1/*
  2 * Windfarm PowerMac thermal control. LM87 sensor
  3 *
  4 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
  5 *
  6 * Released under the term of the GNU GPL v2.
  7 *
  8 */
  9
 10#include <linux/types.h>
 11#include <linux/errno.h>
 12#include <linux/kernel.h>
 13#include <linux/delay.h>
 14#include <linux/slab.h>
 15#include <linux/init.h>
 16#include <linux/wait.h>
 17#include <linux/i2c.h>
 18#include <asm/prom.h>
 19#include <asm/machdep.h>
 20#include <asm/io.h>
 21#include <asm/sections.h>
 22#include <asm/pmac_low_i2c.h>
 23
 24#include "windfarm.h"
 25
 26#define VERSION "1.0"
 27
 28#undef DEBUG
 29
 30#ifdef DEBUG
 31#define DBG(args...)	printk(args)
 32#else
 33#define DBG(args...)	do { } while(0)
 34#endif
 35
 36struct wf_lm87_sensor {
 37	struct i2c_client	*i2c;
 38	struct wf_sensor	sens;
 39};
 40#define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)
 41
 42
 43static int wf_lm87_read_reg(struct i2c_client *chip, int reg)
 44{
 45	int rc, tries = 0;
 46	u8 buf;
 47
 48	for (;;) {
 49		/* Set address */
 50		buf = (u8)reg;
 51		rc = i2c_master_send(chip, &buf, 1);
 52		if (rc <= 0)
 53			goto error;
 54		rc = i2c_master_recv(chip, &buf, 1);
 55		if (rc <= 0)
 56			goto error;
 57		return (int)buf;
 58	error:
 59		DBG("wf_lm87: Error reading LM87, retrying...\n");
 60		if (++tries > 10) {
 61			printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");
 62			return -EIO;
 63		}
 64		msleep(10);
 65	}
 66}
 67
 68static int wf_lm87_get(struct wf_sensor *sr, s32 *value)
 69{
 70	struct wf_lm87_sensor *lm = sr->priv;
 71	s32 temp;
 72
 73	if (lm->i2c == NULL)
 74		return -ENODEV;
 75
 76#define LM87_INT_TEMP		0x27
 77
 78	/* Read temperature register */
 79	temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);
 80	if (temp < 0)
 81		return temp;
 82	*value = temp << 16;
 83
 84	return 0;
 85}
 86
 87static void wf_lm87_release(struct wf_sensor *sr)
 88{
 89	struct wf_lm87_sensor *lm = wf_to_lm87(sr);
 90
 91	kfree(lm);
 92}
 93
 94static struct wf_sensor_ops wf_lm87_ops = {
 95	.get_value	= wf_lm87_get,
 96	.release	= wf_lm87_release,
 97	.owner		= THIS_MODULE,
 98};
 99
100static int wf_lm87_probe(struct i2c_client *client,
101			 const struct i2c_device_id *id)
102{	
103	struct wf_lm87_sensor *lm;
104	const char *name = NULL, *loc;
105	struct device_node *np = NULL;
106	int rc;
107
108	/*
109	 * The lm87 contains a whole pile of sensors, additionally,
110	 * the Xserve G5 has several lm87's. However, for now we only
111	 * care about the internal temperature sensor
112	 */
113	while ((np = of_get_next_child(client->dev.of_node, np)) != NULL) {
114		if (strcmp(np->name, "int-temp"))
115			continue;
116		loc = of_get_property(np, "location", NULL);
117		if (!loc)
118			continue;
119		if (strstr(loc, "DIMM"))
120			name = "dimms-temp";
121		else if (strstr(loc, "Processors"))
122			name = "between-cpus-temp";
123		if (name) {
124			of_node_put(np);
125			break;
126		}
127	}
128	if (!name) {
129		pr_warning("wf_lm87: Unsupported sensor %s\n",
130			   client->dev.of_node->full_name);
131		return -ENODEV;
132	}
133
134	lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
135	if (lm == NULL)
136		return -ENODEV;
137
138	lm->i2c = client;
139	lm->sens.name = name;
140	lm->sens.ops = &wf_lm87_ops;
141	lm->sens.priv = lm;
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
150static int wf_lm87_remove(struct i2c_client *client)
151{
152	struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
153
154	DBG("wf_lm87: i2c detatch called for %s\n", lm->sens.name);
155
156	/* Mark client detached */
157	lm->i2c = NULL;
158
159	/* release sensor */
160	wf_unregister_sensor(&lm->sens);
161
162	return 0;
163}
164
165static const struct i2c_device_id wf_lm87_id[] = {
166	{ "MAC,lm87cimt", 0 },
167	{ }
168};
169MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
170
171static struct i2c_driver wf_lm87_driver = {
172	.driver = {
173		.name	= "wf_lm87",
174	},
175	.probe		= wf_lm87_probe,
176	.remove		= wf_lm87_remove,
177	.id_table	= wf_lm87_id,
178};
179
180static int __init wf_lm87_sensor_init(void)
181{
182	/* We only support this on the Xserve */
183	if (!of_machine_is_compatible("RackMac3,1"))
184		return -ENODEV;
185
186	return i2c_add_driver(&wf_lm87_driver);
187}
188
189static void __exit wf_lm87_sensor_exit(void)
190{
191	i2c_del_driver(&wf_lm87_driver);
192}
193
194
195module_init(wf_lm87_sensor_init);
196module_exit(wf_lm87_sensor_exit);
197
198MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
199MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
200MODULE_LICENSE("GPL");
201