1 /* 2 * Windfarm PowerMac thermal control. MAX6690 sensor. 3 * 4 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org> 5 * 6 * Use and redistribute under the terms of the GNU GPL v2. 7 */ 8 #include <linux/types.h> 9 #include <linux/errno.h> 10 #include <linux/kernel.h> 11 #include <linux/init.h> 12 #include <linux/slab.h> 13 #include <linux/i2c.h> 14 #include <asm/prom.h> 15 #include <asm/pmac_low_i2c.h> 16 17 #include "windfarm.h" 18 19 #define VERSION "0.2" 20 21 /* This currently only exports the external temperature sensor, 22 since that's all the control loops need. */ 23 24 /* Some MAX6690 register numbers */ 25 #define MAX6690_INTERNAL_TEMP 0 26 #define MAX6690_EXTERNAL_TEMP 1 27 28 struct wf_6690_sensor { 29 struct i2c_client i2c; 30 struct wf_sensor sens; 31 }; 32 33 #define wf_to_6690(x) container_of((x), struct wf_6690_sensor, sens) 34 #define i2c_to_6690(x) container_of((x), struct wf_6690_sensor, i2c) 35 36 static int wf_max6690_attach(struct i2c_adapter *adapter); 37 static int wf_max6690_detach(struct i2c_client *client); 38 39 static struct i2c_driver wf_max6690_driver = { 40 .driver = { 41 .name = "wf_max6690", 42 }, 43 .attach_adapter = wf_max6690_attach, 44 .detach_client = wf_max6690_detach, 45 }; 46 47 static int wf_max6690_get(struct wf_sensor *sr, s32 *value) 48 { 49 struct wf_6690_sensor *max = wf_to_6690(sr); 50 s32 data; 51 52 if (max->i2c.adapter == NULL) 53 return -ENODEV; 54 55 /* chip gets initialized by firmware */ 56 data = i2c_smbus_read_byte_data(&max->i2c, MAX6690_EXTERNAL_TEMP); 57 if (data < 0) 58 return data; 59 *value = data << 16; 60 return 0; 61 } 62 63 static void wf_max6690_release(struct wf_sensor *sr) 64 { 65 struct wf_6690_sensor *max = wf_to_6690(sr); 66 67 if (max->i2c.adapter) { 68 i2c_detach_client(&max->i2c); 69 max->i2c.adapter = NULL; 70 } 71 kfree(max); 72 } 73 74 static struct wf_sensor_ops wf_max6690_ops = { 75 .get_value = wf_max6690_get, 76 .release = wf_max6690_release, 77 .owner = THIS_MODULE, 78 }; 79 80 static void wf_max6690_create(struct i2c_adapter *adapter, u8 addr) 81 { 82 struct wf_6690_sensor *max; 83 char *name = "backside-temp"; 84 85 max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL); 86 if (max == NULL) { 87 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor %s: " 88 "no memory\n", name); 89 return; 90 } 91 92 max->sens.ops = &wf_max6690_ops; 93 max->sens.name = name; 94 max->i2c.addr = addr >> 1; 95 max->i2c.adapter = adapter; 96 max->i2c.driver = &wf_max6690_driver; 97 strncpy(max->i2c.name, name, I2C_NAME_SIZE-1); 98 99 if (i2c_attach_client(&max->i2c)) { 100 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n"); 101 goto fail; 102 } 103 104 if (wf_register_sensor(&max->sens)) { 105 i2c_detach_client(&max->i2c); 106 goto fail; 107 } 108 109 return; 110 111 fail: 112 kfree(max); 113 } 114 115 static int wf_max6690_attach(struct i2c_adapter *adapter) 116 { 117 struct device_node *busnode, *dev = NULL; 118 struct pmac_i2c_bus *bus; 119 const char *loc; 120 121 bus = pmac_i2c_adapter_to_bus(adapter); 122 if (bus == NULL) 123 return -ENODEV; 124 busnode = pmac_i2c_get_bus_node(bus); 125 126 while ((dev = of_get_next_child(busnode, dev)) != NULL) { 127 u8 addr; 128 129 /* We must re-match the adapter in order to properly check 130 * the channel on multibus setups 131 */ 132 if (!pmac_i2c_match_adapter(dev, adapter)) 133 continue; 134 if (!of_device_is_compatible(dev, "max6690")) 135 continue; 136 addr = pmac_i2c_get_dev_addr(dev); 137 loc = of_get_property(dev, "hwsensor-location", NULL); 138 if (loc == NULL || addr == 0) 139 continue; 140 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr); 141 if (strcmp(loc, "BACKSIDE")) 142 continue; 143 wf_max6690_create(adapter, addr); 144 } 145 146 return 0; 147 } 148 149 static int wf_max6690_detach(struct i2c_client *client) 150 { 151 struct wf_6690_sensor *max = i2c_to_6690(client); 152 153 max->i2c.adapter = NULL; 154 wf_unregister_sensor(&max->sens); 155 156 return 0; 157 } 158 159 static int __init wf_max6690_sensor_init(void) 160 { 161 /* Don't register on old machines that use therm_pm72 for now */ 162 if (machine_is_compatible("PowerMac7,2") || 163 machine_is_compatible("PowerMac7,3") || 164 machine_is_compatible("RackMac3,1")) 165 return -ENODEV; 166 return i2c_add_driver(&wf_max6690_driver); 167 } 168 169 static void __exit wf_max6690_sensor_exit(void) 170 { 171 i2c_del_driver(&wf_max6690_driver); 172 } 173 174 module_init(wf_max6690_sensor_init); 175 module_exit(wf_max6690_sensor_exit); 176 177 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>"); 178 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control"); 179 MODULE_LICENSE("GPL"); 180