drivers/gpu/drm/amd/display/dc/dce/dce_i2c_sw.c

   1 /*
   2  * Copyright 2018 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * Authors: AMD
  23  *
  24  */
  25
  26 #include <linux/delay.h>
  27
  28 #include "dce_i2c.h"
  29 #include "dce_i2c_sw.h"
  30 #include "include/gpio_service_interface.h"
  31 #define SCL false
  32 #define SDA true
  33
  34 void dce_i2c_sw_construct(
  35         struct dce_i2c_sw *dce_i2c_sw,
  36         struct dc_context *ctx)
  37 {
  38         dce_i2c_sw->ctx = ctx;
  39 }
  40
  41 static inline bool read_bit_from_ddc(
  42         struct ddc *ddc,
  43         bool data_nor_clock)
  44 {
  45         uint32_t value = 0;
  46
  47         if (data_nor_clock)
  48                 dal_gpio_get_value(ddc->pin_data, &value);
  49         else
  50                 dal_gpio_get_value(ddc->pin_clock, &value);
  51
  52         return (value != 0);
  53 }
  54
  55 static inline void write_bit_to_ddc(
  56         struct ddc *ddc,
  57         bool data_nor_clock,
  58         bool bit)
  59 {
  60         uint32_t value = bit ? 1 : 0;
  61
  62         if (data_nor_clock)
  63                 dal_gpio_set_value(ddc->pin_data, value);
  64         else
  65                 dal_gpio_set_value(ddc->pin_clock, value);
  66 }
  67
  68 static void release_engine_dce_sw(
  69         struct resource_pool *pool,
  70         struct dce_i2c_sw *dce_i2c_sw)
  71 {
  72         dal_ddc_close(dce_i2c_sw->ddc);
  73         dce_i2c_sw->ddc = NULL;
  74 }
  75
  76 static bool wait_for_scl_high_sw(
  77         struct dc_context *ctx,
  78         struct ddc *ddc,
  79         uint16_t clock_delay_div_4)
  80 {
  81         uint32_t scl_retry = 0;
  82         uint32_t scl_retry_max = I2C_SW_TIMEOUT_DELAY / clock_delay_div_4;
  83
  84         udelay(clock_delay_div_4);
  85
  86         do {
  87                 if (read_bit_from_ddc(ddc, SCL))
  88                         return true;
  89
  90                 udelay(clock_delay_div_4);
  91
  92                 ++scl_retry;
  93         } while (scl_retry <= scl_retry_max);
  94
  95         return false;
  96 }
  97 static bool write_byte_sw(
  98         struct dc_context *ctx,
  99         struct ddc *ddc_handle,
 100         uint16_t clock_delay_div_4,
 101         uint8_t byte)
 102 {
 103         int32_t shift = 7;
 104         bool ack;
 105
 106         /* bits are transmitted serially, starting from MSB */
 107
 108         do {
 109                 udelay(clock_delay_div_4);
 110
 111                 write_bit_to_ddc(ddc_handle, SDA, (byte >> shift) & 1);
 112
 113                 udelay(clock_delay_div_4);
 114
 115                 write_bit_to_ddc(ddc_handle, SCL, true);
 116
 117                 if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 118                         return false;
 119
 120                 write_bit_to_ddc(ddc_handle, SCL, false);
 121
 122                 --shift;
 123         } while (shift >= 0);
 124
 125         /* The display sends ACK by preventing the SDA from going high
 126          * after the SCL pulse we use to send our last data bit.
 127          * If the SDA goes high after that bit, it's a NACK
 128          */
 129
 130         udelay(clock_delay_div_4);
 131
 132         write_bit_to_ddc(ddc_handle, SDA, true);
 133
 134         udelay(clock_delay_div_4);
 135
 136         write_bit_to_ddc(ddc_handle, SCL, true);
 137
 138         if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 139                 return false;
 140
 141         /* read ACK bit */
 142
 143         ack = !read_bit_from_ddc(ddc_handle, SDA);
 144
 145         udelay(clock_delay_div_4 << 1);
 146
 147         write_bit_to_ddc(ddc_handle, SCL, false);
 148
 149         udelay(clock_delay_div_4 << 1);
 150
 151         return ack;
 152 }
 153
 154 static bool read_byte_sw(
 155         struct dc_context *ctx,
 156         struct ddc *ddc_handle,
 157         uint16_t clock_delay_div_4,
 158         uint8_t *byte,
 159         bool more)
 160 {
 161         int32_t shift = 7;
 162
 163         uint8_t data = 0;
 164
 165         /* The data bits are read from MSB to LSB;
 166          * bit is read while SCL is high
 167          */
 168
 169         do {
 170                 write_bit_to_ddc(ddc_handle, SCL, true);
 171
 172                 if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 173                         return false;
 174
 175                 if (read_bit_from_ddc(ddc_handle, SDA))
 176                         data |= (1 << shift);
 177
 178                 write_bit_to_ddc(ddc_handle, SCL, false);
 179
 180                 udelay(clock_delay_div_4 << 1);
 181
 182                 --shift;
 183         } while (shift >= 0);
 184
 185         /* read only whole byte */
 186
 187         *byte = data;
 188
 189         udelay(clock_delay_div_4);
 190
 191         /* send the acknowledge bit:
 192          * SDA low means ACK, SDA high means NACK
 193          */
 194
 195         write_bit_to_ddc(ddc_handle, SDA, !more);
 196
 197         udelay(clock_delay_div_4);
 198
 199         write_bit_to_ddc(ddc_handle, SCL, true);
 200
 201         if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 202                 return false;
 203
 204         write_bit_to_ddc(ddc_handle, SCL, false);
 205
 206         udelay(clock_delay_div_4);
 207
 208         write_bit_to_ddc(ddc_handle, SDA, true);
 209
 210         udelay(clock_delay_div_4);
 211
 212         return true;
 213 }
 214 static bool stop_sync_sw(
 215         struct dc_context *ctx,
 216         struct ddc *ddc_handle,
 217         uint16_t clock_delay_div_4)
 218 {
 219         uint32_t retry = 0;
 220
 221         /* The I2C communications stop signal is:
 222          * the SDA going high from low, while the SCL is high.
 223          */
 224
 225         write_bit_to_ddc(ddc_handle, SCL, false);
 226
 227         udelay(clock_delay_div_4);
 228
 229         write_bit_to_ddc(ddc_handle, SDA, false);
 230
 231         udelay(clock_delay_div_4);
 232
 233         write_bit_to_ddc(ddc_handle, SCL, true);
 234
 235         if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 236                 return false;
 237
 238         write_bit_to_ddc(ddc_handle, SDA, true);
 239
 240         do {
 241                 udelay(clock_delay_div_4);
 242
 243                 if (read_bit_from_ddc(ddc_handle, SDA))
 244                         return true;
 245
 246                 ++retry;
 247         } while (retry <= 2);
 248
 249         return false;
 250 }
 251 static bool i2c_write_sw(
 252         struct dc_context *ctx,
 253         struct ddc *ddc_handle,
 254         uint16_t clock_delay_div_4,
 255         uint8_t address,
 256         uint32_t length,
 257         const uint8_t *data)
 258 {
 259         uint32_t i = 0;
 260
 261         if (!write_byte_sw(ctx, ddc_handle, clock_delay_div_4, address))
 262                 return false;
 263
 264         while (i < length) {
 265                 if (!write_byte_sw(ctx, ddc_handle, clock_delay_div_4, data[i]))
 266                         return false;
 267                 ++i;
 268         }
 269
 270         return true;
 271 }
 272
 273 static bool i2c_read_sw(
 274         struct dc_context *ctx,
 275         struct ddc *ddc_handle,
 276         uint16_t clock_delay_div_4,
 277         uint8_t address,
 278         uint32_t length,
 279         uint8_t *data)
 280 {
 281         uint32_t i = 0;
 282
 283         if (!write_byte_sw(ctx, ddc_handle, clock_delay_div_4, address))
 284                 return false;
 285
 286         while (i < length) {
 287                 if (!read_byte_sw(ctx, ddc_handle, clock_delay_div_4, data + i,
 288                         i < length - 1))
 289                         return false;
 290                 ++i;
 291         }
 292
 293         return true;
 294 }
 295
 296
 297
 298 static bool start_sync_sw(
 299         struct dc_context *ctx,
 300         struct ddc *ddc_handle,
 301         uint16_t clock_delay_div_4)
 302 {
 303         uint32_t retry = 0;
 304
 305         /* The I2C communications start signal is:
 306          * the SDA going low from high, while the SCL is high.
 307          */
 308
 309         write_bit_to_ddc(ddc_handle, SCL, true);
 310
 311         udelay(clock_delay_div_4);
 312
 313         do {
 314                 write_bit_to_ddc(ddc_handle, SDA, true);
 315
 316                 if (!read_bit_from_ddc(ddc_handle, SDA)) {
 317                         ++retry;
 318                         continue;
 319                 }
 320
 321                 udelay(clock_delay_div_4);
 322
 323                 write_bit_to_ddc(ddc_handle, SCL, true);
 324
 325                 if (!wait_for_scl_high_sw(ctx, ddc_handle, clock_delay_div_4))
 326                         break;
 327
 328                 write_bit_to_ddc(ddc_handle, SDA, false);
 329
 330                 udelay(clock_delay_div_4);
 331
 332                 write_bit_to_ddc(ddc_handle, SCL, false);
 333
 334                 udelay(clock_delay_div_4);
 335
 336                 return true;
 337         } while (retry <= I2C_SW_RETRIES);
 338
 339         return false;
 340 }
 341
 342 static void dce_i2c_sw_engine_set_speed(
 343         struct dce_i2c_sw *engine,
 344         uint32_t speed)
 345 {
 346         ASSERT(speed);
 347
 348         engine->speed = speed ? speed : DCE_I2C_DEFAULT_I2C_SW_SPEED;
 349
 350         engine->clock_delay = 1000 / engine->speed;
 351
 352         if (engine->clock_delay < 12)
 353                 engine->clock_delay = 12;
 354 }
 355
 356 static bool dce_i2c_sw_engine_acquire_engine(
 357         struct dce_i2c_sw *engine,
 358         struct ddc *ddc)
 359 {
 360         enum gpio_result result;
 361
 362         result = dal_ddc_open(ddc, GPIO_MODE_FAST_OUTPUT,
 363                 GPIO_DDC_CONFIG_TYPE_MODE_I2C);
 364
 365         if (result != GPIO_RESULT_OK)
 366                 return false;
 367
 368         engine->ddc = ddc;
 369
 370         return true;
 371 }
 372 bool dce_i2c_engine_acquire_sw(
 373         struct dce_i2c_sw *dce_i2c_sw,
 374         struct ddc *ddc_handle)
 375 {
 376         uint32_t counter = 0;
 377         bool result;
 378
 379         do {
 380
 381                 result = dce_i2c_sw_engine_acquire_engine(
 382                                 dce_i2c_sw, ddc_handle);
 383
 384                 if (result)
 385                         break;
 386
 387                 /* i2c_engine is busy by VBios, lets wait and retry */
 388
 389                 udelay(10);
 390
 391                 ++counter;
 392         } while (counter < 2);
 393
 394         return result;
 395 }
 396
 397
 398
 399
 400 static void dce_i2c_sw_engine_submit_channel_request(
 401         struct dce_i2c_sw *engine,
 402         struct i2c_request_transaction_data *req)
 403 {
 404         struct ddc *ddc = engine->ddc;
 405         uint16_t clock_delay_div_4 = engine->clock_delay >> 2;
 406
 407         /* send sync (start / repeated start) */
 408
 409         bool result = start_sync_sw(engine->ctx, ddc, clock_delay_div_4);
 410
 411         /* process payload */
 412
 413         if (result) {
 414                 switch (req->action) {
 415                 case DCE_I2C_TRANSACTION_ACTION_I2C_WRITE:
 416                 case DCE_I2C_TRANSACTION_ACTION_I2C_WRITE_MOT:
 417                         result = i2c_write_sw(engine->ctx, ddc, clock_delay_div_4,
 418                                 req->address, req->length, req->data);
 419                 break;
 420                 case DCE_I2C_TRANSACTION_ACTION_I2C_READ:
 421                 case DCE_I2C_TRANSACTION_ACTION_I2C_READ_MOT:
 422                         result = i2c_read_sw(engine->ctx, ddc, clock_delay_div_4,
 423                                 req->address, req->length, req->data);
 424                 break;
 425                 default:
 426                         result = false;
 427                 break;
 428                 }
 429         }
 430
 431         /* send stop if not 'mot' or operation failed */
 432
 433         if (!result ||
 434                 (req->action == DCE_I2C_TRANSACTION_ACTION_I2C_WRITE) ||
 435                 (req->action == DCE_I2C_TRANSACTION_ACTION_I2C_READ))
 436                 if (!stop_sync_sw(engine->ctx, ddc, clock_delay_div_4))
 437                         result = false;
 438
 439         req->status = result ?
 440                 I2C_CHANNEL_OPERATION_SUCCEEDED :
 441                 I2C_CHANNEL_OPERATION_FAILED;
 442 }
 443
 444 static bool dce_i2c_sw_engine_submit_payload(
 445         struct dce_i2c_sw *engine,
 446         struct i2c_payload *payload,
 447         bool middle_of_transaction)
 448 {
 449         struct i2c_request_transaction_data request;
 450
 451         if (!payload->write)
 452                 request.action = middle_of_transaction ?
 453                         DCE_I2C_TRANSACTION_ACTION_I2C_READ_MOT :
 454                         DCE_I2C_TRANSACTION_ACTION_I2C_READ;
 455         else
 456                 request.action = middle_of_transaction ?
 457                         DCE_I2C_TRANSACTION_ACTION_I2C_WRITE_MOT :
 458                         DCE_I2C_TRANSACTION_ACTION_I2C_WRITE;
 459
 460         request.address = (uint8_t) ((payload->address << 1) | !payload->write);
 461         request.length = payload->length;
 462         request.data = payload->data;
 463
 464         dce_i2c_sw_engine_submit_channel_request(engine, &request);
 465
 466         if ((request.status == I2C_CHANNEL_OPERATION_ENGINE_BUSY) ||
 467                 (request.status == I2C_CHANNEL_OPERATION_FAILED))
 468                 return false;
 469
 470         return true;
 471 }
 472 bool dce_i2c_submit_command_sw(
 473         struct resource_pool *pool,
 474         struct ddc *ddc,
 475         struct i2c_command *cmd,
 476         struct dce_i2c_sw *dce_i2c_sw)
 477 {
 478         uint8_t index_of_payload = 0;
 479         bool result;
 480
 481         dce_i2c_sw_engine_set_speed(dce_i2c_sw, cmd->speed);
 482
 483         result = true;
 484
 485         while (index_of_payload < cmd->number_of_payloads) {
 486                 bool mot = (index_of_payload != cmd->number_of_payloads - 1);
 487
 488                 struct i2c_payload *payload = cmd->payloads + index_of_payload;
 489
 490                 if (!dce_i2c_sw_engine_submit_payload(
 491                         dce_i2c_sw, payload, mot)) {
 492                         result = false;
 493                         break;
 494                 }
 495
 496                 ++index_of_payload;
 497         }
 498
 499         release_engine_dce_sw(pool, dce_i2c_sw);
 500
 501         return result;
 502 }