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 
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 			 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 
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 
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 
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