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