summaryrefslogtreecommitdiff
path: root/drivers/macintosh/windfarm_ad7417_sensor.c
blob: 125605987b443b6f123070de71d4b72679f298c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Windfarm PowerMac thermal control. AD7417 sensors
 *
 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>

#include "windfarm.h"
#include "windfarm_mpu.h"

#define VERSION "1.0"

struct wf_ad7417_priv {
	struct kref		ref;
	struct i2c_client	*i2c;
	u8			config;
	u8			cpu;
	const struct mpu_data	*mpu;
	struct wf_sensor	sensors[5];
	struct mutex		lock;
};

static int wf_ad7417_temp_get(struct wf_sensor *sr, s32 *value)
{
	struct wf_ad7417_priv *pv = sr->priv;
	u8 buf[2];
	s16 raw;
	int rc;

	*value = 0;
	mutex_lock(&pv->lock);

	/* Read temp register */
	buf[0] = 0;
	rc = i2c_master_send(pv->i2c, buf, 1);
	if (rc < 0)
		goto error;
	rc = i2c_master_recv(pv->i2c, buf, 2);
	if (rc < 0)
		goto error;

	/* Read a a 16-bit signed value */
	raw = be16_to_cpup((__le16 *)buf);

	/* Convert 8.8-bit to 16.16 fixed point */
	*value = ((s32)raw) << 8;

	mutex_unlock(&pv->lock);
	return 0;

error:
	mutex_unlock(&pv->lock);
	return -1;
}

/*
 * Scaling factors for the AD7417 ADC converters (except
 * for the CPU diode which is obtained from the EEPROM).
 * Those values are obtained from the property list of
 * the darwin driver
 */
#define ADC_12V_CURRENT_SCALE	0x0320	/* _AD2 */
#define ADC_CPU_VOLTAGE_SCALE	0x00a0	/* _AD3 */
#define ADC_CPU_CURRENT_SCALE	0x1f40	/* _AD4 */

static void wf_ad7417_adc_convert(struct wf_ad7417_priv *pv,
				  int chan, s32 raw, s32 *value)
{
	switch(chan) {
	case 1: /* Diode */
		*value = (raw * (s32)pv->mpu->mdiode +
			((s32)pv->mpu->bdiode << 12)) >> 2;
		break;
	case 2: /* 12v current */
		*value = raw * ADC_12V_CURRENT_SCALE;
		break;
	case 3: /* core voltage */
		*value = raw * ADC_CPU_VOLTAGE_SCALE;
		break;
	case 4: /* core current */
		*value = raw * ADC_CPU_CURRENT_SCALE;
		break;
	}
}

static int wf_ad7417_adc_get(struct wf_sensor *sr, s32 *value)
{
	struct wf_ad7417_priv *pv = sr->priv;
	int chan = sr - pv->sensors;
	int i, rc;
	u8 buf[2];
	u16 raw;

	*value = 0;
	mutex_lock(&pv->lock);
	for (i = 0; i < 10; i++) {
		/* Set channel */
		buf[0] = 1;
		buf[1] = (pv->config & 0x1f) | (chan << 5);
		rc = i2c_master_send(pv->i2c, buf, 2);
		if (rc < 0)
			goto error;

		/* Wait for conversion */
		msleep(1);

		/* Switch to data register */
		buf[0] = 4;
		rc = i2c_master_send(pv->i2c, buf, 1);
		if (rc < 0)
			goto error;

		/* Read result */
		rc = i2c_master_recv(pv->i2c, buf, 2);
		if (rc < 0)
			goto error;

		/* Read a a 16-bit signed value */
		raw = be16_to_cpup((__le16 *)buf) >> 6;
		wf_ad7417_adc_convert(pv, chan, raw, value);

		dev_vdbg(&pv->i2c->dev, "ADC chan %d [%s]"
			 " raw value: 0x%x, conv to: 0x%08x\n",
			 chan, sr->name, raw, *value);

		mutex_unlock(&pv->lock);
		return 0;

	error:
		dev_dbg(&pv->i2c->dev,
			  "Error reading ADC, try %d...\n", i);
		if (i < 9)
			msleep(10);
	}
	mutex_unlock(&pv->lock);
	return -1;
}

static void wf_ad7417_release(struct kref *ref)
{
	struct wf_ad7417_priv *pv = container_of(ref,
						 struct wf_ad7417_priv, ref);
	kfree(pv);
}

static void wf_ad7417_sensor_release(struct wf_sensor *sr)
{
	struct wf_ad7417_priv *pv = sr->priv;

	kfree(sr->name);
	kref_put(&pv->ref, wf_ad7417_release);
}

static const struct wf_sensor_ops wf_ad7417_temp_ops = {
	.get_value	= wf_ad7417_temp_get,
	.release	= wf_ad7417_sensor_release,
	.owner		= THIS_MODULE,
};

static const struct wf_sensor_ops wf_ad7417_adc_ops = {
	.get_value	= wf_ad7417_adc_get,
	.release	= wf_ad7417_sensor_release,
	.owner		= THIS_MODULE,
};

static void wf_ad7417_add_sensor(struct wf_ad7417_priv *pv,
				 int index, const char *name,
				 const struct wf_sensor_ops *ops)
{
	pv->sensors[index].name = kasprintf(GFP_KERNEL, "%s-%d", name, pv->cpu);
	pv->sensors[index].priv = pv;
	pv->sensors[index].ops = ops;
	if (!wf_register_sensor(&pv->sensors[index]))
		kref_get(&pv->ref);
}

static void wf_ad7417_init_chip(struct wf_ad7417_priv *pv)
{
	int rc;
	u8 buf[2];
	u8 config = 0;

	/*
	 * Read ADC the configuration register and cache it. We
	 * also make sure Config2 contains proper values, I've seen
	 * cases where we got stale grabage in there, thus preventing
	 * proper reading of conv. values
	 */

	/* Clear Config2 */
	buf[0] = 5;
	buf[1] = 0;
	i2c_master_send(pv->i2c, buf, 2);

	/* Read & cache Config1 */
	buf[0] = 1;
	rc = i2c_master_send(pv->i2c, buf, 1);
	if (rc > 0) {
		rc = i2c_master_recv(pv->i2c, buf, 1);
		if (rc > 0) {
			config = buf[0];

			dev_dbg(&pv->i2c->dev, "ADC config reg: %02x\n",
				config);

			/* Disable shutdown mode */
			config &= 0xfe;
			buf[0] = 1;
			buf[1] = config;
			rc = i2c_master_send(pv->i2c, buf, 2);
		}
	}
	if (rc <= 0)
		dev_err(&pv->i2c->dev, "Error reading ADC config\n");

	pv->config = config;
}

static int wf_ad7417_probe(struct i2c_client *client,
			   const struct i2c_device_id *id)
{
	struct wf_ad7417_priv *pv;
	const struct mpu_data *mpu;
	const char *loc;
	int cpu_nr;

	loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
	if (!loc) {
		dev_warn(&client->dev, "Missing hwsensor-location property!\n");
		return -ENXIO;
	}

	/*
	 * Identify which CPU we belong to by looking at the first entry
	 * in the hwsensor-location list
	 */
	if (!strncmp(loc, "CPU A", 5))
		cpu_nr = 0;
	else if (!strncmp(loc, "CPU B", 5))
		cpu_nr = 1;
	else {
		pr_err("wf_ad7417: Can't identify location %s\n", loc);
		return -ENXIO;
	}
	mpu = wf_get_mpu(cpu_nr);
	if (!mpu) {
		dev_err(&client->dev, "Failed to retrieve MPU data\n");
		return -ENXIO;
	}

	pv = kzalloc(sizeof(struct wf_ad7417_priv), GFP_KERNEL);
	if (pv == NULL)
		return -ENODEV;

	kref_init(&pv->ref);
	mutex_init(&pv->lock);
	pv->i2c = client;
	pv->cpu = cpu_nr;
	pv->mpu = mpu;
	dev_set_drvdata(&client->dev, pv);

	/* Initialize the chip */
	wf_ad7417_init_chip(pv);

	/*
	 * We cannot rely on Apple device-tree giving us child
	 * node with the names of the individual sensors so we
	 * just hard code what we know about them
	 */
	wf_ad7417_add_sensor(pv, 0, "cpu-amb-temp", &wf_ad7417_temp_ops);
	wf_ad7417_add_sensor(pv, 1, "cpu-diode-temp", &wf_ad7417_adc_ops);
	wf_ad7417_add_sensor(pv, 2, "cpu-12v-current", &wf_ad7417_adc_ops);
	wf_ad7417_add_sensor(pv, 3, "cpu-voltage", &wf_ad7417_adc_ops);
	wf_ad7417_add_sensor(pv, 4, "cpu-current", &wf_ad7417_adc_ops);

	return 0;
}

static int wf_ad7417_remove(struct i2c_client *client)
{
	struct wf_ad7417_priv *pv = dev_get_drvdata(&client->dev);
	int i;

	/* Mark client detached */
	pv->i2c = NULL;

	/* Release sensor */
	for (i = 0; i < 5; i++)
		wf_unregister_sensor(&pv->sensors[i]);

	kref_put(&pv->ref, wf_ad7417_release);

	return 0;
}

static const struct i2c_device_id wf_ad7417_id[] = {
	{ "MAC,ad7417", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, wf_ad7417_id);

static struct i2c_driver wf_ad7417_driver = {
	.driver = {
		.name	= "wf_ad7417",
	},
	.probe		= wf_ad7417_probe,
	.remove		= wf_ad7417_remove,
	.id_table	= wf_ad7417_id,
};

static int wf_ad7417_init(void)
{
	/* This is only supported on these machines */
	if (!of_machine_is_compatible("PowerMac7,2") &&
	    !of_machine_is_compatible("PowerMac7,3") &&
	    !of_machine_is_compatible("RackMac3,1"))
		return -ENODEV;

	return i2c_add_driver(&wf_ad7417_driver);
}

static void wf_ad7417_exit(void)
{
	i2c_del_driver(&wf_ad7417_driver);
}

module_init(wf_ad7417_init);
module_exit(wf_ad7417_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("ad7417 sensor driver for PowerMacs");
MODULE_LICENSE("GPL");