1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers
4 *
5 * Copyright (C) 2020 Nvidia Technologies Ltd.
6 */
7
8 #include <linux/err.h>
9 #include <linux/i2c.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include "pmbus.h"
14
15 /* Vendor specific registers. */
16 #define MP2888_MFR_SYS_CONFIG 0x44
17 #define MP2888_MFR_READ_CS1_2 0x73
18 #define MP2888_MFR_READ_CS3_4 0x74
19 #define MP2888_MFR_READ_CS5_6 0x75
20 #define MP2888_MFR_READ_CS7_8 0x76
21 #define MP2888_MFR_READ_CS9_10 0x77
22 #define MP2888_MFR_VR_CONFIG1 0xe1
23
24 #define MP2888_TOTAL_CURRENT_RESOLUTION BIT(3)
25 #define MP2888_PHASE_CURRENT_RESOLUTION BIT(4)
26 #define MP2888_DRMOS_KCS GENMASK(2, 0)
27 #define MP2888_TEMP_UNIT 10
28 #define MP2888_MAX_PHASE 10
29
30 struct mp2888_data {
31 struct pmbus_driver_info info;
32 int total_curr_resolution;
33 int phase_curr_resolution;
34 int curr_sense_gain;
35 };
36
37 #define to_mp2888_data(x) container_of(x, struct mp2888_data, info)
38
mp2888_read_byte_data(struct i2c_client * client,int page,int reg)39 static int mp2888_read_byte_data(struct i2c_client *client, int page, int reg)
40 {
41 switch (reg) {
42 case PMBUS_VOUT_MODE:
43 /* Enforce VOUT direct format. */
44 return PB_VOUT_MODE_DIRECT;
45 default:
46 return -ENODATA;
47 }
48 }
49
50 static int
mp2888_current_sense_gain_and_resolution_get(struct i2c_client * client,struct mp2888_data * data)51 mp2888_current_sense_gain_and_resolution_get(struct i2c_client *client, struct mp2888_data *data)
52 {
53 int ret;
54
55 /*
56 * Obtain DrMOS current sense gain of power stage from the register
57 * , bits 0-2. The value is selected as below:
58 * 00b - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/A. Other
59 * values are reserved.
60 */
61 ret = i2c_smbus_read_word_data(client, MP2888_MFR_SYS_CONFIG);
62 if (ret < 0)
63 return ret;
64
65 switch (ret & MP2888_DRMOS_KCS) {
66 case 0:
67 data->curr_sense_gain = 85;
68 break;
69 case 1:
70 data->curr_sense_gain = 97;
71 break;
72 case 2:
73 data->curr_sense_gain = 100;
74 break;
75 case 3:
76 data->curr_sense_gain = 50;
77 break;
78 default:
79 return -EINVAL;
80 }
81
82 /*
83 * Obtain resolution selector for total and phase current report and protection.
84 * 0: original resolution; 1: half resolution (in such case phase current value should
85 * be doubled.
86 */
87 data->total_curr_resolution = (ret & MP2888_TOTAL_CURRENT_RESOLUTION) >> 3;
88 data->phase_curr_resolution = (ret & MP2888_PHASE_CURRENT_RESOLUTION) >> 4;
89
90 return 0;
91 }
92
93 static int
mp2888_read_phase(struct i2c_client * client,struct mp2888_data * data,int page,int phase,u8 reg)94 mp2888_read_phase(struct i2c_client *client, struct mp2888_data *data, int page, int phase, u8 reg)
95 {
96 int ret;
97
98 ret = pmbus_read_word_data(client, page, phase, reg);
99 if (ret < 0)
100 return ret;
101
102 if (!((phase + 1) % 2))
103 ret >>= 8;
104 ret &= 0xff;
105
106 /*
107 * Output value is calculated as: (READ_CSx / 80 – 1.23) / (Kcs * Rcs)
108 * where:
109 * - Kcs is the DrMOS current sense gain of power stage, which is obtained from the
110 * register MP2888_MFR_VR_CONFIG1, bits 13-12 with the following selection of DrMOS
111 * (data->curr_sense_gain):
112 * 00b - 8.5µA/A, 01b - 9.7µA/A, 1b - 10µA/A, 11b - 5µA/A.
113 * - Rcs is the internal phase current sense resistor. This parameter depends on hardware
114 * assembly. By default it is set to 1kΩ. In case of different assembly, user should
115 * scale this parameter by dividing it by Rcs.
116 * If phase current resolution bit is set to 1, READ_CSx value should be doubled.
117 * Note, that current phase sensing, providing by the device is not accurate. This is
118 * because sampling of current occurrence of bit weight has a big deviation, especially for
119 * light load.
120 */
121 ret = DIV_ROUND_CLOSEST(ret * 200 - 19600, data->curr_sense_gain);
122 /* Scale according to total current resolution. */
123 ret = (data->total_curr_resolution) ? ret * 2 : ret;
124 return ret;
125 }
126
127 static int
mp2888_read_phases(struct i2c_client * client,struct mp2888_data * data,int page,int phase)128 mp2888_read_phases(struct i2c_client *client, struct mp2888_data *data, int page, int phase)
129 {
130 int ret;
131
132 switch (phase) {
133 case 0 ... 1:
134 ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS1_2);
135 break;
136 case 2 ... 3:
137 ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS3_4);
138 break;
139 case 4 ... 5:
140 ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS5_6);
141 break;
142 case 6 ... 7:
143 ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS7_8);
144 break;
145 case 8 ... 9:
146 ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS9_10);
147 break;
148 default:
149 return -ENODATA;
150 }
151 return ret;
152 }
153
mp2888_read_word_data(struct i2c_client * client,int page,int phase,int reg)154 static int mp2888_read_word_data(struct i2c_client *client, int page, int phase, int reg)
155 {
156 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
157 struct mp2888_data *data = to_mp2888_data(info);
158 int ret;
159
160 switch (reg) {
161 case PMBUS_READ_VIN:
162 ret = pmbus_read_word_data(client, page, phase, reg);
163 if (ret <= 0)
164 return ret;
165
166 /*
167 * READ_VIN requires fixup to scale it to linear11 format. Register data format
168 * provides 10 bits for mantissa and 6 bits for exponent. Bits 15:10 are set with
169 * the fixed value 111011b.
170 */
171 ret = (ret & GENMASK(9, 0)) | ((ret & GENMASK(31, 10)) << 1);
172 break;
173 case PMBUS_OT_WARN_LIMIT:
174 ret = pmbus_read_word_data(client, page, phase, reg);
175 if (ret < 0)
176 return ret;
177 /*
178 * Chip reports limits in degrees C, but the actual temperature in 10th of
179 * degrees C - scaling is needed to match both.
180 */
181 ret *= MP2888_TEMP_UNIT;
182 break;
183 case PMBUS_READ_IOUT:
184 if (phase != 0xff)
185 return mp2888_read_phases(client, data, page, phase);
186
187 ret = pmbus_read_word_data(client, page, phase, reg);
188 if (ret < 0)
189 return ret;
190 /*
191 * READ_IOUT register has unused bits 15:12 with fixed value 1110b. Clear these
192 * bits and scale with total current resolution. Data is provided in direct format.
193 */
194 ret &= GENMASK(11, 0);
195 ret = data->total_curr_resolution ? ret * 2 : ret;
196 break;
197 case PMBUS_IOUT_OC_WARN_LIMIT:
198 ret = pmbus_read_word_data(client, page, phase, reg);
199 if (ret < 0)
200 return ret;
201 ret &= GENMASK(9, 0);
202 /*
203 * Chip reports limits with resolution 1A or 2A, if total current resolution bit is
204 * set 1. Actual current is reported with 0.25A or respectively 0.5A resolution.
205 * Scaling is needed to match both.
206 */
207 ret = data->total_curr_resolution ? ret * 8 : ret * 4;
208 break;
209 case PMBUS_READ_POUT:
210 case PMBUS_READ_PIN:
211 ret = pmbus_read_word_data(client, page, phase, reg);
212 if (ret < 0)
213 return ret;
214 ret = data->total_curr_resolution ? ret : DIV_ROUND_CLOSEST(ret, 2);
215 break;
216 case PMBUS_POUT_OP_WARN_LIMIT:
217 ret = pmbus_read_word_data(client, page, phase, reg);
218 if (ret < 0)
219 return ret;
220 /*
221 * Chip reports limits with resolution 1W or 2W, if total current resolution bit is
222 * set 1. Actual power is reported with 0.5W or 1W respectively resolution. Scaling
223 * is needed to match both.
224 */
225 ret = data->total_curr_resolution ? ret * 2 : ret;
226 break;
227 /*
228 * The below registers are not implemented by device or implemented not according to the
229 * spec. Skip all of them to avoid exposing non-relevant inputs to sysfs.
230 */
231 case PMBUS_OT_FAULT_LIMIT:
232 case PMBUS_UT_WARN_LIMIT:
233 case PMBUS_UT_FAULT_LIMIT:
234 case PMBUS_VIN_UV_FAULT_LIMIT:
235 case PMBUS_VOUT_UV_WARN_LIMIT:
236 case PMBUS_VOUT_OV_WARN_LIMIT:
237 case PMBUS_VOUT_UV_FAULT_LIMIT:
238 case PMBUS_VOUT_OV_FAULT_LIMIT:
239 case PMBUS_VIN_OV_WARN_LIMIT:
240 case PMBUS_IOUT_OC_LV_FAULT_LIMIT:
241 case PMBUS_IOUT_OC_FAULT_LIMIT:
242 case PMBUS_POUT_MAX:
243 case PMBUS_IOUT_UC_FAULT_LIMIT:
244 case PMBUS_POUT_OP_FAULT_LIMIT:
245 case PMBUS_PIN_OP_WARN_LIMIT:
246 case PMBUS_MFR_VIN_MIN:
247 case PMBUS_MFR_VOUT_MIN:
248 case PMBUS_MFR_VIN_MAX:
249 case PMBUS_MFR_VOUT_MAX:
250 case PMBUS_MFR_IIN_MAX:
251 case PMBUS_MFR_IOUT_MAX:
252 case PMBUS_MFR_PIN_MAX:
253 case PMBUS_MFR_POUT_MAX:
254 case PMBUS_MFR_MAX_TEMP_1:
255 return -ENXIO;
256 default:
257 return -ENODATA;
258 }
259
260 return ret;
261 }
262
mp2888_write_word_data(struct i2c_client * client,int page,int reg,u16 word)263 static int mp2888_write_word_data(struct i2c_client *client, int page, int reg, u16 word)
264 {
265 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
266 struct mp2888_data *data = to_mp2888_data(info);
267
268 switch (reg) {
269 case PMBUS_OT_WARN_LIMIT:
270 word = DIV_ROUND_CLOSEST(word, MP2888_TEMP_UNIT);
271 /* Drop unused bits 15:8. */
272 word = clamp_val(word, 0, GENMASK(7, 0));
273 break;
274 case PMBUS_IOUT_OC_WARN_LIMIT:
275 /* Fix limit according to total curent resolution. */
276 word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 8) :
277 DIV_ROUND_CLOSEST(word, 4);
278 /* Drop unused bits 15:10. */
279 word = clamp_val(word, 0, GENMASK(9, 0));
280 break;
281 case PMBUS_POUT_OP_WARN_LIMIT:
282 /* Fix limit according to total curent resolution. */
283 word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 4) :
284 DIV_ROUND_CLOSEST(word, 2);
285 /* Drop unused bits 15:10. */
286 word = clamp_val(word, 0, GENMASK(9, 0));
287 break;
288 default:
289 return -ENODATA;
290 }
291 return pmbus_write_word_data(client, page, reg, word);
292 }
293
294 static int
mp2888_identify_multiphase(struct i2c_client * client,struct mp2888_data * data,struct pmbus_driver_info * info)295 mp2888_identify_multiphase(struct i2c_client *client, struct mp2888_data *data,
296 struct pmbus_driver_info *info)
297 {
298 int ret;
299
300 ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
301 if (ret < 0)
302 return ret;
303
304 /* Identify multiphase number - could be from 1 to 10. */
305 ret = i2c_smbus_read_word_data(client, MP2888_MFR_VR_CONFIG1);
306 if (ret <= 0)
307 return ret;
308
309 info->phases[0] = ret & GENMASK(3, 0);
310
311 /*
312 * The device provides a total of 10 PWM pins, and can be configured to different phase
313 * count applications for rail.
314 */
315 if (info->phases[0] > MP2888_MAX_PHASE)
316 return -EINVAL;
317
318 return 0;
319 }
320
321 static struct pmbus_driver_info mp2888_info = {
322 .pages = 1,
323 .format[PSC_VOLTAGE_IN] = linear,
324 .format[PSC_VOLTAGE_OUT] = direct,
325 .format[PSC_TEMPERATURE] = direct,
326 .format[PSC_CURRENT_IN] = linear,
327 .format[PSC_CURRENT_OUT] = direct,
328 .format[PSC_POWER] = direct,
329 .m[PSC_TEMPERATURE] = 1,
330 .R[PSC_TEMPERATURE] = 1,
331 .m[PSC_VOLTAGE_OUT] = 1,
332 .R[PSC_VOLTAGE_OUT] = 3,
333 .m[PSC_CURRENT_OUT] = 4,
334 .m[PSC_POWER] = 1,
335 .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_IOUT |
336 PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
337 PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT |
338 PMBUS_PHASE_VIRTUAL,
339 .pfunc[0] = PMBUS_HAVE_IOUT,
340 .pfunc[1] = PMBUS_HAVE_IOUT,
341 .pfunc[2] = PMBUS_HAVE_IOUT,
342 .pfunc[3] = PMBUS_HAVE_IOUT,
343 .pfunc[4] = PMBUS_HAVE_IOUT,
344 .pfunc[5] = PMBUS_HAVE_IOUT,
345 .pfunc[6] = PMBUS_HAVE_IOUT,
346 .pfunc[7] = PMBUS_HAVE_IOUT,
347 .pfunc[8] = PMBUS_HAVE_IOUT,
348 .pfunc[9] = PMBUS_HAVE_IOUT,
349 .read_byte_data = mp2888_read_byte_data,
350 .read_word_data = mp2888_read_word_data,
351 .write_word_data = mp2888_write_word_data,
352 };
353
mp2888_probe(struct i2c_client * client)354 static int mp2888_probe(struct i2c_client *client)
355 {
356 struct pmbus_driver_info *info;
357 struct mp2888_data *data;
358 int ret;
359
360 data = devm_kzalloc(&client->dev, sizeof(struct mp2888_data), GFP_KERNEL);
361 if (!data)
362 return -ENOMEM;
363
364 memcpy(&data->info, &mp2888_info, sizeof(*info));
365 info = &data->info;
366
367 /* Identify multiphase configuration. */
368 ret = mp2888_identify_multiphase(client, data, info);
369 if (ret)
370 return ret;
371
372 /* Obtain current sense gain of power stage and current resolution. */
373 ret = mp2888_current_sense_gain_and_resolution_get(client, data);
374 if (ret)
375 return ret;
376
377 return pmbus_do_probe(client, info);
378 }
379
380 static const struct i2c_device_id mp2888_id[] = {
381 {"mp2888"},
382 {}
383 };
384
385 MODULE_DEVICE_TABLE(i2c, mp2888_id);
386
387 static const struct of_device_id __maybe_unused mp2888_of_match[] = {
388 {.compatible = "mps,mp2888"},
389 {}
390 };
391 MODULE_DEVICE_TABLE(of, mp2888_of_match);
392
393 static struct i2c_driver mp2888_driver = {
394 .driver = {
395 .name = "mp2888",
396 .of_match_table = of_match_ptr(mp2888_of_match),
397 },
398 .probe = mp2888_probe,
399 .id_table = mp2888_id,
400 };
401
402 module_i2c_driver(mp2888_driver);
403
404 MODULE_AUTHOR("Vadim Pasternak <vadimp@nvidia.com>");
405 MODULE_DESCRIPTION("PMBus driver for MPS MP2888 device");
406 MODULE_LICENSE("GPL");
407 MODULE_IMPORT_NS("PMBUS");
408