1 /* 2 * Copyright (C) 2002 Motorola GSG-China 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * Author: 15 * Darius Augulis, Teltonika Inc. 16 * 17 * Desc.: 18 * Implementation of I2C Adapter/Algorithm Driver 19 * for I2C Bus integrated in Freescale i.MX/MXC processors 20 * 21 * Derived from Motorola GSG China I2C example driver 22 * 23 * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de 24 * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de 25 * Copyright (C) 2007 RightHand Technologies, Inc. 26 * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> 27 * 28 * Copyright 2013 Freescale Semiconductor, Inc. 29 * 30 */ 31 32 /** Includes ******************************************************************* 33 *******************************************************************************/ 34 35 #include <linux/clk.h> 36 #include <linux/completion.h> 37 #include <linux/delay.h> 38 #include <linux/dma-mapping.h> 39 #include <linux/dmaengine.h> 40 #include <linux/dmapool.h> 41 #include <linux/err.h> 42 #include <linux/errno.h> 43 #include <linux/i2c.h> 44 #include <linux/init.h> 45 #include <linux/interrupt.h> 46 #include <linux/io.h> 47 #include <linux/kernel.h> 48 #include <linux/module.h> 49 #include <linux/of.h> 50 #include <linux/of_device.h> 51 #include <linux/of_dma.h> 52 #include <linux/platform_data/i2c-imx.h> 53 #include <linux/platform_device.h> 54 #include <linux/sched.h> 55 #include <linux/slab.h> 56 57 /** Defines ******************************************************************** 58 *******************************************************************************/ 59 60 /* This will be the driver name the kernel reports */ 61 #define DRIVER_NAME "imx-i2c" 62 63 /* Default value */ 64 #define IMX_I2C_BIT_RATE 100000 /* 100kHz */ 65 66 /* 67 * Enable DMA if transfer byte size is bigger than this threshold. 68 * As the hardware request, it must bigger than 4 bytes.\ 69 * I have set '16' here, maybe it's not the best but I think it's 70 * the appropriate. 71 */ 72 #define DMA_THRESHOLD 16 73 #define DMA_TIMEOUT 1000 74 75 /* IMX I2C registers: 76 * the I2C register offset is different between SoCs, 77 * to provid support for all these chips, split the 78 * register offset into a fixed base address and a 79 * variable shift value, then the full register offset 80 * will be calculated by 81 * reg_off = ( reg_base_addr << reg_shift) 82 */ 83 #define IMX_I2C_IADR 0x00 /* i2c slave address */ 84 #define IMX_I2C_IFDR 0x01 /* i2c frequency divider */ 85 #define IMX_I2C_I2CR 0x02 /* i2c control */ 86 #define IMX_I2C_I2SR 0x03 /* i2c status */ 87 #define IMX_I2C_I2DR 0x04 /* i2c transfer data */ 88 89 #define IMX_I2C_REGSHIFT 2 90 #define VF610_I2C_REGSHIFT 0 91 92 /* Bits of IMX I2C registers */ 93 #define I2SR_RXAK 0x01 94 #define I2SR_IIF 0x02 95 #define I2SR_SRW 0x04 96 #define I2SR_IAL 0x10 97 #define I2SR_IBB 0x20 98 #define I2SR_IAAS 0x40 99 #define I2SR_ICF 0x80 100 #define I2CR_DMAEN 0x02 101 #define I2CR_RSTA 0x04 102 #define I2CR_TXAK 0x08 103 #define I2CR_MTX 0x10 104 #define I2CR_MSTA 0x20 105 #define I2CR_IIEN 0x40 106 #define I2CR_IEN 0x80 107 108 /* register bits different operating codes definition: 109 * 1) I2SR: Interrupt flags clear operation differ between SoCs: 110 * - write zero to clear(w0c) INT flag on i.MX, 111 * - but write one to clear(w1c) INT flag on Vybrid. 112 * 2) I2CR: I2C module enable operation also differ between SoCs: 113 * - set I2CR_IEN bit enable the module on i.MX, 114 * - but clear I2CR_IEN bit enable the module on Vybrid. 115 */ 116 #define I2SR_CLR_OPCODE_W0C 0x0 117 #define I2SR_CLR_OPCODE_W1C (I2SR_IAL | I2SR_IIF) 118 #define I2CR_IEN_OPCODE_0 0x0 119 #define I2CR_IEN_OPCODE_1 I2CR_IEN 120 121 /** Variables ****************************************************************** 122 *******************************************************************************/ 123 124 /* 125 * sorted list of clock divider, register value pairs 126 * taken from table 26-5, p.26-9, Freescale i.MX 127 * Integrated Portable System Processor Reference Manual 128 * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007 129 * 130 * Duplicated divider values removed from list 131 */ 132 struct imx_i2c_clk_pair { 133 u16 div; 134 u16 val; 135 }; 136 137 static struct imx_i2c_clk_pair imx_i2c_clk_div[] = { 138 { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, 139 { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, 140 { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, 141 { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B }, 142 { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, 143 { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 }, 144 { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, 145 { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, 146 { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, 147 { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, 148 { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E }, 149 { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, 150 { 3072, 0x1E }, { 3840, 0x1F } 151 }; 152 153 /* Vybrid VF610 clock divider, register value pairs */ 154 static struct imx_i2c_clk_pair vf610_i2c_clk_div[] = { 155 { 20, 0x00 }, { 22, 0x01 }, { 24, 0x02 }, { 26, 0x03 }, 156 { 28, 0x04 }, { 30, 0x05 }, { 32, 0x09 }, { 34, 0x06 }, 157 { 36, 0x0A }, { 40, 0x07 }, { 44, 0x0C }, { 48, 0x0D }, 158 { 52, 0x43 }, { 56, 0x0E }, { 60, 0x45 }, { 64, 0x12 }, 159 { 68, 0x0F }, { 72, 0x13 }, { 80, 0x14 }, { 88, 0x15 }, 160 { 96, 0x19 }, { 104, 0x16 }, { 112, 0x1A }, { 128, 0x17 }, 161 { 136, 0x4F }, { 144, 0x1C }, { 160, 0x1D }, { 176, 0x55 }, 162 { 192, 0x1E }, { 208, 0x56 }, { 224, 0x22 }, { 228, 0x24 }, 163 { 240, 0x1F }, { 256, 0x23 }, { 288, 0x5C }, { 320, 0x25 }, 164 { 384, 0x26 }, { 448, 0x2A }, { 480, 0x27 }, { 512, 0x2B }, 165 { 576, 0x2C }, { 640, 0x2D }, { 768, 0x31 }, { 896, 0x32 }, 166 { 960, 0x2F }, { 1024, 0x33 }, { 1152, 0x34 }, { 1280, 0x35 }, 167 { 1536, 0x36 }, { 1792, 0x3A }, { 1920, 0x37 }, { 2048, 0x3B }, 168 { 2304, 0x3C }, { 2560, 0x3D }, { 3072, 0x3E }, { 3584, 0x7A }, 169 { 3840, 0x3F }, { 4096, 0x7B }, { 5120, 0x7D }, { 6144, 0x7E }, 170 }; 171 172 enum imx_i2c_type { 173 IMX1_I2C, 174 IMX21_I2C, 175 VF610_I2C, 176 }; 177 178 struct imx_i2c_hwdata { 179 enum imx_i2c_type devtype; 180 unsigned regshift; 181 struct imx_i2c_clk_pair *clk_div; 182 unsigned ndivs; 183 unsigned i2sr_clr_opcode; 184 unsigned i2cr_ien_opcode; 185 }; 186 187 struct imx_i2c_dma { 188 struct dma_chan *chan_tx; 189 struct dma_chan *chan_rx; 190 struct dma_chan *chan_using; 191 struct completion cmd_complete; 192 dma_addr_t dma_buf; 193 unsigned int dma_len; 194 enum dma_transfer_direction dma_transfer_dir; 195 enum dma_data_direction dma_data_dir; 196 }; 197 198 struct imx_i2c_struct { 199 struct i2c_adapter adapter; 200 struct clk *clk; 201 void __iomem *base; 202 wait_queue_head_t queue; 203 unsigned long i2csr; 204 unsigned int disable_delay; 205 int stopped; 206 unsigned int ifdr; /* IMX_I2C_IFDR */ 207 unsigned int cur_clk; 208 unsigned int bitrate; 209 const struct imx_i2c_hwdata *hwdata; 210 211 struct imx_i2c_dma *dma; 212 }; 213 214 static const struct imx_i2c_hwdata imx1_i2c_hwdata = { 215 .devtype = IMX1_I2C, 216 .regshift = IMX_I2C_REGSHIFT, 217 .clk_div = imx_i2c_clk_div, 218 .ndivs = ARRAY_SIZE(imx_i2c_clk_div), 219 .i2sr_clr_opcode = I2SR_CLR_OPCODE_W0C, 220 .i2cr_ien_opcode = I2CR_IEN_OPCODE_1, 221 222 }; 223 224 static const struct imx_i2c_hwdata imx21_i2c_hwdata = { 225 .devtype = IMX21_I2C, 226 .regshift = IMX_I2C_REGSHIFT, 227 .clk_div = imx_i2c_clk_div, 228 .ndivs = ARRAY_SIZE(imx_i2c_clk_div), 229 .i2sr_clr_opcode = I2SR_CLR_OPCODE_W0C, 230 .i2cr_ien_opcode = I2CR_IEN_OPCODE_1, 231 232 }; 233 234 static struct imx_i2c_hwdata vf610_i2c_hwdata = { 235 .devtype = VF610_I2C, 236 .regshift = VF610_I2C_REGSHIFT, 237 .clk_div = vf610_i2c_clk_div, 238 .ndivs = ARRAY_SIZE(vf610_i2c_clk_div), 239 .i2sr_clr_opcode = I2SR_CLR_OPCODE_W1C, 240 .i2cr_ien_opcode = I2CR_IEN_OPCODE_0, 241 242 }; 243 244 static struct platform_device_id imx_i2c_devtype[] = { 245 { 246 .name = "imx1-i2c", 247 .driver_data = (kernel_ulong_t)&imx1_i2c_hwdata, 248 }, { 249 .name = "imx21-i2c", 250 .driver_data = (kernel_ulong_t)&imx21_i2c_hwdata, 251 }, { 252 /* sentinel */ 253 } 254 }; 255 MODULE_DEVICE_TABLE(platform, imx_i2c_devtype); 256 257 static const struct of_device_id i2c_imx_dt_ids[] = { 258 { .compatible = "fsl,imx1-i2c", .data = &imx1_i2c_hwdata, }, 259 { .compatible = "fsl,imx21-i2c", .data = &imx21_i2c_hwdata, }, 260 { .compatible = "fsl,vf610-i2c", .data = &vf610_i2c_hwdata, }, 261 { /* sentinel */ } 262 }; 263 MODULE_DEVICE_TABLE(of, i2c_imx_dt_ids); 264 265 static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx) 266 { 267 return i2c_imx->hwdata->devtype == IMX1_I2C; 268 } 269 270 static inline void imx_i2c_write_reg(unsigned int val, 271 struct imx_i2c_struct *i2c_imx, unsigned int reg) 272 { 273 writeb(val, i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); 274 } 275 276 static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, 277 unsigned int reg) 278 { 279 return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); 280 } 281 282 /* Functions for DMA support */ 283 static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, 284 dma_addr_t phy_addr) 285 { 286 struct imx_i2c_dma *dma; 287 struct dma_slave_config dma_sconfig; 288 struct device *dev = &i2c_imx->adapter.dev; 289 int ret; 290 291 dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); 292 if (!dma) 293 return; 294 295 dma->chan_tx = dma_request_slave_channel(dev, "tx"); 296 if (!dma->chan_tx) { 297 dev_dbg(dev, "can't request DMA tx channel\n"); 298 goto fail_al; 299 } 300 301 dma_sconfig.dst_addr = phy_addr + 302 (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); 303 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 304 dma_sconfig.dst_maxburst = 1; 305 dma_sconfig.direction = DMA_MEM_TO_DEV; 306 ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig); 307 if (ret < 0) { 308 dev_dbg(dev, "can't configure tx channel\n"); 309 goto fail_tx; 310 } 311 312 dma->chan_rx = dma_request_slave_channel(dev, "rx"); 313 if (!dma->chan_rx) { 314 dev_dbg(dev, "can't request DMA rx channel\n"); 315 goto fail_tx; 316 } 317 318 dma_sconfig.src_addr = phy_addr + 319 (IMX_I2C_I2DR << i2c_imx->hwdata->regshift); 320 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 321 dma_sconfig.src_maxburst = 1; 322 dma_sconfig.direction = DMA_DEV_TO_MEM; 323 ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig); 324 if (ret < 0) { 325 dev_dbg(dev, "can't configure rx channel\n"); 326 goto fail_rx; 327 } 328 329 i2c_imx->dma = dma; 330 init_completion(&dma->cmd_complete); 331 dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", 332 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); 333 334 return; 335 336 fail_rx: 337 dma_release_channel(dma->chan_rx); 338 fail_tx: 339 dma_release_channel(dma->chan_tx); 340 fail_al: 341 devm_kfree(dev, dma); 342 dev_info(dev, "can't use DMA\n"); 343 } 344 345 static void i2c_imx_dma_callback(void *arg) 346 { 347 struct imx_i2c_struct *i2c_imx = (struct imx_i2c_struct *)arg; 348 struct imx_i2c_dma *dma = i2c_imx->dma; 349 350 dma_unmap_single(dma->chan_using->device->dev, dma->dma_buf, 351 dma->dma_len, dma->dma_data_dir); 352 complete(&dma->cmd_complete); 353 } 354 355 static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx, 356 struct i2c_msg *msgs) 357 { 358 struct imx_i2c_dma *dma = i2c_imx->dma; 359 struct dma_async_tx_descriptor *txdesc; 360 struct device *dev = &i2c_imx->adapter.dev; 361 struct device *chan_dev = dma->chan_using->device->dev; 362 363 dma->dma_buf = dma_map_single(chan_dev, msgs->buf, 364 dma->dma_len, dma->dma_data_dir); 365 if (dma_mapping_error(chan_dev, dma->dma_buf)) { 366 dev_err(dev, "DMA mapping failed\n"); 367 goto err_map; 368 } 369 370 txdesc = dmaengine_prep_slave_single(dma->chan_using, dma->dma_buf, 371 dma->dma_len, dma->dma_transfer_dir, 372 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 373 if (!txdesc) { 374 dev_err(dev, "Not able to get desc for DMA xfer\n"); 375 goto err_desc; 376 } 377 378 txdesc->callback = i2c_imx_dma_callback; 379 txdesc->callback_param = i2c_imx; 380 if (dma_submit_error(dmaengine_submit(txdesc))) { 381 dev_err(dev, "DMA submit failed\n"); 382 goto err_submit; 383 } 384 385 dma_async_issue_pending(dma->chan_using); 386 return 0; 387 388 err_submit: 389 err_desc: 390 dma_unmap_single(chan_dev, dma->dma_buf, 391 dma->dma_len, dma->dma_data_dir); 392 err_map: 393 return -EINVAL; 394 } 395 396 static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx) 397 { 398 struct imx_i2c_dma *dma = i2c_imx->dma; 399 400 dma->dma_buf = 0; 401 dma->dma_len = 0; 402 403 dma_release_channel(dma->chan_tx); 404 dma->chan_tx = NULL; 405 406 dma_release_channel(dma->chan_rx); 407 dma->chan_rx = NULL; 408 409 dma->chan_using = NULL; 410 } 411 412 /** Functions for IMX I2C adapter driver *************************************** 413 *******************************************************************************/ 414 415 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy) 416 { 417 unsigned long orig_jiffies = jiffies; 418 unsigned int temp; 419 420 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); 421 422 while (1) { 423 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); 424 425 /* check for arbitration lost */ 426 if (temp & I2SR_IAL) { 427 temp &= ~I2SR_IAL; 428 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); 429 return -EAGAIN; 430 } 431 432 if (for_busy && (temp & I2SR_IBB)) 433 break; 434 if (!for_busy && !(temp & I2SR_IBB)) 435 break; 436 if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { 437 dev_dbg(&i2c_imx->adapter.dev, 438 "<%s> I2C bus is busy\n", __func__); 439 return -ETIMEDOUT; 440 } 441 schedule(); 442 } 443 444 return 0; 445 } 446 447 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx) 448 { 449 wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10); 450 451 if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) { 452 dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__); 453 return -ETIMEDOUT; 454 } 455 dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__); 456 i2c_imx->i2csr = 0; 457 return 0; 458 } 459 460 static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) 461 { 462 if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) { 463 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__); 464 return -EIO; /* No ACK */ 465 } 466 467 dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__); 468 return 0; 469 } 470 471 static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx) 472 { 473 struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div; 474 unsigned int i2c_clk_rate; 475 unsigned int div; 476 int i; 477 478 /* Divider value calculation */ 479 i2c_clk_rate = clk_get_rate(i2c_imx->clk); 480 if (i2c_imx->cur_clk == i2c_clk_rate) 481 return; 482 483 i2c_imx->cur_clk = i2c_clk_rate; 484 485 div = (i2c_clk_rate + i2c_imx->bitrate - 1) / i2c_imx->bitrate; 486 if (div < i2c_clk_div[0].div) 487 i = 0; 488 else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div) 489 i = i2c_imx->hwdata->ndivs - 1; 490 else 491 for (i = 0; i2c_clk_div[i].div < div; i++) 492 ; 493 494 /* Store divider value */ 495 i2c_imx->ifdr = i2c_clk_div[i].val; 496 497 /* 498 * There dummy delay is calculated. 499 * It should be about one I2C clock period long. 500 * This delay is used in I2C bus disable function 501 * to fix chip hardware bug. 502 */ 503 i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div 504 + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); 505 506 #ifdef CONFIG_I2C_DEBUG_BUS 507 dev_dbg(&i2c_imx->adapter.dev, "I2C_CLK=%d, REQ DIV=%d\n", 508 i2c_clk_rate, div); 509 dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n", 510 i2c_clk_div[i].val, i2c_clk_div[i].div); 511 #endif 512 } 513 514 static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) 515 { 516 unsigned int temp = 0; 517 int result; 518 519 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); 520 521 i2c_imx_set_clk(i2c_imx); 522 523 result = clk_prepare_enable(i2c_imx->clk); 524 if (result) 525 return result; 526 imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR); 527 /* Enable I2C controller */ 528 imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); 529 imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode, i2c_imx, IMX_I2C_I2CR); 530 531 /* Wait controller to be stable */ 532 udelay(50); 533 534 /* Start I2C transaction */ 535 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 536 temp |= I2CR_MSTA; 537 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 538 result = i2c_imx_bus_busy(i2c_imx, 1); 539 if (result) 540 return result; 541 i2c_imx->stopped = 0; 542 543 temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; 544 temp &= ~I2CR_DMAEN; 545 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 546 return result; 547 } 548 549 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) 550 { 551 unsigned int temp = 0; 552 553 if (!i2c_imx->stopped) { 554 /* Stop I2C transaction */ 555 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); 556 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 557 temp &= ~(I2CR_MSTA | I2CR_MTX); 558 if (i2c_imx->dma) 559 temp &= ~I2CR_DMAEN; 560 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 561 } 562 if (is_imx1_i2c(i2c_imx)) { 563 /* 564 * This delay caused by an i.MXL hardware bug. 565 * If no (or too short) delay, no "STOP" bit will be generated. 566 */ 567 udelay(i2c_imx->disable_delay); 568 } 569 570 if (!i2c_imx->stopped) { 571 i2c_imx_bus_busy(i2c_imx, 0); 572 i2c_imx->stopped = 1; 573 } 574 575 /* Disable I2C controller */ 576 temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, 577 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 578 clk_disable_unprepare(i2c_imx->clk); 579 } 580 581 static irqreturn_t i2c_imx_isr(int irq, void *dev_id) 582 { 583 struct imx_i2c_struct *i2c_imx = dev_id; 584 unsigned int temp; 585 586 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); 587 if (temp & I2SR_IIF) { 588 /* save status register */ 589 i2c_imx->i2csr = temp; 590 temp &= ~I2SR_IIF; 591 temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF); 592 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); 593 wake_up(&i2c_imx->queue); 594 return IRQ_HANDLED; 595 } 596 597 return IRQ_NONE; 598 } 599 600 static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx, 601 struct i2c_msg *msgs) 602 { 603 int result; 604 unsigned long time_left; 605 unsigned int temp = 0; 606 unsigned long orig_jiffies = jiffies; 607 struct imx_i2c_dma *dma = i2c_imx->dma; 608 struct device *dev = &i2c_imx->adapter.dev; 609 610 dma->chan_using = dma->chan_tx; 611 dma->dma_transfer_dir = DMA_MEM_TO_DEV; 612 dma->dma_data_dir = DMA_TO_DEVICE; 613 dma->dma_len = msgs->len - 1; 614 result = i2c_imx_dma_xfer(i2c_imx, msgs); 615 if (result) 616 return result; 617 618 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 619 temp |= I2CR_DMAEN; 620 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 621 622 /* 623 * Write slave address. 624 * The first byte must be transmitted by the CPU. 625 */ 626 imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); 627 reinit_completion(&i2c_imx->dma->cmd_complete); 628 time_left = wait_for_completion_timeout( 629 &i2c_imx->dma->cmd_complete, 630 msecs_to_jiffies(DMA_TIMEOUT)); 631 if (time_left == 0) { 632 dmaengine_terminate_all(dma->chan_using); 633 return -ETIMEDOUT; 634 } 635 636 /* Waiting for transfer complete. */ 637 while (1) { 638 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); 639 if (temp & I2SR_ICF) 640 break; 641 if (time_after(jiffies, orig_jiffies + 642 msecs_to_jiffies(DMA_TIMEOUT))) { 643 dev_dbg(dev, "<%s> Timeout\n", __func__); 644 return -ETIMEDOUT; 645 } 646 schedule(); 647 } 648 649 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 650 temp &= ~I2CR_DMAEN; 651 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 652 653 /* The last data byte must be transferred by the CPU. */ 654 imx_i2c_write_reg(msgs->buf[msgs->len-1], 655 i2c_imx, IMX_I2C_I2DR); 656 result = i2c_imx_trx_complete(i2c_imx); 657 if (result) 658 return result; 659 660 return i2c_imx_acked(i2c_imx); 661 } 662 663 static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, 664 struct i2c_msg *msgs, bool is_lastmsg) 665 { 666 int result; 667 unsigned long time_left; 668 unsigned int temp; 669 unsigned long orig_jiffies = jiffies; 670 struct imx_i2c_dma *dma = i2c_imx->dma; 671 struct device *dev = &i2c_imx->adapter.dev; 672 673 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 674 temp |= I2CR_DMAEN; 675 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 676 677 dma->chan_using = dma->chan_rx; 678 dma->dma_transfer_dir = DMA_DEV_TO_MEM; 679 dma->dma_data_dir = DMA_FROM_DEVICE; 680 /* The last two data bytes must be transferred by the CPU. */ 681 dma->dma_len = msgs->len - 2; 682 result = i2c_imx_dma_xfer(i2c_imx, msgs); 683 if (result) 684 return result; 685 686 reinit_completion(&i2c_imx->dma->cmd_complete); 687 time_left = wait_for_completion_timeout( 688 &i2c_imx->dma->cmd_complete, 689 msecs_to_jiffies(DMA_TIMEOUT)); 690 if (time_left == 0) { 691 dmaengine_terminate_all(dma->chan_using); 692 return -ETIMEDOUT; 693 } 694 695 /* waiting for transfer complete. */ 696 while (1) { 697 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); 698 if (temp & I2SR_ICF) 699 break; 700 if (time_after(jiffies, orig_jiffies + 701 msecs_to_jiffies(DMA_TIMEOUT))) { 702 dev_dbg(dev, "<%s> Timeout\n", __func__); 703 return -ETIMEDOUT; 704 } 705 schedule(); 706 } 707 708 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 709 temp &= ~I2CR_DMAEN; 710 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 711 712 /* read n-1 byte data */ 713 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 714 temp |= I2CR_TXAK; 715 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 716 717 msgs->buf[msgs->len-2] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); 718 /* read n byte data */ 719 result = i2c_imx_trx_complete(i2c_imx); 720 if (result) 721 return result; 722 723 if (is_lastmsg) { 724 /* 725 * It must generate STOP before read I2DR to prevent 726 * controller from generating another clock cycle 727 */ 728 dev_dbg(dev, "<%s> clear MSTA\n", __func__); 729 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 730 temp &= ~(I2CR_MSTA | I2CR_MTX); 731 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 732 i2c_imx_bus_busy(i2c_imx, 0); 733 i2c_imx->stopped = 1; 734 } else { 735 /* 736 * For i2c master receiver repeat restart operation like: 737 * read -> repeat MSTA -> read/write 738 * The controller must set MTX before read the last byte in 739 * the first read operation, otherwise the first read cost 740 * one extra clock cycle. 741 */ 742 temp = readb(i2c_imx->base + IMX_I2C_I2CR); 743 temp |= I2CR_MTX; 744 writeb(temp, i2c_imx->base + IMX_I2C_I2CR); 745 } 746 msgs->buf[msgs->len-1] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); 747 748 return 0; 749 } 750 751 static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) 752 { 753 int i, result; 754 755 dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", 756 __func__, msgs->addr << 1); 757 758 /* write slave address */ 759 imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR); 760 result = i2c_imx_trx_complete(i2c_imx); 761 if (result) 762 return result; 763 result = i2c_imx_acked(i2c_imx); 764 if (result) 765 return result; 766 dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); 767 768 /* write data */ 769 for (i = 0; i < msgs->len; i++) { 770 dev_dbg(&i2c_imx->adapter.dev, 771 "<%s> write byte: B%d=0x%X\n", 772 __func__, i, msgs->buf[i]); 773 imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR); 774 result = i2c_imx_trx_complete(i2c_imx); 775 if (result) 776 return result; 777 result = i2c_imx_acked(i2c_imx); 778 if (result) 779 return result; 780 } 781 return 0; 782 } 783 784 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg) 785 { 786 int i, result; 787 unsigned int temp; 788 int block_data = msgs->flags & I2C_M_RECV_LEN; 789 790 dev_dbg(&i2c_imx->adapter.dev, 791 "<%s> write slave address: addr=0x%x\n", 792 __func__, (msgs->addr << 1) | 0x01); 793 794 /* write slave address */ 795 imx_i2c_write_reg((msgs->addr << 1) | 0x01, i2c_imx, IMX_I2C_I2DR); 796 result = i2c_imx_trx_complete(i2c_imx); 797 if (result) 798 return result; 799 result = i2c_imx_acked(i2c_imx); 800 if (result) 801 return result; 802 803 dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__); 804 805 /* setup bus to read data */ 806 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 807 temp &= ~I2CR_MTX; 808 809 /* 810 * Reset the I2CR_TXAK flag initially for SMBus block read since the 811 * length is unknown 812 */ 813 if ((msgs->len - 1) || block_data) 814 temp &= ~I2CR_TXAK; 815 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 816 imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */ 817 818 dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); 819 820 if (i2c_imx->dma && msgs->len >= DMA_THRESHOLD && !block_data) 821 return i2c_imx_dma_read(i2c_imx, msgs, is_lastmsg); 822 823 /* read data */ 824 for (i = 0; i < msgs->len; i++) { 825 u8 len = 0; 826 827 result = i2c_imx_trx_complete(i2c_imx); 828 if (result) 829 return result; 830 /* 831 * First byte is the length of remaining packet 832 * in the SMBus block data read. Add it to 833 * msgs->len. 834 */ 835 if ((!i) && block_data) { 836 len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); 837 if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX)) 838 return -EPROTO; 839 dev_dbg(&i2c_imx->adapter.dev, 840 "<%s> read length: 0x%X\n", 841 __func__, len); 842 msgs->len += len; 843 } 844 if (i == (msgs->len - 1)) { 845 if (is_lastmsg) { 846 /* 847 * It must generate STOP before read I2DR to prevent 848 * controller from generating another clock cycle 849 */ 850 dev_dbg(&i2c_imx->adapter.dev, 851 "<%s> clear MSTA\n", __func__); 852 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 853 temp &= ~(I2CR_MSTA | I2CR_MTX); 854 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 855 i2c_imx_bus_busy(i2c_imx, 0); 856 i2c_imx->stopped = 1; 857 } else { 858 /* 859 * For i2c master receiver repeat restart operation like: 860 * read -> repeat MSTA -> read/write 861 * The controller must set MTX before read the last byte in 862 * the first read operation, otherwise the first read cost 863 * one extra clock cycle. 864 */ 865 temp = readb(i2c_imx->base + IMX_I2C_I2CR); 866 temp |= I2CR_MTX; 867 writeb(temp, i2c_imx->base + IMX_I2C_I2CR); 868 } 869 } else if (i == (msgs->len - 2)) { 870 dev_dbg(&i2c_imx->adapter.dev, 871 "<%s> set TXAK\n", __func__); 872 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 873 temp |= I2CR_TXAK; 874 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 875 } 876 if ((!i) && block_data) 877 msgs->buf[0] = len; 878 else 879 msgs->buf[i] = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); 880 dev_dbg(&i2c_imx->adapter.dev, 881 "<%s> read byte: B%d=0x%X\n", 882 __func__, i, msgs->buf[i]); 883 } 884 return 0; 885 } 886 887 static int i2c_imx_xfer(struct i2c_adapter *adapter, 888 struct i2c_msg *msgs, int num) 889 { 890 unsigned int i, temp; 891 int result; 892 bool is_lastmsg = false; 893 struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter); 894 895 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); 896 897 /* Start I2C transfer */ 898 result = i2c_imx_start(i2c_imx); 899 if (result) 900 goto fail0; 901 902 /* read/write data */ 903 for (i = 0; i < num; i++) { 904 if (i == num - 1) 905 is_lastmsg = true; 906 907 if (i) { 908 dev_dbg(&i2c_imx->adapter.dev, 909 "<%s> repeated start\n", __func__); 910 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 911 temp |= I2CR_RSTA; 912 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); 913 result = i2c_imx_bus_busy(i2c_imx, 1); 914 if (result) 915 goto fail0; 916 } 917 dev_dbg(&i2c_imx->adapter.dev, 918 "<%s> transfer message: %d\n", __func__, i); 919 /* write/read data */ 920 #ifdef CONFIG_I2C_DEBUG_BUS 921 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); 922 dev_dbg(&i2c_imx->adapter.dev, 923 "<%s> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", 924 __func__, 925 (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0), 926 (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0), 927 (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0)); 928 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); 929 dev_dbg(&i2c_imx->adapter.dev, 930 "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", 931 __func__, 932 (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0), 933 (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0), 934 (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0), 935 (temp & I2SR_RXAK ? 1 : 0)); 936 #endif 937 if (msgs[i].flags & I2C_M_RD) 938 result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg); 939 else { 940 if (i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD) 941 result = i2c_imx_dma_write(i2c_imx, &msgs[i]); 942 else 943 result = i2c_imx_write(i2c_imx, &msgs[i]); 944 } 945 if (result) 946 goto fail0; 947 } 948 949 fail0: 950 /* Stop I2C transfer */ 951 i2c_imx_stop(i2c_imx); 952 953 dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__, 954 (result < 0) ? "error" : "success msg", 955 (result < 0) ? result : num); 956 return (result < 0) ? result : num; 957 } 958 959 static u32 i2c_imx_func(struct i2c_adapter *adapter) 960 { 961 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL 962 | I2C_FUNC_SMBUS_READ_BLOCK_DATA; 963 } 964 965 static struct i2c_algorithm i2c_imx_algo = { 966 .master_xfer = i2c_imx_xfer, 967 .functionality = i2c_imx_func, 968 }; 969 970 static int i2c_imx_probe(struct platform_device *pdev) 971 { 972 const struct of_device_id *of_id = of_match_device(i2c_imx_dt_ids, 973 &pdev->dev); 974 struct imx_i2c_struct *i2c_imx; 975 struct resource *res; 976 struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev); 977 void __iomem *base; 978 int irq, ret; 979 dma_addr_t phy_addr; 980 981 dev_dbg(&pdev->dev, "<%s>\n", __func__); 982 983 irq = platform_get_irq(pdev, 0); 984 if (irq < 0) { 985 dev_err(&pdev->dev, "can't get irq number\n"); 986 return irq; 987 } 988 989 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 990 base = devm_ioremap_resource(&pdev->dev, res); 991 if (IS_ERR(base)) 992 return PTR_ERR(base); 993 994 phy_addr = (dma_addr_t)res->start; 995 i2c_imx = devm_kzalloc(&pdev->dev, sizeof(*i2c_imx), GFP_KERNEL); 996 if (!i2c_imx) 997 return -ENOMEM; 998 999 if (of_id) 1000 i2c_imx->hwdata = of_id->data; 1001 else 1002 i2c_imx->hwdata = (struct imx_i2c_hwdata *) 1003 platform_get_device_id(pdev)->driver_data; 1004 1005 /* Setup i2c_imx driver structure */ 1006 strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx->adapter.name)); 1007 i2c_imx->adapter.owner = THIS_MODULE; 1008 i2c_imx->adapter.algo = &i2c_imx_algo; 1009 i2c_imx->adapter.dev.parent = &pdev->dev; 1010 i2c_imx->adapter.nr = pdev->id; 1011 i2c_imx->adapter.dev.of_node = pdev->dev.of_node; 1012 i2c_imx->base = base; 1013 1014 /* Get I2C clock */ 1015 i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); 1016 if (IS_ERR(i2c_imx->clk)) { 1017 dev_err(&pdev->dev, "can't get I2C clock\n"); 1018 return PTR_ERR(i2c_imx->clk); 1019 } 1020 1021 ret = clk_prepare_enable(i2c_imx->clk); 1022 if (ret) { 1023 dev_err(&pdev->dev, "can't enable I2C clock\n"); 1024 return ret; 1025 } 1026 /* Request IRQ */ 1027 ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0, 1028 pdev->name, i2c_imx); 1029 if (ret) { 1030 dev_err(&pdev->dev, "can't claim irq %d\n", irq); 1031 goto clk_disable; 1032 } 1033 1034 /* Init queue */ 1035 init_waitqueue_head(&i2c_imx->queue); 1036 1037 /* Set up adapter data */ 1038 i2c_set_adapdata(&i2c_imx->adapter, i2c_imx); 1039 1040 /* Set up clock divider */ 1041 i2c_imx->bitrate = IMX_I2C_BIT_RATE; 1042 ret = of_property_read_u32(pdev->dev.of_node, 1043 "clock-frequency", &i2c_imx->bitrate); 1044 if (ret < 0 && pdata && pdata->bitrate) 1045 i2c_imx->bitrate = pdata->bitrate; 1046 1047 /* Set up chip registers to defaults */ 1048 imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN, 1049 i2c_imx, IMX_I2C_I2CR); 1050 imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); 1051 1052 /* Add I2C adapter */ 1053 ret = i2c_add_numbered_adapter(&i2c_imx->adapter); 1054 if (ret < 0) { 1055 dev_err(&pdev->dev, "registration failed\n"); 1056 goto clk_disable; 1057 } 1058 1059 /* Set up platform driver data */ 1060 platform_set_drvdata(pdev, i2c_imx); 1061 clk_disable_unprepare(i2c_imx->clk); 1062 1063 dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq); 1064 dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res); 1065 dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n", 1066 i2c_imx->adapter.name); 1067 dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); 1068 1069 /* Init DMA config if supported */ 1070 i2c_imx_dma_request(i2c_imx, phy_addr); 1071 1072 return 0; /* Return OK */ 1073 1074 clk_disable: 1075 clk_disable_unprepare(i2c_imx->clk); 1076 return ret; 1077 } 1078 1079 static int i2c_imx_remove(struct platform_device *pdev) 1080 { 1081 struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev); 1082 1083 /* remove adapter */ 1084 dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); 1085 i2c_del_adapter(&i2c_imx->adapter); 1086 1087 if (i2c_imx->dma) 1088 i2c_imx_dma_free(i2c_imx); 1089 1090 /* setup chip registers to defaults */ 1091 imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR); 1092 imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR); 1093 imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR); 1094 imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR); 1095 1096 return 0; 1097 } 1098 1099 static struct platform_driver i2c_imx_driver = { 1100 .probe = i2c_imx_probe, 1101 .remove = i2c_imx_remove, 1102 .driver = { 1103 .name = DRIVER_NAME, 1104 .of_match_table = i2c_imx_dt_ids, 1105 }, 1106 .id_table = imx_i2c_devtype, 1107 }; 1108 1109 static int __init i2c_adap_imx_init(void) 1110 { 1111 return platform_driver_register(&i2c_imx_driver); 1112 } 1113 subsys_initcall(i2c_adap_imx_init); 1114 1115 static void __exit i2c_adap_imx_exit(void) 1116 { 1117 platform_driver_unregister(&i2c_imx_driver); 1118 } 1119 module_exit(i2c_adap_imx_exit); 1120 1121 MODULE_LICENSE("GPL"); 1122 MODULE_AUTHOR("Darius Augulis"); 1123 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus"); 1124 MODULE_ALIAS("platform:" DRIVER_NAME); 1125