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
34struct 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
41static 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
66static 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
85static 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
92static 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
98static 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
148static 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
161static const struct i2c_device_id wf_lm87_id[] = {
162	{ "MAC,lm87cimt", 0 },
163	{ }
164};
165MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
166
167static const struct of_device_id wf_lm87_of_id[] = {
168	{ .compatible = "lm87cimt", },
169	{ }
170};
171MODULE_DEVICE_TABLE(of, wf_lm87_of_id);
172
173static 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
183static 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
192static void __exit wf_lm87_sensor_exit(void)
193{
194	i2c_del_driver(&wf_lm87_driver);
195}
196
197
198module_init(wf_lm87_sensor_init);
199module_exit(wf_lm87_sensor_exit);
200
201MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
202MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
203MODULE_LICENSE("GPL");
204
205