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 34 struct 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 41 static 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 66 static 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 85 static 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 92 static 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 98 static 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 } 147 148 static int wf_lm87_remove(struct i2c_client *client) 149 { 150 struct wf_lm87_sensor *lm = i2c_get_clientdata(client); 151 152 DBG("wf_lm87: i2c detatch called for %s\n", lm->sens.name); 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_lm87_id[] = { 164 { "MAC,lm87cimt", 0 }, 165 { } 166 }; 167 MODULE_DEVICE_TABLE(i2c, wf_lm87_id); 168 169 static struct i2c_driver wf_lm87_driver = { 170 .driver = { 171 .name = "wf_lm87", 172 }, 173 .probe = wf_lm87_probe, 174 .remove = wf_lm87_remove, 175 .id_table = wf_lm87_id, 176 }; 177 178 static int __init wf_lm87_sensor_init(void) 179 { 180 /* We only support this on the Xserve */ 181 if (!of_machine_is_compatible("RackMac3,1")) 182 return -ENODEV; 183 184 return i2c_add_driver(&wf_lm87_driver); 185 } 186 187 static void __exit wf_lm87_sensor_exit(void) 188 { 189 i2c_del_driver(&wf_lm87_driver); 190 } 191 192 193 module_init(wf_lm87_sensor_init); 194 module_exit(wf_lm87_sensor_exit); 195 196 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 197 MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control"); 198 MODULE_LICENSE("GPL"); 199 200