drivers/i2c/busses/i2c-xlp9xx.c

   1 /*
   2  * Copyright (c) 2003-2015 Broadcom Corporation
   3  *
   4  * This file is licensed under the terms of the GNU General Public
   5  * License version 2. This program is licensed "as is" without any
   6  * warranty of any kind, whether express or implied.
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/clk.h>
  11 #include <linux/completion.h>
  12 #include <linux/i2c.h>
  13 #include <linux/init.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/io.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19
  20 #define XLP9XX_I2C_DIV                  0x0
  21 #define XLP9XX_I2C_CTRL                 0x1
  22 #define XLP9XX_I2C_CMD                  0x2
  23 #define XLP9XX_I2C_STATUS               0x3
  24 #define XLP9XX_I2C_MTXFIFO              0x4
  25 #define XLP9XX_I2C_MRXFIFO              0x5
  26 #define XLP9XX_I2C_MFIFOCTRL            0x6
  27 #define XLP9XX_I2C_STXFIFO              0x7
  28 #define XLP9XX_I2C_SRXFIFO              0x8
  29 #define XLP9XX_I2C_SFIFOCTRL            0x9
  30 #define XLP9XX_I2C_SLAVEADDR            0xA
  31 #define XLP9XX_I2C_OWNADDR              0xB
  32 #define XLP9XX_I2C_FIFOWCNT             0xC
  33 #define XLP9XX_I2C_INTEN                0xD
  34 #define XLP9XX_I2C_INTST                0xE
  35 #define XLP9XX_I2C_WAITCNT              0xF
  36 #define XLP9XX_I2C_TIMEOUT              0X10
  37 #define XLP9XX_I2C_GENCALLADDR          0x11
  38
  39 #define XLP9XX_I2C_CMD_START            BIT(7)
  40 #define XLP9XX_I2C_CMD_STOP             BIT(6)
  41 #define XLP9XX_I2C_CMD_READ             BIT(5)
  42 #define XLP9XX_I2C_CMD_WRITE            BIT(4)
  43 #define XLP9XX_I2C_CMD_ACK              BIT(3)
  44
  45 #define XLP9XX_I2C_CTRL_MCTLEN_SHIFT    16
  46 #define XLP9XX_I2C_CTRL_MCTLEN_MASK     0xffff0000
  47 #define XLP9XX_I2C_CTRL_RST             BIT(8)
  48 #define XLP9XX_I2C_CTRL_EN              BIT(6)
  49 #define XLP9XX_I2C_CTRL_MASTER          BIT(4)
  50 #define XLP9XX_I2C_CTRL_FIFORD          BIT(1)
  51 #define XLP9XX_I2C_CTRL_ADDMODE         BIT(0)
  52
  53 #define XLP9XX_I2C_INTEN_NACKADDR       BIT(25)
  54 #define XLP9XX_I2C_INTEN_SADDR          BIT(13)
  55 #define XLP9XX_I2C_INTEN_DATADONE       BIT(12)
  56 #define XLP9XX_I2C_INTEN_ARLOST         BIT(11)
  57 #define XLP9XX_I2C_INTEN_MFIFOFULL      BIT(4)
  58 #define XLP9XX_I2C_INTEN_MFIFOEMTY      BIT(3)
  59 #define XLP9XX_I2C_INTEN_MFIFOHI        BIT(2)
  60 #define XLP9XX_I2C_INTEN_BUSERR         BIT(0)
  61
  62 #define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT         8
  63 #define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT         0
  64 #define XLP9XX_I2C_MFIFOCTRL_RST                BIT(16)
  65
  66 #define XLP9XX_I2C_SLAVEADDR_RW                 BIT(0)
  67 #define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT         1
  68
  69 #define XLP9XX_I2C_IP_CLK_FREQ          133000000UL
  70 #define XLP9XX_I2C_DEFAULT_FREQ         100000
  71 #define XLP9XX_I2C_HIGH_FREQ            400000
  72 #define XLP9XX_I2C_FIFO_SIZE            0x80U
  73 #define XLP9XX_I2C_TIMEOUT_MS           1000
  74
  75 #define XLP9XX_I2C_FIFO_WCNT_MASK       0xff
  76 #define XLP9XX_I2C_STATUS_ERRMASK       (XLP9XX_I2C_INTEN_ARLOST | \
  77                         XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_BUSERR)
  78
  79 struct xlp9xx_i2c_dev {
  80         struct device *dev;
  81         struct i2c_adapter adapter;
  82         struct completion msg_complete;
  83         int irq;
  84         bool msg_read;
  85         bool len_recv;
  86         bool client_pec;
  87         u32 __iomem *base;
  88         u32 msg_buf_remaining;
  89         u32 msg_len;
  90         u32 ip_clk_hz;
  91         u32 clk_hz;
  92         u32 msg_err;
  93         u8 *msg_buf;
  94 };
  95
  96 static inline void xlp9xx_write_i2c_reg(struct xlp9xx_i2c_dev *priv,
  97                                         unsigned long reg, u32 val)
  98 {
  99         writel(val, priv->base + reg);
 100 }
 101
 102 static inline u32 xlp9xx_read_i2c_reg(struct xlp9xx_i2c_dev *priv,
 103                                       unsigned long reg)
 104 {
 105         return readl(priv->base + reg);
 106 }
 107
 108 static void xlp9xx_i2c_mask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
 109 {
 110         u32 inten;
 111
 112         inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
 113         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
 114 }
 115
 116 static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
 117 {
 118         u32 inten;
 119
 120         inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) | mask;
 121         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
 122 }
 123
 124 static void xlp9xx_i2c_update_rx_fifo_thres(struct xlp9xx_i2c_dev *priv)
 125 {
 126         u32 thres;
 127
 128         thres = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
 129         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
 130                              thres << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT);
 131 }
 132
 133 static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
 134 {
 135         u32 len, i;
 136         u8 *buf = priv->msg_buf;
 137
 138         len = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
 139         for (i = 0; i < len; i++)
 140                 xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MTXFIFO, buf[i]);
 141         priv->msg_buf_remaining -= len;
 142         priv->msg_buf += len;
 143 }
 144
 145 static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
 146 {
 147         u32 len, i;
 148         u8 rlen, *buf = priv->msg_buf;
 149
 150         len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
 151                                   XLP9XX_I2C_FIFO_WCNT_MASK;
 152         if (!len)
 153                 return;
 154         if (priv->len_recv) {
 155                 /* read length byte */
 156                 rlen = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
 157                 *buf++ = rlen;
 158                 len--;
 159                 if (priv->client_pec)
 160                         ++rlen;
 161                 /* update remaining bytes and message length */
 162                 priv->msg_buf_remaining = rlen;
 163                 priv->msg_len = rlen + 1;
 164                 priv->len_recv = false;
 165         }
 166
 167         len = min(priv->msg_buf_remaining, len);
 168         for (i = 0; i < len; i++, buf++)
 169                 *buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
 170
 171         priv->msg_buf_remaining -= len;
 172         priv->msg_buf = buf;
 173
 174         if (priv->msg_buf_remaining)
 175                 xlp9xx_i2c_update_rx_fifo_thres(priv);
 176 }
 177
 178 static irqreturn_t xlp9xx_i2c_isr(int irq, void *dev_id)
 179 {
 180         struct xlp9xx_i2c_dev *priv = dev_id;
 181         u32 status;
 182
 183         status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTST);
 184         if (status == 0)
 185                 return IRQ_NONE;
 186
 187         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
 188         if (status & XLP9XX_I2C_STATUS_ERRMASK) {
 189                 priv->msg_err = status;
 190                 goto xfer_done;
 191         }
 192
 193         /* SADDR ACK for SMBUS_QUICK */
 194         if ((status & XLP9XX_I2C_INTEN_SADDR) && (priv->msg_len == 0))
 195                 goto xfer_done;
 196
 197         if (!priv->msg_read) {
 198                 if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
 199                         /* TX FIFO got empty, fill it up again */
 200                         if (priv->msg_buf_remaining)
 201                                 xlp9xx_i2c_fill_tx_fifo(priv);
 202                         else
 203                                 xlp9xx_i2c_mask_irq(priv,
 204                                                     XLP9XX_I2C_INTEN_MFIFOEMTY);
 205                 }
 206         } else {
 207                 if (status & (XLP9XX_I2C_INTEN_DATADONE |
 208                               XLP9XX_I2C_INTEN_MFIFOHI)) {
 209                         /* data is in FIFO, read it */
 210                         if (priv->msg_buf_remaining)
 211                                 xlp9xx_i2c_drain_rx_fifo(priv);
 212                 }
 213         }
 214
 215         /* Transfer complete */
 216         if (status & XLP9XX_I2C_INTEN_DATADONE)
 217                 goto xfer_done;
 218
 219         return IRQ_HANDLED;
 220
 221 xfer_done:
 222         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
 223         complete(&priv->msg_complete);
 224         return IRQ_HANDLED;
 225 }
 226
 227 static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
 228 {
 229         u32 prescale;
 230
 231         /*
 232          * The controller uses 5 * SCL clock internally.
 233          * So prescale value should be divided by 5.
 234          */
 235         prescale = DIV_ROUND_UP(priv->ip_clk_hz, priv->clk_hz);
 236         prescale = ((prescale - 8) / 5) - 1;
 237         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
 238         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN |
 239                              XLP9XX_I2C_CTRL_MASTER);
 240         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_DIV, prescale);
 241         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
 242
 243         return 0;
 244 }
 245
 246 static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
 247                                int last_msg)
 248 {
 249         unsigned long timeleft;
 250         u32 intr_mask, cmd, val, len;
 251
 252         priv->msg_buf = msg->buf;
 253         priv->msg_buf_remaining = priv->msg_len = msg->len;
 254         priv->msg_err = 0;
 255         priv->msg_read = (msg->flags & I2C_M_RD);
 256         reinit_completion(&priv->msg_complete);
 257
 258         /* Reset FIFO */
 259         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
 260                              XLP9XX_I2C_MFIFOCTRL_RST);
 261
 262         /* set FIFO threshold if reading */
 263         if (priv->msg_read)
 264                 xlp9xx_i2c_update_rx_fifo_thres(priv);
 265
 266         /* set slave addr */
 267         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_SLAVEADDR,
 268                              (msg->addr << XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT) |
 269                              (priv->msg_read ? XLP9XX_I2C_SLAVEADDR_RW : 0));
 270
 271         /* Build control word for transfer */
 272         val = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_CTRL);
 273         if (!priv->msg_read)
 274                 val &= ~XLP9XX_I2C_CTRL_FIFORD;
 275         else
 276                 val |= XLP9XX_I2C_CTRL_FIFORD;  /* read */
 277
 278         if (msg->flags & I2C_M_TEN)
 279                 val |= XLP9XX_I2C_CTRL_ADDMODE; /* 10-bit address mode*/
 280         else
 281                 val &= ~XLP9XX_I2C_CTRL_ADDMODE;
 282
 283         priv->len_recv = msg->flags & I2C_M_RECV_LEN;
 284         len = priv->len_recv ? XLP9XX_I2C_FIFO_SIZE : msg->len;
 285         priv->client_pec = msg->flags & I2C_CLIENT_PEC;
 286
 287         /* set data length to be transferred */
 288         val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |
 289               (len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
 290         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);
 291
 292         /* fill fifo during tx */
 293         if (!priv->msg_read)
 294                 xlp9xx_i2c_fill_tx_fifo(priv);
 295
 296         /* set interrupt mask */
 297         intr_mask = (XLP9XX_I2C_INTEN_ARLOST | XLP9XX_I2C_INTEN_BUSERR |
 298                      XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_DATADONE);
 299
 300         if (priv->msg_read) {
 301                 intr_mask |= XLP9XX_I2C_INTEN_MFIFOHI;
 302                 if (msg->len == 0)
 303                         intr_mask |= XLP9XX_I2C_INTEN_SADDR;
 304         } else {
 305                 if (msg->len == 0)
 306                         intr_mask |= XLP9XX_I2C_INTEN_SADDR;
 307                 else
 308                         intr_mask |= XLP9XX_I2C_INTEN_MFIFOEMTY;
 309         }
 310         xlp9xx_i2c_unmask_irq(priv, intr_mask);
 311
 312         /* set cmd reg */
 313         cmd = XLP9XX_I2C_CMD_START;
 314         cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
 315         if (last_msg)
 316                 cmd |= XLP9XX_I2C_CMD_STOP;
 317
 318         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);
 319
 320         timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
 321         timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);
 322
 323         if (priv->msg_err) {
 324                 dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
 325                 if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
 326                         xlp9xx_i2c_init(priv);
 327                 return -EIO;
 328         }
 329
 330         if (timeleft == 0) {
 331                 dev_dbg(priv->dev, "i2c transfer timed out!\n");
 332                 xlp9xx_i2c_init(priv);
 333                 return -ETIMEDOUT;
 334         }
 335
 336         /* update msg->len with actual received length */
 337         if (msg->flags & I2C_M_RECV_LEN)
 338                 msg->len = priv->msg_len;
 339         return 0;
 340 }
 341
 342 static int xlp9xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 343                            int num)
 344 {
 345         int i, ret;
 346         struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);
 347
 348         for (i = 0; i < num; i++) {
 349                 ret = xlp9xx_i2c_xfer_msg(priv, &msgs[i], i == num - 1);
 350                 if (ret != 0)
 351                         return ret;
 352         }
 353
 354         return num;
 355 }
 356
 357 static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
 358 {
 359         return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C |
 360                 I2C_FUNC_10BIT_ADDR;
 361 }
 362
 363 static const struct i2c_algorithm xlp9xx_i2c_algo = {
 364         .master_xfer = xlp9xx_i2c_xfer,
 365         .functionality = xlp9xx_i2c_functionality,
 366 };
 367
 368 static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
 369                                     struct xlp9xx_i2c_dev *priv)
 370 {
 371         struct clk *clk;
 372         u32 freq;
 373         int err;
 374
 375         clk = devm_clk_get(&pdev->dev, NULL);
 376         if (IS_ERR(clk)) {
 377                 priv->ip_clk_hz = XLP9XX_I2C_IP_CLK_FREQ;
 378                 dev_dbg(&pdev->dev, "using default input frequency %u\n",
 379                         priv->ip_clk_hz);
 380         } else {
 381                 priv->ip_clk_hz = clk_get_rate(clk);
 382         }
 383
 384         err = device_property_read_u32(&pdev->dev, "clock-frequency", &freq);
 385         if (err) {
 386                 freq = XLP9XX_I2C_DEFAULT_FREQ;
 387                 dev_dbg(&pdev->dev, "using default frequency %u\n", freq);
 388         } else if (freq == 0 || freq > XLP9XX_I2C_HIGH_FREQ) {
 389                 dev_warn(&pdev->dev, "invalid frequency %u, using default\n",
 390                          freq);
 391                 freq = XLP9XX_I2C_DEFAULT_FREQ;
 392         }
 393         priv->clk_hz = freq;
 394
 395         return 0;
 396 }
 397
 398 static int xlp9xx_i2c_probe(struct platform_device *pdev)
 399 {
 400         struct xlp9xx_i2c_dev *priv;
 401         struct resource *res;
 402         int err = 0;
 403
 404         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 405         if (!priv)
 406                 return -ENOMEM;
 407
 408         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 409         priv->base = devm_ioremap_resource(&pdev->dev, res);
 410         if (IS_ERR(priv->base))
 411                 return PTR_ERR(priv->base);
 412
 413         priv->irq = platform_get_irq(pdev, 0);
 414         if (priv->irq <= 0) {
 415                 dev_err(&pdev->dev, "invalid irq!\n");
 416                 return priv->irq;
 417         }
 418
 419         xlp9xx_i2c_get_frequency(pdev, priv);
 420         xlp9xx_i2c_init(priv);
 421
 422         err = devm_request_irq(&pdev->dev, priv->irq, xlp9xx_i2c_isr, 0,
 423                                pdev->name, priv);
 424         if (err) {
 425                 dev_err(&pdev->dev, "IRQ request failed!\n");
 426                 return err;
 427         }
 428
 429         init_completion(&priv->msg_complete);
 430         priv->adapter.dev.parent = &pdev->dev;
 431         priv->adapter.algo = &xlp9xx_i2c_algo;
 432         priv->adapter.class = I2C_CLASS_HWMON;
 433         ACPI_COMPANION_SET(&priv->adapter.dev, ACPI_COMPANION(&pdev->dev));
 434         priv->adapter.dev.of_node = pdev->dev.of_node;
 435         priv->dev = &pdev->dev;
 436
 437         snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
 438         i2c_set_adapdata(&priv->adapter, priv);
 439
 440         err = i2c_add_adapter(&priv->adapter);
 441         if (err)
 442                 return err;
 443
 444         platform_set_drvdata(pdev, priv);
 445         dev_dbg(&pdev->dev, "I2C bus:%d added\n", priv->adapter.nr);
 446
 447         return 0;
 448 }
 449
 450 static int xlp9xx_i2c_remove(struct platform_device *pdev)
 451 {
 452         struct xlp9xx_i2c_dev *priv;
 453
 454         priv = platform_get_drvdata(pdev);
 455         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
 456         synchronize_irq(priv->irq);
 457         i2c_del_adapter(&priv->adapter);
 458         xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, 0);
 459
 460         return 0;
 461 }
 462
 463 static const struct of_device_id xlp9xx_i2c_of_match[] = {
 464         { .compatible = "netlogic,xlp980-i2c", },
 465         { /* sentinel */ },
 466 };
 467 MODULE_DEVICE_TABLE(of, xlp9xx_i2c_of_match);
 468
 469 #ifdef CONFIG_ACPI
 470 static const struct acpi_device_id xlp9xx_i2c_acpi_ids[] = {
 471         {"BRCM9007", 0},
 472         {"CAV9007",  0},
 473         {}
 474 };
 475 MODULE_DEVICE_TABLE(acpi, xlp9xx_i2c_acpi_ids);
 476 #endif
 477
 478 static struct platform_driver xlp9xx_i2c_driver = {
 479         .probe = xlp9xx_i2c_probe,
 480         .remove = xlp9xx_i2c_remove,
 481         .driver = {
 482                 .name = "xlp9xx-i2c",
 483                 .of_match_table = xlp9xx_i2c_of_match,
 484                 .acpi_match_table = ACPI_PTR(xlp9xx_i2c_acpi_ids),
 485         },
 486 };
 487
 488 module_platform_driver(xlp9xx_i2c_driver);
 489
 490 MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@broadcom.com>");
 491 MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
 492 MODULE_LICENSE("GPL v2");