drivers/i2c/busses/i2c-bcm-kona.c

   1 /*
   2  * Copyright (C) 2013 Broadcom Corporation
   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 as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/device.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/sched.h>
  18 #include <linux/i2c.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/clk.h>
  22 #include <linux/io.h>
  23 #include <linux/slab.h>
  24
  25 /* Hardware register offsets and field defintions */
  26 #define CS_OFFSET                               0x00000020
  27 #define CS_ACK_SHIFT                            3
  28 #define CS_ACK_MASK                             0x00000008
  29 #define CS_ACK_CMD_GEN_START                    0x00000000
  30 #define CS_ACK_CMD_GEN_RESTART                  0x00000001
  31 #define CS_CMD_SHIFT                            1
  32 #define CS_CMD_CMD_NO_ACTION                    0x00000000
  33 #define CS_CMD_CMD_START_RESTART                0x00000001
  34 #define CS_CMD_CMD_STOP                         0x00000002
  35 #define CS_EN_SHIFT                             0
  36 #define CS_EN_CMD_ENABLE_BSC                    0x00000001
  37
  38 #define TIM_OFFSET                              0x00000024
  39 #define TIM_PRESCALE_SHIFT                      6
  40 #define TIM_P_SHIFT                             3
  41 #define TIM_NO_DIV_SHIFT                        2
  42 #define TIM_DIV_SHIFT                           0
  43
  44 #define DAT_OFFSET                              0x00000028
  45
  46 #define TOUT_OFFSET                             0x0000002c
  47
  48 #define TXFCR_OFFSET                            0x0000003c
  49 #define TXFCR_FIFO_FLUSH_MASK                   0x00000080
  50 #define TXFCR_FIFO_EN_MASK                      0x00000040
  51
  52 #define IER_OFFSET                              0x00000044
  53 #define IER_READ_COMPLETE_INT_MASK              0x00000010
  54 #define IER_I2C_INT_EN_MASK                     0x00000008
  55 #define IER_FIFO_INT_EN_MASK                    0x00000002
  56 #define IER_NOACK_EN_MASK                       0x00000001
  57
  58 #define ISR_OFFSET                              0x00000048
  59 #define ISR_RESERVED_MASK                       0xffffff60
  60 #define ISR_CMDBUSY_MASK                        0x00000080
  61 #define ISR_READ_COMPLETE_MASK                  0x00000010
  62 #define ISR_SES_DONE_MASK                       0x00000008
  63 #define ISR_ERR_MASK                            0x00000004
  64 #define ISR_TXFIFOEMPTY_MASK                    0x00000002
  65 #define ISR_NOACK_MASK                          0x00000001
  66
  67 #define CLKEN_OFFSET                            0x0000004C
  68 #define CLKEN_AUTOSENSE_OFF_MASK                0x00000080
  69 #define CLKEN_M_SHIFT                           4
  70 #define CLKEN_N_SHIFT                           1
  71 #define CLKEN_CLKEN_MASK                        0x00000001
  72
  73 #define FIFO_STATUS_OFFSET                      0x00000054
  74 #define FIFO_STATUS_RXFIFO_EMPTY_MASK           0x00000004
  75 #define FIFO_STATUS_TXFIFO_EMPTY_MASK           0x00000010
  76
  77 #define HSTIM_OFFSET                            0x00000058
  78 #define HSTIM_HS_MODE_MASK                      0x00008000
  79 #define HSTIM_HS_HOLD_SHIFT                     10
  80 #define HSTIM_HS_HIGH_PHASE_SHIFT               5
  81 #define HSTIM_HS_SETUP_SHIFT                    0
  82
  83 #define PADCTL_OFFSET                           0x0000005c
  84 #define PADCTL_PAD_OUT_EN_MASK                  0x00000004
  85
  86 #define RXFCR_OFFSET                            0x00000068
  87 #define RXFCR_NACK_EN_SHIFT                     7
  88 #define RXFCR_READ_COUNT_SHIFT                  0
  89 #define RXFIFORDOUT_OFFSET                      0x0000006c
  90
  91 /* Locally used constants */
  92 #define MAX_RX_FIFO_SIZE                64U /* bytes */
  93 #define MAX_TX_FIFO_SIZE                64U /* bytes */
  94
  95 #define STD_EXT_CLK_FREQ                13000000UL
  96 #define HS_EXT_CLK_FREQ                 104000000UL
  97
  98 #define MASTERCODE                      0x08 /* Mastercodes are 0000_1xxxb */
  99
 100 #define I2C_TIMEOUT                     100 /* msecs */
 101
 102 /* Operations that can be commanded to the controller */
 103 enum bcm_kona_cmd_t {
 104         BCM_CMD_NOACTION = 0,
 105         BCM_CMD_START,
 106         BCM_CMD_RESTART,
 107         BCM_CMD_STOP,
 108 };
 109
 110 enum bus_speed_index {
 111         BCM_SPD_100K = 0,
 112         BCM_SPD_400K,
 113         BCM_SPD_1MHZ,
 114 };
 115
 116 enum hs_bus_speed_index {
 117         BCM_SPD_3P4MHZ = 0,
 118 };
 119
 120 /* Internal divider settings for standard mode, fast mode and fast mode plus */
 121 struct bus_speed_cfg {
 122         uint8_t time_m;         /* Number of cycles for setup time */
 123         uint8_t time_n;         /* Number of cycles for hold time */
 124         uint8_t prescale;       /* Prescale divider */
 125         uint8_t time_p;         /* Timing coefficient */
 126         uint8_t no_div;         /* Disable clock divider */
 127         uint8_t time_div;       /* Post-prescale divider */
 128 };
 129
 130 /* Internal divider settings for high-speed mode */
 131 struct hs_bus_speed_cfg {
 132         uint8_t hs_hold;        /* Number of clock cycles SCL stays low until
 133                                    the end of bit period */
 134         uint8_t hs_high_phase;  /* Number of clock cycles SCL stays high
 135                                    before it falls */
 136         uint8_t hs_setup;       /* Number of clock cycles SCL stays low
 137                                    before it rises  */
 138         uint8_t prescale;       /* Prescale divider */
 139         uint8_t time_p;         /* Timing coefficient */
 140         uint8_t no_div;         /* Disable clock divider */
 141         uint8_t time_div;       /* Post-prescale divider */
 142 };
 143
 144 static const struct bus_speed_cfg std_cfg_table[] = {
 145         [BCM_SPD_100K] = {0x01, 0x01, 0x03, 0x06, 0x00, 0x02},
 146         [BCM_SPD_400K] = {0x05, 0x01, 0x03, 0x05, 0x01, 0x02},
 147         [BCM_SPD_1MHZ] = {0x01, 0x01, 0x03, 0x01, 0x01, 0x03},
 148 };
 149
 150 static const struct hs_bus_speed_cfg hs_cfg_table[] = {
 151         [BCM_SPD_3P4MHZ] = {0x01, 0x08, 0x14, 0x00, 0x06, 0x01, 0x00},
 152 };
 153
 154 struct bcm_kona_i2c_dev {
 155         struct device *device;
 156
 157         void __iomem *base;
 158         int irq;
 159         struct clk *external_clk;
 160
 161         struct i2c_adapter adapter;
 162
 163         struct completion done;
 164
 165         const struct bus_speed_cfg *std_cfg;
 166         const struct hs_bus_speed_cfg *hs_cfg;
 167 };
 168
 169 static void bcm_kona_i2c_send_cmd_to_ctrl(struct bcm_kona_i2c_dev *dev,
 170                                           enum bcm_kona_cmd_t cmd)
 171 {
 172         dev_dbg(dev->device, "%s, %d\n", __func__, cmd);
 173
 174         switch (cmd) {
 175         case BCM_CMD_NOACTION:
 176                 writel((CS_CMD_CMD_NO_ACTION << CS_CMD_SHIFT) |
 177                        (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
 178                        dev->base + CS_OFFSET);
 179                 break;
 180
 181         case BCM_CMD_START:
 182                 writel((CS_ACK_CMD_GEN_START << CS_ACK_SHIFT) |
 183                        (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
 184                        (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
 185                        dev->base + CS_OFFSET);
 186                 break;
 187
 188         case BCM_CMD_RESTART:
 189                 writel((CS_ACK_CMD_GEN_RESTART << CS_ACK_SHIFT) |
 190                        (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) |
 191                        (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
 192                        dev->base + CS_OFFSET);
 193                 break;
 194
 195         case BCM_CMD_STOP:
 196                 writel((CS_CMD_CMD_STOP << CS_CMD_SHIFT) |
 197                        (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT),
 198                        dev->base + CS_OFFSET);
 199                 break;
 200
 201         default:
 202                 dev_err(dev->device, "Unknown command %d\n", cmd);
 203         }
 204 }
 205
 206 static void bcm_kona_i2c_enable_clock(struct bcm_kona_i2c_dev *dev)
 207 {
 208         writel(readl(dev->base + CLKEN_OFFSET) | CLKEN_CLKEN_MASK,
 209                dev->base + CLKEN_OFFSET);
 210 }
 211
 212 static void bcm_kona_i2c_disable_clock(struct bcm_kona_i2c_dev *dev)
 213 {
 214         writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_CLKEN_MASK,
 215                dev->base + CLKEN_OFFSET);
 216 }
 217
 218 static irqreturn_t bcm_kona_i2c_isr(int irq, void *devid)
 219 {
 220         struct bcm_kona_i2c_dev *dev = devid;
 221         uint32_t status = readl(dev->base + ISR_OFFSET);
 222
 223         if ((status & ~ISR_RESERVED_MASK) == 0)
 224                 return IRQ_NONE;
 225
 226         /* Must flush the TX FIFO when NAK detected */
 227         if (status & ISR_NOACK_MASK)
 228                 writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
 229                        dev->base + TXFCR_OFFSET);
 230
 231         writel(status & ~ISR_RESERVED_MASK, dev->base + ISR_OFFSET);
 232         complete(&dev->done);
 233
 234         return IRQ_HANDLED;
 235 }
 236
 237 /* Wait for ISR_CMDBUSY_MASK to go low before writing to CS, DAT, or RCD */
 238 static int bcm_kona_i2c_wait_if_busy(struct bcm_kona_i2c_dev *dev)
 239 {
 240         unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT);
 241
 242         while (readl(dev->base + ISR_OFFSET) & ISR_CMDBUSY_MASK)
 243                 if (time_after(jiffies, timeout)) {
 244                         dev_err(dev->device, "CMDBUSY timeout\n");
 245                         return -ETIMEDOUT;
 246                 }
 247
 248         return 0;
 249 }
 250
 251 /* Send command to I2C bus */
 252 static int bcm_kona_send_i2c_cmd(struct bcm_kona_i2c_dev *dev,
 253                                  enum bcm_kona_cmd_t cmd)
 254 {
 255         int rc;
 256         unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
 257
 258         /* Make sure the hardware is ready */
 259         rc = bcm_kona_i2c_wait_if_busy(dev);
 260         if (rc < 0)
 261                 return rc;
 262
 263         /* Unmask the session done interrupt */
 264         writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET);
 265
 266         /* Mark as incomplete before sending the command */
 267         reinit_completion(&dev->done);
 268
 269         /* Send the command */
 270         bcm_kona_i2c_send_cmd_to_ctrl(dev, cmd);
 271
 272         /* Wait for transaction to finish or timeout */
 273         time_left = wait_for_completion_timeout(&dev->done, time_left);
 274
 275         /* Mask all interrupts */
 276         writel(0, dev->base + IER_OFFSET);
 277
 278         if (!time_left) {
 279                 dev_err(dev->device, "controller timed out\n");
 280                 rc = -ETIMEDOUT;
 281         }
 282
 283         /* Clear command */
 284         bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
 285
 286         return rc;
 287 }
 288
 289 /* Read a single RX FIFO worth of data from the i2c bus */
 290 static int bcm_kona_i2c_read_fifo_single(struct bcm_kona_i2c_dev *dev,
 291                                          uint8_t *buf, unsigned int len,
 292                                          unsigned int last_byte_nak)
 293 {
 294         unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
 295
 296         /* Mark as incomplete before starting the RX FIFO */
 297         reinit_completion(&dev->done);
 298
 299         /* Unmask the read complete interrupt */
 300         writel(IER_READ_COMPLETE_INT_MASK, dev->base + IER_OFFSET);
 301
 302         /* Start the RX FIFO */
 303         writel((last_byte_nak << RXFCR_NACK_EN_SHIFT) |
 304                (len << RXFCR_READ_COUNT_SHIFT),
 305                 dev->base + RXFCR_OFFSET);
 306
 307         /* Wait for FIFO read to complete */
 308         time_left = wait_for_completion_timeout(&dev->done, time_left);
 309
 310         /* Mask all interrupts */
 311         writel(0, dev->base + IER_OFFSET);
 312
 313         if (!time_left) {
 314                 dev_err(dev->device, "RX FIFO time out\n");
 315                 return -EREMOTEIO;
 316         }
 317
 318         /* Read data from FIFO */
 319         for (; len > 0; len--, buf++)
 320                 *buf = readl(dev->base + RXFIFORDOUT_OFFSET);
 321
 322         return 0;
 323 }
 324
 325 /* Read any amount of data using the RX FIFO from the i2c bus */
 326 static int bcm_kona_i2c_read_fifo(struct bcm_kona_i2c_dev *dev,
 327                                   struct i2c_msg *msg)
 328 {
 329         unsigned int bytes_to_read = MAX_RX_FIFO_SIZE;
 330         unsigned int last_byte_nak = 0;
 331         unsigned int bytes_read = 0;
 332         int rc;
 333
 334         uint8_t *tmp_buf = msg->buf;
 335
 336         while (bytes_read < msg->len) {
 337                 if (msg->len - bytes_read <= MAX_RX_FIFO_SIZE) {
 338                         last_byte_nak = 1; /* NAK last byte of transfer */
 339                         bytes_to_read = msg->len - bytes_read;
 340                 }
 341
 342                 rc = bcm_kona_i2c_read_fifo_single(dev, tmp_buf, bytes_to_read,
 343                                                    last_byte_nak);
 344                 if (rc < 0)
 345                         return -EREMOTEIO;
 346
 347                 bytes_read += bytes_to_read;
 348                 tmp_buf += bytes_to_read;
 349         }
 350
 351         return 0;
 352 }
 353
 354 /* Write a single byte of data to the i2c bus */
 355 static int bcm_kona_i2c_write_byte(struct bcm_kona_i2c_dev *dev, uint8_t data,
 356                                    unsigned int nak_expected)
 357 {
 358         int rc;
 359         unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
 360         unsigned int nak_received;
 361
 362         /* Make sure the hardware is ready */
 363         rc = bcm_kona_i2c_wait_if_busy(dev);
 364         if (rc < 0)
 365                 return rc;
 366
 367         /* Clear pending session done interrupt */
 368         writel(ISR_SES_DONE_MASK, dev->base + ISR_OFFSET);
 369
 370         /* Unmask the session done interrupt */
 371         writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET);
 372
 373         /* Mark as incomplete before sending the data */
 374         reinit_completion(&dev->done);
 375
 376         /* Send one byte of data */
 377         writel(data, dev->base + DAT_OFFSET);
 378
 379         /* Wait for byte to be written */
 380         time_left = wait_for_completion_timeout(&dev->done, time_left);
 381
 382         /* Mask all interrupts */
 383         writel(0, dev->base + IER_OFFSET);
 384
 385         if (!time_left) {
 386                 dev_dbg(dev->device, "controller timed out\n");
 387                 return -ETIMEDOUT;
 388         }
 389
 390         nak_received = readl(dev->base + CS_OFFSET) & CS_ACK_MASK ? 1 : 0;
 391
 392         if (nak_received ^ nak_expected) {
 393                 dev_dbg(dev->device, "unexpected NAK/ACK\n");
 394                 return -EREMOTEIO;
 395         }
 396
 397         return 0;
 398 }
 399
 400 /* Write a single TX FIFO worth of data to the i2c bus */
 401 static int bcm_kona_i2c_write_fifo_single(struct bcm_kona_i2c_dev *dev,
 402                                           uint8_t *buf, unsigned int len)
 403 {
 404         int k;
 405         unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT);
 406         unsigned int fifo_status;
 407
 408         /* Mark as incomplete before sending data to the TX FIFO */
 409         reinit_completion(&dev->done);
 410
 411         /* Unmask the fifo empty and nak interrupt */
 412         writel(IER_FIFO_INT_EN_MASK | IER_NOACK_EN_MASK,
 413                dev->base + IER_OFFSET);
 414
 415         /* Disable IRQ to load a FIFO worth of data without interruption */
 416         disable_irq(dev->irq);
 417
 418         /* Write data into FIFO */
 419         for (k = 0; k < len; k++)
 420                 writel(buf[k], (dev->base + DAT_OFFSET));
 421
 422         /* Enable IRQ now that data has been loaded */
 423         enable_irq(dev->irq);
 424
 425         /* Wait for FIFO to empty */
 426         do {
 427                 time_left = wait_for_completion_timeout(&dev->done, time_left);
 428                 fifo_status = readl(dev->base + FIFO_STATUS_OFFSET);
 429         } while (time_left && !(fifo_status & FIFO_STATUS_TXFIFO_EMPTY_MASK));
 430
 431         /* Mask all interrupts */
 432         writel(0, dev->base + IER_OFFSET);
 433
 434         /* Check if there was a NAK */
 435         if (readl(dev->base + CS_OFFSET) & CS_ACK_MASK) {
 436                 dev_err(dev->device, "unexpected NAK\n");
 437                 return -EREMOTEIO;
 438         }
 439
 440         /* Check if a timeout occured */
 441         if (!time_left) {
 442                 dev_err(dev->device, "completion timed out\n");
 443                 return -EREMOTEIO;
 444         }
 445
 446         return 0;
 447 }
 448
 449
 450 /* Write any amount of data using TX FIFO to the i2c bus */
 451 static int bcm_kona_i2c_write_fifo(struct bcm_kona_i2c_dev *dev,
 452                                    struct i2c_msg *msg)
 453 {
 454         unsigned int bytes_to_write = MAX_TX_FIFO_SIZE;
 455         unsigned int bytes_written = 0;
 456         int rc;
 457
 458         uint8_t *tmp_buf = msg->buf;
 459
 460         while (bytes_written < msg->len) {
 461                 if (msg->len - bytes_written <= MAX_TX_FIFO_SIZE)
 462                         bytes_to_write = msg->len - bytes_written;
 463
 464                 rc = bcm_kona_i2c_write_fifo_single(dev, tmp_buf,
 465                                                     bytes_to_write);
 466                 if (rc < 0)
 467                         return -EREMOTEIO;
 468
 469                 bytes_written += bytes_to_write;
 470                 tmp_buf += bytes_to_write;
 471         }
 472
 473         return 0;
 474 }
 475
 476 /* Send i2c address */
 477 static int bcm_kona_i2c_do_addr(struct bcm_kona_i2c_dev *dev,
 478                                      struct i2c_msg *msg)
 479 {
 480         unsigned char addr;
 481
 482         if (msg->flags & I2C_M_TEN) {
 483                 /* First byte is 11110XX0 where XX is upper 2 bits */
 484                 addr = 0xF0 | ((msg->addr & 0x300) >> 7);
 485                 if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
 486                         return -EREMOTEIO;
 487
 488                 /* Second byte is the remaining 8 bits */
 489                 addr = msg->addr & 0xFF;
 490                 if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
 491                         return -EREMOTEIO;
 492
 493                 if (msg->flags & I2C_M_RD) {
 494                         /* For read, send restart command */
 495                         if (bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART) < 0)
 496                                 return -EREMOTEIO;
 497
 498                         /* Then re-send the first byte with the read bit set */
 499                         addr = 0xF0 | ((msg->addr & 0x300) >> 7) | 0x01;
 500                         if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
 501                                 return -EREMOTEIO;
 502                 }
 503         } else {
 504                 addr = i2c_8bit_addr_from_msg(msg);
 505
 506                 if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0)
 507                         return -EREMOTEIO;
 508         }
 509
 510         return 0;
 511 }
 512
 513 static void bcm_kona_i2c_enable_autosense(struct bcm_kona_i2c_dev *dev)
 514 {
 515         writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_AUTOSENSE_OFF_MASK,
 516                dev->base + CLKEN_OFFSET);
 517 }
 518
 519 static void bcm_kona_i2c_config_timing(struct bcm_kona_i2c_dev *dev)
 520 {
 521         writel(readl(dev->base + HSTIM_OFFSET) & ~HSTIM_HS_MODE_MASK,
 522                dev->base + HSTIM_OFFSET);
 523
 524         writel((dev->std_cfg->prescale << TIM_PRESCALE_SHIFT) |
 525                (dev->std_cfg->time_p << TIM_P_SHIFT) |
 526                (dev->std_cfg->no_div << TIM_NO_DIV_SHIFT) |
 527                (dev->std_cfg->time_div  << TIM_DIV_SHIFT),
 528                dev->base + TIM_OFFSET);
 529
 530         writel((dev->std_cfg->time_m << CLKEN_M_SHIFT) |
 531                (dev->std_cfg->time_n << CLKEN_N_SHIFT) |
 532                CLKEN_CLKEN_MASK,
 533                dev->base + CLKEN_OFFSET);
 534 }
 535
 536 static void bcm_kona_i2c_config_timing_hs(struct bcm_kona_i2c_dev *dev)
 537 {
 538         writel((dev->hs_cfg->prescale << TIM_PRESCALE_SHIFT) |
 539                (dev->hs_cfg->time_p << TIM_P_SHIFT) |
 540                (dev->hs_cfg->no_div << TIM_NO_DIV_SHIFT) |
 541                (dev->hs_cfg->time_div << TIM_DIV_SHIFT),
 542                dev->base + TIM_OFFSET);
 543
 544         writel((dev->hs_cfg->hs_hold << HSTIM_HS_HOLD_SHIFT) |
 545                (dev->hs_cfg->hs_high_phase << HSTIM_HS_HIGH_PHASE_SHIFT) |
 546                (dev->hs_cfg->hs_setup << HSTIM_HS_SETUP_SHIFT),
 547                dev->base + HSTIM_OFFSET);
 548
 549         writel(readl(dev->base + HSTIM_OFFSET) | HSTIM_HS_MODE_MASK,
 550                dev->base + HSTIM_OFFSET);
 551 }
 552
 553 static int bcm_kona_i2c_switch_to_hs(struct bcm_kona_i2c_dev *dev)
 554 {
 555         int rc;
 556
 557         /* Send mastercode at standard speed */
 558         rc = bcm_kona_i2c_write_byte(dev, MASTERCODE, 1);
 559         if (rc < 0) {
 560                 pr_err("High speed handshake failed\n");
 561                 return rc;
 562         }
 563
 564         /* Configure external clock to higher frequency */
 565         rc = clk_set_rate(dev->external_clk, HS_EXT_CLK_FREQ);
 566         if (rc) {
 567                 dev_err(dev->device, "%s: clk_set_rate returned %d\n",
 568                         __func__, rc);
 569                 return rc;
 570         }
 571
 572         /* Reconfigure internal dividers */
 573         bcm_kona_i2c_config_timing_hs(dev);
 574
 575         /* Send a restart command */
 576         rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
 577         if (rc < 0)
 578                 dev_err(dev->device, "High speed restart command failed\n");
 579
 580         return rc;
 581 }
 582
 583 static int bcm_kona_i2c_switch_to_std(struct bcm_kona_i2c_dev *dev)
 584 {
 585         int rc;
 586
 587         /* Reconfigure internal dividers */
 588         bcm_kona_i2c_config_timing(dev);
 589
 590         /* Configure external clock to lower frequency */
 591         rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ);
 592         if (rc) {
 593                 dev_err(dev->device, "%s: clk_set_rate returned %d\n",
 594                         __func__, rc);
 595         }
 596
 597         return rc;
 598 }
 599
 600 /* Master transfer function */
 601 static int bcm_kona_i2c_xfer(struct i2c_adapter *adapter,
 602                              struct i2c_msg msgs[], int num)
 603 {
 604         struct bcm_kona_i2c_dev *dev = i2c_get_adapdata(adapter);
 605         struct i2c_msg *pmsg;
 606         int rc = 0;
 607         int i;
 608
 609         rc = clk_prepare_enable(dev->external_clk);
 610         if (rc) {
 611                 dev_err(dev->device, "%s: peri clock enable failed. err %d\n",
 612                         __func__, rc);
 613                 return rc;
 614         }
 615
 616         /* Enable pad output */
 617         writel(0, dev->base + PADCTL_OFFSET);
 618
 619         /* Enable internal clocks */
 620         bcm_kona_i2c_enable_clock(dev);
 621
 622         /* Send start command */
 623         rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_START);
 624         if (rc < 0) {
 625                 dev_err(dev->device, "Start command failed rc = %d\n", rc);
 626                 goto xfer_disable_pad;
 627         }
 628
 629         /* Switch to high speed if applicable */
 630         if (dev->hs_cfg) {
 631                 rc = bcm_kona_i2c_switch_to_hs(dev);
 632                 if (rc < 0)
 633                         goto xfer_send_stop;
 634         }
 635
 636         /* Loop through all messages */
 637         for (i = 0; i < num; i++) {
 638                 pmsg = &msgs[i];
 639
 640                 /* Send restart for subsequent messages */
 641                 if ((i != 0) && ((pmsg->flags & I2C_M_NOSTART) == 0)) {
 642                         rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART);
 643                         if (rc < 0) {
 644                                 dev_err(dev->device,
 645                                         "restart cmd failed rc = %d\n", rc);
 646                                 goto xfer_send_stop;
 647                         }
 648                 }
 649
 650                 /* Send slave address */
 651                 if (!(pmsg->flags & I2C_M_NOSTART)) {
 652                         rc = bcm_kona_i2c_do_addr(dev, pmsg);
 653                         if (rc < 0) {
 654                                 dev_err(dev->device,
 655                                         "NAK from addr %2.2x msg#%d rc = %d\n",
 656                                         pmsg->addr, i, rc);
 657                                 goto xfer_send_stop;
 658                         }
 659                 }
 660
 661                 /* Perform data transfer */
 662                 if (pmsg->flags & I2C_M_RD) {
 663                         rc = bcm_kona_i2c_read_fifo(dev, pmsg);
 664                         if (rc < 0) {
 665                                 dev_err(dev->device, "read failure\n");
 666                                 goto xfer_send_stop;
 667                         }
 668                 } else {
 669                         rc = bcm_kona_i2c_write_fifo(dev, pmsg);
 670                         if (rc < 0) {
 671                                 dev_err(dev->device, "write failure");
 672                                 goto xfer_send_stop;
 673                         }
 674                 }
 675         }
 676
 677         rc = num;
 678
 679 xfer_send_stop:
 680         /* Send a STOP command */
 681         bcm_kona_send_i2c_cmd(dev, BCM_CMD_STOP);
 682
 683         /* Return from high speed if applicable */
 684         if (dev->hs_cfg) {
 685                 int hs_rc = bcm_kona_i2c_switch_to_std(dev);
 686
 687                 if (hs_rc)
 688                         rc = hs_rc;
 689         }
 690
 691 xfer_disable_pad:
 692         /* Disable pad output */
 693         writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
 694
 695         /* Stop internal clock */
 696         bcm_kona_i2c_disable_clock(dev);
 697
 698         clk_disable_unprepare(dev->external_clk);
 699
 700         return rc;
 701 }
 702
 703 static uint32_t bcm_kona_i2c_functionality(struct i2c_adapter *adap)
 704 {
 705         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
 706             I2C_FUNC_NOSTART;
 707 }
 708
 709 static const struct i2c_algorithm bcm_algo = {
 710         .master_xfer = bcm_kona_i2c_xfer,
 711         .functionality = bcm_kona_i2c_functionality,
 712 };
 713
 714 static int bcm_kona_i2c_assign_bus_speed(struct bcm_kona_i2c_dev *dev)
 715 {
 716         unsigned int bus_speed;
 717         int ret = of_property_read_u32(dev->device->of_node, "clock-frequency",
 718                                        &bus_speed);
 719         if (ret < 0) {
 720                 dev_err(dev->device, "missing clock-frequency property\n");
 721                 return -ENODEV;
 722         }
 723
 724         switch (bus_speed) {
 725         case 100000:
 726                 dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
 727                 break;
 728         case 400000:
 729                 dev->std_cfg = &std_cfg_table[BCM_SPD_400K];
 730                 break;
 731         case 1000000:
 732                 dev->std_cfg = &std_cfg_table[BCM_SPD_1MHZ];
 733                 break;
 734         case 3400000:
 735                 /* Send mastercode at 100k */
 736                 dev->std_cfg = &std_cfg_table[BCM_SPD_100K];
 737                 dev->hs_cfg = &hs_cfg_table[BCM_SPD_3P4MHZ];
 738                 break;
 739         default:
 740                 pr_err("%d hz bus speed not supported\n", bus_speed);
 741                 pr_err("Valid speeds are 100khz, 400khz, 1mhz, and 3.4mhz\n");
 742                 return -EINVAL;
 743         }
 744
 745         return 0;
 746 }
 747
 748 static int bcm_kona_i2c_probe(struct platform_device *pdev)
 749 {
 750         int rc = 0;
 751         struct bcm_kona_i2c_dev *dev;
 752         struct i2c_adapter *adap;
 753         struct resource *iomem;
 754
 755         /* Allocate memory for private data structure */
 756         dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
 757         if (!dev)
 758                 return -ENOMEM;
 759
 760         platform_set_drvdata(pdev, dev);
 761         dev->device = &pdev->dev;
 762         init_completion(&dev->done);
 763
 764         /* Map hardware registers */
 765         iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 766         dev->base = devm_ioremap_resource(dev->device, iomem);
 767         if (IS_ERR(dev->base))
 768                 return -ENOMEM;
 769
 770         /* Get and enable external clock */
 771         dev->external_clk = devm_clk_get(dev->device, NULL);
 772         if (IS_ERR(dev->external_clk)) {
 773                 dev_err(dev->device, "couldn't get clock\n");
 774                 return -ENODEV;
 775         }
 776
 777         rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ);
 778         if (rc) {
 779                 dev_err(dev->device, "%s: clk_set_rate returned %d\n",
 780                         __func__, rc);
 781                 return rc;
 782         }
 783
 784         rc = clk_prepare_enable(dev->external_clk);
 785         if (rc) {
 786                 dev_err(dev->device, "couldn't enable clock\n");
 787                 return rc;
 788         }
 789
 790         /* Parse bus speed */
 791         rc = bcm_kona_i2c_assign_bus_speed(dev);
 792         if (rc)
 793                 goto probe_disable_clk;
 794
 795         /* Enable internal clocks */
 796         bcm_kona_i2c_enable_clock(dev);
 797
 798         /* Configure internal dividers */
 799         bcm_kona_i2c_config_timing(dev);
 800
 801         /* Disable timeout */
 802         writel(0, dev->base + TOUT_OFFSET);
 803
 804         /* Enable autosense */
 805         bcm_kona_i2c_enable_autosense(dev);
 806
 807         /* Enable TX FIFO */
 808         writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK,
 809                dev->base + TXFCR_OFFSET);
 810
 811         /* Mask all interrupts */
 812         writel(0, dev->base + IER_OFFSET);
 813
 814         /* Clear all pending interrupts */
 815         writel(ISR_CMDBUSY_MASK |
 816                ISR_READ_COMPLETE_MASK |
 817                ISR_SES_DONE_MASK |
 818                ISR_ERR_MASK |
 819                ISR_TXFIFOEMPTY_MASK |
 820                ISR_NOACK_MASK,
 821                dev->base + ISR_OFFSET);
 822
 823         /* Get the interrupt number */
 824         dev->irq = platform_get_irq(pdev, 0);
 825         if (dev->irq < 0) {
 826                 dev_err(dev->device, "no irq resource\n");
 827                 rc = -ENODEV;
 828                 goto probe_disable_clk;
 829         }
 830
 831         /* register the ISR handler */
 832         rc = devm_request_irq(&pdev->dev, dev->irq, bcm_kona_i2c_isr,
 833                               IRQF_SHARED, pdev->name, dev);
 834         if (rc) {
 835                 dev_err(dev->device, "failed to request irq %i\n", dev->irq);
 836                 goto probe_disable_clk;
 837         }
 838
 839         /* Enable the controller but leave it idle */
 840         bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION);
 841
 842         /* Disable pad output */
 843         writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET);
 844
 845         /* Disable internal clock */
 846         bcm_kona_i2c_disable_clock(dev);
 847
 848         /* Disable external clock */
 849         clk_disable_unprepare(dev->external_clk);
 850
 851         /* Add the i2c adapter */
 852         adap = &dev->adapter;
 853         i2c_set_adapdata(adap, dev);
 854         adap->owner = THIS_MODULE;
 855         strlcpy(adap->name, "Broadcom I2C adapter", sizeof(adap->name));
 856         adap->algo = &bcm_algo;
 857         adap->dev.parent = &pdev->dev;
 858         adap->dev.of_node = pdev->dev.of_node;
 859
 860         rc = i2c_add_adapter(adap);
 861         if (rc)
 862                 return rc;
 863
 864         dev_info(dev->device, "device registered successfully\n");
 865
 866         return 0;
 867
 868 probe_disable_clk:
 869         bcm_kona_i2c_disable_clock(dev);
 870         clk_disable_unprepare(dev->external_clk);
 871
 872         return rc;
 873 }
 874
 875 static int bcm_kona_i2c_remove(struct platform_device *pdev)
 876 {
 877         struct bcm_kona_i2c_dev *dev = platform_get_drvdata(pdev);
 878
 879         i2c_del_adapter(&dev->adapter);
 880
 881         return 0;
 882 }
 883
 884 static const struct of_device_id bcm_kona_i2c_of_match[] = {
 885         {.compatible = "brcm,kona-i2c",},
 886         {},
 887 };
 888 MODULE_DEVICE_TABLE(of, bcm_kona_i2c_of_match);
 889
 890 static struct platform_driver bcm_kona_i2c_driver = {
 891         .driver = {
 892                    .name = "bcm-kona-i2c",
 893                    .of_match_table = bcm_kona_i2c_of_match,
 894                    },
 895         .probe = bcm_kona_i2c_probe,
 896         .remove = bcm_kona_i2c_remove,
 897 };
 898 module_platform_driver(bcm_kona_i2c_driver);
 899
 900 MODULE_AUTHOR("Tim Kryger <[email protected]>");
 901 MODULE_DESCRIPTION("Broadcom Kona I2C Driver");
 902 MODULE_LICENSE("GPL v2");