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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 | ||
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 | |
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 | |
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 - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/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 * 100 - 9800, data->curr_sense_gain); | |
122 | ret = (data->phase_curr_resolution) ? ret * 2 : ret; | |
123 | /* Scale according to total current resolution. */ | |
124 | ret = (data->total_curr_resolution) ? ret * 8 : ret * 4; | |
125 | return ret; | |
126 | } | |
127 | ||
128 | static int | |
129 | mp2888_read_phases(struct i2c_client *client, struct mp2888_data *data, int page, int phase) | |
130 | { | |
131 | int ret; | |
132 | ||
133 | switch (phase) { | |
134 | case 0 ... 1: | |
135 | ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS1_2); | |
136 | break; | |
137 | case 2 ... 3: | |
138 | ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS3_4); | |
139 | break; | |
140 | case 4 ... 5: | |
141 | ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS5_6); | |
142 | break; | |
143 | case 6 ... 7: | |
144 | ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS7_8); | |
145 | break; | |
146 | case 8 ... 9: | |
147 | ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS9_10); | |
148 | break; | |
149 | default: | |
150 | return -ENODATA; | |
151 | } | |
152 | return ret; | |
153 | } | |
154 | ||
155 | static int mp2888_read_word_data(struct i2c_client *client, int page, int phase, int reg) | |
156 | { | |
157 | const struct pmbus_driver_info *info = pmbus_get_driver_info(client); | |
158 | struct mp2888_data *data = to_mp2888_data(info); | |
159 | int ret; | |
160 | ||
161 | switch (reg) { | |
162 | case PMBUS_READ_VIN: | |
163 | ret = pmbus_read_word_data(client, page, phase, reg); | |
164 | if (ret <= 0) | |
165 | return ret; | |
166 | ||
167 | /* | |
168 | * READ_VIN requires fixup to scale it to linear11 format. Register data format | |
169 | * provides 10 bits for mantissa and 6 bits for exponent. Bits 15:10 are set with | |
170 | * the fixed value 111011b. | |
171 | */ | |
172 | ret = (ret & GENMASK(9, 0)) | ((ret & GENMASK(31, 10)) << 1); | |
173 | break; | |
174 | case PMBUS_OT_WARN_LIMIT: | |
175 | ret = pmbus_read_word_data(client, page, phase, reg); | |
176 | if (ret < 0) | |
177 | return ret; | |
178 | /* | |
179 | * Chip reports limits in degrees C, but the actual temperature in 10th of | |
180 | * degrees C - scaling is needed to match both. | |
181 | */ | |
182 | ret *= MP2888_TEMP_UNIT; | |
183 | break; | |
184 | case PMBUS_READ_IOUT: | |
185 | if (phase != 0xff) | |
186 | return mp2888_read_phases(client, data, page, phase); | |
187 | ||
188 | ret = pmbus_read_word_data(client, page, phase, reg); | |
189 | if (ret < 0) | |
190 | return ret; | |
191 | /* | |
192 | * READ_IOUT register has unused bits 15:12 with fixed value 1110b. Clear these | |
193 | * bits and scale with total current resolution. Data is provided in direct format. | |
194 | */ | |
195 | ret &= GENMASK(11, 0); | |
196 | ret = data->total_curr_resolution ? ret * 2 : ret; | |
197 | break; | |
198 | case PMBUS_IOUT_OC_WARN_LIMIT: | |
199 | ret = pmbus_read_word_data(client, page, phase, reg); | |
200 | if (ret < 0) | |
201 | return ret; | |
202 | ret &= GENMASK(9, 0); | |
203 | /* | |
204 | * Chip reports limits with resolution 1A or 2A, if total current resolution bit is | |
205 | * set 1. Actual current is reported with 0.25A or respectively 0.5A resolution. | |
206 | * Scaling is needed to match both. | |
207 | */ | |
208 | ret = data->total_curr_resolution ? ret * 8 : ret * 4; | |
209 | break; | |
210 | case PMBUS_READ_POUT: | |
211 | case PMBUS_READ_PIN: | |
212 | ret = pmbus_read_word_data(client, page, phase, reg); | |
213 | if (ret < 0) | |
214 | return ret; | |
215 | ret = data->total_curr_resolution ? ret * 2 : ret; | |
216 | break; | |
217 | case PMBUS_POUT_OP_WARN_LIMIT: | |
218 | ret = pmbus_read_word_data(client, page, phase, reg); | |
219 | if (ret < 0) | |
220 | return ret; | |
221 | /* | |
222 | * Chip reports limits with resolution 1W or 2W, if total current resolution bit is | |
223 | * set 1. Actual power is reported with 0.5W or 1W respectively resolution. Scaling | |
224 | * is needed to match both. | |
225 | */ | |
226 | ret = data->total_curr_resolution ? ret * 4 : ret * 2; | |
227 | break; | |
228 | /* | |
229 | * The below registers are not implemented by device or implemented not according to the | |
230 | * spec. Skip all of them to avoid exposing non-relevant inputs to sysfs. | |
231 | */ | |
232 | case PMBUS_OT_FAULT_LIMIT: | |
233 | case PMBUS_UT_WARN_LIMIT: | |
234 | case PMBUS_UT_FAULT_LIMIT: | |
235 | case PMBUS_VIN_UV_FAULT_LIMIT: | |
236 | case PMBUS_VOUT_UV_WARN_LIMIT: | |
237 | case PMBUS_VOUT_OV_WARN_LIMIT: | |
238 | case PMBUS_VOUT_UV_FAULT_LIMIT: | |
239 | case PMBUS_VOUT_OV_FAULT_LIMIT: | |
240 | case PMBUS_VIN_OV_WARN_LIMIT: | |
241 | case PMBUS_IOUT_OC_LV_FAULT_LIMIT: | |
242 | case PMBUS_IOUT_OC_FAULT_LIMIT: | |
243 | case PMBUS_POUT_MAX: | |
244 | case PMBUS_IOUT_UC_FAULT_LIMIT: | |
245 | case PMBUS_POUT_OP_FAULT_LIMIT: | |
246 | case PMBUS_PIN_OP_WARN_LIMIT: | |
247 | case PMBUS_MFR_VIN_MIN: | |
248 | case PMBUS_MFR_VOUT_MIN: | |
249 | case PMBUS_MFR_VIN_MAX: | |
250 | case PMBUS_MFR_VOUT_MAX: | |
251 | case PMBUS_MFR_IIN_MAX: | |
252 | case PMBUS_MFR_IOUT_MAX: | |
253 | case PMBUS_MFR_PIN_MAX: | |
254 | case PMBUS_MFR_POUT_MAX: | |
255 | case PMBUS_MFR_MAX_TEMP_1: | |
256 | return -ENXIO; | |
257 | default: | |
258 | return -ENODATA; | |
259 | } | |
260 | ||
261 | return ret; | |
262 | } | |
263 | ||
264 | static int mp2888_write_word_data(struct i2c_client *client, int page, int reg, u16 word) | |
265 | { | |
266 | const struct pmbus_driver_info *info = pmbus_get_driver_info(client); | |
267 | struct mp2888_data *data = to_mp2888_data(info); | |
268 | ||
269 | switch (reg) { | |
270 | case PMBUS_OT_WARN_LIMIT: | |
271 | word = DIV_ROUND_CLOSEST(word, MP2888_TEMP_UNIT); | |
272 | /* Drop unused bits 15:8. */ | |
273 | word = clamp_val(word, 0, GENMASK(7, 0)); | |
274 | break; | |
275 | case PMBUS_IOUT_OC_WARN_LIMIT: | |
276 | /* Fix limit according to total curent resolution. */ | |
277 | word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 8) : | |
278 | DIV_ROUND_CLOSEST(word, 4); | |
279 | /* Drop unused bits 15:10. */ | |
280 | word = clamp_val(word, 0, GENMASK(9, 0)); | |
281 | break; | |
282 | case PMBUS_POUT_OP_WARN_LIMIT: | |
283 | /* Fix limit according to total curent resolution. */ | |
284 | word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 4) : | |
285 | DIV_ROUND_CLOSEST(word, 2); | |
286 | /* Drop unused bits 15:10. */ | |
287 | word = clamp_val(word, 0, GENMASK(9, 0)); | |
288 | break; | |
289 | default: | |
290 | return -ENODATA; | |
291 | } | |
292 | return pmbus_write_word_data(client, page, reg, word); | |
293 | } | |
294 | ||
295 | static int | |
296 | mp2888_identify_multiphase(struct i2c_client *client, struct mp2888_data *data, | |
297 | struct pmbus_driver_info *info) | |
298 | { | |
299 | int ret; | |
300 | ||
301 | ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0); | |
302 | if (ret < 0) | |
303 | return ret; | |
304 | ||
305 | /* Identify multiphase number - could be from 1 to 10. */ | |
306 | ret = i2c_smbus_read_word_data(client, MP2888_MFR_VR_CONFIG1); | |
307 | if (ret <= 0) | |
308 | return ret; | |
309 | ||
310 | info->phases[0] = ret & GENMASK(3, 0); | |
311 | ||
312 | /* | |
313 | * The device provides a total of 10 PWM pins, and can be configured to different phase | |
314 | * count applications for rail. | |
315 | */ | |
316 | if (info->phases[0] > MP2888_MAX_PHASE) | |
317 | return -EINVAL; | |
318 | ||
319 | return 0; | |
320 | } | |
321 | ||
322 | static struct pmbus_driver_info mp2888_info = { | |
323 | .pages = 1, | |
324 | .format[PSC_VOLTAGE_IN] = linear, | |
325 | .format[PSC_VOLTAGE_OUT] = direct, | |
326 | .format[PSC_TEMPERATURE] = direct, | |
327 | .format[PSC_CURRENT_IN] = linear, | |
328 | .format[PSC_CURRENT_OUT] = direct, | |
329 | .format[PSC_POWER] = direct, | |
330 | .m[PSC_TEMPERATURE] = 1, | |
331 | .R[PSC_TEMPERATURE] = 1, | |
332 | .m[PSC_VOLTAGE_OUT] = 1, | |
333 | .R[PSC_VOLTAGE_OUT] = 3, | |
334 | .m[PSC_CURRENT_OUT] = 4, | |
335 | .m[PSC_POWER] = 1, | |
336 | .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_IOUT | | |
337 | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | | |
338 | PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT | | |
339 | PMBUS_PHASE_VIRTUAL, | |
340 | .pfunc[0] = PMBUS_HAVE_IOUT, | |
341 | .pfunc[1] = PMBUS_HAVE_IOUT, | |
342 | .pfunc[2] = PMBUS_HAVE_IOUT, | |
343 | .pfunc[3] = PMBUS_HAVE_IOUT, | |
344 | .pfunc[4] = PMBUS_HAVE_IOUT, | |
345 | .pfunc[5] = PMBUS_HAVE_IOUT, | |
346 | .pfunc[6] = PMBUS_HAVE_IOUT, | |
347 | .pfunc[7] = PMBUS_HAVE_IOUT, | |
348 | .pfunc[8] = PMBUS_HAVE_IOUT, | |
349 | .pfunc[9] = PMBUS_HAVE_IOUT, | |
350 | .read_byte_data = mp2888_read_byte_data, | |
351 | .read_word_data = mp2888_read_word_data, | |
352 | .write_word_data = mp2888_write_word_data, | |
353 | }; | |
354 | ||
355 | static int mp2888_probe(struct i2c_client *client) | |
356 | { | |
357 | struct pmbus_driver_info *info; | |
358 | struct mp2888_data *data; | |
359 | int ret; | |
360 | ||
361 | data = devm_kzalloc(&client->dev, sizeof(struct mp2888_data), GFP_KERNEL); | |
362 | if (!data) | |
363 | return -ENOMEM; | |
364 | ||
365 | memcpy(&data->info, &mp2888_info, sizeof(*info)); | |
366 | info = &data->info; | |
367 | ||
368 | /* Identify multiphase configuration. */ | |
369 | ret = mp2888_identify_multiphase(client, data, info); | |
370 | if (ret) | |
371 | return ret; | |
372 | ||
373 | /* Obtain current sense gain of power stage and current resolution. */ | |
374 | ret = mp2888_current_sense_gain_and_resolution_get(client, data); | |
375 | if (ret) | |
376 | return ret; | |
377 | ||
378 | return pmbus_do_probe(client, info); | |
379 | } | |
380 | ||
381 | static const struct i2c_device_id mp2888_id[] = { | |
382 | {"mp2888", 0}, | |
383 | {} | |
384 | }; | |
385 | ||
386 | MODULE_DEVICE_TABLE(i2c, mp2888_id); | |
387 | ||
388 | static const struct of_device_id __maybe_unused mp2888_of_match[] = { | |
389 | {.compatible = "mps,mp2888"}, | |
390 | {} | |
391 | }; | |
392 | MODULE_DEVICE_TABLE(of, mp2888_of_match); | |
393 | ||
394 | static struct i2c_driver mp2888_driver = { | |
395 | .driver = { | |
396 | .name = "mp2888", | |
397 | .of_match_table = of_match_ptr(mp2888_of_match), | |
398 | }, | |
399 | .probe_new = mp2888_probe, | |
400 | .id_table = mp2888_id, | |
401 | }; | |
402 | ||
403 | module_i2c_driver(mp2888_driver); | |
404 | ||
405 | MODULE_AUTHOR("Vadim Pasternak <vadimp@nvidia.com>"); | |
406 | MODULE_DESCRIPTION("PMBus driver for MPS MP2888 device"); | |
407 | MODULE_LICENSE("GPL"); | |
408 | MODULE_IMPORT_NS(PMBUS); |