1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Windfarm PowerMac thermal control. MAX6690 sensor. 4 * 5 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org> 6 */ 7 #include <linux/types.h> 8 #include <linux/errno.h> 9 #include <linux/kernel.h> 10 #include <linux/init.h> 11 #include <linux/slab.h> 12 #include <linux/i2c.h> 13 14 #include <asm/pmac_low_i2c.h> 15 16 #include "windfarm.h" 17 18 #define VERSION "1.0" 19 20 /* This currently only exports the external temperature sensor, 21 since that's all the control loops need. */ 22 23 /* Some MAX6690 register numbers */ 24 #define MAX6690_INTERNAL_TEMP 0 25 #define MAX6690_EXTERNAL_TEMP 1 26 27 struct wf_6690_sensor { 28 struct i2c_client *i2c; 29 struct wf_sensor sens; 30 }; 31 32 #define wf_to_6690(x) container_of((x), struct wf_6690_sensor, sens) 33 34 static int wf_max6690_get(struct wf_sensor *sr, s32 *value) 35 { 36 struct wf_6690_sensor *max = wf_to_6690(sr); 37 s32 data; 38 39 if (max->i2c == NULL) 40 return -ENODEV; 41 42 /* chip gets initialized by firmware */ 43 data = i2c_smbus_read_byte_data(max->i2c, MAX6690_EXTERNAL_TEMP); 44 if (data < 0) 45 return data; 46 *value = data << 16; 47 return 0; 48 } 49 50 static void wf_max6690_release(struct wf_sensor *sr) 51 { 52 struct wf_6690_sensor *max = wf_to_6690(sr); 53 54 kfree(max); 55 } 56 57 static const struct wf_sensor_ops wf_max6690_ops = { 58 .get_value = wf_max6690_get, 59 .release = wf_max6690_release, 60 .owner = THIS_MODULE, 61 }; 62 63 static int wf_max6690_probe(struct i2c_client *client) 64 { 65 const char *name, *loc; 66 struct wf_6690_sensor *max; 67 int rc; 68 69 loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL); 70 if (!loc) { 71 dev_warn(&client->dev, "Missing hwsensor-location property!\n"); 72 return -ENXIO; 73 } 74 75 /* 76 * We only expose the external temperature register for 77 * now as this is all we need for our control loops 78 */ 79 if (!strcmp(loc, "BACKSIDE") || !strcmp(loc, "SYS CTRLR AMBIENT")) 80 name = "backside-temp"; 81 else if (!strcmp(loc, "NB Ambient")) 82 name = "north-bridge-temp"; 83 else if (!strcmp(loc, "GPU Ambient")) 84 name = "gpu-temp"; 85 else 86 return -ENXIO; 87 88 max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL); 89 if (max == NULL) { 90 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: " 91 "no memory\n"); 92 return -ENOMEM; 93 } 94 95 max->i2c = client; 96 max->sens.name = name; 97 max->sens.ops = &wf_max6690_ops; 98 i2c_set_clientdata(client, max); 99 100 rc = wf_register_sensor(&max->sens); 101 if (rc) 102 kfree(max); 103 return rc; 104 } 105 106 static void wf_max6690_remove(struct i2c_client *client) 107 { 108 struct wf_6690_sensor *max = i2c_get_clientdata(client); 109 110 max->i2c = NULL; 111 wf_unregister_sensor(&max->sens); 112 } 113 114 static const struct i2c_device_id wf_max6690_id[] = { 115 { "MAC,max6690", 0 }, 116 { } 117 }; 118 MODULE_DEVICE_TABLE(i2c, wf_max6690_id); 119 120 static const struct of_device_id wf_max6690_of_id[] = { 121 { .compatible = "max6690", }, 122 { } 123 }; 124 MODULE_DEVICE_TABLE(of, wf_max6690_of_id); 125 126 static struct i2c_driver wf_max6690_driver = { 127 .driver = { 128 .name = "wf_max6690", 129 .of_match_table = wf_max6690_of_id, 130 }, 131 .probe_new = wf_max6690_probe, 132 .remove = wf_max6690_remove, 133 .id_table = wf_max6690_id, 134 }; 135 136 module_i2c_driver(wf_max6690_driver); 137 138 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>"); 139 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control"); 140 MODULE_LICENSE("GPL"); 141