drivers/macintosh/windfarm_ad7417_sensor.c

   1 /*
   2  * Windfarm PowerMac thermal control. AD7417 sensors
   3  *
   4  * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
   5  *
   6  * Released under the term of the GNU GPL v2.
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/kernel.h>
  12 #include <linux/delay.h>
  13 #include <linux/slab.h>
  14 #include <linux/init.h>
  15 #include <linux/wait.h>
  16 #include <linux/i2c.h>
  17 #include <asm/prom.h>
  18 #include <asm/machdep.h>
  19 #include <asm/io.h>
  20 #include <asm/sections.h>
  21
  22 #include "windfarm.h"
  23 #include "windfarm_mpu.h"
  24
  25 #define VERSION "1.0"
  26
  27 struct wf_ad7417_priv {
  28         struct kref             ref;
  29         struct i2c_client       *i2c;
  30         u8                      config;
  31         u8                      cpu;
  32         const struct mpu_data   *mpu;
  33         struct wf_sensor        sensors[5];
  34         struct mutex            lock;
  35 };
  36
  37 static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
  38 {
  39         struct wf_ad7417_priv *pv = sr->priv;
  40         u8 buf[2];
  41         s16 raw;
  42         int rc;
  43
  44         *value = 0;
  45         mutex_lock(&pv->lock);
  46
  47         /* Read temp register */
  48         buf[0] = 0;
  49         rc = i2c_master_send(pv->i2c, buf, 1);
  50         if (rc < 0)
  51                 goto error;
  52         rc = i2c_master_recv(pv->i2c, buf, 2);
  53         if (rc < 0)
  54                 goto error;
  55
  56         /* Read a a 16-bit signed value */
  57         raw = be16_to_cpup((__le16 *)buf);
  58
  59         /* Convert 8.8-bit to 16.16 fixed point */
  60         *value = ((s32)raw) << 8;
  61
  62         mutex_unlock(&pv->lock);
  63         return 0;
  64
  65 error:
  66         mutex_unlock(&pv->lock);
  67         return -1;
  68 }
  69
  70 /*
  71  * Scaling factors for the AD7417 ADC converters (except
  72  * for the CPU diode which is obtained from the EEPROM).
  73  * Those values are obtained from the property list of
  74  * the darwin driver
  75  */
  76 #define ADC_12V_CURRENT_SCALE   0x0320  /* _AD2 */
  77 #define ADC_CPU_VOLTAGE_SCALE   0x00a0  /* _AD3 */
  78 #define ADC_CPU_CURRENT_SCALE   0x1f40  /* _AD4 */
  79
  80 static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
  81                                   int chan, s32 raw, s32 *value)
  82 {
  83         switch(chan) {
  84         case 1: /* Diode */
  85                 *value = (raw * (s32)pv->mpu->mdiode +
  86                         ((s32)pv->mpu->bdiode << 12)) >> 2;
  87                 break;
  88         case 2: /* 12v current */
  89                 *value = raw * ADC_12V_CURRENT_SCALE;
  90                 break;
  91         case 3: /* core voltage */
  92                 *value = raw * ADC_CPU_VOLTAGE_SCALE;
  93                 break;
  94         case 4: /* core current */
  95                 *value = raw * ADC_CPU_CURRENT_SCALE;
  96                 break;
  97         }
  98 }
  99
 100 static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
 101 {
 102         struct wf_ad7417_priv *pv = sr->priv;
 103         int chan = sr - pv->sensors;
 104         int i, rc;
 105         u8 buf[2];
 106         u16 raw;
 107
 108         *value = 0;
 109         mutex_lock(&pv->lock);
 110         for (i = 0; i < 10; i++) {
 111                 /* Set channel */
 112                 buf[0] = 1;
 113                 buf[1] = (pv->config & 0x1f) | (chan << 5);
 114                 rc = i2c_master_send(pv->i2c, buf, 2);
 115                 if (rc < 0)
 116                         goto error;
 117
 118                 /* Wait for conversion */
 119                 msleep(1);
 120
 121                 /* Switch to data register */
 122                 buf[0] = 4;
 123                 rc = i2c_master_send(pv->i2c, buf, 1);
 124                 if (rc < 0)
 125                         goto error;
 126
 127                 /* Read result */
 128                 rc = i2c_master_recv(pv->i2c, buf, 2);
 129                 if (rc < 0)
 130                         goto error;
 131
 132                 /* Read a a 16-bit signed value */
 133                 raw = be16_to_cpup((__le16 *)buf) >> 6;
 134                 wf_ad7417_adc_convert(pv, chan, raw, value);
 135
 136                 dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
 137                          " raw value: 0x%x, conv to: 0x%08x\n",
 138                          chan, sr->name, raw, *value);
 139
 140                 mutex_unlock(&pv->lock);
 141                 return 0;
 142
 143         error:
 144                 dev_dbg(&pv->i2c->dev,
 145                           "Error reading ADC, try %d...\n", i);
 146                 if (i < 9)
 147                         msleep(10);
 148         }
 149         mutex_unlock(&pv->lock);
 150         return -1;
 151 }
 152
 153 static void wf_ad7417_release(struct kref *ref)
 154 {
 155         struct wf_ad7417_priv *pv = container_of(ref,
 156                                                  struct wf_ad7417_priv, ref);
 157         kfree(pv);
 158 }
 159
 160 static void wf_ad7417_sensor_release(struct wf_sensor *sr)
 161 {
 162         struct wf_ad7417_priv *pv = sr->priv;
 163
 164         kfree(sr->name);
 165         kref_put(&pv->ref, wf_ad7417_release);
 166 }
 167
 168 static const struct wf_sensor_ops wf_ad7417_temp_ops = {
 169         .get_value      = wf_ad7417_temp_get,
 170         .release        = wf_ad7417_sensor_release,
 171         .owner          = THIS_MODULE,
 172 };
 173
 174 static const struct wf_sensor_ops wf_ad7417_adc_ops = {
 175         .get_value      = wf_ad7417_adc_get,
 176         .release        = wf_ad7417_sensor_release,
 177         .owner          = THIS_MODULE,
 178 };
 179
 180 static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
 181                                  int index, const char *name,
 182                                  const struct wf_sensor_ops *ops)
 183 {
 184         pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
 185         pv->sensors[index].priv = pv;
 186         pv->sensors[index].ops = ops;
 187         if (!wf_register_sensor(&pv->sensors[index]))
 188                 kref_get(&pv->ref);
 189 }
 190
 191 static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
 192 {
 193         int rc;
 194         u8 buf[2];
 195         u8 config = 0;
 196
 197         /*
 198          * Read ADC the configuration register and cache it. We
 199          * also make sure Config2 contains proper values, I've seen
 200          * cases where we got stale grabage in there, thus preventing
 201          * proper reading of conv. values
 202          */
 203
 204         /* Clear Config2 */
 205         buf[0] = 5;
 206         buf[1] = 0;
 207         i2c_master_send(pv->i2c, buf, 2);
 208
 209         /* Read & cache Config1 */
 210         buf[0] = 1;
 211         rc = i2c_master_send(pv->i2c, buf, 1);
 212         if (rc > 0) {
 213                 rc = i2c_master_recv(pv->i2c, buf, 1);
 214                 if (rc > 0) {
 215                         config = buf[0];
 216
 217                         dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
 218                                 config);
 219
 220                         /* Disable shutdown mode */
 221                         config &= 0xfe;
 222                         buf[0] = 1;
 223                         buf[1] = config;
 224                         rc = i2c_master_send(pv->i2c, buf, 2);
 225                 }
 226         }
 227         if (rc <= 0)
 228                 dev_err(&pv->i2c->dev, "Error reading ADC config\n");
 229
 230         pv->config = config;
 231 }
 232
 233 static int wf_ad7417_probe(struct i2c_client *client,
 234                            const struct i2c_device_id *id)
 235 {
 236         struct wf_ad7417_priv *pv;
 237         const struct mpu_data *mpu;
 238         const char *loc;
 239         int cpu_nr;
 240
 241         loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
 242         if (!loc) {
 243                 dev_warn(&client->dev, "Missing hwsensor-location property!\n");
 244                 return -ENXIO;
 245         }
 246
 247         /*
 248          * Identify which CPU we belong to by looking at the first entry
 249          * in the hwsensor-location list
 250          */
 251         if (!strncmp(loc, "CPU A", 5))
 252                 cpu_nr = 0;
 253         else if (!strncmp(loc, "CPU B", 5))
 254                 cpu_nr = 1;
 255         else {
 256                 pr_err("wf_ad7417: Can't identify location %s\n", loc);
 257                 return -ENXIO;
 258         }
 259         mpu = wf_get_mpu(cpu_nr);
 260         if (!mpu) {
 261                 dev_err(&client->dev, "Failed to retrieve MPU data\n");
 262                 return -ENXIO;
 263         }
 264
 265         pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
 266         if (pv == NULL)
 267                 return -ENODEV;
 268
 269         kref_init(&pv->ref);
 270         mutex_init(&pv->lock);
 271         pv->i2c = client;
 272         pv->cpu = cpu_nr;
 273         pv->mpu = mpu;
 274         dev_set_drvdata(&client->dev, pv);
 275
 276         /* Initialize the chip */
 277         wf_ad7417_init_chip(pv);
 278
 279         /*
 280          * We cannot rely on Apple device-tree giving us child
 281          * node with the names of the individual sensors so we
 282          * just hard code what we know about them
 283          */
 284         wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
 285         wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
 286         wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
 287         wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
 288         wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);
 289
 290         return 0;
 291 }
 292
 293 static int wf_ad7417_remove(struct i2c_client *client)
 294 {
 295         struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
 296         int i;
 297
 298         /* Mark client detached */
 299         pv->i2c = NULL;
 300
 301         /* Release sensor */
 302         for (i = 0; i < 5; i++)
 303                 wf_unregister_sensor(&pv->sensors[i]);
 304
 305         kref_put(&pv->ref, wf_ad7417_release);
 306
 307         return 0;
 308 }
 309
 310 static const struct i2c_device_id wf_ad7417_id[] = {
 311         { "MAC,ad7417", 0 },
 312         { }
 313 };
 314 MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);
 315
 316 static struct i2c_driver wf_ad7417_driver = {
 317         .driver = {
 318                 .name   = "wf_ad7417",
 319         },
 320         .probe          = wf_ad7417_probe,
 321         .remove         = wf_ad7417_remove,
 322         .id_table       = wf_ad7417_id,
 323 };
 324
 325 static int wf_ad7417_init(void)
 326 {
 327         /* This is only supported on these machines */
 328         if (!of_machine_is_compatible("PowerMac7,2") &&
 329             !of_machine_is_compatible("PowerMac7,3") &&
 330             !of_machine_is_compatible("RackMac3,1"))
 331                 return -ENODEV;
 332
 333         return i2c_add_driver(&wf_ad7417_driver);
 334 }
 335
 336 static void wf_ad7417_exit(void)
 337 {
 338         i2c_del_driver(&wf_ad7417_driver);
 339 }
 340
 341 module_init(wf_ad7417_init);
 342 module_exit(wf_ad7417_exit);
 343
 344 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 345 MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
 346 MODULE_LICENSE("GPL");
 347