drivers/media/i2c/max9271.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017-2020 Jacopo Mondi
   4  * Copyright (C) 2017-2020 Kieran Bingham
   5  * Copyright (C) 2017-2020 Laurent Pinchart
   6  * Copyright (C) 2017-2020 Niklas Söderlund
   7  * Copyright (C) 2016 Renesas Electronics Corporation
   8  * Copyright (C) 2015 Cogent Embedded, Inc.
   9  *
  10  * This file exports functions to control the Maxim MAX9271 GMSL serializer
  11  * chip. This is not a self-contained driver, as MAX9271 is usually embedded in
  12  * camera modules with at least one image sensor and optional additional
  13  * components, such as uController units or ISPs/DSPs.
  14  *
  15  * Drivers for the camera modules (i.e. rdacm20/21) are expected to use
  16  * functions exported from this library driver to maximize code re-use.
  17  */
  18
  19 #include <linux/delay.h>
  20 #include <linux/i2c.h>
  21 #include <linux/module.h>
  22
  23 #include "max9271.h"
  24
  25 static int max9271_read(struct max9271_device *dev, u8 reg)
  26 {
  27         int ret;
  28
  29         dev_dbg(&dev->client->dev, "%s(0x%02x)\n", __func__, reg);
  30
  31         ret = i2c_smbus_read_byte_data(dev->client, reg);
  32         if (ret < 0)
  33                 dev_dbg(&dev->client->dev,
  34                         "%s: register 0x%02x read failed (%d)\n",
  35                         __func__, reg, ret);
  36
  37         return ret;
  38 }
  39
  40 static int max9271_write(struct max9271_device *dev, u8 reg, u8 val)
  41 {
  42         int ret;
  43
  44         dev_dbg(&dev->client->dev, "%s(0x%02x, 0x%02x)\n", __func__, reg, val);
  45
  46         ret = i2c_smbus_write_byte_data(dev->client, reg, val);
  47         if (ret < 0)
  48                 dev_err(&dev->client->dev,
  49                         "%s: register 0x%02x write failed (%d)\n",
  50                         __func__, reg, ret);
  51
  52         return ret;
  53 }
  54
  55 /*
  56  * max9271_pclk_detect() - Detect valid pixel clock from image sensor
  57  *
  58  * Wait up to 10ms for a valid pixel clock.
  59  *
  60  * Returns 0 for success, < 0 for pixel clock not properly detected
  61  */
  62 static int max9271_pclk_detect(struct max9271_device *dev)
  63 {
  64         unsigned int i;
  65         int ret;
  66
  67         for (i = 0; i < 100; i++) {
  68                 ret = max9271_read(dev, 0x15);
  69                 if (ret < 0)
  70                         return ret;
  71
  72                 if (ret & MAX9271_PCLKDET)
  73                         return 0;
  74
  75                 usleep_range(50, 100);
  76         }
  77
  78         dev_err(&dev->client->dev, "Unable to detect valid pixel clock\n");
  79
  80         return -EIO;
  81 }
  82
  83 void max9271_wake_up(struct max9271_device *dev)
  84 {
  85         /*
  86          * Use the chip default address as this function has to be called
  87          * before any other one.
  88          */
  89         dev->client->addr = MAX9271_DEFAULT_ADDR;
  90         i2c_smbus_read_byte(dev->client);
  91         usleep_range(5000, 8000);
  92 }
  93 EXPORT_SYMBOL_GPL(max9271_wake_up);
  94
  95 int max9271_set_serial_link(struct max9271_device *dev, bool enable)
  96 {
  97         int ret;
  98         u8 val = MAX9271_REVCCEN | MAX9271_FWDCCEN;
  99
 100         if (enable) {
 101                 ret = max9271_pclk_detect(dev);
 102                 if (ret)
 103                         return ret;
 104
 105                 val |= MAX9271_SEREN;
 106         } else {
 107                 val |= MAX9271_CLINKEN;
 108         }
 109
 110         /*
 111          * The serializer temporarily disables the reverse control channel for
 112          * 350µs after starting/stopping the forward serial link, but the
 113          * deserializer synchronization time isn't clearly documented.
 114          *
 115          * According to the serializer datasheet we should wait 3ms, while
 116          * according to the deserializer datasheet we should wait 5ms.
 117          *
 118          * Short delays here appear to show bit-errors in the writes following.
 119          * Therefore a conservative delay seems best here.
 120          */
 121         ret = max9271_write(dev, 0x04, val);
 122         if (ret < 0)
 123                 return ret;
 124
 125         usleep_range(5000, 8000);
 126
 127         return 0;
 128 }
 129 EXPORT_SYMBOL_GPL(max9271_set_serial_link);
 130
 131 int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config)
 132 {
 133         int ret;
 134
 135         ret = max9271_write(dev, 0x0d, i2c_config);
 136         if (ret < 0)
 137                 return ret;
 138
 139         /* The delay required after an I2C bus configuration change is not
 140          * characterized in the serializer manual. Sleep up to 5msec to
 141          * stay safe.
 142          */
 143         usleep_range(3500, 5000);
 144
 145         return 0;
 146 }
 147 EXPORT_SYMBOL_GPL(max9271_configure_i2c);
 148
 149 int max9271_set_high_threshold(struct max9271_device *dev, bool enable)
 150 {
 151         int ret;
 152
 153         ret = max9271_read(dev, 0x08);
 154         if (ret < 0)
 155                 return ret;
 156
 157         /*
 158          * Enable or disable reverse channel high threshold to increase
 159          * immunity to power supply noise.
 160          */
 161         ret = max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0));
 162         if (ret < 0)
 163                 return ret;
 164
 165         usleep_range(2000, 2500);
 166
 167         return 0;
 168 }
 169 EXPORT_SYMBOL_GPL(max9271_set_high_threshold);
 170
 171 int max9271_configure_gmsl_link(struct max9271_device *dev)
 172 {
 173         int ret;
 174
 175         /*
 176          * Configure the GMSL link:
 177          *
 178          * - Double input mode, high data rate, 24-bit mode
 179          * - Latch input data on PCLKIN rising edge
 180          * - Enable HS/VS encoding
 181          * - 1-bit parity error detection
 182          *
 183          * TODO: Make the GMSL link configuration parametric.
 184          */
 185         ret = max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN |
 186                             MAX9271_EDC_1BIT_PARITY);
 187         if (ret < 0)
 188                 return ret;
 189
 190         usleep_range(5000, 8000);
 191
 192         /*
 193          * Adjust spread spectrum to +4% and auto-detect pixel clock
 194          * and serial link rate.
 195          */
 196         ret = max9271_write(dev, 0x02,
 197                             MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES |
 198                             MAX9271_PCLK_AUTODETECT |
 199                             MAX9271_SERIAL_AUTODETECT);
 200         if (ret < 0)
 201                 return ret;
 202
 203         usleep_range(5000, 8000);
 204
 205         return 0;
 206 }
 207 EXPORT_SYMBOL_GPL(max9271_configure_gmsl_link);
 208
 209 int max9271_set_gpios(struct max9271_device *dev, u8 gpio_mask)
 210 {
 211         int ret;
 212
 213         ret = max9271_read(dev, 0x0f);
 214         if (ret < 0)
 215                 return 0;
 216
 217         ret |= gpio_mask;
 218         ret = max9271_write(dev, 0x0f, ret);
 219         if (ret < 0) {
 220                 dev_err(&dev->client->dev, "Failed to set gpio (%d)\n", ret);
 221                 return ret;
 222         }
 223
 224         usleep_range(3500, 5000);
 225
 226         return 0;
 227 }
 228 EXPORT_SYMBOL_GPL(max9271_set_gpios);
 229
 230 int max9271_clear_gpios(struct max9271_device *dev, u8 gpio_mask)
 231 {
 232         int ret;
 233
 234         ret = max9271_read(dev, 0x0f);
 235         if (ret < 0)
 236                 return 0;
 237
 238         ret &= ~gpio_mask;
 239         ret = max9271_write(dev, 0x0f, ret);
 240         if (ret < 0) {
 241                 dev_err(&dev->client->dev, "Failed to clear gpio (%d)\n", ret);
 242                 return ret;
 243         }
 244
 245         usleep_range(3500, 5000);
 246
 247         return 0;
 248 }
 249 EXPORT_SYMBOL_GPL(max9271_clear_gpios);
 250
 251 int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask)
 252 {
 253         int ret;
 254
 255         ret = max9271_read(dev, 0x0e);
 256         if (ret < 0)
 257                 return 0;
 258
 259         /* BIT(0) reserved: GPO is always enabled. */
 260         ret |= (gpio_mask & ~BIT(0));
 261         ret = max9271_write(dev, 0x0e, ret);
 262         if (ret < 0) {
 263                 dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret);
 264                 return ret;
 265         }
 266
 267         usleep_range(3500, 5000);
 268
 269         return 0;
 270 }
 271 EXPORT_SYMBOL_GPL(max9271_enable_gpios);
 272
 273 int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask)
 274 {
 275         int ret;
 276
 277         ret = max9271_read(dev, 0x0e);
 278         if (ret < 0)
 279                 return 0;
 280
 281         /* BIT(0) reserved: GPO cannot be disabled */
 282         ret &= ~(gpio_mask | BIT(0));
 283         ret = max9271_write(dev, 0x0e, ret);
 284         if (ret < 0) {
 285                 dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret);
 286                 return ret;
 287         }
 288
 289         usleep_range(3500, 5000);
 290
 291         return 0;
 292 }
 293 EXPORT_SYMBOL_GPL(max9271_disable_gpios);
 294
 295 int max9271_verify_id(struct max9271_device *dev)
 296 {
 297         int ret;
 298
 299         ret = max9271_read(dev, 0x1e);
 300         if (ret < 0) {
 301                 dev_err(&dev->client->dev, "MAX9271 ID read failed (%d)\n",
 302                         ret);
 303                 return ret;
 304         }
 305
 306         if (ret != MAX9271_ID) {
 307                 dev_err(&dev->client->dev, "MAX9271 ID mismatch (0x%02x)\n",
 308                         ret);
 309                 return -ENXIO;
 310         }
 311
 312         return 0;
 313 }
 314 EXPORT_SYMBOL_GPL(max9271_verify_id);
 315
 316 int max9271_set_address(struct max9271_device *dev, u8 addr)
 317 {
 318         int ret;
 319
 320         ret = max9271_write(dev, 0x00, addr << 1);
 321         if (ret < 0) {
 322                 dev_err(&dev->client->dev,
 323                         "MAX9271 I2C address change failed (%d)\n", ret);
 324                 return ret;
 325         }
 326         usleep_range(3500, 5000);
 327
 328         return 0;
 329 }
 330 EXPORT_SYMBOL_GPL(max9271_set_address);
 331
 332 int max9271_set_deserializer_address(struct max9271_device *dev, u8 addr)
 333 {
 334         int ret;
 335
 336         ret = max9271_write(dev, 0x01, addr << 1);
 337         if (ret < 0) {
 338                 dev_err(&dev->client->dev,
 339                         "MAX9271 deserializer address set failed (%d)\n", ret);
 340                 return ret;
 341         }
 342         usleep_range(3500, 5000);
 343
 344         return 0;
 345 }
 346 EXPORT_SYMBOL_GPL(max9271_set_deserializer_address);
 347
 348 int max9271_set_translation(struct max9271_device *dev, u8 source, u8 dest)
 349 {
 350         int ret;
 351
 352         ret = max9271_write(dev, 0x09, source << 1);
 353         if (ret < 0) {
 354                 dev_err(&dev->client->dev,
 355                         "MAX9271 I2C translation setup failed (%d)\n", ret);
 356                 return ret;
 357         }
 358         usleep_range(3500, 5000);
 359
 360         ret = max9271_write(dev, 0x0a, dest << 1);
 361         if (ret < 0) {
 362                 dev_err(&dev->client->dev,
 363                         "MAX9271 I2C translation setup failed (%d)\n", ret);
 364                 return ret;
 365         }
 366         usleep_range(3500, 5000);
 367
 368         return 0;
 369 }
 370 EXPORT_SYMBOL_GPL(max9271_set_translation);
 371
 372 MODULE_DESCRIPTION("Maxim MAX9271 GMSL Serializer");
 373 MODULE_AUTHOR("Jacopo Mondi");
 374 MODULE_LICENSE("GPL v2");