1 /* 2 * drivers/i2c/busses/i2c-tegra.c 3 * 4 * Copyright (C) 2010 Google, Inc. 5 * Author: Colin Cross <ccross@android.com> 6 * 7 * This software is licensed under the terms of the GNU General Public 8 * License version 2, as published by the Free Software Foundation, and 9 * may be copied, distributed, and modified under those terms. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 */ 17 18 #include <linux/kernel.h> 19 #include <linux/init.h> 20 #include <linux/platform_device.h> 21 #include <linux/clk.h> 22 #include <linux/err.h> 23 #include <linux/i2c.h> 24 #include <linux/io.h> 25 #include <linux/interrupt.h> 26 #include <linux/delay.h> 27 #include <linux/slab.h> 28 #include <linux/of_device.h> 29 #include <linux/module.h> 30 #include <linux/reset.h> 31 32 #include <asm/unaligned.h> 33 34 #define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) 35 #define BYTES_PER_FIFO_WORD 4 36 37 #define I2C_CNFG 0x000 38 #define I2C_CNFG_DEBOUNCE_CNT_SHIFT 12 39 #define I2C_CNFG_PACKET_MODE_EN (1<<10) 40 #define I2C_CNFG_NEW_MASTER_FSM (1<<11) 41 #define I2C_STATUS 0x01C 42 #define I2C_SL_CNFG 0x020 43 #define I2C_SL_CNFG_NACK (1<<1) 44 #define I2C_SL_CNFG_NEWSL (1<<2) 45 #define I2C_SL_ADDR1 0x02c 46 #define I2C_SL_ADDR2 0x030 47 #define I2C_TX_FIFO 0x050 48 #define I2C_RX_FIFO 0x054 49 #define I2C_PACKET_TRANSFER_STATUS 0x058 50 #define I2C_FIFO_CONTROL 0x05c 51 #define I2C_FIFO_CONTROL_TX_FLUSH (1<<1) 52 #define I2C_FIFO_CONTROL_RX_FLUSH (1<<0) 53 #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT 5 54 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT 2 55 #define I2C_FIFO_STATUS 0x060 56 #define I2C_FIFO_STATUS_TX_MASK 0xF0 57 #define I2C_FIFO_STATUS_TX_SHIFT 4 58 #define I2C_FIFO_STATUS_RX_MASK 0x0F 59 #define I2C_FIFO_STATUS_RX_SHIFT 0 60 #define I2C_INT_MASK 0x064 61 #define I2C_INT_STATUS 0x068 62 #define I2C_INT_PACKET_XFER_COMPLETE (1<<7) 63 #define I2C_INT_ALL_PACKETS_XFER_COMPLETE (1<<6) 64 #define I2C_INT_TX_FIFO_OVERFLOW (1<<5) 65 #define I2C_INT_RX_FIFO_UNDERFLOW (1<<4) 66 #define I2C_INT_NO_ACK (1<<3) 67 #define I2C_INT_ARBITRATION_LOST (1<<2) 68 #define I2C_INT_TX_FIFO_DATA_REQ (1<<1) 69 #define I2C_INT_RX_FIFO_DATA_REQ (1<<0) 70 #define I2C_CLK_DIVISOR 0x06c 71 #define I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT 16 72 #define I2C_CLK_MULTIPLIER_STD_FAST_MODE 8 73 74 #define DVC_CTRL_REG1 0x000 75 #define DVC_CTRL_REG1_INTR_EN (1<<10) 76 #define DVC_CTRL_REG2 0x004 77 #define DVC_CTRL_REG3 0x008 78 #define DVC_CTRL_REG3_SW_PROG (1<<26) 79 #define DVC_CTRL_REG3_I2C_DONE_INTR_EN (1<<30) 80 #define DVC_STATUS 0x00c 81 #define DVC_STATUS_I2C_DONE_INTR (1<<30) 82 83 #define I2C_ERR_NONE 0x00 84 #define I2C_ERR_NO_ACK 0x01 85 #define I2C_ERR_ARBITRATION_LOST 0x02 86 #define I2C_ERR_UNKNOWN_INTERRUPT 0x04 87 88 #define PACKET_HEADER0_HEADER_SIZE_SHIFT 28 89 #define PACKET_HEADER0_PACKET_ID_SHIFT 16 90 #define PACKET_HEADER0_CONT_ID_SHIFT 12 91 #define PACKET_HEADER0_PROTOCOL_I2C (1<<4) 92 93 #define I2C_HEADER_HIGHSPEED_MODE (1<<22) 94 #define I2C_HEADER_CONT_ON_NAK (1<<21) 95 #define I2C_HEADER_SEND_START_BYTE (1<<20) 96 #define I2C_HEADER_READ (1<<19) 97 #define I2C_HEADER_10BIT_ADDR (1<<18) 98 #define I2C_HEADER_IE_ENABLE (1<<17) 99 #define I2C_HEADER_REPEAT_START (1<<16) 100 #define I2C_HEADER_CONTINUE_XFER (1<<15) 101 #define I2C_HEADER_MASTER_ADDR_SHIFT 12 102 #define I2C_HEADER_SLAVE_ADDR_SHIFT 1 103 /* 104 * msg_end_type: The bus control which need to be send at end of transfer. 105 * @MSG_END_STOP: Send stop pulse at end of transfer. 106 * @MSG_END_REPEAT_START: Send repeat start at end of transfer. 107 * @MSG_END_CONTINUE: The following on message is coming and so do not send 108 * stop or repeat start. 109 */ 110 enum msg_end_type { 111 MSG_END_STOP, 112 MSG_END_REPEAT_START, 113 MSG_END_CONTINUE, 114 }; 115 116 /** 117 * struct tegra_i2c_hw_feature : Different HW support on Tegra 118 * @has_continue_xfer_support: Continue transfer supports. 119 * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer 120 * complete interrupt per packet basis. 121 * @has_single_clk_source: The i2c controller has single clock source. Tegra30 122 * and earlier Socs has two clock sources i.e. div-clk and 123 * fast-clk. 124 * @clk_divisor_hs_mode: Clock divisor in HS mode. 125 * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is 126 * applicable if there is no fast clock source i.e. single clock 127 * source. 128 */ 129 130 struct tegra_i2c_hw_feature { 131 bool has_continue_xfer_support; 132 bool has_per_pkt_xfer_complete_irq; 133 bool has_single_clk_source; 134 int clk_divisor_hs_mode; 135 int clk_divisor_std_fast_mode; 136 }; 137 138 /** 139 * struct tegra_i2c_dev - per device i2c context 140 * @dev: device reference for power management 141 * @hw: Tegra i2c hw feature. 142 * @adapter: core i2c layer adapter information 143 * @div_clk: clock reference for div clock of i2c controller. 144 * @fast_clk: clock reference for fast clock of i2c controller. 145 * @base: ioremapped registers cookie 146 * @cont_id: i2c controller id, used for for packet header 147 * @irq: irq number of transfer complete interrupt 148 * @is_dvc: identifies the DVC i2c controller, has a different register layout 149 * @msg_complete: transfer completion notifier 150 * @msg_err: error code for completed message 151 * @msg_buf: pointer to current message data 152 * @msg_buf_remaining: size of unsent data in the message buffer 153 * @msg_read: identifies read transfers 154 * @bus_clk_rate: current i2c bus clock rate 155 * @is_suspended: prevents i2c controller accesses after suspend is called 156 */ 157 struct tegra_i2c_dev { 158 struct device *dev; 159 const struct tegra_i2c_hw_feature *hw; 160 struct i2c_adapter adapter; 161 struct clk *div_clk; 162 struct clk *fast_clk; 163 struct reset_control *rst; 164 void __iomem *base; 165 int cont_id; 166 int irq; 167 bool irq_disabled; 168 int is_dvc; 169 struct completion msg_complete; 170 int msg_err; 171 u8 *msg_buf; 172 size_t msg_buf_remaining; 173 int msg_read; 174 u32 bus_clk_rate; 175 bool is_suspended; 176 }; 177 178 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg) 179 { 180 writel(val, i2c_dev->base + reg); 181 } 182 183 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) 184 { 185 return readl(i2c_dev->base + reg); 186 } 187 188 /* 189 * i2c_writel and i2c_readl will offset the register if necessary to talk 190 * to the I2C block inside the DVC block 191 */ 192 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev, 193 unsigned long reg) 194 { 195 if (i2c_dev->is_dvc) 196 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40; 197 return reg; 198 } 199 200 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, 201 unsigned long reg) 202 { 203 writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 204 205 /* Read back register to make sure that register writes completed */ 206 if (reg != I2C_TX_FIFO) 207 readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 208 } 209 210 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) 211 { 212 return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 213 } 214 215 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data, 216 unsigned long reg, int len) 217 { 218 writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); 219 } 220 221 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data, 222 unsigned long reg, int len) 223 { 224 readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); 225 } 226 227 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) 228 { 229 u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); 230 int_mask &= ~mask; 231 i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); 232 } 233 234 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) 235 { 236 u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); 237 int_mask |= mask; 238 i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); 239 } 240 241 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) 242 { 243 unsigned long timeout = jiffies + HZ; 244 u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL); 245 val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH; 246 i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); 247 248 while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) & 249 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) { 250 if (time_after(jiffies, timeout)) { 251 dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n"); 252 return -ETIMEDOUT; 253 } 254 msleep(1); 255 } 256 return 0; 257 } 258 259 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) 260 { 261 u32 val; 262 int rx_fifo_avail; 263 u8 *buf = i2c_dev->msg_buf; 264 size_t buf_remaining = i2c_dev->msg_buf_remaining; 265 int words_to_transfer; 266 267 val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); 268 rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >> 269 I2C_FIFO_STATUS_RX_SHIFT; 270 271 /* Rounds down to not include partial word at the end of buf */ 272 words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; 273 if (words_to_transfer > rx_fifo_avail) 274 words_to_transfer = rx_fifo_avail; 275 276 i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer); 277 278 buf += words_to_transfer * BYTES_PER_FIFO_WORD; 279 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; 280 rx_fifo_avail -= words_to_transfer; 281 282 /* 283 * If there is a partial word at the end of buf, handle it manually to 284 * prevent overwriting past the end of buf 285 */ 286 if (rx_fifo_avail > 0 && buf_remaining > 0) { 287 BUG_ON(buf_remaining > 3); 288 val = i2c_readl(i2c_dev, I2C_RX_FIFO); 289 memcpy(buf, &val, buf_remaining); 290 buf_remaining = 0; 291 rx_fifo_avail--; 292 } 293 294 BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); 295 i2c_dev->msg_buf_remaining = buf_remaining; 296 i2c_dev->msg_buf = buf; 297 return 0; 298 } 299 300 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) 301 { 302 u32 val; 303 int tx_fifo_avail; 304 u8 *buf = i2c_dev->msg_buf; 305 size_t buf_remaining = i2c_dev->msg_buf_remaining; 306 int words_to_transfer; 307 308 val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); 309 tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >> 310 I2C_FIFO_STATUS_TX_SHIFT; 311 312 /* Rounds down to not include partial word at the end of buf */ 313 words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; 314 315 /* It's very common to have < 4 bytes, so optimize that case. */ 316 if (words_to_transfer) { 317 if (words_to_transfer > tx_fifo_avail) 318 words_to_transfer = tx_fifo_avail; 319 320 /* 321 * Update state before writing to FIFO. If this casues us 322 * to finish writing all bytes (AKA buf_remaining goes to 0) we 323 * have a potential for an interrupt (PACKET_XFER_COMPLETE is 324 * not maskable). We need to make sure that the isr sees 325 * buf_remaining as 0 and doesn't call us back re-entrantly. 326 */ 327 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; 328 tx_fifo_avail -= words_to_transfer; 329 i2c_dev->msg_buf_remaining = buf_remaining; 330 i2c_dev->msg_buf = buf + 331 words_to_transfer * BYTES_PER_FIFO_WORD; 332 barrier(); 333 334 i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); 335 336 buf += words_to_transfer * BYTES_PER_FIFO_WORD; 337 } 338 339 /* 340 * If there is a partial word at the end of buf, handle it manually to 341 * prevent reading past the end of buf, which could cross a page 342 * boundary and fault. 343 */ 344 if (tx_fifo_avail > 0 && buf_remaining > 0) { 345 BUG_ON(buf_remaining > 3); 346 memcpy(&val, buf, buf_remaining); 347 348 /* Again update before writing to FIFO to make sure isr sees. */ 349 i2c_dev->msg_buf_remaining = 0; 350 i2c_dev->msg_buf = NULL; 351 barrier(); 352 353 i2c_writel(i2c_dev, val, I2C_TX_FIFO); 354 } 355 356 return 0; 357 } 358 359 /* 360 * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller) 361 * block. This block is identical to the rest of the I2C blocks, except that 362 * it only supports master mode, it has registers moved around, and it needs 363 * some extra init to get it into I2C mode. The register moves are handled 364 * by i2c_readl and i2c_writel 365 */ 366 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev) 367 { 368 u32 val = 0; 369 val = dvc_readl(i2c_dev, DVC_CTRL_REG3); 370 val |= DVC_CTRL_REG3_SW_PROG; 371 val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN; 372 dvc_writel(i2c_dev, val, DVC_CTRL_REG3); 373 374 val = dvc_readl(i2c_dev, DVC_CTRL_REG1); 375 val |= DVC_CTRL_REG1_INTR_EN; 376 dvc_writel(i2c_dev, val, DVC_CTRL_REG1); 377 } 378 379 static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev) 380 { 381 int ret; 382 if (!i2c_dev->hw->has_single_clk_source) { 383 ret = clk_prepare_enable(i2c_dev->fast_clk); 384 if (ret < 0) { 385 dev_err(i2c_dev->dev, 386 "Enabling fast clk failed, err %d\n", ret); 387 return ret; 388 } 389 } 390 ret = clk_prepare_enable(i2c_dev->div_clk); 391 if (ret < 0) { 392 dev_err(i2c_dev->dev, 393 "Enabling div clk failed, err %d\n", ret); 394 clk_disable_unprepare(i2c_dev->fast_clk); 395 } 396 return ret; 397 } 398 399 static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev) 400 { 401 clk_disable_unprepare(i2c_dev->div_clk); 402 if (!i2c_dev->hw->has_single_clk_source) 403 clk_disable_unprepare(i2c_dev->fast_clk); 404 } 405 406 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) 407 { 408 u32 val; 409 int err = 0; 410 int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE; 411 u32 clk_divisor; 412 413 err = tegra_i2c_clock_enable(i2c_dev); 414 if (err < 0) { 415 dev_err(i2c_dev->dev, "Clock enable failed %d\n", err); 416 return err; 417 } 418 419 reset_control_assert(i2c_dev->rst); 420 udelay(2); 421 reset_control_deassert(i2c_dev->rst); 422 423 if (i2c_dev->is_dvc) 424 tegra_dvc_init(i2c_dev); 425 426 val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN | 427 (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT); 428 i2c_writel(i2c_dev, val, I2C_CNFG); 429 i2c_writel(i2c_dev, 0, I2C_INT_MASK); 430 431 clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1); 432 clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * clk_multiplier); 433 434 /* Make sure clock divisor programmed correctly */ 435 clk_divisor = i2c_dev->hw->clk_divisor_hs_mode; 436 clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode << 437 I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT; 438 i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR); 439 440 if (!i2c_dev->is_dvc) { 441 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); 442 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL; 443 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG); 444 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1); 445 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2); 446 447 } 448 449 val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT | 450 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT; 451 i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); 452 453 if (tegra_i2c_flush_fifos(i2c_dev)) 454 err = -ETIMEDOUT; 455 456 tegra_i2c_clock_disable(i2c_dev); 457 458 if (i2c_dev->irq_disabled) { 459 i2c_dev->irq_disabled = 0; 460 enable_irq(i2c_dev->irq); 461 } 462 463 return err; 464 } 465 466 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) 467 { 468 u32 status; 469 const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; 470 struct tegra_i2c_dev *i2c_dev = dev_id; 471 472 status = i2c_readl(i2c_dev, I2C_INT_STATUS); 473 474 if (status == 0) { 475 dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n", 476 i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS), 477 i2c_readl(i2c_dev, I2C_STATUS), 478 i2c_readl(i2c_dev, I2C_CNFG)); 479 i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; 480 481 if (!i2c_dev->irq_disabled) { 482 disable_irq_nosync(i2c_dev->irq); 483 i2c_dev->irq_disabled = 1; 484 } 485 goto err; 486 } 487 488 if (unlikely(status & status_err)) { 489 if (status & I2C_INT_NO_ACK) 490 i2c_dev->msg_err |= I2C_ERR_NO_ACK; 491 if (status & I2C_INT_ARBITRATION_LOST) 492 i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST; 493 goto err; 494 } 495 496 if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { 497 if (i2c_dev->msg_buf_remaining) 498 tegra_i2c_empty_rx_fifo(i2c_dev); 499 else 500 BUG(); 501 } 502 503 if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { 504 if (i2c_dev->msg_buf_remaining) 505 tegra_i2c_fill_tx_fifo(i2c_dev); 506 else 507 tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ); 508 } 509 510 i2c_writel(i2c_dev, status, I2C_INT_STATUS); 511 if (i2c_dev->is_dvc) 512 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); 513 514 if (status & I2C_INT_PACKET_XFER_COMPLETE) { 515 BUG_ON(i2c_dev->msg_buf_remaining); 516 complete(&i2c_dev->msg_complete); 517 } 518 return IRQ_HANDLED; 519 err: 520 /* An error occurred, mask all interrupts */ 521 tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | 522 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | 523 I2C_INT_RX_FIFO_DATA_REQ); 524 i2c_writel(i2c_dev, status, I2C_INT_STATUS); 525 if (i2c_dev->is_dvc) 526 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); 527 528 complete(&i2c_dev->msg_complete); 529 return IRQ_HANDLED; 530 } 531 532 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, 533 struct i2c_msg *msg, enum msg_end_type end_state) 534 { 535 u32 packet_header; 536 u32 int_mask; 537 int ret; 538 539 tegra_i2c_flush_fifos(i2c_dev); 540 541 if (msg->len == 0) 542 return -EINVAL; 543 544 i2c_dev->msg_buf = msg->buf; 545 i2c_dev->msg_buf_remaining = msg->len; 546 i2c_dev->msg_err = I2C_ERR_NONE; 547 i2c_dev->msg_read = (msg->flags & I2C_M_RD); 548 reinit_completion(&i2c_dev->msg_complete); 549 550 packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) | 551 PACKET_HEADER0_PROTOCOL_I2C | 552 (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) | 553 (1 << PACKET_HEADER0_PACKET_ID_SHIFT); 554 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 555 556 packet_header = msg->len - 1; 557 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 558 559 packet_header = I2C_HEADER_IE_ENABLE; 560 if (end_state == MSG_END_CONTINUE) 561 packet_header |= I2C_HEADER_CONTINUE_XFER; 562 else if (end_state == MSG_END_REPEAT_START) 563 packet_header |= I2C_HEADER_REPEAT_START; 564 if (msg->flags & I2C_M_TEN) { 565 packet_header |= msg->addr; 566 packet_header |= I2C_HEADER_10BIT_ADDR; 567 } else { 568 packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT; 569 } 570 if (msg->flags & I2C_M_IGNORE_NAK) 571 packet_header |= I2C_HEADER_CONT_ON_NAK; 572 if (msg->flags & I2C_M_RD) 573 packet_header |= I2C_HEADER_READ; 574 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 575 576 if (!(msg->flags & I2C_M_RD)) 577 tegra_i2c_fill_tx_fifo(i2c_dev); 578 579 int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; 580 if (i2c_dev->hw->has_per_pkt_xfer_complete_irq) 581 int_mask |= I2C_INT_PACKET_XFER_COMPLETE; 582 if (msg->flags & I2C_M_RD) 583 int_mask |= I2C_INT_RX_FIFO_DATA_REQ; 584 else if (i2c_dev->msg_buf_remaining) 585 int_mask |= I2C_INT_TX_FIFO_DATA_REQ; 586 tegra_i2c_unmask_irq(i2c_dev, int_mask); 587 dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n", 588 i2c_readl(i2c_dev, I2C_INT_MASK)); 589 590 ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT); 591 tegra_i2c_mask_irq(i2c_dev, int_mask); 592 593 if (ret == 0) { 594 dev_err(i2c_dev->dev, "i2c transfer timed out\n"); 595 596 tegra_i2c_init(i2c_dev); 597 return -ETIMEDOUT; 598 } 599 600 dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n", 601 ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err); 602 603 if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) 604 return 0; 605 606 /* 607 * NACK interrupt is generated before the I2C controller generates the 608 * STOP condition on the bus. So wait for 2 clock periods before resetting 609 * the controller so that STOP condition has been delivered properly. 610 */ 611 if (i2c_dev->msg_err == I2C_ERR_NO_ACK) 612 udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); 613 614 tegra_i2c_init(i2c_dev); 615 if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { 616 if (msg->flags & I2C_M_IGNORE_NAK) 617 return 0; 618 return -EREMOTEIO; 619 } 620 621 return -EIO; 622 } 623 624 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], 625 int num) 626 { 627 struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); 628 int i; 629 int ret = 0; 630 631 if (i2c_dev->is_suspended) 632 return -EBUSY; 633 634 ret = tegra_i2c_clock_enable(i2c_dev); 635 if (ret < 0) { 636 dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret); 637 return ret; 638 } 639 640 for (i = 0; i < num; i++) { 641 enum msg_end_type end_type = MSG_END_STOP; 642 if (i < (num - 1)) { 643 if (msgs[i + 1].flags & I2C_M_NOSTART) 644 end_type = MSG_END_CONTINUE; 645 else 646 end_type = MSG_END_REPEAT_START; 647 } 648 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type); 649 if (ret) 650 break; 651 } 652 tegra_i2c_clock_disable(i2c_dev); 653 return ret ?: i; 654 } 655 656 static u32 tegra_i2c_func(struct i2c_adapter *adap) 657 { 658 struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); 659 u32 ret = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | 660 I2C_FUNC_PROTOCOL_MANGLING; 661 662 if (i2c_dev->hw->has_continue_xfer_support) 663 ret |= I2C_FUNC_NOSTART; 664 return ret; 665 } 666 667 static const struct i2c_algorithm tegra_i2c_algo = { 668 .master_xfer = tegra_i2c_xfer, 669 .functionality = tegra_i2c_func, 670 }; 671 672 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = { 673 .has_continue_xfer_support = false, 674 .has_per_pkt_xfer_complete_irq = false, 675 .has_single_clk_source = false, 676 .clk_divisor_hs_mode = 3, 677 .clk_divisor_std_fast_mode = 0, 678 }; 679 680 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = { 681 .has_continue_xfer_support = true, 682 .has_per_pkt_xfer_complete_irq = false, 683 .has_single_clk_source = false, 684 .clk_divisor_hs_mode = 3, 685 .clk_divisor_std_fast_mode = 0, 686 }; 687 688 static const struct tegra_i2c_hw_feature tegra114_i2c_hw = { 689 .has_continue_xfer_support = true, 690 .has_per_pkt_xfer_complete_irq = true, 691 .has_single_clk_source = true, 692 .clk_divisor_hs_mode = 1, 693 .clk_divisor_std_fast_mode = 0x19, 694 }; 695 696 /* Match table for of_platform binding */ 697 static const struct of_device_id tegra_i2c_of_match[] = { 698 { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, }, 699 { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, }, 700 { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, }, 701 { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, }, 702 {}, 703 }; 704 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match); 705 706 static int tegra_i2c_probe(struct platform_device *pdev) 707 { 708 struct tegra_i2c_dev *i2c_dev; 709 struct resource *res; 710 struct clk *div_clk; 711 struct clk *fast_clk; 712 void __iomem *base; 713 int irq; 714 int ret = 0; 715 716 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 717 base = devm_ioremap_resource(&pdev->dev, res); 718 if (IS_ERR(base)) 719 return PTR_ERR(base); 720 721 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 722 if (!res) { 723 dev_err(&pdev->dev, "no irq resource\n"); 724 return -EINVAL; 725 } 726 irq = res->start; 727 728 div_clk = devm_clk_get(&pdev->dev, "div-clk"); 729 if (IS_ERR(div_clk)) { 730 dev_err(&pdev->dev, "missing controller clock"); 731 return PTR_ERR(div_clk); 732 } 733 734 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); 735 if (!i2c_dev) 736 return -ENOMEM; 737 738 i2c_dev->base = base; 739 i2c_dev->div_clk = div_clk; 740 i2c_dev->adapter.algo = &tegra_i2c_algo; 741 i2c_dev->irq = irq; 742 i2c_dev->cont_id = pdev->id; 743 i2c_dev->dev = &pdev->dev; 744 745 i2c_dev->rst = devm_reset_control_get(&pdev->dev, "i2c"); 746 if (IS_ERR(i2c_dev->rst)) { 747 dev_err(&pdev->dev, "missing controller reset"); 748 return PTR_ERR(i2c_dev->rst); 749 } 750 751 ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency", 752 &i2c_dev->bus_clk_rate); 753 if (ret) 754 i2c_dev->bus_clk_rate = 100000; /* default clock rate */ 755 756 i2c_dev->hw = &tegra20_i2c_hw; 757 758 if (pdev->dev.of_node) { 759 const struct of_device_id *match; 760 match = of_match_device(tegra_i2c_of_match, &pdev->dev); 761 i2c_dev->hw = match->data; 762 i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node, 763 "nvidia,tegra20-i2c-dvc"); 764 } else if (pdev->id == 3) { 765 i2c_dev->is_dvc = 1; 766 } 767 init_completion(&i2c_dev->msg_complete); 768 769 if (!i2c_dev->hw->has_single_clk_source) { 770 fast_clk = devm_clk_get(&pdev->dev, "fast-clk"); 771 if (IS_ERR(fast_clk)) { 772 dev_err(&pdev->dev, "missing fast clock"); 773 return PTR_ERR(fast_clk); 774 } 775 i2c_dev->fast_clk = fast_clk; 776 } 777 778 platform_set_drvdata(pdev, i2c_dev); 779 780 ret = tegra_i2c_init(i2c_dev); 781 if (ret) { 782 dev_err(&pdev->dev, "Failed to initialize i2c controller"); 783 return ret; 784 } 785 786 ret = devm_request_irq(&pdev->dev, i2c_dev->irq, 787 tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev); 788 if (ret) { 789 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); 790 return ret; 791 } 792 793 i2c_set_adapdata(&i2c_dev->adapter, i2c_dev); 794 i2c_dev->adapter.owner = THIS_MODULE; 795 i2c_dev->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_DEPRECATED; 796 strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter", 797 sizeof(i2c_dev->adapter.name)); 798 i2c_dev->adapter.algo = &tegra_i2c_algo; 799 i2c_dev->adapter.dev.parent = &pdev->dev; 800 i2c_dev->adapter.nr = pdev->id; 801 i2c_dev->adapter.dev.of_node = pdev->dev.of_node; 802 803 ret = i2c_add_numbered_adapter(&i2c_dev->adapter); 804 if (ret) { 805 dev_err(&pdev->dev, "Failed to add I2C adapter\n"); 806 return ret; 807 } 808 809 return 0; 810 } 811 812 static int tegra_i2c_remove(struct platform_device *pdev) 813 { 814 struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev); 815 i2c_del_adapter(&i2c_dev->adapter); 816 return 0; 817 } 818 819 #ifdef CONFIG_PM_SLEEP 820 static int tegra_i2c_suspend(struct device *dev) 821 { 822 struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); 823 824 i2c_lock_adapter(&i2c_dev->adapter); 825 i2c_dev->is_suspended = true; 826 i2c_unlock_adapter(&i2c_dev->adapter); 827 828 return 0; 829 } 830 831 static int tegra_i2c_resume(struct device *dev) 832 { 833 struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); 834 int ret; 835 836 i2c_lock_adapter(&i2c_dev->adapter); 837 838 ret = tegra_i2c_init(i2c_dev); 839 840 if (ret) { 841 i2c_unlock_adapter(&i2c_dev->adapter); 842 return ret; 843 } 844 845 i2c_dev->is_suspended = false; 846 847 i2c_unlock_adapter(&i2c_dev->adapter); 848 849 return 0; 850 } 851 852 static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume); 853 #define TEGRA_I2C_PM (&tegra_i2c_pm) 854 #else 855 #define TEGRA_I2C_PM NULL 856 #endif 857 858 static struct platform_driver tegra_i2c_driver = { 859 .probe = tegra_i2c_probe, 860 .remove = tegra_i2c_remove, 861 .driver = { 862 .name = "tegra-i2c", 863 .owner = THIS_MODULE, 864 .of_match_table = tegra_i2c_of_match, 865 .pm = TEGRA_I2C_PM, 866 }, 867 }; 868 869 static int __init tegra_i2c_init_driver(void) 870 { 871 return platform_driver_register(&tegra_i2c_driver); 872 } 873 874 static void __exit tegra_i2c_exit_driver(void) 875 { 876 platform_driver_unregister(&tegra_i2c_driver); 877 } 878 879 subsys_initcall(tegra_i2c_init_driver); 880 module_exit(tegra_i2c_exit_driver); 881 882 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver"); 883 MODULE_AUTHOR("Colin Cross"); 884 MODULE_LICENSE("GPL v2"); 885