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(client: 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(objp: 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(node: client->dev.of_node, name: "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(size: 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, data: max); |
99 | |
100 | rc = wf_register_sensor(sr: &max->sens); |
101 | if (rc) |
102 | kfree(objp: 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(sr: &max->sens); |
112 | } |
113 | |
114 | static const struct i2c_device_id wf_max6690_id[] = { |
115 | { "MAC,max6690" , 0 }, |
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" ); |
141 | |