drivers/macintosh/windfarm_ad7417_sensor.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Windfarm PowerMac thermal control. AD7417 sensors
   4  *
   5  * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/errno.h>
  10 #include <linux/kernel.h>
  11 #include <linux/delay.h>
  12 #include <linux/slab.h>
  13 #include <linux/init.h>
  14 #include <linux/wait.h>
  15 #include <linux/i2c.h>
  16 #include <asm/prom.h>
  17 #include <asm/machdep.h>
  18 #include <asm/io.h>
  19 #include <asm/sections.h>
  20
  21 #include "windfarm.h"
  22 #include "windfarm_mpu.h"
  23
  24 #define VERSION "1.0"
  25
  26 struct wf_ad7417_priv {
  27         struct kref             ref;
  28         struct i2c_client       *i2c;
  29         u8                      config;
  30         u8                      cpu;
  31         const struct mpu_data   *mpu;
  32         struct wf_sensor        sensors[5];
  33         struct mutex            lock;
  34 };
  35
  36 static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
  37 {
  38         struct wf_ad7417_priv *pv = sr->priv;
  39         u8 buf[2];
  40         s16 raw;
  41         int rc;
  42
  43         *value = 0;
  44         mutex_lock(&pv->lock);
  45
  46         /* Read temp register */
  47         buf[0] = 0;
  48         rc = i2c_master_send(pv->i2c, buf, 1);
  49         if (rc < 0)
  50                 goto error;
  51         rc = i2c_master_recv(pv->i2c, buf, 2);
  52         if (rc < 0)
  53                 goto error;
  54
  55         /* Read a a 16-bit signed value */
  56         raw = be16_to_cpup((__le16 *)buf);
  57
  58         /* Convert 8.8-bit to 16.16 fixed point */
  59         *value = ((s32)raw) << 8;
  60
  61         mutex_unlock(&pv->lock);
  62         return 0;
  63
  64 error:
  65         mutex_unlock(&pv->lock);
  66         return -1;
  67 }
  68
  69 /*
  70  * Scaling factors for the AD7417 ADC converters (except
  71  * for the CPU diode which is obtained from the EEPROM).
  72  * Those values are obtained from the property list of
  73  * the darwin driver
  74  */
  75 #define ADC_12V_CURRENT_SCALE   0x0320  /* _AD2 */
  76 #define ADC_CPU_VOLTAGE_SCALE   0x00a0  /* _AD3 */
  77 #define ADC_CPU_CURRENT_SCALE   0x1f40  /* _AD4 */
  78
  79 static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
  80                                   int chan, s32 raw, s32 *value)
  81 {
  82         switch(chan) {
  83         case 1: /* Diode */
  84                 *value = (raw * (s32)pv->mpu->mdiode +
  85                         ((s32)pv->mpu->bdiode << 12)) >> 2;
  86                 break;
  87         case 2: /* 12v current */
  88                 *value = raw * ADC_12V_CURRENT_SCALE;
  89                 break;
  90         case 3: /* core voltage */
  91                 *value = raw * ADC_CPU_VOLTAGE_SCALE;
  92                 break;
  93         case 4: /* core current */
  94                 *value = raw * ADC_CPU_CURRENT_SCALE;
  95                 break;
  96         }
  97 }
  98
  99 static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
 100 {
 101         struct wf_ad7417_priv *pv = sr->priv;
 102         int chan = sr - pv->sensors;
 103         int i, rc;
 104         u8 buf[2];
 105         u16 raw;
 106
 107         *value = 0;
 108         mutex_lock(&pv->lock);
 109         for (i = 0; i < 10; i++) {
 110                 /* Set channel */
 111                 buf[0] = 1;
 112                 buf[1] = (pv->config & 0x1f) | (chan << 5);
 113                 rc = i2c_master_send(pv->i2c, buf, 2);
 114                 if (rc < 0)
 115                         goto error;
 116
 117                 /* Wait for conversion */
 118                 msleep(1);
 119
 120                 /* Switch to data register */
 121                 buf[0] = 4;
 122                 rc = i2c_master_send(pv->i2c, buf, 1);
 123                 if (rc < 0)
 124                         goto error;
 125
 126                 /* Read result */
 127                 rc = i2c_master_recv(pv->i2c, buf, 2);
 128                 if (rc < 0)
 129                         goto error;
 130
 131                 /* Read a a 16-bit signed value */
 132                 raw = be16_to_cpup((__le16 *)buf) >> 6;
 133                 wf_ad7417_adc_convert(pv, chan, raw, value);
 134
 135                 dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
 136                          " raw value: 0x%x, conv to: 0x%08x\n",
 137                          chan, sr->name, raw, *value);
 138
 139                 mutex_unlock(&pv->lock);
 140                 return 0;
 141
 142         error:
 143                 dev_dbg(&pv->i2c->dev,
 144                           "Error reading ADC, try %d...\n", i);
 145                 if (i < 9)
 146                         msleep(10);
 147         }
 148         mutex_unlock(&pv->lock);
 149         return -1;
 150 }
 151
 152 static void wf_ad7417_release(struct kref *ref)
 153 {
 154         struct wf_ad7417_priv *pv = container_of(ref,
 155                                                  struct wf_ad7417_priv, ref);
 156         kfree(pv);
 157 }
 158
 159 static void wf_ad7417_sensor_release(struct wf_sensor *sr)
 160 {
 161         struct wf_ad7417_priv *pv = sr->priv;
 162
 163         kfree(sr->name);
 164         kref_put(&pv->ref, wf_ad7417_release);
 165 }
 166
 167 static const struct wf_sensor_ops wf_ad7417_temp_ops = {
 168         .get_value      = wf_ad7417_temp_get,
 169         .release        = wf_ad7417_sensor_release,
 170         .owner          = THIS_MODULE,
 171 };
 172
 173 static const struct wf_sensor_ops wf_ad7417_adc_ops = {
 174         .get_value      = wf_ad7417_adc_get,
 175         .release        = wf_ad7417_sensor_release,
 176         .owner          = THIS_MODULE,
 177 };
 178
 179 static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
 180                                  int index, const char *name,
 181                                  const struct wf_sensor_ops *ops)
 182 {
 183         pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
 184         pv->sensors[index].priv = pv;
 185         pv->sensors[index].ops = ops;
 186         if (!wf_register_sensor(&pv->sensors[index]))
 187                 kref_get(&pv->ref);
 188 }
 189
 190 static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
 191 {
 192         int rc;
 193         u8 buf[2];
 194         u8 config = 0;
 195
 196         /*
 197          * Read ADC the configuration register and cache it. We
 198          * also make sure Config2 contains proper values, I've seen
 199          * cases where we got stale grabage in there, thus preventing
 200          * proper reading of conv. values
 201          */
 202
 203         /* Clear Config2 */
 204         buf[0] = 5;
 205         buf[1] = 0;
 206         i2c_master_send(pv->i2c, buf, 2);
 207
 208         /* Read & cache Config1 */
 209         buf[0] = 1;
 210         rc = i2c_master_send(pv->i2c, buf, 1);
 211         if (rc > 0) {
 212                 rc = i2c_master_recv(pv->i2c, buf, 1);
 213                 if (rc > 0) {
 214                         config = buf[0];
 215
 216                         dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
 217                                 config);
 218
 219                         /* Disable shutdown mode */
 220                         config &= 0xfe;
 221                         buf[0] = 1;
 222                         buf[1] = config;
 223                         rc = i2c_master_send(pv->i2c, buf, 2);
 224                 }
 225         }
 226         if (rc <= 0)
 227                 dev_err(&pv->i2c->dev, "Error reading ADC config\n");
 228
 229         pv->config = config;
 230 }
 231
 232 static int wf_ad7417_probe(struct i2c_client *client,
 233                            const struct i2c_device_id *id)
 234 {
 235         struct wf_ad7417_priv *pv;
 236         const struct mpu_data *mpu;
 237         const char *loc;
 238         int cpu_nr;
 239
 240         loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
 241         if (!loc) {
 242                 dev_warn(&client->dev, "Missing hwsensor-location property!\n");
 243                 return -ENXIO;
 244         }
 245
 246         /*
 247          * Identify which CPU we belong to by looking at the first entry
 248          * in the hwsensor-location list
 249          */
 250         if (!strncmp(loc, "CPU A", 5))
 251                 cpu_nr = 0;
 252         else if (!strncmp(loc, "CPU B", 5))
 253                 cpu_nr = 1;
 254         else {
 255                 pr_err("wf_ad7417: Can't identify location %s\n", loc);
 256                 return -ENXIO;
 257         }
 258         mpu = wf_get_mpu(cpu_nr);
 259         if (!mpu) {
 260                 dev_err(&client->dev, "Failed to retrieve MPU data\n");
 261                 return -ENXIO;
 262         }
 263
 264         pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
 265         if (pv == NULL)
 266                 return -ENODEV;
 267
 268         kref_init(&pv->ref);
 269         mutex_init(&pv->lock);
 270         pv->i2c = client;
 271         pv->cpu = cpu_nr;
 272         pv->mpu = mpu;
 273         dev_set_drvdata(&client->dev, pv);
 274
 275         /* Initialize the chip */
 276         wf_ad7417_init_chip(pv);
 277
 278         /*
 279          * We cannot rely on Apple device-tree giving us child
 280          * node with the names of the individual sensors so we
 281          * just hard code what we know about them
 282          */
 283         wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
 284         wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
 285         wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
 286         wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
 287         wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);
 288
 289         return 0;
 290 }
 291
 292 static int wf_ad7417_remove(struct i2c_client *client)
 293 {
 294         struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
 295         int i;
 296
 297         /* Mark client detached */
 298         pv->i2c = NULL;
 299
 300         /* Release sensor */
 301         for (i = 0; i < 5; i++)
 302                 wf_unregister_sensor(&pv->sensors[i]);
 303
 304         kref_put(&pv->ref, wf_ad7417_release);
 305
 306         return 0;
 307 }
 308
 309 static const struct i2c_device_id wf_ad7417_id[] = {
 310         { "MAC,ad7417", 0 },
 311         { }
 312 };
 313 MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);
 314
 315 static struct i2c_driver wf_ad7417_driver = {
 316         .driver = {
 317                 .name   = "wf_ad7417",
 318         },
 319         .probe          = wf_ad7417_probe,
 320         .remove         = wf_ad7417_remove,
 321         .id_table       = wf_ad7417_id,
 322 };
 323
 324 static int wf_ad7417_init(void)
 325 {
 326         /* This is only supported on these machines */
 327         if (!of_machine_is_compatible("PowerMac7,2") &&
 328             !of_machine_is_compatible("PowerMac7,3") &&
 329             !of_machine_is_compatible("RackMac3,1"))
 330                 return -ENODEV;
 331
 332         return i2c_add_driver(&wf_ad7417_driver);
 333 }
 334
 335 static void wf_ad7417_exit(void)
 336 {
 337         i2c_del_driver(&wf_ad7417_driver);
 338 }
 339
 340 module_init(wf_ad7417_init);
 341 module_exit(wf_ad7417_exit);
 342
 343 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 344 MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
 345 MODULE_LICENSE("GPL");
 346