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"); 375