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