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/clk/tegra.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 void __iomem *base; 164 int cont_id; 165 int irq; 166 bool irq_disabled; 167 int is_dvc; 168 struct completion msg_complete; 169 int msg_err; 170 u8 *msg_buf; 171 size_t msg_buf_remaining; 172 int msg_read; 173 u32 bus_clk_rate; 174 bool is_suspended; 175 }; 176 177 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg) 178 { 179 writel(val, i2c_dev->base + reg); 180 } 181 182 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) 183 { 184 return readl(i2c_dev->base + reg); 185 } 186 187 /* 188 * i2c_writel and i2c_readl will offset the register if necessary to talk 189 * to the I2C block inside the DVC block 190 */ 191 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev, 192 unsigned long reg) 193 { 194 if (i2c_dev->is_dvc) 195 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40; 196 return reg; 197 } 198 199 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, 200 unsigned long reg) 201 { 202 writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 203 204 /* Read back register to make sure that register writes completed */ 205 if (reg != I2C_TX_FIFO) 206 readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 207 } 208 209 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg) 210 { 211 return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg)); 212 } 213 214 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data, 215 unsigned long reg, int len) 216 { 217 writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); 218 } 219 220 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data, 221 unsigned long reg, int len) 222 { 223 readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len); 224 } 225 226 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) 227 { 228 u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); 229 int_mask &= ~mask; 230 i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); 231 } 232 233 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask) 234 { 235 u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK); 236 int_mask |= mask; 237 i2c_writel(i2c_dev, int_mask, I2C_INT_MASK); 238 } 239 240 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) 241 { 242 unsigned long timeout = jiffies + HZ; 243 u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL); 244 val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH; 245 i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); 246 247 while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) & 248 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) { 249 if (time_after(jiffies, timeout)) { 250 dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n"); 251 return -ETIMEDOUT; 252 } 253 msleep(1); 254 } 255 return 0; 256 } 257 258 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev) 259 { 260 u32 val; 261 int rx_fifo_avail; 262 u8 *buf = i2c_dev->msg_buf; 263 size_t buf_remaining = i2c_dev->msg_buf_remaining; 264 int words_to_transfer; 265 266 val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); 267 rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >> 268 I2C_FIFO_STATUS_RX_SHIFT; 269 270 /* Rounds down to not include partial word at the end of buf */ 271 words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; 272 if (words_to_transfer > rx_fifo_avail) 273 words_to_transfer = rx_fifo_avail; 274 275 i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer); 276 277 buf += words_to_transfer * BYTES_PER_FIFO_WORD; 278 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; 279 rx_fifo_avail -= words_to_transfer; 280 281 /* 282 * If there is a partial word at the end of buf, handle it manually to 283 * prevent overwriting past the end of buf 284 */ 285 if (rx_fifo_avail > 0 && buf_remaining > 0) { 286 BUG_ON(buf_remaining > 3); 287 val = i2c_readl(i2c_dev, I2C_RX_FIFO); 288 memcpy(buf, &val, buf_remaining); 289 buf_remaining = 0; 290 rx_fifo_avail--; 291 } 292 293 BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0); 294 i2c_dev->msg_buf_remaining = buf_remaining; 295 i2c_dev->msg_buf = buf; 296 return 0; 297 } 298 299 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) 300 { 301 u32 val; 302 int tx_fifo_avail; 303 u8 *buf = i2c_dev->msg_buf; 304 size_t buf_remaining = i2c_dev->msg_buf_remaining; 305 int words_to_transfer; 306 307 val = i2c_readl(i2c_dev, I2C_FIFO_STATUS); 308 tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >> 309 I2C_FIFO_STATUS_TX_SHIFT; 310 311 /* Rounds down to not include partial word at the end of buf */ 312 words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; 313 314 /* It's very common to have < 4 bytes, so optimize that case. */ 315 if (words_to_transfer) { 316 if (words_to_transfer > tx_fifo_avail) 317 words_to_transfer = tx_fifo_avail; 318 319 /* 320 * Update state before writing to FIFO. If this casues us 321 * to finish writing all bytes (AKA buf_remaining goes to 0) we 322 * have a potential for an interrupt (PACKET_XFER_COMPLETE is 323 * not maskable). We need to make sure that the isr sees 324 * buf_remaining as 0 and doesn't call us back re-entrantly. 325 */ 326 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; 327 tx_fifo_avail -= words_to_transfer; 328 i2c_dev->msg_buf_remaining = buf_remaining; 329 i2c_dev->msg_buf = buf + 330 words_to_transfer * BYTES_PER_FIFO_WORD; 331 barrier(); 332 333 i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); 334 335 buf += words_to_transfer * BYTES_PER_FIFO_WORD; 336 } 337 338 /* 339 * If there is a partial word at the end of buf, handle it manually to 340 * prevent reading past the end of buf, which could cross a page 341 * boundary and fault. 342 */ 343 if (tx_fifo_avail > 0 && buf_remaining > 0) { 344 BUG_ON(buf_remaining > 3); 345 memcpy(&val, buf, buf_remaining); 346 347 /* Again update before writing to FIFO to make sure isr sees. */ 348 i2c_dev->msg_buf_remaining = 0; 349 i2c_dev->msg_buf = NULL; 350 barrier(); 351 352 i2c_writel(i2c_dev, val, I2C_TX_FIFO); 353 } 354 355 return 0; 356 } 357 358 /* 359 * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller) 360 * block. This block is identical to the rest of the I2C blocks, except that 361 * it only supports master mode, it has registers moved around, and it needs 362 * some extra init to get it into I2C mode. The register moves are handled 363 * by i2c_readl and i2c_writel 364 */ 365 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev) 366 { 367 u32 val = 0; 368 val = dvc_readl(i2c_dev, DVC_CTRL_REG3); 369 val |= DVC_CTRL_REG3_SW_PROG; 370 val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN; 371 dvc_writel(i2c_dev, val, DVC_CTRL_REG3); 372 373 val = dvc_readl(i2c_dev, DVC_CTRL_REG1); 374 val |= DVC_CTRL_REG1_INTR_EN; 375 dvc_writel(i2c_dev, val, DVC_CTRL_REG1); 376 } 377 378 static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev) 379 { 380 int ret; 381 if (!i2c_dev->hw->has_single_clk_source) { 382 ret = clk_prepare_enable(i2c_dev->fast_clk); 383 if (ret < 0) { 384 dev_err(i2c_dev->dev, 385 "Enabling fast clk failed, err %d\n", ret); 386 return ret; 387 } 388 } 389 ret = clk_prepare_enable(i2c_dev->div_clk); 390 if (ret < 0) { 391 dev_err(i2c_dev->dev, 392 "Enabling div clk failed, err %d\n", ret); 393 clk_disable_unprepare(i2c_dev->fast_clk); 394 } 395 return ret; 396 } 397 398 static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev) 399 { 400 clk_disable_unprepare(i2c_dev->div_clk); 401 if (!i2c_dev->hw->has_single_clk_source) 402 clk_disable_unprepare(i2c_dev->fast_clk); 403 } 404 405 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) 406 { 407 u32 val; 408 int err = 0; 409 int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE; 410 u32 clk_divisor; 411 412 err = tegra_i2c_clock_enable(i2c_dev); 413 if (err < 0) { 414 dev_err(i2c_dev->dev, "Clock enable failed %d\n", err); 415 return err; 416 } 417 418 tegra_periph_reset_assert(i2c_dev->div_clk); 419 udelay(2); 420 tegra_periph_reset_deassert(i2c_dev->div_clk); 421 422 if (i2c_dev->is_dvc) 423 tegra_dvc_init(i2c_dev); 424 425 val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN | 426 (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT); 427 i2c_writel(i2c_dev, val, I2C_CNFG); 428 i2c_writel(i2c_dev, 0, I2C_INT_MASK); 429 430 clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1); 431 clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * clk_multiplier); 432 433 /* Make sure clock divisor programmed correctly */ 434 clk_divisor = i2c_dev->hw->clk_divisor_hs_mode; 435 clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode << 436 I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT; 437 i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR); 438 439 if (!i2c_dev->is_dvc) { 440 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); 441 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL; 442 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG); 443 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1); 444 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2); 445 446 } 447 448 val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT | 449 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT; 450 i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL); 451 452 if (tegra_i2c_flush_fifos(i2c_dev)) 453 err = -ETIMEDOUT; 454 455 tegra_i2c_clock_disable(i2c_dev); 456 457 if (i2c_dev->irq_disabled) { 458 i2c_dev->irq_disabled = 0; 459 enable_irq(i2c_dev->irq); 460 } 461 462 return err; 463 } 464 465 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) 466 { 467 u32 status; 468 const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; 469 struct tegra_i2c_dev *i2c_dev = dev_id; 470 471 status = i2c_readl(i2c_dev, I2C_INT_STATUS); 472 473 if (status == 0) { 474 dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n", 475 i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS), 476 i2c_readl(i2c_dev, I2C_STATUS), 477 i2c_readl(i2c_dev, I2C_CNFG)); 478 i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT; 479 480 if (!i2c_dev->irq_disabled) { 481 disable_irq_nosync(i2c_dev->irq); 482 i2c_dev->irq_disabled = 1; 483 } 484 goto err; 485 } 486 487 if (unlikely(status & status_err)) { 488 if (status & I2C_INT_NO_ACK) 489 i2c_dev->msg_err |= I2C_ERR_NO_ACK; 490 if (status & I2C_INT_ARBITRATION_LOST) 491 i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST; 492 goto err; 493 } 494 495 if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) { 496 if (i2c_dev->msg_buf_remaining) 497 tegra_i2c_empty_rx_fifo(i2c_dev); 498 else 499 BUG(); 500 } 501 502 if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) { 503 if (i2c_dev->msg_buf_remaining) 504 tegra_i2c_fill_tx_fifo(i2c_dev); 505 else 506 tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ); 507 } 508 509 i2c_writel(i2c_dev, status, I2C_INT_STATUS); 510 if (i2c_dev->is_dvc) 511 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); 512 513 if (status & I2C_INT_PACKET_XFER_COMPLETE) { 514 BUG_ON(i2c_dev->msg_buf_remaining); 515 complete(&i2c_dev->msg_complete); 516 } 517 return IRQ_HANDLED; 518 err: 519 /* An error occurred, mask all interrupts */ 520 tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | 521 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | 522 I2C_INT_RX_FIFO_DATA_REQ); 523 i2c_writel(i2c_dev, status, I2C_INT_STATUS); 524 if (i2c_dev->is_dvc) 525 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); 526 527 complete(&i2c_dev->msg_complete); 528 return IRQ_HANDLED; 529 } 530 531 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, 532 struct i2c_msg *msg, enum msg_end_type end_state) 533 { 534 u32 packet_header; 535 u32 int_mask; 536 int ret; 537 538 tegra_i2c_flush_fifos(i2c_dev); 539 540 if (msg->len == 0) 541 return -EINVAL; 542 543 i2c_dev->msg_buf = msg->buf; 544 i2c_dev->msg_buf_remaining = msg->len; 545 i2c_dev->msg_err = I2C_ERR_NONE; 546 i2c_dev->msg_read = (msg->flags & I2C_M_RD); 547 INIT_COMPLETION(i2c_dev->msg_complete); 548 549 packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) | 550 PACKET_HEADER0_PROTOCOL_I2C | 551 (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) | 552 (1 << PACKET_HEADER0_PACKET_ID_SHIFT); 553 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 554 555 packet_header = msg->len - 1; 556 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 557 558 packet_header = I2C_HEADER_IE_ENABLE; 559 if (end_state == MSG_END_CONTINUE) 560 packet_header |= I2C_HEADER_CONTINUE_XFER; 561 else if (end_state == MSG_END_REPEAT_START) 562 packet_header |= I2C_HEADER_REPEAT_START; 563 if (msg->flags & I2C_M_TEN) { 564 packet_header |= msg->addr; 565 packet_header |= I2C_HEADER_10BIT_ADDR; 566 } else { 567 packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT; 568 } 569 if (msg->flags & I2C_M_IGNORE_NAK) 570 packet_header |= I2C_HEADER_CONT_ON_NAK; 571 if (msg->flags & I2C_M_RD) 572 packet_header |= I2C_HEADER_READ; 573 i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO); 574 575 if (!(msg->flags & I2C_M_RD)) 576 tegra_i2c_fill_tx_fifo(i2c_dev); 577 578 int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; 579 if (i2c_dev->hw->has_per_pkt_xfer_complete_irq) 580 int_mask |= I2C_INT_PACKET_XFER_COMPLETE; 581 if (msg->flags & I2C_M_RD) 582 int_mask |= I2C_INT_RX_FIFO_DATA_REQ; 583 else if (i2c_dev->msg_buf_remaining) 584 int_mask |= I2C_INT_TX_FIFO_DATA_REQ; 585 tegra_i2c_unmask_irq(i2c_dev, int_mask); 586 dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n", 587 i2c_readl(i2c_dev, I2C_INT_MASK)); 588 589 ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT); 590 tegra_i2c_mask_irq(i2c_dev, int_mask); 591 592 if (ret == 0) { 593 dev_err(i2c_dev->dev, "i2c transfer timed out\n"); 594 595 tegra_i2c_init(i2c_dev); 596 return -ETIMEDOUT; 597 } 598 599 dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n", 600 ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err); 601 602 if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) 603 return 0; 604 605 /* 606 * NACK interrupt is generated before the I2C controller generates the 607 * STOP condition on the bus. So wait for 2 clock periods before resetting 608 * the controller so that STOP condition has been delivered properly. 609 */ 610 if (i2c_dev->msg_err == I2C_ERR_NO_ACK) 611 udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); 612 613 tegra_i2c_init(i2c_dev); 614 if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { 615 if (msg->flags & I2C_M_IGNORE_NAK) 616 return 0; 617 return -EREMOTEIO; 618 } 619 620 return -EIO; 621 } 622 623 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], 624 int num) 625 { 626 struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); 627 int i; 628 int ret = 0; 629 630 if (i2c_dev->is_suspended) 631 return -EBUSY; 632 633 ret = tegra_i2c_clock_enable(i2c_dev); 634 if (ret < 0) { 635 dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret); 636 return ret; 637 } 638 639 for (i = 0; i < num; i++) { 640 enum msg_end_type end_type = MSG_END_STOP; 641 if (i < (num - 1)) { 642 if (msgs[i + 1].flags & I2C_M_NOSTART) 643 end_type = MSG_END_CONTINUE; 644 else 645 end_type = MSG_END_REPEAT_START; 646 } 647 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type); 648 if (ret) 649 break; 650 } 651 tegra_i2c_clock_disable(i2c_dev); 652 return ret ?: i; 653 } 654 655 static u32 tegra_i2c_func(struct i2c_adapter *adap) 656 { 657 struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); 658 u32 ret = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | 659 I2C_FUNC_PROTOCOL_MANGLING; 660 661 if (i2c_dev->hw->has_continue_xfer_support) 662 ret |= I2C_FUNC_NOSTART; 663 return ret; 664 } 665 666 static const struct i2c_algorithm tegra_i2c_algo = { 667 .master_xfer = tegra_i2c_xfer, 668 .functionality = tegra_i2c_func, 669 }; 670 671 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = { 672 .has_continue_xfer_support = false, 673 .has_per_pkt_xfer_complete_irq = false, 674 .has_single_clk_source = false, 675 .clk_divisor_hs_mode = 3, 676 .clk_divisor_std_fast_mode = 0, 677 }; 678 679 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = { 680 .has_continue_xfer_support = true, 681 .has_per_pkt_xfer_complete_irq = false, 682 .has_single_clk_source = false, 683 .clk_divisor_hs_mode = 3, 684 .clk_divisor_std_fast_mode = 0, 685 }; 686 687 static const struct tegra_i2c_hw_feature tegra114_i2c_hw = { 688 .has_continue_xfer_support = true, 689 .has_per_pkt_xfer_complete_irq = true, 690 .has_single_clk_source = true, 691 .clk_divisor_hs_mode = 1, 692 .clk_divisor_std_fast_mode = 0x19, 693 }; 694 695 /* Match table for of_platform binding */ 696 static const struct of_device_id tegra_i2c_of_match[] = { 697 { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, }, 698 { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, }, 699 { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, }, 700 { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, }, 701 {}, 702 }; 703 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match); 704 705 static int tegra_i2c_probe(struct platform_device *pdev) 706 { 707 struct tegra_i2c_dev *i2c_dev; 708 struct resource *res; 709 struct clk *div_clk; 710 struct clk *fast_clk; 711 void __iomem *base; 712 int irq; 713 int ret = 0; 714 715 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 716 base = devm_ioremap_resource(&pdev->dev, res); 717 if (IS_ERR(base)) 718 return PTR_ERR(base); 719 720 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 721 if (!res) { 722 dev_err(&pdev->dev, "no irq resource\n"); 723 return -EINVAL; 724 } 725 irq = res->start; 726 727 div_clk = devm_clk_get(&pdev->dev, "div-clk"); 728 if (IS_ERR(div_clk)) { 729 dev_err(&pdev->dev, "missing controller clock"); 730 return PTR_ERR(div_clk); 731 } 732 733 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); 734 if (!i2c_dev) { 735 dev_err(&pdev->dev, "Could not allocate struct tegra_i2c_dev"); 736 return -ENOMEM; 737 } 738 739 i2c_dev->base = base; 740 i2c_dev->div_clk = div_clk; 741 i2c_dev->adapter.algo = &tegra_i2c_algo; 742 i2c_dev->irq = irq; 743 i2c_dev->cont_id = pdev->id; 744 i2c_dev->dev = &pdev->dev; 745 746 ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency", 747 &i2c_dev->bus_clk_rate); 748 if (ret) 749 i2c_dev->bus_clk_rate = 100000; /* default clock rate */ 750 751 i2c_dev->hw = &tegra20_i2c_hw; 752 753 if (pdev->dev.of_node) { 754 const struct of_device_id *match; 755 match = of_match_device(tegra_i2c_of_match, &pdev->dev); 756 i2c_dev->hw = match->data; 757 i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node, 758 "nvidia,tegra20-i2c-dvc"); 759 } else if (pdev->id == 3) { 760 i2c_dev->is_dvc = 1; 761 } 762 init_completion(&i2c_dev->msg_complete); 763 764 if (!i2c_dev->hw->has_single_clk_source) { 765 fast_clk = devm_clk_get(&pdev->dev, "fast-clk"); 766 if (IS_ERR(fast_clk)) { 767 dev_err(&pdev->dev, "missing fast clock"); 768 return PTR_ERR(fast_clk); 769 } 770 i2c_dev->fast_clk = fast_clk; 771 } 772 773 platform_set_drvdata(pdev, i2c_dev); 774 775 ret = tegra_i2c_init(i2c_dev); 776 if (ret) { 777 dev_err(&pdev->dev, "Failed to initialize i2c controller"); 778 return ret; 779 } 780 781 ret = devm_request_irq(&pdev->dev, i2c_dev->irq, 782 tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev); 783 if (ret) { 784 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); 785 return ret; 786 } 787 788 i2c_set_adapdata(&i2c_dev->adapter, i2c_dev); 789 i2c_dev->adapter.owner = THIS_MODULE; 790 i2c_dev->adapter.class = I2C_CLASS_HWMON; 791 strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter", 792 sizeof(i2c_dev->adapter.name)); 793 i2c_dev->adapter.algo = &tegra_i2c_algo; 794 i2c_dev->adapter.dev.parent = &pdev->dev; 795 i2c_dev->adapter.nr = pdev->id; 796 i2c_dev->adapter.dev.of_node = pdev->dev.of_node; 797 798 ret = i2c_add_numbered_adapter(&i2c_dev->adapter); 799 if (ret) { 800 dev_err(&pdev->dev, "Failed to add I2C adapter\n"); 801 return ret; 802 } 803 804 return 0; 805 } 806 807 static int tegra_i2c_remove(struct platform_device *pdev) 808 { 809 struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev); 810 i2c_del_adapter(&i2c_dev->adapter); 811 return 0; 812 } 813 814 #ifdef CONFIG_PM_SLEEP 815 static int tegra_i2c_suspend(struct device *dev) 816 { 817 struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); 818 819 i2c_lock_adapter(&i2c_dev->adapter); 820 i2c_dev->is_suspended = true; 821 i2c_unlock_adapter(&i2c_dev->adapter); 822 823 return 0; 824 } 825 826 static int tegra_i2c_resume(struct device *dev) 827 { 828 struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); 829 int ret; 830 831 i2c_lock_adapter(&i2c_dev->adapter); 832 833 ret = tegra_i2c_init(i2c_dev); 834 835 if (ret) { 836 i2c_unlock_adapter(&i2c_dev->adapter); 837 return ret; 838 } 839 840 i2c_dev->is_suspended = false; 841 842 i2c_unlock_adapter(&i2c_dev->adapter); 843 844 return 0; 845 } 846 847 static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume); 848 #define TEGRA_I2C_PM (&tegra_i2c_pm) 849 #else 850 #define TEGRA_I2C_PM NULL 851 #endif 852 853 static struct platform_driver tegra_i2c_driver = { 854 .probe = tegra_i2c_probe, 855 .remove = tegra_i2c_remove, 856 .driver = { 857 .name = "tegra-i2c", 858 .owner = THIS_MODULE, 859 .of_match_table = tegra_i2c_of_match, 860 .pm = TEGRA_I2C_PM, 861 }, 862 }; 863 864 static int __init tegra_i2c_init_driver(void) 865 { 866 return platform_driver_register(&tegra_i2c_driver); 867 } 868 869 static void __exit tegra_i2c_exit_driver(void) 870 { 871 platform_driver_unregister(&tegra_i2c_driver); 872 } 873 874 subsys_initcall(tegra_i2c_init_driver); 875 module_exit(tegra_i2c_exit_driver); 876 877 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver"); 878 MODULE_AUTHOR("Colin Cross"); 879 MODULE_LICENSE("GPL v2"); 880