1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hardware monitoring driver for Maxim MAX16508, MAX16600, MAX16601,
4 * and MAX16602.
5 *
6 * Implementation notes:
7 *
8 * This chip series supports two rails, VCORE and VSA. Telemetry information
9 * for the two rails is reported in two subsequent I2C addresses. The driver
10 * instantiates a dummy I2C client at the second I2C address to report
11 * information for the VSA rail in a single instance of the driver.
12 * Telemetry for the VSA rail is reported to the PMBus core in PMBus page 2.
13 *
14 * The chip reports input current using two separate methods. The input current
15 * reported with the standard READ_IIN command is derived from the output
16 * current. The first method is reported to the PMBus core with PMBus page 0,
17 * the second method is reported with PMBus page 1.
18 *
19 * The chip supports reading per-phase temperatures and per-phase input/output
20 * currents for VCORE. Telemetry is reported in vendor specific registers.
21 * The driver translates the vendor specific register values to PMBus standard
22 * register values and reports per-phase information in PMBus page 0.
23 *
24 * Copyright 2019, 2020 Google LLC.
25 */
26
27#include <linux/bits.h>
28#include <linux/i2c.h>
29#include <linux/init.h>
30#include <linux/kernel.h>
31#include <linux/module.h>
32
33#include "pmbus.h"
34
35enum chips { max16508, max16600, max16601, max16602 };
36
37#define REG_DEFAULT_NUM_POP	0xc4
38#define REG_SETPT_DVID		0xd1
39#define  DAC_10MV_MODE		BIT(4)
40#define REG_IOUT_AVG_PK		0xee
41#define REG_IIN_SENSOR		0xf1
42#define REG_TOTAL_INPUT_POWER	0xf2
43#define REG_PHASE_ID		0xf3
44#define  CORE_RAIL_INDICATOR	BIT(7)
45#define REG_PHASE_REPORTING	0xf4
46
47#define MAX16601_NUM_PHASES	8
48
49struct max16601_data {
50	enum chips id;
51	struct pmbus_driver_info info;
52	struct i2c_client *vsa;
53	int iout_avg_pkg;
54};
55
56#define to_max16601_data(x) container_of(x, struct max16601_data, info)
57
58static int max16601_read_byte(struct i2c_client *client, int page, int reg)
59{
60	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
61	struct max16601_data *data = to_max16601_data(info);
62
63	if (page > 0) {
64		if (page == 2)	/* VSA */
65			return i2c_smbus_read_byte_data(data->vsa, reg);
66		return -EOPNOTSUPP;
67	}
68	return -ENODATA;
69}
70
71static int max16601_read_word(struct i2c_client *client, int page, int phase,
72			      int reg)
73{
74	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
75	struct max16601_data *data = to_max16601_data(info);
76	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
77	int ret;
78
79	switch (page) {
80	case 0:		/* VCORE */
81		if (phase == 0xff)
82			return -ENODATA;
83		switch (reg) {
84		case PMBUS_READ_IIN:
85		case PMBUS_READ_IOUT:
86		case PMBUS_READ_TEMPERATURE_1:
87			ret = i2c_smbus_write_byte_data(client, REG_PHASE_ID,
88							phase);
89			if (ret)
90				return ret;
91			ret = i2c_smbus_read_block_data(client,
92							REG_PHASE_REPORTING,
93							buf);
94			if (ret < 0)
95				return ret;
96			if (ret < 6)
97				return -EIO;
98			switch (reg) {
99			case PMBUS_READ_TEMPERATURE_1:
100				return buf[1] << 8 | buf[0];
101			case PMBUS_READ_IOUT:
102				return buf[3] << 8 | buf[2];
103			case PMBUS_READ_IIN:
104				return buf[5] << 8 | buf[4];
105			default:
106				break;
107			}
108		}
109		return -EOPNOTSUPP;
110	case 1:		/* VCORE, read IIN/PIN from sensor element */
111		switch (reg) {
112		case PMBUS_READ_IIN:
113			return i2c_smbus_read_word_data(client, REG_IIN_SENSOR);
114		case PMBUS_READ_PIN:
115			return i2c_smbus_read_word_data(client,
116							REG_TOTAL_INPUT_POWER);
117		default:
118			break;
119		}
120		return -EOPNOTSUPP;
121	case 2:		/* VSA */
122		switch (reg) {
123		case PMBUS_VIRT_READ_IOUT_MAX:
124			ret = i2c_smbus_read_word_data(data->vsa,
125						       REG_IOUT_AVG_PK);
126			if (ret < 0)
127				return ret;
128			if (sign_extend32(ret, 10) >
129			    sign_extend32(data->iout_avg_pkg, 10))
130				data->iout_avg_pkg = ret;
131			return data->iout_avg_pkg;
132		case PMBUS_VIRT_RESET_IOUT_HISTORY:
133			return 0;
134		case PMBUS_IOUT_OC_FAULT_LIMIT:
135		case PMBUS_IOUT_OC_WARN_LIMIT:
136		case PMBUS_OT_FAULT_LIMIT:
137		case PMBUS_OT_WARN_LIMIT:
138		case PMBUS_READ_IIN:
139		case PMBUS_READ_IOUT:
140		case PMBUS_READ_TEMPERATURE_1:
141		case PMBUS_STATUS_WORD:
142			return i2c_smbus_read_word_data(data->vsa, reg);
143		default:
144			return -EOPNOTSUPP;
145		}
146	default:
147		return -EOPNOTSUPP;
148	}
149}
150
151static int max16601_write_byte(struct i2c_client *client, int page, u8 reg)
152{
153	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
154	struct max16601_data *data = to_max16601_data(info);
155
156	if (page == 2) {
157		if (reg == PMBUS_CLEAR_FAULTS)
158			return i2c_smbus_write_byte(data->vsa, reg);
159		return -EOPNOTSUPP;
160	}
161	return -ENODATA;
162}
163
164static int max16601_write_word(struct i2c_client *client, int page, int reg,
165			       u16 value)
166{
167	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
168	struct max16601_data *data = to_max16601_data(info);
169
170	switch (page) {
171	case 0:		/* VCORE */
172		return -ENODATA;
173	case 1:		/* VCORE IIN/PIN from sensor element */
174	default:
175		return -EOPNOTSUPP;
176	case 2:		/* VSA */
177		switch (reg) {
178		case PMBUS_VIRT_RESET_IOUT_HISTORY:
179			data->iout_avg_pkg = 0xfc00;
180			return 0;
181		case PMBUS_IOUT_OC_FAULT_LIMIT:
182		case PMBUS_IOUT_OC_WARN_LIMIT:
183		case PMBUS_OT_FAULT_LIMIT:
184		case PMBUS_OT_WARN_LIMIT:
185			return i2c_smbus_write_word_data(data->vsa, reg, value);
186		default:
187			return -EOPNOTSUPP;
188		}
189	}
190}
191
192static int max16601_identify(struct i2c_client *client,
193			     struct pmbus_driver_info *info)
194{
195	struct max16601_data *data = to_max16601_data(info);
196	int reg;
197
198	reg = i2c_smbus_read_byte_data(client, REG_SETPT_DVID);
199	if (reg < 0)
200		return reg;
201	if (reg & DAC_10MV_MODE)
202		info->vrm_version[0] = vr13;
203	else
204		info->vrm_version[0] = vr12;
205
206	if (data->id != max16600 && data->id != max16601 && data->id != max16602)
207		return 0;
208
209	reg = i2c_smbus_read_byte_data(client, REG_DEFAULT_NUM_POP);
210	if (reg < 0)
211		return reg;
212
213	/*
214	 * If REG_DEFAULT_NUM_POP returns 0, we don't know how many phases
215	 * are populated. Stick with the default in that case.
216	 */
217	reg &= 0x0f;
218	if (reg && reg <= MAX16601_NUM_PHASES)
219		info->phases[0] = reg;
220
221	return 0;
222}
223
224static struct pmbus_driver_info max16601_info = {
225	.pages = 3,
226	.format[PSC_VOLTAGE_IN] = linear,
227	.format[PSC_VOLTAGE_OUT] = vid,
228	.format[PSC_CURRENT_IN] = linear,
229	.format[PSC_CURRENT_OUT] = linear,
230	.format[PSC_TEMPERATURE] = linear,
231	.format[PSC_POWER] = linear,
232	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
233		PMBUS_HAVE_STATUS_INPUT |
234		PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
235		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
236		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
237		PMBUS_HAVE_POUT | PMBUS_PAGE_VIRTUAL | PMBUS_PHASE_VIRTUAL,
238	.func[1] = PMBUS_HAVE_IIN | PMBUS_HAVE_PIN | PMBUS_PAGE_VIRTUAL,
239	.func[2] = PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT |
240		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
241		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_PAGE_VIRTUAL,
242	.phases[0] = MAX16601_NUM_PHASES,
243	.pfunc[0] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
244	.pfunc[1] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
245	.pfunc[2] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
246	.pfunc[3] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
247	.pfunc[4] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
248	.pfunc[5] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
249	.pfunc[6] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
250	.pfunc[7] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
251	.identify = max16601_identify,
252	.read_byte_data = max16601_read_byte,
253	.read_word_data = max16601_read_word,
254	.write_byte = max16601_write_byte,
255	.write_word_data = max16601_write_word,
256};
257
258static void max16601_remove(void *_data)
259{
260	struct max16601_data *data = _data;
261
262	i2c_unregister_device(data->vsa);
263}
264
265static const struct i2c_device_id max16601_id[] = {
266	{"max16508", max16508},
267	{"max16600", max16600},
268	{"max16601", max16601},
269	{"max16602", max16602},
270	{}
271};
272MODULE_DEVICE_TABLE(i2c, max16601_id);
273
274static int max16601_get_id(struct i2c_client *client)
275{
276	struct device *dev = &client->dev;
277	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
278	enum chips id;
279	int ret;
280
281	ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
282	if (ret < 0 || ret < 11)
283		return -ENODEV;
284
285	/*
286	 * PMBUS_IC_DEVICE_ID is expected to return MAX1660[012]y.xx",
287	 * "MAX16500y.xx".cdxxcccccccccc, or "MAX16508y.xx".
288	 */
289	if (!strncmp(buf, "MAX16500", 8) || !strncmp(buf, "MAX16508", 8)) {
290		id = max16508;
291	} else if (!strncmp(buf, "MAX16600", 8)) {
292		id = max16600;
293	} else if (!strncmp(buf, "MAX16601", 8)) {
294		id = max16601;
295	} else if (!strncmp(buf, "MAX16602", 8)) {
296		id = max16602;
297	} else {
298		buf[ret] = '\0';
299		dev_err(dev, "Unsupported chip '%s'\n", buf);
300		return -ENODEV;
301	}
302	return id;
303}
304
305static int max16601_probe(struct i2c_client *client)
306{
307	struct device *dev = &client->dev;
308	const struct i2c_device_id *id;
309	struct max16601_data *data;
310	int ret, chip_id;
311
312	if (!i2c_check_functionality(client->adapter,
313				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
314				     I2C_FUNC_SMBUS_READ_BLOCK_DATA))
315		return -ENODEV;
316
317	chip_id = max16601_get_id(client);
318	if (chip_id < 0)
319		return chip_id;
320
321	id = i2c_match_id(max16601_id, client);
322	if (chip_id != id->driver_data)
323		dev_warn(&client->dev,
324			 "Device mismatch: Configured %s (%d), detected %d\n",
325			 id->name, (int) id->driver_data, chip_id);
326
327	ret = i2c_smbus_read_byte_data(client, REG_PHASE_ID);
328	if (ret < 0)
329		return ret;
330	if (!(ret & CORE_RAIL_INDICATOR)) {
331		dev_err(dev,
332			"Driver must be instantiated on CORE rail I2C address\n");
333		return -ENODEV;
334	}
335
336	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
337	if (!data)
338		return -ENOMEM;
339
340	data->id = chip_id;
341	data->iout_avg_pkg = 0xfc00;
342	data->vsa = i2c_new_dummy_device(client->adapter, client->addr + 1);
343	if (IS_ERR(data->vsa)) {
344		dev_err(dev, "Failed to register VSA client\n");
345		return PTR_ERR(data->vsa);
346	}
347	ret = devm_add_action_or_reset(dev, max16601_remove, data);
348	if (ret)
349		return ret;
350
351	data->info = max16601_info;
352
353	return pmbus_do_probe(client, &data->info);
354}
355
356static struct i2c_driver max16601_driver = {
357	.driver = {
358		   .name = "max16601",
359		   },
360	.probe = max16601_probe,
361	.id_table = max16601_id,
362};
363
364module_i2c_driver(max16601_driver);
365
366MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
367MODULE_DESCRIPTION("PMBus driver for Maxim MAX16601");
368MODULE_LICENSE("GPL v2");
369MODULE_IMPORT_NS(PMBUS);
370