           |  +15          |  +15 to  +30
 123                  *  6           |  +30          |  +30 to  +45
 124                  *  7           |  +45          |  +45 to  +60
 125                  *  8           |  +60          |  +60 to  +75
 126                  *  9           |  +75          |  +75 to  +90
 127                  * 10           |  +90          |  +90 to +105
 128                  * 11           | +105          | +105 to +120
 129                  * 12           | +120          | +120 to +135
 130                  */
 131
 132                 /* calculate thermal limitation */
 133                 min = (priv->comp * 15) - 60;
 134                 max = min + 15;
 135
 136                 /*
 137                  * we need to wait 300us after changing comparator offset
 138                  * to get stable temperature.
 139                  * see "Usage Notes" on datasheet
 140                  */
 141                 rcar_thermal_bset(priv, THSCR, CPTAP, priv->comp);
 142                 udelay(300);
 143
 144                 /* calculate current temperature */
 145                 val = rcar_thermal_read(priv, THSSR) & CTEMP;
 146                 val = (val * 5) - 65;
 147
 148                 dev_dbg(priv->dev, "comp/min/max/val = %d/%d/%d/%d\n",
 149                         priv->comp, min, max, val);
 150
 151                 /*
 152                  * If val is same as min/max, then,
 153                  * it should try again on next comparator.
 154                  * But the val might be correct temperature.
 155                  * Keep it on "tmp" and compare with next val.
 156                  */
 157                 if (tmp == val)
 158                         break;
 159
 160                 if (val <= min) {
 161                         tmp = min;
 162                         priv->comp--; /* try again */
 163                 } else if (val >= max) {
 164                         tmp = max;
 165                         priv->comp++; /* try again */
 166                 } else {
 167                         tmp = val;
 168                         break;
 169                 }
 170         }
 171
 172         *temp = tmp;
 173         return 0;
 174 }
 175
 176 static struct thermal_zone_device_ops rcar_thermal_zone_ops = {
 177         .get_temp = rcar_thermal_get_temp,
 178 };
 179
 180 /*
 181  *              platform functions
 182  */
 183 static int rcar_thermal_probe(struct platform_device *pdev)
 184 {
 185         struct thermal_zone_device *zone;
 186         struct rcar_thermal_priv *priv;
 187         struct resource *res;
 188         int ret;
 189
 190         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 191         if (!res) {
 192                 dev_err(&pdev->dev, "Could not get platform resource\n");
 193                 return -ENODEV;
 194         }
 195
 196         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 197         if (!priv) {
 198                 dev_err(&pdev->dev, "Could not allocate priv\n");
 199                 return -ENOMEM;
 200         }
 201
 202         priv->comp = 4; /* basic setup */
 203         priv->dev = &pdev->dev;
 204         spin_lock_init(&priv->lock);
 205         priv->base = devm_ioremap_nocache(&pdev->dev,
 206                                           res->start, resource_size(res));
 207         if (!priv->base) {
 208                 dev_err(&pdev->dev, "Unable to ioremap thermal register\n");
 209                 ret = -ENOMEM;
 210                 goto error_free_priv;
 211         }
 212
 213         zone = thermal_zone_device_register("rcar_thermal", 0, priv,
 214                                             &rcar_thermal_zone_ops, 0, 0);
 215         if (IS_ERR(zone)) {
 216                 dev_err(&pdev->dev, "thermal zone device is NULL\n");
 217                 ret = PTR_ERR(zone);
 218                 goto error_iounmap;
 219         }
 220
 221         platform_set_drvdata(pdev, zone);
 222
 223         dev_info(&pdev->dev, "proved\n");
 224
 225         return 0;
 226
 227 error_iounmap:
 228         devm_iounmap(&pdev->dev, priv->base);
 229 error_free_priv:
 230         devm_kfree(&pdev->dev, priv);
 231
 232         return ret;
 233 }
 234
 235 static int rcar_thermal_remove(struct platform_device *pdev)
 236 {
 237         struct thermal_zone_device *zone = platform_get_drvdata(pdev);
 238         struct rcar_thermal_priv *priv = zone->devdata;
 239
 240         thermal_zone_device_unregister(zone);
 241         platform_set_drvdata(pdev, NULL);
 242
 243         devm_iounmap(&pdev->dev, priv->base);
 244         devm_kfree(&pdev->dev, priv);
 245
 246         return 0;
 247 }
 248
 249 static struct platform_driver rcar_thermal_driver = {
 250         .driver = {
 251                 .name   = "rcar_thermal",
 252         },
 253         .probe          = rcar_thermal_probe,
 254         .remove         = rcar_thermal_remove,
 255 };
 256 module_platform_driver(rcar_thermal_driver);
 257
 258 MODULE_LICENSE("GPL");
 259 MODULE_DESCRIPTION("R-Car THS/TSC thermal sensor driver");
 260 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");