1/*
2 * Hardware monitoring driver for ZL6100 and compatibles
3 *
4 * Copyright (c) 2011 Ericsson AB.
5 * Copyright (c) 2012 Guenter Roeck
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/err.h>
26#include <linux/slab.h>
27#include <linux/i2c.h>
28#include <linux/ktime.h>
29#include <linux/delay.h>
30#include "pmbus.h"
31
32enum chips { zl2004, zl2005, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105,
33	     zl9101, zl9117 };
34
35struct zl6100_data {
36	int id;
37	ktime_t access;		/* chip access time */
38	int delay;		/* Delay between chip accesses in uS */
39	struct pmbus_driver_info info;
40};
41
42#define to_zl6100_data(x)  container_of(x, struct zl6100_data, info)
43
44#define ZL6100_MFR_CONFIG		0xd0
45#define ZL6100_DEVICE_ID		0xe4
46
47#define ZL6100_MFR_XTEMP_ENABLE		(1 << 7)
48
49#define MFR_VMON_OV_FAULT_LIMIT		0xf5
50#define MFR_VMON_UV_FAULT_LIMIT		0xf6
51#define MFR_READ_VMON			0xf7
52
53#define VMON_UV_WARNING			(1 << 5)
54#define VMON_OV_WARNING			(1 << 4)
55#define VMON_UV_FAULT			(1 << 1)
56#define VMON_OV_FAULT			(1 << 0)
57
58#define ZL6100_WAIT_TIME		1000	/* uS	*/
59
60static ushort delay = ZL6100_WAIT_TIME;
61module_param(delay, ushort, 0644);
62MODULE_PARM_DESC(delay, "Delay between chip accesses in uS");
63
64/* Convert linear sensor value to milli-units */
65static long zl6100_l2d(s16 l)
66{
67	s16 exponent;
68	s32 mantissa;
69	long val;
70
71	exponent = l >> 11;
72	mantissa = ((s16)((l & 0x7ff) << 5)) >> 5;
73
74	val = mantissa;
75
76	/* scale result to milli-units */
77	val = val * 1000L;
78
79	if (exponent >= 0)
80		val <<= exponent;
81	else
82		val >>= -exponent;
83
84	return val;
85}
86
87#define MAX_MANTISSA	(1023 * 1000)
88#define MIN_MANTISSA	(511 * 1000)
89
90static u16 zl6100_d2l(long val)
91{
92	s16 exponent = 0, mantissa;
93	bool negative = false;
94
95	/* simple case */
96	if (val == 0)
97		return 0;
98
99	if (val < 0) {
100		negative = true;
101		val = -val;
102	}
103
104	/* Reduce large mantissa until it fits into 10 bit */
105	while (val >= MAX_MANTISSA && exponent < 15) {
106		exponent++;
107		val >>= 1;
108	}
109	/* Increase small mantissa to improve precision */
110	while (val < MIN_MANTISSA && exponent > -15) {
111		exponent--;
112		val <<= 1;
113	}
114
115	/* Convert mantissa from milli-units to units */
116	mantissa = DIV_ROUND_CLOSEST(val, 1000);
117
118	/* Ensure that resulting number is within range */
119	if (mantissa > 0x3ff)
120		mantissa = 0x3ff;
121
122	/* restore sign */
123	if (negative)
124		mantissa = -mantissa;
125
126	/* Convert to 5 bit exponent, 11 bit mantissa */
127	return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
128}
129
130/* Some chips need a delay between accesses */
131static inline void zl6100_wait(const struct zl6100_data *data)
132{
133	if (data->delay) {
134		s64 delta = ktime_us_delta(ktime_get(), data->access);
135		if (delta < data->delay)
136			udelay(data->delay - delta);
137	}
138}
139
140static int zl6100_read_word_data(struct i2c_client *client, int page, int reg)
141{
142	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
143	struct zl6100_data *data = to_zl6100_data(info);
144	int ret, vreg;
145
146	if (page > 0)
147		return -ENXIO;
148
149	if (data->id == zl2005) {
150		/*
151		 * Limit register detection is not reliable on ZL2005.
152		 * Make sure registers are not erroneously detected.
153		 */
154		switch (reg) {
155		case PMBUS_VOUT_OV_WARN_LIMIT:
156		case PMBUS_VOUT_UV_WARN_LIMIT:
157		case PMBUS_IOUT_OC_WARN_LIMIT:
158			return -ENXIO;
159		}
160	}
161
162	switch (reg) {
163	case PMBUS_VIRT_READ_VMON:
164		vreg = MFR_READ_VMON;
165		break;
166	case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
167	case PMBUS_VIRT_VMON_OV_FAULT_LIMIT:
168		vreg = MFR_VMON_OV_FAULT_LIMIT;
169		break;
170	case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
171	case PMBUS_VIRT_VMON_UV_FAULT_LIMIT:
172		vreg = MFR_VMON_UV_FAULT_LIMIT;
173		break;
174	default:
175		if (reg >= PMBUS_VIRT_BASE)
176			return -ENXIO;
177		vreg = reg;
178		break;
179	}
180
181	zl6100_wait(data);
182	ret = pmbus_read_word_data(client, page, vreg);
183	data->access = ktime_get();
184	if (ret < 0)
185		return ret;
186
187	switch (reg) {
188	case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
189		ret = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(ret) * 9, 10));
190		break;
191	case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
192		ret = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(ret) * 11, 10));
193		break;
194	}
195
196	return ret;
197}
198
199static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
200{
201	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
202	struct zl6100_data *data = to_zl6100_data(info);
203	int ret, status;
204
205	if (page > 0)
206		return -ENXIO;
207
208	zl6100_wait(data);
209
210	switch (reg) {
211	case PMBUS_VIRT_STATUS_VMON:
212		ret = pmbus_read_byte_data(client, 0,
213					   PMBUS_STATUS_MFR_SPECIFIC);
214		if (ret < 0)
215			break;
216
217		status = 0;
218		if (ret & VMON_UV_WARNING)
219			status |= PB_VOLTAGE_UV_WARNING;
220		if (ret & VMON_OV_WARNING)
221			status |= PB_VOLTAGE_OV_WARNING;
222		if (ret & VMON_UV_FAULT)
223			status |= PB_VOLTAGE_UV_FAULT;
224		if (ret & VMON_OV_FAULT)
225			status |= PB_VOLTAGE_OV_FAULT;
226		ret = status;
227		break;
228	default:
229		ret = pmbus_read_byte_data(client, page, reg);
230		break;
231	}
232	data->access = ktime_get();
233
234	return ret;
235}
236
237static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
238				  u16 word)
239{
240	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
241	struct zl6100_data *data = to_zl6100_data(info);
242	int ret, vreg;
243
244	if (page > 0)
245		return -ENXIO;
246
247	switch (reg) {
248	case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
249		word = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(word) * 10, 9));
250		vreg = MFR_VMON_OV_FAULT_LIMIT;
251		pmbus_clear_cache(client);
252		break;
253	case PMBUS_VIRT_VMON_OV_FAULT_LIMIT:
254		vreg = MFR_VMON_OV_FAULT_LIMIT;
255		pmbus_clear_cache(client);
256		break;
257	case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
258		word = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(word) * 10, 11));
259		vreg = MFR_VMON_UV_FAULT_LIMIT;
260		pmbus_clear_cache(client);
261		break;
262	case PMBUS_VIRT_VMON_UV_FAULT_LIMIT:
263		vreg = MFR_VMON_UV_FAULT_LIMIT;
264		pmbus_clear_cache(client);
265		break;
266	default:
267		if (reg >= PMBUS_VIRT_BASE)
268			return -ENXIO;
269		vreg = reg;
270	}
271
272	zl6100_wait(data);
273	ret = pmbus_write_word_data(client, page, vreg, word);
274	data->access = ktime_get();
275
276	return ret;
277}
278
279static int zl6100_write_byte(struct i2c_client *client, int page, u8 value)
280{
281	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
282	struct zl6100_data *data = to_zl6100_data(info);
283	int ret;
284
285	if (page > 0)
286		return -ENXIO;
287
288	zl6100_wait(data);
289	ret = pmbus_write_byte(client, page, value);
290	data->access = ktime_get();
291
292	return ret;
293}
294
295static const struct i2c_device_id zl6100_id[] = {
296	{"bmr450", zl2005},
297	{"bmr451", zl2005},
298	{"bmr462", zl2008},
299	{"bmr463", zl2008},
300	{"bmr464", zl2008},
301	{"zl2004", zl2004},
302	{"zl2005", zl2005},
303	{"zl2006", zl2006},
304	{"zl2008", zl2008},
305	{"zl2105", zl2105},
306	{"zl2106", zl2106},
307	{"zl6100", zl6100},
308	{"zl6105", zl6105},
309	{"zl9101", zl9101},
310	{"zl9117", zl9117},
311	{ }
312};
313MODULE_DEVICE_TABLE(i2c, zl6100_id);
314
315static int zl6100_probe(struct i2c_client *client,
316			const struct i2c_device_id *id)
317{
318	int ret;
319	struct zl6100_data *data;
320	struct pmbus_driver_info *info;
321	u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
322	const struct i2c_device_id *mid;
323
324	if (!i2c_check_functionality(client->adapter,
325				     I2C_FUNC_SMBUS_READ_WORD_DATA
326				     | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
327		return -ENODEV;
328
329	ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID,
330					device_id);
331	if (ret < 0) {
332		dev_err(&client->dev, "Failed to read device ID\n");
333		return ret;
334	}
335	device_id[ret] = '\0';
336	dev_info(&client->dev, "Device ID %s\n", device_id);
337
338	mid = NULL;
339	for (mid = zl6100_id; mid->name[0]; mid++) {
340		if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
341			break;
342	}
343	if (!mid->name[0]) {
344		dev_err(&client->dev, "Unsupported device\n");
345		return -ENODEV;
346	}
347	if (id->driver_data != mid->driver_data)
348		dev_notice(&client->dev,
349			   "Device mismatch: Configured %s, detected %s\n",
350			   id->name, mid->name);
351
352	data = devm_kzalloc(&client->dev, sizeof(struct zl6100_data),
353			    GFP_KERNEL);
354	if (!data)
355		return -ENOMEM;
356
357	data->id = mid->driver_data;
358
359	/*
360	 * According to information from the chip vendor, all currently
361	 * supported chips are known to require a wait time between I2C
362	 * accesses.
363	 */
364	data->delay = delay;
365
366	/*
367	 * Since there was a direct I2C device access above, wait before
368	 * accessing the chip again.
369	 */
370	data->access = ktime_get();
371	zl6100_wait(data);
372
373	info = &data->info;
374
375	info->pages = 1;
376	info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
377	  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
378	  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
379	  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
380
381	/*
382	 * ZL2004, ZL9101M, and ZL9117M support monitoring an extra voltage
383	 * (VMON for ZL2004, VDRV for ZL9101M and ZL9117M). Report it as vmon.
384	 */
385	if (data->id == zl2004 || data->id == zl9101 || data->id == zl9117)
386		info->func[0] |= PMBUS_HAVE_VMON | PMBUS_HAVE_STATUS_VMON;
387
388	ret = i2c_smbus_read_word_data(client, ZL6100_MFR_CONFIG);
389	if (ret < 0)
390		return ret;
391
392	if (ret & ZL6100_MFR_XTEMP_ENABLE)
393		info->func[0] |= PMBUS_HAVE_TEMP2;
394
395	data->access = ktime_get();
396	zl6100_wait(data);
397
398	info->read_word_data = zl6100_read_word_data;
399	info->read_byte_data = zl6100_read_byte_data;
400	info->write_word_data = zl6100_write_word_data;
401	info->write_byte = zl6100_write_byte;
402
403	return pmbus_do_probe(client, mid, info);
404}
405
406static struct i2c_driver zl6100_driver = {
407	.driver = {
408		   .name = "zl6100",
409		   },
410	.probe = zl6100_probe,
411	.remove = pmbus_do_remove,
412	.id_table = zl6100_id,
413};
414
415module_i2c_driver(zl6100_driver);
416
417MODULE_AUTHOR("Guenter Roeck");
418MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles");
419MODULE_LICENSE("GPL");
420