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 #include <asm/prom.h>
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
wf_lm87_read_reg(struct i2c_client * chip,int reg)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
wf_lm87_get(struct wf_sensor * sr,s32 * value)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
wf_lm87_release(struct wf_sensor * sr)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
wf_lm87_probe(struct i2c_client * client,const struct i2c_device_id * id)98 static int wf_lm87_probe(struct i2c_client *client,
99 const struct i2c_device_id *id)
100 {
101 struct wf_lm87_sensor *lm;
102 const char *name = NULL, *loc;
103 struct device_node *np = NULL;
104 int rc;
105
106 /*
107 * The lm87 contains a whole pile of sensors, additionally,
108 * the Xserve G5 has several lm87's. However, for now we only
109 * care about the internal temperature sensor
110 */
111 for_each_child_of_node(client->dev.of_node, np) {
112 if (!of_node_name_eq(np, "int-temp"))
113 continue;
114 loc = of_get_property(np, "location", NULL);
115 if (!loc)
116 continue;
117 if (strstr(loc, "DIMM"))
118 name = "dimms-temp";
119 else if (strstr(loc, "Processors"))
120 name = "between-cpus-temp";
121 if (name) {
122 of_node_put(np);
123 break;
124 }
125 }
126 if (!name) {
127 pr_warn("wf_lm87: Unsupported sensor %pOF\n",
128 client->dev.of_node);
129 return -ENODEV;
130 }
131
132 lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
133 if (lm == NULL)
134 return -ENODEV;
135
136 lm->i2c = client;
137 lm->sens.name = name;
138 lm->sens.ops = &wf_lm87_ops;
139 lm->sens.priv = lm;
140 i2c_set_clientdata(client, lm);
141
142 rc = wf_register_sensor(&lm->sens);
143 if (rc)
144 kfree(lm);
145 return rc;
146 }
147
wf_lm87_remove(struct i2c_client * client)148 static int wf_lm87_remove(struct i2c_client *client)
149 {
150 struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
151
152 /* Mark client detached */
153 lm->i2c = NULL;
154
155 /* release sensor */
156 wf_unregister_sensor(&lm->sens);
157
158 return 0;
159 }
160
161 static const struct i2c_device_id wf_lm87_id[] = {
162 { "MAC,lm87cimt", 0 },
163 { }
164 };
165 MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
166
167 static const struct of_device_id wf_lm87_of_id[] = {
168 { .compatible = "lm87cimt", },
169 { }
170 };
171 MODULE_DEVICE_TABLE(of, wf_lm87_of_id);
172
173 static struct i2c_driver wf_lm87_driver = {
174 .driver = {
175 .name = "wf_lm87",
176 .of_match_table = wf_lm87_of_id,
177 },
178 .probe = wf_lm87_probe,
179 .remove = wf_lm87_remove,
180 .id_table = wf_lm87_id,
181 };
182
wf_lm87_sensor_init(void)183 static int __init wf_lm87_sensor_init(void)
184 {
185 /* We only support this on the Xserve */
186 if (!of_machine_is_compatible("RackMac3,1"))
187 return -ENODEV;
188
189 return i2c_add_driver(&wf_lm87_driver);
190 }
191
wf_lm87_sensor_exit(void)192 static void __exit wf_lm87_sensor_exit(void)
193 {
194 i2c_del_driver(&wf_lm87_driver);
195 }
196
197
198 module_init(wf_lm87_sensor_init);
199 module_exit(wf_lm87_sensor_exit);
200
201 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
202 MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
203 MODULE_LICENSE("GPL");
204
205
