drivers/macintosh/windfarm_lm87_sensor.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Windfarm PowerMac thermal control. LM87 sensor
   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
  17 #include <asm/machdep.h>
  18 #include <asm/io.h>
  19 #include <asm/sections.h>
  20 #include <asm/pmac_low_i2c.h>
  21
  22 #include "windfarm.h"
  23
  24 #define VERSION "1.0"
  25
  26 #undef DEBUG
  27
  28 #ifdef DEBUG
  29 #define DBG(args...)    printk(args)
  30 #else
  31 #define DBG(args...)    do { } while(0)
  32 #endif
  33
  34 struct wf_lm87_sensor {
  35         struct i2c_client       *i2c;
  36         struct wf_sensor        sens;
  37 };
  38 #define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)
  39
  40
  41 static int wf_lm87_read_reg(struct i2c_client *chip, int reg)
  42 {
  43         int rc, tries = 0;
  44         u8 buf;
  45
  46         for (;;) {
  47                 /* Set address */
  48                 buf = (u8)reg;
  49                 rc = i2c_master_send(chip, &buf, 1);
  50                 if (rc <= 0)
  51                         goto error;
  52                 rc = i2c_master_recv(chip, &buf, 1);
  53                 if (rc <= 0)
  54                         goto error;
  55                 return (int)buf;
  56         error:
  57                 DBG("wf_lm87: Error reading LM87, retrying...\n");
  58                 if (++tries > 10) {
  59                         printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");
  60                         return -EIO;
  61                 }
  62                 msleep(10);
  63         }
  64 }
  65
  66 static int wf_lm87_get(struct wf_sensor *sr, s32 *value)
  67 {
  68         struct wf_lm87_sensor *lm = sr->priv;
  69         s32 temp;
  70
  71         if (lm->i2c == NULL)
  72                 return -ENODEV;
  73
  74 #define LM87_INT_TEMP           0x27
  75
  76         /* Read temperature register */
  77         temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);
  78         if (temp < 0)
  79                 return temp;
  80         *value = temp << 16;
  81
  82         return 0;
  83 }
  84
  85 static void wf_lm87_release(struct wf_sensor *sr)
  86 {
  87         struct wf_lm87_sensor *lm = wf_to_lm87(sr);
  88
  89         kfree(lm);
  90 }
  91
  92 static const struct wf_sensor_ops wf_lm87_ops = {
  93         .get_value      = wf_lm87_get,
  94         .release        = wf_lm87_release,
  95         .owner          = THIS_MODULE,
  96 };
  97
  98 static int wf_lm87_probe(struct i2c_client *client)
  99 {
 100         struct wf_lm87_sensor *lm;
 101         const char *name = NULL, *loc;
 102         struct device_node *np = NULL;
 103         int rc;
 104
 105         /*
 106          * The lm87 contains a whole pile of sensors, additionally,
 107          * the Xserve G5 has several lm87's. However, for now we only
 108          * care about the internal temperature sensor
 109          */
 110         for_each_child_of_node(client->dev.of_node, np) {
 111                 if (!of_node_name_eq(np, "int-temp"))
 112                         continue;
 113                 loc = of_get_property(np, "location", NULL);
 114                 if (!loc)
 115                         continue;
 116                 if (strstr(loc, "DIMM"))
 117                         name = "dimms-temp";
 118                 else if (strstr(loc, "Processors"))
 119                         name = "between-cpus-temp";
 120                 if (name) {
 121                         of_node_put(np);
 122                         break;
 123                 }
 124         }
 125         if (!name) {
 126                 pr_warn("wf_lm87: Unsupported sensor %pOF\n",
 127                         client->dev.of_node);
 128                 return -ENODEV;
 129         }
 130
 131         lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
 132         if (lm == NULL)
 133                 return -ENODEV;
 134
 135         lm->i2c = client;
 136         lm->sens.name = name;
 137         lm->sens.ops = &wf_lm87_ops;
 138         lm->sens.priv = lm;
 139         i2c_set_clientdata(client, lm);
 140
 141         rc = wf_register_sensor(&lm->sens);
 142         if (rc)
 143                 kfree(lm);
 144         return rc;
 145 }
 146
 147 static void wf_lm87_remove(struct i2c_client *client)
 148 {
 149         struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
 150
 151         /* Mark client detached */
 152         lm->i2c = NULL;
 153
 154         /* release sensor */
 155         wf_unregister_sensor(&lm->sens);
 156 }
 157
 158 static const struct i2c_device_id wf_lm87_id[] = {
 159         { "MAC,lm87cimt", 0 },
 160         { }
 161 };
 162 MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
 163
 164 static const struct of_device_id wf_lm87_of_id[] = {
 165         { .compatible = "lm87cimt", },
 166         { }
 167 };
 168 MODULE_DEVICE_TABLE(of, wf_lm87_of_id);
 169
 170 static struct i2c_driver wf_lm87_driver = {
 171         .driver = {
 172                 .name   = "wf_lm87",
 173                 .of_match_table = wf_lm87_of_id,
 174         },
 175         .probe          = wf_lm87_probe,
 176         .remove         = wf_lm87_remove,
 177         .id_table       = wf_lm87_id,
 178 };
 179
 180 static int __init wf_lm87_sensor_init(void)
 181 {
 182         /* We only support this on the Xserve */
 183         if (!of_machine_is_compatible("RackMac3,1"))
 184                 return -ENODEV;
 185
 186         return i2c_add_driver(&wf_lm87_driver);
 187 }
 188
 189 static void __exit wf_lm87_sensor_exit(void)
 190 {
 191         i2c_del_driver(&wf_lm87_driver);
 192 }
 193
 194
 195 module_init(wf_lm87_sensor_init);
 196 module_exit(wf_lm87_sensor_exit);
 197
 198 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 199 MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
 200 MODULE_LICENSE("GPL");
 201