xref: /openbmc/linux/drivers/hwmon/pmbus/fsp-3y.c (revision 1975d167)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Hardware monitoring driver for FSP 3Y-Power PSUs
4  *
5  * Copyright (c) 2021 Václav Kubernát, CESNET
6  *
7  * This driver is mostly reverse engineered with the help of a tool called pmbus_peek written by
8  * David Brownell (and later adopted by Jan Kundrát). The device has some sort of a timing issue
9  * when switching pages, details are explained in the code. The driver support is limited. It
10  * exposes only the values, that have been tested to work correctly. Unsupported values either
11  * aren't supported by the devices or their encondings are unknown.
12  */
13 
14 #include <linux/delay.h>
15 #include <linux/i2c.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include "pmbus.h"
19 
20 #define YM2151_PAGE_12V_LOG	0x00
21 #define YM2151_PAGE_12V_REAL	0x00
22 #define YM2151_PAGE_5VSB_LOG	0x01
23 #define YM2151_PAGE_5VSB_REAL	0x20
24 #define YH5151E_PAGE_12V_LOG	0x00
25 #define YH5151E_PAGE_12V_REAL	0x00
26 #define YH5151E_PAGE_5V_LOG	0x01
27 #define YH5151E_PAGE_5V_REAL	0x10
28 #define YH5151E_PAGE_3V3_LOG	0x02
29 #define YH5151E_PAGE_3V3_REAL	0x11
30 
31 enum chips {
32 	ym2151e,
33 	yh5151e
34 };
35 
36 struct fsp3y_data {
37 	struct pmbus_driver_info info;
38 	int chip;
39 	int page;
40 
41 	bool vout_linear_11;
42 };
43 
44 #define to_fsp3y_data(x) container_of(x, struct fsp3y_data, info)
45 
page_log_to_page_real(int page_log,enum chips chip)46 static int page_log_to_page_real(int page_log, enum chips chip)
47 {
48 	switch (chip) {
49 	case ym2151e:
50 		switch (page_log) {
51 		case YM2151_PAGE_12V_LOG:
52 			return YM2151_PAGE_12V_REAL;
53 		case YM2151_PAGE_5VSB_LOG:
54 			return YM2151_PAGE_5VSB_REAL;
55 		}
56 		return -EINVAL;
57 	case yh5151e:
58 		switch (page_log) {
59 		case YH5151E_PAGE_12V_LOG:
60 			return YH5151E_PAGE_12V_REAL;
61 		case YH5151E_PAGE_5V_LOG:
62 			return YH5151E_PAGE_5V_REAL;
63 		case YH5151E_PAGE_3V3_LOG:
64 			return YH5151E_PAGE_3V3_REAL;
65 		}
66 		return -EINVAL;
67 	}
68 
69 	return -EINVAL;
70 }
71 
set_page(struct i2c_client * client,int page_log)72 static int set_page(struct i2c_client *client, int page_log)
73 {
74 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
75 	struct fsp3y_data *data = to_fsp3y_data(info);
76 	int rv;
77 	int page_real;
78 
79 	if (page_log < 0)
80 		return 0;
81 
82 	page_real = page_log_to_page_real(page_log, data->chip);
83 	if (page_real < 0)
84 		return page_real;
85 
86 	if (data->page != page_real) {
87 		rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page_real);
88 		if (rv < 0)
89 			return rv;
90 
91 		data->page = page_real;
92 
93 		/*
94 		 * Testing showed that the device has a timing issue. After
95 		 * setting a page, it takes a while, before the device actually
96 		 * gives the correct values from the correct page. 20 ms was
97 		 * tested to be enough to not give wrong values (15 ms wasn't
98 		 * enough).
99 		 */
100 		usleep_range(20000, 30000);
101 	}
102 
103 	return 0;
104 }
105 
fsp3y_read_byte_data(struct i2c_client * client,int page,int reg)106 static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg)
107 {
108 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
109 	struct fsp3y_data *data = to_fsp3y_data(info);
110 	int rv;
111 
112 	/*
113 	 * Inject an exponent for non-compliant YH5151-E.
114 	 */
115 	if (data->vout_linear_11 && reg == PMBUS_VOUT_MODE)
116 		return 0x1A;
117 
118 	rv = set_page(client, page);
119 	if (rv < 0)
120 		return rv;
121 
122 	return i2c_smbus_read_byte_data(client, reg);
123 }
124 
fsp3y_read_word_data(struct i2c_client * client,int page,int phase,int reg)125 static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase, int reg)
126 {
127 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
128 	struct fsp3y_data *data = to_fsp3y_data(info);
129 	int rv;
130 
131 	/*
132 	 * This masks commands which weren't tested to work correctly. Some of
133 	 * the masked commands return 0xFFFF. These would probably get tagged as
134 	 * invalid by pmbus_core. Other ones do return values which might be
135 	 * useful (that is, they are not 0xFFFF), but their encoding is unknown,
136 	 * and so they are unsupported.
137 	 */
138 	switch (reg) {
139 	case PMBUS_READ_FAN_SPEED_1:
140 	case PMBUS_READ_IIN:
141 	case PMBUS_READ_IOUT:
142 	case PMBUS_READ_PIN:
143 	case PMBUS_READ_POUT:
144 	case PMBUS_READ_TEMPERATURE_1:
145 	case PMBUS_READ_TEMPERATURE_2:
146 	case PMBUS_READ_TEMPERATURE_3:
147 	case PMBUS_READ_VIN:
148 	case PMBUS_READ_VOUT:
149 	case PMBUS_STATUS_WORD:
150 		break;
151 	default:
152 		return -ENXIO;
153 	}
154 
155 	rv = set_page(client, page);
156 	if (rv < 0)
157 		return rv;
158 
159 	rv = i2c_smbus_read_word_data(client, reg);
160 	if (rv < 0)
161 		return rv;
162 
163 	/*
164 	 * Handle YH-5151E non-compliant linear11 vout voltage.
165 	 */
166 	if (data->vout_linear_11 && reg == PMBUS_READ_VOUT)
167 		rv = sign_extend32(rv, 10) & 0xffff;
168 
169 	return rv;
170 }
171 
172 static struct pmbus_driver_info fsp3y_info[] = {
173 	[ym2151e] = {
174 		.pages = 2,
175 		.func[YM2151_PAGE_12V_LOG] =
176 			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
177 			PMBUS_HAVE_PIN | PMBUS_HAVE_POUT  |
178 			PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
179 			PMBUS_HAVE_VIN | PMBUS_HAVE_IIN |
180 			PMBUS_HAVE_FAN12,
181 		.func[YM2151_PAGE_5VSB_LOG] =
182 			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT,
183 		.read_word_data = fsp3y_read_word_data,
184 		.read_byte_data = fsp3y_read_byte_data,
185 	},
186 	[yh5151e] = {
187 		.pages = 3,
188 		.func[YH5151E_PAGE_12V_LOG] =
189 			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
190 			PMBUS_HAVE_POUT  |
191 			PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3,
192 		.func[YH5151E_PAGE_5V_LOG] =
193 			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
194 			PMBUS_HAVE_POUT,
195 		.func[YH5151E_PAGE_3V3_LOG] =
196 			PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
197 			PMBUS_HAVE_POUT,
198 		.read_word_data = fsp3y_read_word_data,
199 		.read_byte_data = fsp3y_read_byte_data,
200 	}
201 };
202 
fsp3y_detect(struct i2c_client * client)203 static int fsp3y_detect(struct i2c_client *client)
204 {
205 	int rv;
206 	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
207 
208 	rv = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
209 	if (rv < 0)
210 		return rv;
211 
212 	buf[rv] = '\0';
213 
214 	if (rv == 8) {
215 		if (!strcmp(buf, "YM-2151E"))
216 			return ym2151e;
217 		else if (!strcmp(buf, "YH-5151E"))
218 			return yh5151e;
219 	}
220 
221 	dev_err(&client->dev, "Unsupported model %.*s\n", rv, buf);
222 	return -ENODEV;
223 }
224 
225 static const struct i2c_device_id fsp3y_id[] = {
226 	{"ym2151e", ym2151e},
227 	{"yh5151e", yh5151e},
228 	{ }
229 };
230 
fsp3y_probe(struct i2c_client * client)231 static int fsp3y_probe(struct i2c_client *client)
232 {
233 	struct fsp3y_data *data;
234 	const struct i2c_device_id *id;
235 	int rv;
236 
237 	data = devm_kzalloc(&client->dev, sizeof(struct fsp3y_data), GFP_KERNEL);
238 	if (!data)
239 		return -ENOMEM;
240 
241 	data->chip = fsp3y_detect(client);
242 	if (data->chip < 0)
243 		return data->chip;
244 
245 	id = i2c_match_id(fsp3y_id, client);
246 	if (data->chip != id->driver_data)
247 		dev_warn(&client->dev, "Device mismatch: Configured %s (%d), detected %d\n",
248 			 id->name, (int)id->driver_data, data->chip);
249 
250 	rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
251 	if (rv < 0)
252 		return rv;
253 	data->page = rv;
254 
255 	data->info = fsp3y_info[data->chip];
256 
257 	/*
258 	 * YH-5151E sometimes reports vout in linear11 and sometimes in
259 	 * linear16. This depends on the exact individual piece of hardware. One
260 	 * YH-5151E can use linear16 and another might use linear11 instead.
261 	 *
262 	 * The format can be recognized by reading VOUT_MODE - if it doesn't
263 	 * report a valid exponent, then vout uses linear11. Otherwise, the
264 	 * device is compliant and uses linear16.
265 	 */
266 	data->vout_linear_11 = false;
267 	if (data->chip == yh5151e) {
268 		rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
269 		if (rv < 0)
270 			return rv;
271 
272 		if (rv == 0xFF)
273 			data->vout_linear_11 = true;
274 	}
275 
276 	return pmbus_do_probe(client, &data->info);
277 }
278 
279 MODULE_DEVICE_TABLE(i2c, fsp3y_id);
280 
281 static struct i2c_driver fsp3y_driver = {
282 	.driver = {
283 		   .name = "fsp3y",
284 		   },
285 	.probe = fsp3y_probe,
286 	.id_table = fsp3y_id
287 };
288 
289 module_i2c_driver(fsp3y_driver);
290 
291 MODULE_AUTHOR("Václav Kubernát");
292 MODULE_DESCRIPTION("PMBus driver for FSP/3Y-Power power supplies");
293 MODULE_LICENSE("GPL");
294 MODULE_IMPORT_NS(PMBUS);
295