1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Renesas Solutions Highlander FPGA I2C/SMBus support. 4 * 5 * Supported devices: R0P7780LC0011RL, R0P7785LC0011RL 6 * 7 * Copyright (C) 2008 Paul Mundt 8 * Copyright (C) 2008 Renesas Solutions Corp. 9 * Copyright (C) 2008 Atom Create Engineering Co., Ltd. 10 */ 11 #include <linux/module.h> 12 #include <linux/interrupt.h> 13 #include <linux/i2c.h> 14 #include <linux/platform_device.h> 15 #include <linux/completion.h> 16 #include <linux/io.h> 17 #include <linux/delay.h> 18 #include <linux/slab.h> 19 20 #define SMCR 0x00 21 #define SMCR_START (1 << 0) 22 #define SMCR_IRIC (1 << 1) 23 #define SMCR_BBSY (1 << 2) 24 #define SMCR_ACKE (1 << 3) 25 #define SMCR_RST (1 << 4) 26 #define SMCR_IEIC (1 << 6) 27 28 #define SMSMADR 0x02 29 30 #define SMMR 0x04 31 #define SMMR_MODE0 (1 << 0) 32 #define SMMR_MODE1 (1 << 1) 33 #define SMMR_CAP (1 << 3) 34 #define SMMR_TMMD (1 << 4) 35 #define SMMR_SP (1 << 7) 36 37 #define SMSADR 0x06 38 #define SMTRDR 0x46 39 40 struct highlander_i2c_dev { 41 struct device *dev; 42 void __iomem *base; 43 struct i2c_adapter adapter; 44 struct completion cmd_complete; 45 unsigned long last_read_time; 46 int irq; 47 u8 *buf; 48 size_t buf_len; 49 }; 50 51 static bool iic_force_poll, iic_force_normal; 52 static int iic_timeout = 1000, iic_read_delay; 53 54 static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev) 55 { 56 iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR); 57 } 58 59 static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev) 60 { 61 iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR); 62 } 63 64 static inline void highlander_i2c_start(struct highlander_i2c_dev *dev) 65 { 66 iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR); 67 } 68 69 static inline void highlander_i2c_done(struct highlander_i2c_dev *dev) 70 { 71 iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR); 72 } 73 74 static void highlander_i2c_setup(struct highlander_i2c_dev *dev) 75 { 76 u16 smmr; 77 78 smmr = ioread16(dev->base + SMMR); 79 smmr |= SMMR_TMMD; 80 81 if (iic_force_normal) 82 smmr &= ~SMMR_SP; 83 else 84 smmr |= SMMR_SP; 85 86 iowrite16(smmr, dev->base + SMMR); 87 } 88 89 static void smbus_write_data(u8 *src, u16 *dst, int len) 90 { 91 for (; len > 1; len -= 2) { 92 *dst++ = be16_to_cpup((__be16 *)src); 93 src += 2; 94 } 95 96 if (len) 97 *dst = *src << 8; 98 } 99 100 static void smbus_read_data(u16 *src, u8 *dst, int len) 101 { 102 for (; len > 1; len -= 2) { 103 *(__be16 *)dst = cpu_to_be16p(src++); 104 dst += 2; 105 } 106 107 if (len) 108 *dst = *src >> 8; 109 } 110 111 static void highlander_i2c_command(struct highlander_i2c_dev *dev, 112 u8 command, int len) 113 { 114 unsigned int i; 115 u16 cmd = (command << 8) | command; 116 117 for (i = 0; i < len; i += 2) { 118 if (len - i == 1) 119 cmd = command << 8; 120 iowrite16(cmd, dev->base + SMSADR + i); 121 dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd); 122 } 123 } 124 125 static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev) 126 { 127 unsigned long timeout; 128 129 timeout = jiffies + msecs_to_jiffies(iic_timeout); 130 while (ioread16(dev->base + SMCR) & SMCR_BBSY) { 131 if (time_after(jiffies, timeout)) { 132 dev_warn(dev->dev, "timeout waiting for bus ready\n"); 133 return -ETIMEDOUT; 134 } 135 136 msleep(1); 137 } 138 139 return 0; 140 } 141 142 static int highlander_i2c_reset(struct highlander_i2c_dev *dev) 143 { 144 iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR); 145 return highlander_i2c_wait_for_bbsy(dev); 146 } 147 148 static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev) 149 { 150 u16 tmp = ioread16(dev->base + SMCR); 151 152 if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) { 153 dev_warn(dev->dev, "ack abnormality\n"); 154 return highlander_i2c_reset(dev); 155 } 156 157 return 0; 158 } 159 160 static irqreturn_t highlander_i2c_irq(int irq, void *dev_id) 161 { 162 struct highlander_i2c_dev *dev = dev_id; 163 164 highlander_i2c_done(dev); 165 complete(&dev->cmd_complete); 166 167 return IRQ_HANDLED; 168 } 169 170 static void highlander_i2c_poll(struct highlander_i2c_dev *dev) 171 { 172 unsigned long timeout; 173 u16 smcr; 174 175 timeout = jiffies + msecs_to_jiffies(iic_timeout); 176 for (;;) { 177 smcr = ioread16(dev->base + SMCR); 178 179 /* 180 * Don't bother checking ACKE here, this and the reset 181 * are handled in highlander_i2c_wait_xfer_done() when 182 * waiting for the ACK. 183 */ 184 185 if (smcr & SMCR_IRIC) 186 return; 187 if (time_after(jiffies, timeout)) 188 break; 189 190 cpu_relax(); 191 cond_resched(); 192 } 193 194 dev_err(dev->dev, "polling timed out\n"); 195 } 196 197 static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev) 198 { 199 if (dev->irq) 200 wait_for_completion_timeout(&dev->cmd_complete, 201 msecs_to_jiffies(iic_timeout)); 202 else 203 /* busy looping, the IRQ of champions */ 204 highlander_i2c_poll(dev); 205 206 return highlander_i2c_wait_for_ack(dev); 207 } 208 209 static int highlander_i2c_read(struct highlander_i2c_dev *dev) 210 { 211 int i, cnt; 212 u16 data[16]; 213 214 if (highlander_i2c_wait_for_bbsy(dev)) 215 return -EAGAIN; 216 217 highlander_i2c_start(dev); 218 219 if (highlander_i2c_wait_xfer_done(dev)) { 220 dev_err(dev->dev, "Arbitration loss\n"); 221 return -EAGAIN; 222 } 223 224 /* 225 * The R0P7780LC0011RL FPGA needs a significant delay between 226 * data read cycles, otherwise the transceiver gets confused and 227 * garbage is returned when the read is subsequently aborted. 228 * 229 * It is not sufficient to wait for BBSY. 230 * 231 * While this generally only applies to the older SH7780-based 232 * Highlanders, the same issue can be observed on SH7785 ones, 233 * albeit less frequently. SH7780-based Highlanders may need 234 * this to be as high as 1000 ms. 235 */ 236 if (iic_read_delay && time_before(jiffies, dev->last_read_time + 237 msecs_to_jiffies(iic_read_delay))) 238 msleep(jiffies_to_msecs((dev->last_read_time + 239 msecs_to_jiffies(iic_read_delay)) - jiffies)); 240 241 cnt = (dev->buf_len + 1) >> 1; 242 for (i = 0; i < cnt; i++) { 243 data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16))); 244 dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]); 245 } 246 247 smbus_read_data(data, dev->buf, dev->buf_len); 248 249 dev->last_read_time = jiffies; 250 251 return 0; 252 } 253 254 static int highlander_i2c_write(struct highlander_i2c_dev *dev) 255 { 256 int i, cnt; 257 u16 data[16]; 258 259 smbus_write_data(dev->buf, data, dev->buf_len); 260 261 cnt = (dev->buf_len + 1) >> 1; 262 for (i = 0; i < cnt; i++) { 263 iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16))); 264 dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]); 265 } 266 267 if (highlander_i2c_wait_for_bbsy(dev)) 268 return -EAGAIN; 269 270 highlander_i2c_start(dev); 271 272 return highlander_i2c_wait_xfer_done(dev); 273 } 274 275 static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, 276 unsigned short flags, char read_write, 277 u8 command, int size, 278 union i2c_smbus_data *data) 279 { 280 struct highlander_i2c_dev *dev = i2c_get_adapdata(adap); 281 u16 tmp; 282 283 init_completion(&dev->cmd_complete); 284 285 dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n", 286 addr, command, read_write, size); 287 288 /* 289 * Set up the buffer and transfer size 290 */ 291 switch (size) { 292 case I2C_SMBUS_BYTE_DATA: 293 dev->buf = &data->byte; 294 dev->buf_len = 1; 295 break; 296 case I2C_SMBUS_I2C_BLOCK_DATA: 297 dev->buf = &data->block[1]; 298 dev->buf_len = data->block[0]; 299 break; 300 default: 301 dev_err(dev->dev, "unsupported command %d\n", size); 302 return -EINVAL; 303 } 304 305 /* 306 * Encode the mode setting 307 */ 308 tmp = ioread16(dev->base + SMMR); 309 tmp &= ~(SMMR_MODE0 | SMMR_MODE1); 310 311 switch (dev->buf_len) { 312 case 1: 313 /* default */ 314 break; 315 case 8: 316 tmp |= SMMR_MODE0; 317 break; 318 case 16: 319 tmp |= SMMR_MODE1; 320 break; 321 case 32: 322 tmp |= (SMMR_MODE0 | SMMR_MODE1); 323 break; 324 default: 325 dev_err(dev->dev, "unsupported xfer size %zu\n", dev->buf_len); 326 return -EINVAL; 327 } 328 329 iowrite16(tmp, dev->base + SMMR); 330 331 /* Ensure we're in a sane state */ 332 highlander_i2c_done(dev); 333 334 /* Set slave address */ 335 iowrite16((addr << 1) | read_write, dev->base + SMSMADR); 336 337 highlander_i2c_command(dev, command, dev->buf_len); 338 339 if (read_write == I2C_SMBUS_READ) 340 return highlander_i2c_read(dev); 341 else 342 return highlander_i2c_write(dev); 343 } 344 345 static u32 highlander_i2c_func(struct i2c_adapter *adapter) 346 { 347 return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK; 348 } 349 350 static const struct i2c_algorithm highlander_i2c_algo = { 351 .smbus_xfer = highlander_i2c_smbus_xfer, 352 .functionality = highlander_i2c_func, 353 }; 354 355 static int highlander_i2c_probe(struct platform_device *pdev) 356 { 357 struct highlander_i2c_dev *dev; 358 struct i2c_adapter *adap; 359 struct resource *res; 360 int ret; 361 362 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 363 if (unlikely(!res)) { 364 dev_err(&pdev->dev, "no mem resource\n"); 365 return -ENODEV; 366 } 367 368 dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL); 369 if (unlikely(!dev)) 370 return -ENOMEM; 371 372 dev->base = ioremap(res->start, resource_size(res)); 373 if (unlikely(!dev->base)) { 374 ret = -ENXIO; 375 goto err; 376 } 377 378 dev->dev = &pdev->dev; 379 platform_set_drvdata(pdev, dev); 380 381 dev->irq = platform_get_irq(pdev, 0); 382 if (dev->irq < 0 || iic_force_poll) 383 dev->irq = 0; 384 385 if (dev->irq) { 386 ret = request_irq(dev->irq, highlander_i2c_irq, 0, 387 pdev->name, dev); 388 if (unlikely(ret)) 389 goto err_unmap; 390 391 highlander_i2c_irq_enable(dev); 392 } else { 393 dev_notice(&pdev->dev, "no IRQ, using polling mode\n"); 394 highlander_i2c_irq_disable(dev); 395 } 396 397 dev->last_read_time = jiffies; /* initial read jiffies */ 398 399 highlander_i2c_setup(dev); 400 401 adap = &dev->adapter; 402 i2c_set_adapdata(adap, dev); 403 adap->owner = THIS_MODULE; 404 adap->class = I2C_CLASS_HWMON; 405 strscpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name)); 406 adap->algo = &highlander_i2c_algo; 407 adap->dev.parent = &pdev->dev; 408 adap->nr = pdev->id; 409 410 /* 411 * Reset the adapter 412 */ 413 ret = highlander_i2c_reset(dev); 414 if (unlikely(ret)) { 415 dev_err(&pdev->dev, "controller didn't come up\n"); 416 goto err_free_irq; 417 } 418 419 ret = i2c_add_numbered_adapter(adap); 420 if (unlikely(ret)) { 421 dev_err(&pdev->dev, "failure adding adapter\n"); 422 goto err_free_irq; 423 } 424 425 return 0; 426 427 err_free_irq: 428 if (dev->irq) 429 free_irq(dev->irq, dev); 430 err_unmap: 431 iounmap(dev->base); 432 err: 433 kfree(dev); 434 435 return ret; 436 } 437 438 static void highlander_i2c_remove(struct platform_device *pdev) 439 { 440 struct highlander_i2c_dev *dev = platform_get_drvdata(pdev); 441 442 i2c_del_adapter(&dev->adapter); 443 444 if (dev->irq) 445 free_irq(dev->irq, dev); 446 447 iounmap(dev->base); 448 kfree(dev); 449 } 450 451 static struct platform_driver highlander_i2c_driver = { 452 .driver = { 453 .name = "i2c-highlander", 454 }, 455 456 .probe = highlander_i2c_probe, 457 .remove_new = highlander_i2c_remove, 458 }; 459 460 module_platform_driver(highlander_i2c_driver); 461 462 MODULE_AUTHOR("Paul Mundt"); 463 MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter"); 464 MODULE_LICENSE("GPL v2"); 465 466 module_param(iic_force_poll, bool, 0); 467 module_param(iic_force_normal, bool, 0); 468 module_param(iic_timeout, int, 0); 469 module_param(iic_read_delay, int, 0); 470 471 MODULE_PARM_DESC(iic_force_poll, "Force polling mode"); 472 MODULE_PARM_DESC(iic_force_normal, 473 "Force normal mode (100 kHz), default is fast mode (400 kHz)"); 474 MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)"); 475 MODULE_PARM_DESC(iic_read_delay, 476 "Delay between data read cycles (default 0 ms)"); 477