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
 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{	
100	struct wf_lm87_sensor *lm;
101	const char *name = NULL, *loc;
102	struct device_node *np = NULL;
103	int rc;
104
105	/*
106	 * The lm87 contains a whole pile of sensors, additionally,
107	 * the Xserve G5 has several lm87's. However, for now we only
108	 * care about the internal temperature sensor
109	 */
110	for_each_child_of_node(client->dev.of_node, np) {
111		if (!of_node_name_eq(np, "int-temp"))
112			continue;
113		loc = of_get_property(np, "location", NULL);
114		if (!loc)
115			continue;
116		if (strstr(loc, "DIMM"))
117			name = "dimms-temp";
118		else if (strstr(loc, "Processors"))
119			name = "between-cpus-temp";
120		if (name) {
121			of_node_put(np);
122			break;
123		}
124	}
125	if (!name) {
126		pr_warn("wf_lm87: Unsupported sensor %pOF\n",
127			client->dev.of_node);
128		return -ENODEV;
129	}
130
131	lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
132	if (lm == NULL)
133		return -ENODEV;
134
135	lm->i2c = client;
136	lm->sens.name = name;
137	lm->sens.ops = &wf_lm87_ops;
138	lm->sens.priv = lm;
139	i2c_set_clientdata(client, lm);
140
141	rc = wf_register_sensor(&lm->sens);
142	if (rc)
143		kfree(lm);
144	return rc;
145}
146
147static void wf_lm87_remove(struct i2c_client *client)
148{
149	struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
150
151	/* Mark client detached */
152	lm->i2c = NULL;
153
154	/* release sensor */
155	wf_unregister_sensor(&lm->sens);
156}
157
158static const struct i2c_device_id wf_lm87_id[] = {
159	{ "MAC,lm87cimt", 0 },
160	{ }
161};
162MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
163
164static const struct of_device_id wf_lm87_of_id[] = {
165	{ .compatible = "lm87cimt", },
166	{ }
167};
168MODULE_DEVICE_TABLE(of, wf_lm87_of_id);
169
170static struct i2c_driver wf_lm87_driver = {
171	.driver = {
172		.name	= "wf_lm87",
173		.of_match_table = wf_lm87_of_id,
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