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1/*
2 * Windfarm PowerMac thermal control. AD7417 sensors
3 *
4 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
5 *
6 * Released under the term of the GNU GPL v2.
7 */
8
9#include <linux/types.h>
10#include <linux/errno.h>
11#include <linux/kernel.h>
12#include <linux/delay.h>
13#include <linux/slab.h>
14#include <linux/init.h>
15#include <linux/wait.h>
16#include <linux/i2c.h>
17#include <asm/prom.h>
18#include <asm/machdep.h>
19#include <asm/io.h>
20#include <asm/sections.h>
21
22#include "windfarm.h"
23#include "windfarm_mpu.h"
24
25#define VERSION "1.0"
26
27struct wf_ad7417_priv {
28 struct kref ref;
29 struct i2c_client *i2c;
30 u8 config;
31 u8 cpu;
32 const struct mpu_data *mpu;
33 struct wf_sensor sensors[5];
34 struct mutex lock;
35};
36
37static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
38{
39 struct wf_ad7417_priv *pv = sr->priv;
40 u8 buf[2];
41 s16 raw;
42 int rc;
43
44 *value = 0;
45 mutex_lock(&pv->lock);
46
47 /* Read temp register */
48 buf[0] = 0;
49 rc = i2c_master_send(pv->i2c, buf, 1);
50 if (rc < 0)
51 goto error;
52 rc = i2c_master_recv(pv->i2c, buf, 2);
53 if (rc < 0)
54 goto error;
55
56 /* Read a a 16-bit signed value */
57 raw = be16_to_cpup((__le16 *)buf);
58
59 /* Convert 8.8-bit to 16.16 fixed point */
60 *value = ((s32)raw) << 8;
61
62 mutex_unlock(&pv->lock);
63 return 0;
64
65error:
66 mutex_unlock(&pv->lock);
67 return -1;
68}
69
70/*
71 * Scaling factors for the AD7417 ADC converters (except
72 * for the CPU diode which is obtained from the EEPROM).
73 * Those values are obtained from the property list of
74 * the darwin driver
75 */
76#define ADC_12V_CURRENT_SCALE 0x0320 /* _AD2 */
77#define ADC_CPU_VOLTAGE_SCALE 0x00a0 /* _AD3 */
78#define ADC_CPU_CURRENT_SCALE 0x1f40 /* _AD4 */
79
80static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
81 int chan, s32 raw, s32 *value)
82{
83 switch(chan) {
84 case 1: /* Diode */
85 *value = (raw * (s32)pv->mpu->mdiode +
86 ((s32)pv->mpu->bdiode << 12)) >> 2;
87 break;
88 case 2: /* 12v current */
89 *value = raw * ADC_12V_CURRENT_SCALE;
90 break;
91 case 3: /* core voltage */
92 *value = raw * ADC_CPU_VOLTAGE_SCALE;
93 break;
94 case 4: /* core current */
95 *value = raw * ADC_CPU_CURRENT_SCALE;
96 break;
97 }
98}
99
100static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
101{
102 struct wf_ad7417_priv *pv = sr->priv;
103 int chan = sr - pv->sensors;
104 int i, rc;
105 u8 buf[2];
106 u16 raw;
107
108 *value = 0;
109 mutex_lock(&pv->lock);
110 for (i = 0; i < 10; i++) {
111 /* Set channel */
112 buf[0] = 1;
113 buf[1] = (pv->config & 0x1f) | (chan << 5);
114 rc = i2c_master_send(pv->i2c, buf, 2);
115 if (rc < 0)
116 goto error;
117
118 /* Wait for conversion */
119 msleep(1);
120
121 /* Switch to data register */
122 buf[0] = 4;
123 rc = i2c_master_send(pv->i2c, buf, 1);
124 if (rc < 0)
125 goto error;
126
127 /* Read result */
128 rc = i2c_master_recv(pv->i2c, buf, 2);
129 if (rc < 0)
130 goto error;
131
132 /* Read a a 16-bit signed value */
133 raw = be16_to_cpup((__le16 *)buf) >> 6;
134 wf_ad7417_adc_convert(pv, chan, raw, value);
135
136 dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
137 " raw value: 0x%x, conv to: 0x%08x\n",
138 chan, sr->name, raw, *value);
139
140 mutex_unlock(&pv->lock);
141 return 0;
142
143 error:
144 dev_dbg(&pv->i2c->dev,
145 "Error reading ADC, try %d...\n", i);
146 if (i < 9)
147 msleep(10);
148 }
149 mutex_unlock(&pv->lock);
150 return -1;
151}
152
153static void wf_ad7417_release(struct kref *ref)
154{
155 struct wf_ad7417_priv *pv = container_of(ref,
156 struct wf_ad7417_priv, ref);
157 kfree(pv);
158}
159
160static void wf_ad7417_sensor_release(struct wf_sensor *sr)
161{
162 struct wf_ad7417_priv *pv = sr->priv;
163
164 kfree(sr->name);
165 kref_put(&pv->ref, wf_ad7417_release);
166}
167
168static const struct wf_sensor_ops wf_ad7417_temp_ops = {
169 .get_value = wf_ad7417_temp_get,
170 .release = wf_ad7417_sensor_release,
171 .owner = THIS_MODULE,
172};
173
174static const struct wf_sensor_ops wf_ad7417_adc_ops = {
175 .get_value = wf_ad7417_adc_get,
176 .release = wf_ad7417_sensor_release,
177 .owner = THIS_MODULE,
178};
179
180static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
181 int index, const char *name,
182 const struct wf_sensor_ops *ops)
183{
184 pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
185 pv->sensors[index].priv = pv;
186 pv->sensors[index].ops = ops;
187 if (!wf_register_sensor(&pv->sensors[index]))
188 kref_get(&pv->ref);
189}
190
191static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
192{
193 int rc;
194 u8 buf[2];
195 u8 config = 0;
196
197 /*
198 * Read ADC the configuration register and cache it. We
199 * also make sure Config2 contains proper values, I've seen
200 * cases where we got stale grabage in there, thus preventing
201 * proper reading of conv. values
202 */
203
204 /* Clear Config2 */
205 buf[0] = 5;
206 buf[1] = 0;
207 i2c_master_send(pv->i2c, buf, 2);
208
209 /* Read & cache Config1 */
210 buf[0] = 1;
211 rc = i2c_master_send(pv->i2c, buf, 1);
212 if (rc > 0) {
213 rc = i2c_master_recv(pv->i2c, buf, 1);
214 if (rc > 0) {
215 config = buf[0];
216
217 dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
218 config);
219
220 /* Disable shutdown mode */
221 config &= 0xfe;
222 buf[0] = 1;
223 buf[1] = config;
224 rc = i2c_master_send(pv->i2c, buf, 2);
225 }
226 }
227 if (rc <= 0)
228 dev_err(&pv->i2c->dev, "Error reading ADC config\n");
229
230 pv->config = config;
231}
232
233static int wf_ad7417_probe(struct i2c_client *client,
234 const struct i2c_device_id *id)
235{
236 struct wf_ad7417_priv *pv;
237 const struct mpu_data *mpu;
238 const char *loc;
239 int cpu_nr;
240
241 loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
242 if (!loc) {
243 dev_warn(&client->dev, "Missing hwsensor-location property!\n");
244 return -ENXIO;
245 }
246
247 /*
248 * Identify which CPU we belong to by looking at the first entry
249 * in the hwsensor-location list
250 */
251 if (!strncmp(loc, "CPU A", 5))
252 cpu_nr = 0;
253 else if (!strncmp(loc, "CPU B", 5))
254 cpu_nr = 1;
255 else {
256 pr_err("wf_ad7417: Can't identify location %s\n", loc);
257 return -ENXIO;
258 }
259 mpu = wf_get_mpu(cpu_nr);
260 if (!mpu) {
261 dev_err(&client->dev, "Failed to retrieve MPU data\n");
262 return -ENXIO;
263 }
264
265 pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
266 if (pv == NULL)
267 return -ENODEV;
268
269 kref_init(&pv->ref);
270 mutex_init(&pv->lock);
271 pv->i2c = client;
272 pv->cpu = cpu_nr;
273 pv->mpu = mpu;
274 dev_set_drvdata(&client->dev, pv);
275
276 /* Initialize the chip */
277 wf_ad7417_init_chip(pv);
278
279 /*
280 * We cannot rely on Apple device-tree giving us child
281 * node with the names of the individual sensors so we
282 * just hard code what we know about them
283 */
284 wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
285 wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
286 wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
287 wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
288 wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);
289
290 return 0;
291}
292
293static int wf_ad7417_remove(struct i2c_client *client)
294{
295 struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
296 int i;
297
298 /* Mark client detached */
299 pv->i2c = NULL;
300
301 /* Release sensor */
302 for (i = 0; i < 5; i++)
303 wf_unregister_sensor(&pv->sensors[i]);
304
305 kref_put(&pv->ref, wf_ad7417_release);
306
307 return 0;
308}
309
310static const struct i2c_device_id wf_ad7417_id[] = {
311 { "MAC,ad7417", 0 },
312 { }
313};
314MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);
315
316static struct i2c_driver wf_ad7417_driver = {
317 .driver = {
318 .name = "wf_ad7417",
319 },
320 .probe = wf_ad7417_probe,
321 .remove = wf_ad7417_remove,
322 .id_table = wf_ad7417_id,
323};
324
325static int wf_ad7417_init(void)
326{
327 /* This is only supported on these machines */
328 if (!of_machine_is_compatible("PowerMac7,2") &&
329 !of_machine_is_compatible("PowerMac7,3") &&
330 !of_machine_is_compatible("RackMac3,1"))
331 return -ENODEV;
332
333 return i2c_add_driver(&wf_ad7417_driver);
334}
335
336static void wf_ad7417_exit(void)
337{
338 i2c_del_driver(&wf_ad7417_driver);
339}
340
341module_init(wf_ad7417_init);
342module_exit(wf_ad7417_exit);
343
344MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
345MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
346MODULE_LICENSE("GPL");
347
348

Warning: That file was not part of the compilation database. It may have many parsing errors.