1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Windfarm PowerMac thermal control. AD7417 sensors 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 21 #include "windfarm.h" 22 #include "windfarm_mpu.h" 23 24 #define VERSION "1.0" 25 26 struct wf_ad7417_priv { 27 struct kref ref; 28 struct i2c_client *i2c; 29 u8 config; 30 u8 cpu; 31 const struct mpu_data *mpu; 32 struct wf_sensor sensors[5]; 33 struct mutex lock; 34 }; 35 36 static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value) 37 { 38 struct wf_ad7417_priv *pv = sr->priv; 39 u8 buf[2]; 40 s16 raw; 41 int rc; 42 43 *value = 0; 44 mutex_lock(&pv->lock); 45 46 /* Read temp register */ 47 buf[0] = 0; 48 rc = i2c_master_send(pv->i2c, buf, 1); 49 if (rc < 0) 50 goto error; 51 rc = i2c_master_recv(pv->i2c, buf, 2); 52 if (rc < 0) 53 goto error; 54 55 /* Read a a 16-bit signed value */ 56 raw = be16_to_cpup((__le16 *)buf); 57 58 /* Convert 8.8-bit to 16.16 fixed point */ 59 *value = ((s32)raw) << 8; 60 61 mutex_unlock(&pv->lock); 62 return 0; 63 64 error: 65 mutex_unlock(&pv->lock); 66 return -1; 67 } 68 69 /* 70 * Scaling factors for the AD7417 ADC converters (except 71 * for the CPU diode which is obtained from the EEPROM). 72 * Those values are obtained from the property list of 73 * the darwin driver 74 */ 75 #define ADC_12V_CURRENT_SCALE 0x0320 /* _AD2 */ 76 #define ADC_CPU_VOLTAGE_SCALE 0x00a0 /* _AD3 */ 77 #define ADC_CPU_CURRENT_SCALE 0x1f40 /* _AD4 */ 78 79 static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv, 80 int chan, s32 raw, s32 *value) 81 { 82 switch(chan) { 83 case 1: /* Diode */ 84 *value = (raw * (s32)pv->mpu->mdiode + 85 ((s32)pv->mpu->bdiode << 12)) >> 2; 86 break; 87 case 2: /* 12v current */ 88 *value = raw * ADC_12V_CURRENT_SCALE; 89 break; 90 case 3: /* core voltage */ 91 *value = raw * ADC_CPU_VOLTAGE_SCALE; 92 break; 93 case 4: /* core current */ 94 *value = raw * ADC_CPU_CURRENT_SCALE; 95 break; 96 } 97 } 98 99 static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value) 100 { 101 struct wf_ad7417_priv *pv = sr->priv; 102 int chan = sr - pv->sensors; 103 int i, rc; 104 u8 buf[2]; 105 u16 raw; 106 107 *value = 0; 108 mutex_lock(&pv->lock); 109 for (i = 0; i < 10; i++) { 110 /* Set channel */ 111 buf[0] = 1; 112 buf[1] = (pv->config & 0x1f) | (chan << 5); 113 rc = i2c_master_send(pv->i2c, buf, 2); 114 if (rc < 0) 115 goto error; 116 117 /* Wait for conversion */ 118 msleep(1); 119 120 /* Switch to data register */ 121 buf[0] = 4; 122 rc = i2c_master_send(pv->i2c, buf, 1); 123 if (rc < 0) 124 goto error; 125 126 /* Read result */ 127 rc = i2c_master_recv(pv->i2c, buf, 2); 128 if (rc < 0) 129 goto error; 130 131 /* Read a a 16-bit signed value */ 132 raw = be16_to_cpup((__le16 *)buf) >> 6; 133 wf_ad7417_adc_convert(pv, chan, raw, value); 134 135 dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]" 136 " raw value: 0x%x, conv to: 0x%08x\n", 137 chan, sr->name, raw, *value); 138 139 mutex_unlock(&pv->lock); 140 return 0; 141 142 error: 143 dev_dbg(&pv->i2c->dev, 144 "Error reading ADC, try %d...\n", i); 145 if (i < 9) 146 msleep(10); 147 } 148 mutex_unlock(&pv->lock); 149 return -1; 150 } 151 152 static void wf_ad7417_release(struct kref *ref) 153 { 154 struct wf_ad7417_priv *pv = container_of(ref, 155 struct wf_ad7417_priv, ref); 156 kfree(pv); 157 } 158 159 static void wf_ad7417_sensor_release(struct wf_sensor *sr) 160 { 161 struct wf_ad7417_priv *pv = sr->priv; 162 163 kfree(sr->name); 164 kref_put(&pv->ref, wf_ad7417_release); 165 } 166 167 static const struct wf_sensor_ops wf_ad7417_temp_ops = { 168 .get_value = wf_ad7417_temp_get, 169 .release = wf_ad7417_sensor_release, 170 .owner = THIS_MODULE, 171 }; 172 173 static const struct wf_sensor_ops wf_ad7417_adc_ops = { 174 .get_value = wf_ad7417_adc_get, 175 .release = wf_ad7417_sensor_release, 176 .owner = THIS_MODULE, 177 }; 178 179 static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv, 180 int index, const char *name, 181 const struct wf_sensor_ops *ops) 182 { 183 pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu); 184 pv->sensors[index].priv = pv; 185 pv->sensors[index].ops = ops; 186 if (!wf_register_sensor(&pv->sensors[index])) 187 kref_get(&pv->ref); 188 } 189 190 static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv) 191 { 192 int rc; 193 u8 buf[2]; 194 u8 config = 0; 195 196 /* 197 * Read ADC the configuration register and cache it. We 198 * also make sure Config2 contains proper values, I've seen 199 * cases where we got stale grabage in there, thus preventing 200 * proper reading of conv. values 201 */ 202 203 /* Clear Config2 */ 204 buf[0] = 5; 205 buf[1] = 0; 206 i2c_master_send(pv->i2c, buf, 2); 207 208 /* Read & cache Config1 */ 209 buf[0] = 1; 210 rc = i2c_master_send(pv->i2c, buf, 1); 211 if (rc > 0) { 212 rc = i2c_master_recv(pv->i2c, buf, 1); 213 if (rc > 0) { 214 config = buf[0]; 215 216 dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n", 217 config); 218 219 /* Disable shutdown mode */ 220 config &= 0xfe; 221 buf[0] = 1; 222 buf[1] = config; 223 rc = i2c_master_send(pv->i2c, buf, 2); 224 } 225 } 226 if (rc <= 0) 227 dev_err(&pv->i2c->dev, "Error reading ADC config\n"); 228 229 pv->config = config; 230 } 231 232 static int wf_ad7417_probe(struct i2c_client *client, 233 const struct i2c_device_id *id) 234 { 235 struct wf_ad7417_priv *pv; 236 const struct mpu_data *mpu; 237 const char *loc; 238 int cpu_nr; 239 240 loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL); 241 if (!loc) { 242 dev_warn(&client->dev, "Missing hwsensor-location property!\n"); 243 return -ENXIO; 244 } 245 246 /* 247 * Identify which CPU we belong to by looking at the first entry 248 * in the hwsensor-location list 249 */ 250 if (!strncmp(loc, "CPU A", 5)) 251 cpu_nr = 0; 252 else if (!strncmp(loc, "CPU B", 5)) 253 cpu_nr = 1; 254 else { 255 pr_err("wf_ad7417: Can't identify location %s\n", loc); 256 return -ENXIO; 257 } 258 mpu = wf_get_mpu(cpu_nr); 259 if (!mpu) { 260 dev_err(&client->dev, "Failed to retrieve MPU data\n"); 261 return -ENXIO; 262 } 263 264 pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL); 265 if (pv == NULL) 266 return -ENODEV; 267 268 kref_init(&pv->ref); 269 mutex_init(&pv->lock); 270 pv->i2c = client; 271 pv->cpu = cpu_nr; 272 pv->mpu = mpu; 273 dev_set_drvdata(&client->dev, pv); 274 275 /* Initialize the chip */ 276 wf_ad7417_init_chip(pv); 277 278 /* 279 * We cannot rely on Apple device-tree giving us child 280 * node with the names of the individual sensors so we 281 * just hard code what we know about them 282 */ 283 wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops); 284 wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops); 285 wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops); 286 wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops); 287 wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops); 288 289 return 0; 290 } 291 292 static int wf_ad7417_remove(struct i2c_client *client) 293 { 294 struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev); 295 int i; 296 297 /* Mark client detached */ 298 pv->i2c = NULL; 299 300 /* Release sensor */ 301 for (i = 0; i < 5; i++) 302 wf_unregister_sensor(&pv->sensors[i]); 303 304 kref_put(&pv->ref, wf_ad7417_release); 305 306 return 0; 307 } 308 309 static const struct i2c_device_id wf_ad7417_id[] = { 310 { "MAC,ad7417", 0 }, 311 { } 312 }; 313 MODULE_DEVICE_TABLE(i2c, wf_ad7417_id); 314 315 static struct i2c_driver wf_ad7417_driver = { 316 .driver = { 317 .name = "wf_ad7417", 318 }, 319 .probe = wf_ad7417_probe, 320 .remove = wf_ad7417_remove, 321 .id_table = wf_ad7417_id, 322 }; 323 324 static int wf_ad7417_init(void) 325 { 326 /* This is only supported on these machines */ 327 if (!of_machine_is_compatible("PowerMac7,2") && 328 !of_machine_is_compatible("PowerMac7,3") && 329 !of_machine_is_compatible("RackMac3,1")) 330 return -ENODEV; 331 332 return i2c_add_driver(&wf_ad7417_driver); 333 } 334 335 static void wf_ad7417_exit(void) 336 { 337 i2c_del_driver(&wf_ad7417_driver); 338 } 339 340 module_init(wf_ad7417_init); 341 module_exit(wf_ad7417_exit); 342 343 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); 344 MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs"); 345 MODULE_LICENSE("GPL"); 346 347