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 36 struct 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 43 static 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 68 static 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 87 static 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 94 static struct wf_sensor_ops wf_lm87_ops = { 95 .get_value = wf_lm87_get, 96 .release = wf_lm87_release, 97 .owner = THIS_MODULE, 98 }; 99 100 static 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 } 149 150 static 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 } 164 165 static const struct i2c_device_id wf_lm87_id[] = { 166 { "MAC,lm87cimt", 0 }, 167 { } 168 }; 169 MODULE_DEVICE_TABLE(i2c, wf_lm87_id); 170 171 static 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 }; 179 180 static 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 } 188 189 static void __exit wf_lm87_sensor_exit(void) 190 { 191 i2c_del_driver(&wf_lm87_driver); 192 } 193 194 195 module_init(wf_lm87_sensor_init); 196 module_exit(wf_lm87_sensor_exit); 197 198 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 199 MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control"); 200 MODULE_LICENSE("GPL"); 201 202