1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Windfarm PowerMac thermal control. LM75 sensor
4  *
5  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
6  *                    <benh@kernel.crashing.org>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/kernel.h>
12 #include <linux/delay.h>
13 #include <linux/slab.h>
14 #include <linux/init.h>
15 #include <linux/wait.h>
16 #include <linux/i2c.h>
17 #include <linux/of_device.h>
18 #include <asm/machdep.h>
19 #include <asm/io.h>
20 #include <asm/sections.h>
21 #include <asm/pmac_low_i2c.h>
22 
23 #include "windfarm.h"
24 
25 #define VERSION "1.0"
26 
27 #undef DEBUG
28 
29 #ifdef DEBUG
30 #define DBG(args...)	printk(args)
31 #else
32 #define DBG(args...)	do { } while(0)
33 #endif
34 
35 struct wf_lm75_sensor {
36 	int			ds1775 : 1;
37 	int			inited : 1;
38 	struct i2c_client	*i2c;
39 	struct wf_sensor	sens;
40 };
41 #define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
42 
43 static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
44 {
45 	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
46 	s32 data;
47 
48 	if (lm->i2c == NULL)
49 		return -ENODEV;
50 
51 	/* Init chip if necessary */
52 	if (!lm->inited) {
53 		u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
54 
55 		DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
56 		    sr->name, cfg);
57 
58 		/* clear shutdown bit, keep other settings as left by
59 		 * the firmware for now
60 		 */
61 		cfg_new = cfg & ~0x01;
62 		i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
63 		lm->inited = 1;
64 
65 		/* If we just powered it up, let's wait 200 ms */
66 		msleep(200);
67 	}
68 
69 	/* Read temperature register */
70 	data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
71 	data <<= 8;
72 	*value = data;
73 
74 	return 0;
75 }
76 
77 static void wf_lm75_release(struct wf_sensor *sr)
78 {
79 	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
80 
81 	kfree(lm);
82 }
83 
84 static const struct wf_sensor_ops wf_lm75_ops = {
85 	.get_value	= wf_lm75_get,
86 	.release	= wf_lm75_release,
87 	.owner		= THIS_MODULE,
88 };
89 
90 static int wf_lm75_probe(struct i2c_client *client,
91 			 const struct i2c_device_id *id)
92 {
93 	struct wf_lm75_sensor *lm;
94 	int rc, ds1775;
95 	const char *name, *loc;
96 
97 	if (id)
98 		ds1775 = id->driver_data;
99 	else
100 		ds1775 = !!of_device_get_match_data(&client->dev);
101 
102 	DBG("wf_lm75: creating  %s device at address 0x%02x\n",
103 	    ds1775 ? "ds1775" : "lm75", client->addr);
104 
105 	loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
106 	if (!loc) {
107 		dev_warn(&client->dev, "Missing hwsensor-location property!\n");
108 		return -ENXIO;
109 	}
110 
111 	/* Usual rant about sensor names not beeing very consistent in
112 	 * the device-tree, oh well ...
113 	 * Add more entries below as you deal with more setups
114 	 */
115 	if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
116 		name = "hd-temp";
117 	else if (!strcmp(loc, "Incoming Air Temp"))
118 		name = "incoming-air-temp";
119 	else if (!strcmp(loc, "ODD Temp"))
120 		name = "optical-drive-temp";
121 	else if (!strcmp(loc, "HD Temp"))
122 		name = "hard-drive-temp";
123 	else if (!strcmp(loc, "PCI SLOTS"))
124 		name = "slots-temp";
125 	else if (!strcmp(loc, "CPU A INLET"))
126 		name = "cpu-inlet-temp-0";
127 	else if (!strcmp(loc, "CPU B INLET"))
128 		name = "cpu-inlet-temp-1";
129 	else
130 		return -ENXIO;
131 
132 
133 	lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
134 	if (lm == NULL)
135 		return -ENODEV;
136 
137 	lm->inited = 0;
138 	lm->ds1775 = ds1775;
139 	lm->i2c = client;
140 	lm->sens.name = name;
141 	lm->sens.ops = &wf_lm75_ops;
142 	i2c_set_clientdata(client, lm);
143 
144 	rc = wf_register_sensor(&lm->sens);
145 	if (rc)
146 		kfree(lm);
147 	return rc;
148 }
149 
150 static int wf_lm75_remove(struct i2c_client *client)
151 {
152 	struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
153 
154 	/* Mark client detached */
155 	lm->i2c = NULL;
156 
157 	/* release sensor */
158 	wf_unregister_sensor(&lm->sens);
159 
160 	return 0;
161 }
162 
163 static const struct i2c_device_id wf_lm75_id[] = {
164 	{ "MAC,lm75", 0 },
165 	{ "MAC,ds1775", 1 },
166 	{ }
167 };
168 MODULE_DEVICE_TABLE(i2c, wf_lm75_id);
169 
170 static const struct of_device_id wf_lm75_of_id[] = {
171 	{ .compatible = "lm75", .data = (void *)0},
172 	{ .compatible = "ds1775", .data = (void *)1 },
173 	{ }
174 };
175 MODULE_DEVICE_TABLE(of, wf_lm75_of_id);
176 
177 static struct i2c_driver wf_lm75_driver = {
178 	.driver = {
179 		.name	= "wf_lm75",
180 		.of_match_table = wf_lm75_of_id,
181 	},
182 	.probe		= wf_lm75_probe,
183 	.remove		= wf_lm75_remove,
184 	.id_table	= wf_lm75_id,
185 };
186 
187 module_i2c_driver(wf_lm75_driver);
188 
189 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
190 MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
191 MODULE_LICENSE("GPL");
192 
193