drivers/macintosh/windfarm_max6690_sensor.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Windfarm PowerMac thermal control.  MAX6690 sensor.
   4  *
   5  * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
   6  */
   7 #include <linux/types.h>
   8 #include <linux/errno.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/slab.h>
  12 #include <linux/i2c.h>
  13
  14 #include <asm/pmac_low_i2c.h>
  15
  16 #include "windfarm.h"
  17
  18 #define VERSION "1.0"
  19
  20 /* This currently only exports the external temperature sensor,
  21    since that's all the control loops need. */
  22
  23 /* Some MAX6690 register numbers */
  24 #define MAX6690_INTERNAL_TEMP   0
  25 #define MAX6690_EXTERNAL_TEMP   1
  26
  27 struct wf_6690_sensor {
  28         struct i2c_client       *i2c;
  29         struct wf_sensor        sens;
  30 };
  31
  32 #define wf_to_6690(x)   container_of((x), struct wf_6690_sensor, sens)
  33
  34 static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
  35 {
  36         struct wf_6690_sensor *max = wf_to_6690(sr);
  37         s32 data;
  38
  39         if (max->i2c == NULL)
  40                 return -ENODEV;
  41
  42         /* chip gets initialized by firmware */
  43         data = i2c_smbus_read_byte_data(max->i2c, MAX6690_EXTERNAL_TEMP);
  44         if (data < 0)
  45                 return data;
  46         *value = data << 16;
  47         return 0;
  48 }
  49
  50 static void wf_max6690_release(struct wf_sensor *sr)
  51 {
  52         struct wf_6690_sensor *max = wf_to_6690(sr);
  53
  54         kfree(max);
  55 }
  56
  57 static const struct wf_sensor_ops wf_max6690_ops = {
  58         .get_value      = wf_max6690_get,
  59         .release        = wf_max6690_release,
  60         .owner          = THIS_MODULE,
  61 };
  62
  63 static int wf_max6690_probe(struct i2c_client *client)
  64 {
  65         const char *name, *loc;
  66         struct wf_6690_sensor *max;
  67         int rc;
  68
  69         loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
  70         if (!loc) {
  71                 dev_warn(&client->dev, "Missing hwsensor-location property!\n");
  72                 return -ENXIO;
  73         }
  74
  75         /*
  76          * We only expose the external temperature register for
  77          * now as this is all we need for our control loops
  78          */
  79         if (!strcmp(loc, "BACKSIDE") || !strcmp(loc, "SYS CTRLR AMBIENT"))
  80                 name = "backside-temp";
  81         else if (!strcmp(loc, "NB Ambient"))
  82                 name = "north-bridge-temp";
  83         else if (!strcmp(loc, "GPU Ambient"))
  84                 name = "gpu-temp";
  85         else
  86                 return -ENXIO;
  87
  88         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  89         if (max == NULL) {
  90                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
  91                        "no memory\n");
  92                 return -ENOMEM;
  93         }
  94
  95         max->i2c = client;
  96         max->sens.name = name;
  97         max->sens.ops = &wf_max6690_ops;
  98         i2c_set_clientdata(client, max);
  99
 100         rc = wf_register_sensor(&max->sens);
 101         if (rc)
 102                 kfree(max);
 103         return rc;
 104 }
 105
 106 static void wf_max6690_remove(struct i2c_client *client)
 107 {
 108         struct wf_6690_sensor *max = i2c_get_clientdata(client);
 109
 110         max->i2c = NULL;
 111         wf_unregister_sensor(&max->sens);
 112 }
 113
 114 static const struct i2c_device_id wf_max6690_id[] = {
 115         { "MAC,max6690" },
 116         { }
 117 };
 118 MODULE_DEVICE_TABLE(i2c, wf_max6690_id);
 119
 120 static const struct of_device_id wf_max6690_of_id[] = {
 121         { .compatible = "max6690", },
 122         { }
 123 };
 124 MODULE_DEVICE_TABLE(of, wf_max6690_of_id);
 125
 126 static struct i2c_driver wf_max6690_driver = {
 127         .driver = {
 128                 .name           = "wf_max6690",
 129                 .of_match_table = wf_max6690_of_id,
 130         },
 131         .probe          = wf_max6690_probe,
 132         .remove         = wf_max6690_remove,
 133         .id_table       = wf_max6690_id,
 134 };
 135
 136 module_i2c_driver(wf_max6690_driver);
 137
 138 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 139 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 140 MODULE_LICENSE("GPL");