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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
31enum chips {
32 ym2151e,
33 yh5151e
34};
35
36struct 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
46static 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
72static 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
106static 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
125static 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
172static 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 PMBUS_HAVE_IIN,
184 .read_word_data = fsp3y_read_word_data,
185 .read_byte_data = fsp3y_read_byte_data,
186 },
187 [yh5151e] = {
188 .pages = 3,
189 .func[YH5151E_PAGE_12V_LOG] =
190 PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
191 PMBUS_HAVE_POUT |
192 PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3,
193 .func[YH5151E_PAGE_5V_LOG] =
194 PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
195 PMBUS_HAVE_POUT,
196 .func[YH5151E_PAGE_3V3_LOG] =
197 PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
198 PMBUS_HAVE_POUT,
199 .read_word_data = fsp3y_read_word_data,
200 .read_byte_data = fsp3y_read_byte_data,
201 }
202};
203
204static int fsp3y_detect(struct i2c_client *client)
205{
206 int rv;
207 u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
208
209 rv = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
210 if (rv < 0)
211 return rv;
212
213 buf[rv] = '\0';
214
215 if (rv == 8) {
216 if (!strcmp(buf, "YM-2151E"))
217 return ym2151e;
218 else if (!strcmp(buf, "YH-5151E"))
219 return yh5151e;
220 }
221
222 dev_err(&client->dev, "Unsupported model %.*s\n", rv, buf);
223 return -ENODEV;
224}
225
226static const struct i2c_device_id fsp3y_id[] = {
227 {"ym2151e", ym2151e},
228 {"yh5151e", yh5151e},
229 { }
230};
231
232static int fsp3y_probe(struct i2c_client *client)
233{
234 struct fsp3y_data *data;
235 const struct i2c_device_id *id;
236 int rv;
237
238 data = devm_kzalloc(&client->dev, sizeof(struct fsp3y_data), GFP_KERNEL);
239 if (!data)
240 return -ENOMEM;
241
242 data->chip = fsp3y_detect(client);
243 if (data->chip < 0)
244 return data->chip;
245
246 id = i2c_match_id(fsp3y_id, client);
247 if (data->chip != id->driver_data)
248 dev_warn(&client->dev, "Device mismatch: Configured %s (%d), detected %d\n",
249 id->name, (int)id->driver_data, data->chip);
250
251 rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
252 if (rv < 0)
253 return rv;
254 data->page = rv;
255
256 data->info = fsp3y_info[data->chip];
257
258 /*
259 * YH-5151E sometimes reports vout in linear11 and sometimes in
260 * linear16. This depends on the exact individual piece of hardware. One
261 * YH-5151E can use linear16 and another might use linear11 instead.
262 *
263 * The format can be recognized by reading VOUT_MODE - if it doesn't
264 * report a valid exponent, then vout uses linear11. Otherwise, the
265 * device is compliant and uses linear16.
266 */
267 data->vout_linear_11 = false;
268 if (data->chip == yh5151e) {
269 rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
270 if (rv < 0)
271 return rv;
272
273 if (rv == 0xFF)
274 data->vout_linear_11 = true;
275 }
276
277 return pmbus_do_probe(client, &data->info);
278}
279
280MODULE_DEVICE_TABLE(i2c, fsp3y_id);
281
282static struct i2c_driver fsp3y_driver = {
283 .driver = {
284 .name = "fsp3y",
285 },
286 .probe_new = fsp3y_probe,
287 .id_table = fsp3y_id
288};
289
290module_i2c_driver(fsp3y_driver);
291
292MODULE_AUTHOR("Václav Kubernát");
293MODULE_DESCRIPTION("PMBus driver for FSP/3Y-Power power supplies");
294MODULE_LICENSE("GPL");
295MODULE_IMPORT_NS(PMBUS);