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 int max9271_set_serial_link(struct max9271_device *dev, bool enable) 84 { 85 int ret; 86 u8 val = MAX9271_REVCCEN | MAX9271_FWDCCEN; 87 88 if (enable) { 89 ret = max9271_pclk_detect(dev); 90 if (ret) 91 return ret; 92 93 val |= MAX9271_SEREN; 94 } else { 95 val |= MAX9271_CLINKEN; 96 } 97 98 /* 99 * The serializer temporarily disables the reverse control channel for 100 * 350µs after starting/stopping the forward serial link, but the 101 * deserializer synchronization time isn't clearly documented. 102 * 103 * According to the serializer datasheet we should wait 3ms, while 104 * according to the deserializer datasheet we should wait 5ms. 105 * 106 * Short delays here appear to show bit-errors in the writes following. 107 * Therefore a conservative delay seems best here. 108 */ 109 ret = max9271_write(dev, 0x04, val); 110 if (ret < 0) 111 return ret; 112 113 usleep_range(5000, 8000); 114 115 return 0; 116 } 117 EXPORT_SYMBOL_GPL(max9271_set_serial_link); 118 119 int max9271_configure_i2c(struct max9271_device *dev, u8 i2c_config) 120 { 121 int ret; 122 123 ret = max9271_write(dev, 0x0d, i2c_config); 124 if (ret < 0) 125 return ret; 126 127 /* The delay required after an I2C bus configuration change is not 128 * characterized in the serializer manual. Sleep up to 5msec to 129 * stay safe. 130 */ 131 usleep_range(3500, 5000); 132 133 return 0; 134 } 135 EXPORT_SYMBOL_GPL(max9271_configure_i2c); 136 137 int max9271_set_high_threshold(struct max9271_device *dev, bool enable) 138 { 139 int ret; 140 141 ret = max9271_read(dev, 0x08); 142 if (ret < 0) 143 return ret; 144 145 /* 146 * Enable or disable reverse channel high threshold to increase 147 * immunity to power supply noise. 148 */ 149 ret = max9271_write(dev, 0x08, enable ? ret | BIT(0) : ret & ~BIT(0)); 150 if (ret < 0) 151 return ret; 152 153 usleep_range(2000, 2500); 154 155 return 0; 156 } 157 EXPORT_SYMBOL_GPL(max9271_set_high_threshold); 158 159 int max9271_configure_gmsl_link(struct max9271_device *dev) 160 { 161 int ret; 162 163 /* 164 * Configure the GMSL link: 165 * 166 * - Double input mode, high data rate, 24-bit mode 167 * - Latch input data on PCLKIN rising edge 168 * - Enable HS/VS encoding 169 * - 1-bit parity error detection 170 * 171 * TODO: Make the GMSL link configuration parametric. 172 */ 173 ret = max9271_write(dev, 0x07, MAX9271_DBL | MAX9271_HVEN | 174 MAX9271_EDC_1BIT_PARITY); 175 if (ret < 0) 176 return ret; 177 178 usleep_range(5000, 8000); 179 180 /* 181 * Adjust spread spectrum to +4% and auto-detect pixel clock 182 * and serial link rate. 183 */ 184 ret = max9271_write(dev, 0x02, 185 MAX9271_SPREAD_SPECT_4 | MAX9271_R02_RES | 186 MAX9271_PCLK_AUTODETECT | 187 MAX9271_SERIAL_AUTODETECT); 188 if (ret < 0) 189 return ret; 190 191 usleep_range(5000, 8000); 192 193 return 0; 194 } 195 EXPORT_SYMBOL_GPL(max9271_configure_gmsl_link); 196 197 int max9271_set_gpios(struct max9271_device *dev, u8 gpio_mask) 198 { 199 int ret; 200 201 ret = max9271_read(dev, 0x0f); 202 if (ret < 0) 203 return 0; 204 205 ret |= gpio_mask; 206 ret = max9271_write(dev, 0x0f, ret); 207 if (ret < 0) { 208 dev_err(&dev->client->dev, "Failed to set gpio (%d)\n", ret); 209 return ret; 210 } 211 212 usleep_range(3500, 5000); 213 214 return 0; 215 } 216 EXPORT_SYMBOL_GPL(max9271_set_gpios); 217 218 int max9271_clear_gpios(struct max9271_device *dev, u8 gpio_mask) 219 { 220 int ret; 221 222 ret = max9271_read(dev, 0x0f); 223 if (ret < 0) 224 return 0; 225 226 ret &= ~gpio_mask; 227 ret = max9271_write(dev, 0x0f, ret); 228 if (ret < 0) { 229 dev_err(&dev->client->dev, "Failed to clear gpio (%d)\n", ret); 230 return ret; 231 } 232 233 usleep_range(3500, 5000); 234 235 return 0; 236 } 237 EXPORT_SYMBOL_GPL(max9271_clear_gpios); 238 239 int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask) 240 { 241 int ret; 242 243 ret = max9271_read(dev, 0x0e); 244 if (ret < 0) 245 return 0; 246 247 /* BIT(0) reserved: GPO is always enabled. */ 248 ret |= (gpio_mask & ~BIT(0)); 249 ret = max9271_write(dev, 0x0e, ret); 250 if (ret < 0) { 251 dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret); 252 return ret; 253 } 254 255 usleep_range(3500, 5000); 256 257 return 0; 258 } 259 EXPORT_SYMBOL_GPL(max9271_enable_gpios); 260 261 int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask) 262 { 263 int ret; 264 265 ret = max9271_read(dev, 0x0e); 266 if (ret < 0) 267 return 0; 268 269 /* BIT(0) reserved: GPO cannot be disabled */ 270 ret &= ~(gpio_mask | BIT(0)); 271 ret = max9271_write(dev, 0x0e, ret); 272 if (ret < 0) { 273 dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret); 274 return ret; 275 } 276 277 usleep_range(3500, 5000); 278 279 return 0; 280 } 281 EXPORT_SYMBOL_GPL(max9271_disable_gpios); 282 283 int max9271_verify_id(struct max9271_device *dev) 284 { 285 int ret; 286 287 ret = max9271_read(dev, 0x1e); 288 if (ret < 0) { 289 dev_err(&dev->client->dev, "MAX9271 ID read failed (%d)\n", 290 ret); 291 return ret; 292 } 293 294 if (ret != MAX9271_ID) { 295 dev_err(&dev->client->dev, "MAX9271 ID mismatch (0x%02x)\n", 296 ret); 297 return -ENXIO; 298 } 299 300 return 0; 301 } 302 EXPORT_SYMBOL_GPL(max9271_verify_id); 303 304 int max9271_set_address(struct max9271_device *dev, u8 addr) 305 { 306 int ret; 307 308 ret = max9271_write(dev, 0x00, addr << 1); 309 if (ret < 0) { 310 dev_err(&dev->client->dev, 311 "MAX9271 I2C address change failed (%d)\n", ret); 312 return ret; 313 } 314 usleep_range(3500, 5000); 315 316 return 0; 317 } 318 EXPORT_SYMBOL_GPL(max9271_set_address); 319 320 int max9271_set_deserializer_address(struct max9271_device *dev, u8 addr) 321 { 322 int ret; 323 324 ret = max9271_write(dev, 0x01, addr << 1); 325 if (ret < 0) { 326 dev_err(&dev->client->dev, 327 "MAX9271 deserializer address set failed (%d)\n", ret); 328 return ret; 329 } 330 usleep_range(3500, 5000); 331 332 return 0; 333 } 334 EXPORT_SYMBOL_GPL(max9271_set_deserializer_address); 335 336 int max9271_set_translation(struct max9271_device *dev, u8 source, u8 dest) 337 { 338 int ret; 339 340 ret = max9271_write(dev, 0x09, source << 1); 341 if (ret < 0) { 342 dev_err(&dev->client->dev, 343 "MAX9271 I2C translation setup failed (%d)\n", ret); 344 return ret; 345 } 346 usleep_range(3500, 5000); 347 348 ret = max9271_write(dev, 0x0a, dest << 1); 349 if (ret < 0) { 350 dev_err(&dev->client->dev, 351 "MAX9271 I2C translation setup failed (%d)\n", ret); 352 return ret; 353 } 354 usleep_range(3500, 5000); 355 356 return 0; 357 } 358 EXPORT_SYMBOL_GPL(max9271_set_translation); 359 360 MODULE_DESCRIPTION("Maxim MAX9271 GMSL Serializer"); 361 MODULE_AUTHOR("Jacopo Mondi"); 362 MODULE_LICENSE("GPL v2"); 363