drivers/i2c/busses/i2c-sirf.c

   1 /*
   2  * I2C bus driver for CSR SiRFprimaII
   3  *
   4  * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   5  *
   6  * Licensed under GPLv2 or later.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/i2c.h>
  15 #include <linux/clk.h>
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18
  19 #define SIRFSOC_I2C_CLK_CTRL            0x00
  20 #define SIRFSOC_I2C_STATUS              0x0C
  21 #define SIRFSOC_I2C_CTRL                0x10
  22 #define SIRFSOC_I2C_IO_CTRL             0x14
  23 #define SIRFSOC_I2C_SDA_DELAY           0x18
  24 #define SIRFSOC_I2C_CMD_START           0x1C
  25 #define SIRFSOC_I2C_CMD_BUF             0x30
  26 #define SIRFSOC_I2C_DATA_BUF            0x80
  27
  28 #define SIRFSOC_I2C_CMD_BUF_MAX         16
  29 #define SIRFSOC_I2C_DATA_BUF_MAX        16
  30
  31 #define SIRFSOC_I2C_CMD(x)              (SIRFSOC_I2C_CMD_BUF + (x)*0x04)
  32 #define SIRFSOC_I2C_DATA_MASK(x)        (0xFF<<(((x)&3)*8))
  33 #define SIRFSOC_I2C_DATA_SHIFT(x)       (((x)&3)*8)
  34
  35 #define SIRFSOC_I2C_DIV_MASK            (0xFFFF)
  36
  37 /* I2C status flags */
  38 #define SIRFSOC_I2C_STAT_BUSY           BIT(0)
  39 #define SIRFSOC_I2C_STAT_TIP            BIT(1)
  40 #define SIRFSOC_I2C_STAT_NACK           BIT(2)
  41 #define SIRFSOC_I2C_STAT_TR_INT         BIT(4)
  42 #define SIRFSOC_I2C_STAT_STOP           BIT(6)
  43 #define SIRFSOC_I2C_STAT_CMD_DONE       BIT(8)
  44 #define SIRFSOC_I2C_STAT_ERR            BIT(9)
  45 #define SIRFSOC_I2C_CMD_INDEX           (0x1F<<16)
  46
  47 /* I2C control flags */
  48 #define SIRFSOC_I2C_RESET               BIT(0)
  49 #define SIRFSOC_I2C_CORE_EN             BIT(1)
  50 #define SIRFSOC_I2C_MASTER_MODE         BIT(2)
  51 #define SIRFSOC_I2C_CMD_DONE_EN         BIT(11)
  52 #define SIRFSOC_I2C_ERR_INT_EN          BIT(12)
  53
  54 #define SIRFSOC_I2C_SDA_DELAY_MASK      (0xFF)
  55 #define SIRFSOC_I2C_SCLF_FILTER         (3<<8)
  56
  57 #define SIRFSOC_I2C_START_CMD           BIT(0)
  58
  59 #define SIRFSOC_I2C_CMD_RP(x)           ((x)&0x7)
  60 #define SIRFSOC_I2C_NACK                BIT(3)
  61 #define SIRFSOC_I2C_WRITE               BIT(4)
  62 #define SIRFSOC_I2C_READ                BIT(5)
  63 #define SIRFSOC_I2C_STOP                BIT(6)
  64 #define SIRFSOC_I2C_START               BIT(7)
  65
  66 #define SIRFSOC_I2C_DEFAULT_SPEED 100000
  67
  68 struct sirfsoc_i2c {
  69         void __iomem *base;
  70         struct clk *clk;
  71         u32 cmd_ptr;            /* Current position in CMD buffer */
  72         u8 *buf;                /* Buffer passed by user */
  73         u32 msg_len;            /* Message length */
  74         u32 finished_len;       /* number of bytes read/written */
  75         u32 read_cmd_len;       /* number of read cmd sent */
  76         int msg_read;           /* 1 indicates a read message */
  77         int err_status;         /* 1 indicates an error on bus */
  78
  79         u32 sda_delay;          /* For suspend/resume */
  80         u32 clk_div;
  81         int last;               /* Last message in transfer, STOP cmd can be sent */
  82
  83         struct completion done; /* indicates completion of message transfer */
  84         struct i2c_adapter adapter;
  85 };
  86
  87 static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
  88 {
  89         u32 data = 0;
  90         int i;
  91
  92         for (i = 0; i < siic->read_cmd_len; i++) {
  93                 if (!(i & 0x3))
  94                         data = readl(siic->base + SIRFSOC_I2C_DATA_BUF + i);
  95                 siic->buf[siic->finished_len++] =
  96                         (u8)((data & SIRFSOC_I2C_DATA_MASK(i)) >>
  97                                 SIRFSOC_I2C_DATA_SHIFT(i));
  98         }
  99 }
 100
 101 static void i2c_sirfsoc_queue_cmd(struct sirfsoc_i2c *siic)
 102 {
 103         u32 regval;
 104         int i = 0;
 105
 106         if (siic->msg_read) {
 107                 while (((siic->finished_len + i) < siic->msg_len)
 108                                 && (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) {
 109                         regval = SIRFSOC_I2C_READ | SIRFSOC_I2C_CMD_RP(0);
 110                         if (((siic->finished_len + i) ==
 111                                         (siic->msg_len - 1)) && siic->last)
 112                                 regval |= SIRFSOC_I2C_STOP | SIRFSOC_I2C_NACK;
 113                         writel(regval,
 114                                 siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
 115                         i++;
 116                 }
 117
 118                 siic->read_cmd_len = i;
 119         } else {
 120                 while ((siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX - 1)
 121                                 && (siic->finished_len < siic->msg_len)) {
 122                         regval = SIRFSOC_I2C_WRITE | SIRFSOC_I2C_CMD_RP(0);
 123                         if ((siic->finished_len == (siic->msg_len - 1))
 124                                 && siic->last)
 125                                 regval |= SIRFSOC_I2C_STOP;
 126                         writel(regval,
 127                                 siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
 128                         writel(siic->buf[siic->finished_len++],
 129                                 siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
 130                 }
 131         }
 132         siic->cmd_ptr = 0;
 133
 134         /* Trigger the transfer */
 135         writel(SIRFSOC_I2C_START_CMD, siic->base + SIRFSOC_I2C_CMD_START);
 136 }
 137
 138 static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id)
 139 {
 140         struct sirfsoc_i2c *siic = (struct sirfsoc_i2c *)dev_id;
 141         u32 i2c_stat = readl(siic->base + SIRFSOC_I2C_STATUS);
 142
 143         if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {
 144                 /* Error conditions */
 145                 siic->err_status = 1;
 146                 writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);
 147
 148                 if (i2c_stat & SIRFSOC_I2C_STAT_NACK)
 149                         dev_err(&siic->adapter.dev, "ACK not received\n");
 150                 else
 151                         dev_err(&siic->adapter.dev, "I2C error\n");
 152
 153                 complete(&siic->done);
 154         } else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {
 155                 /* CMD buffer execution complete */
 156                 if (siic->msg_read)
 157                         i2c_sirfsoc_read_data(siic);
 158                 if (siic->finished_len == siic->msg_len)
 159                         complete(&siic->done);
 160                 else /* Fill a new CMD buffer for left data */
 161                         i2c_sirfsoc_queue_cmd(siic);
 162
 163                 writel(SIRFSOC_I2C_STAT_CMD_DONE, siic->base + SIRFSOC_I2C_STATUS);
 164         }
 165
 166         return IRQ_HANDLED;
 167 }
 168
 169 static void i2c_sirfsoc_set_address(struct sirfsoc_i2c *siic,
 170         struct i2c_msg *msg)
 171 {
 172         unsigned char addr;
 173         u32 regval = SIRFSOC_I2C_START | SIRFSOC_I2C_CMD_RP(0) | SIRFSOC_I2C_WRITE;
 174
 175         /* no data and last message -> add STOP */
 176         if (siic->last && (msg->len == 0))
 177                 regval |= SIRFSOC_I2C_STOP;
 178
 179         writel(regval, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
 180
 181         addr = msg->addr << 1;  /* Generate address */
 182         if (msg->flags & I2C_M_RD)
 183                 addr |= 1;
 184
 185         writel(addr, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
 186 }
 187
 188 static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg)
 189 {
 190         u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);
 191         /* timeout waiting for the xfer to finish or fail */
 192         int timeout = msecs_to_jiffies((msg->len + 1) * 50);
 193         int ret = 0;
 194
 195         i2c_sirfsoc_set_address(siic, msg);
 196
 197         writel(regval | SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN,
 198                 siic->base + SIRFSOC_I2C_CTRL);
 199         i2c_sirfsoc_queue_cmd(siic);
 200
 201         if (wait_for_completion_timeout(&siic->done, timeout) == 0) {
 202                 siic->err_status = 1;
 203                 dev_err(&siic->adapter.dev, "Transfer timeout\n");
 204         }
 205
 206         writel(regval & ~(SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN),
 207                 siic->base + SIRFSOC_I2C_CTRL);
 208         writel(0, siic->base + SIRFSOC_I2C_CMD_START);
 209
 210         if (siic->err_status) {
 211                 writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
 212                         siic->base + SIRFSOC_I2C_CTRL);
 213                 while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
 214                         cpu_relax();
 215
 216                 ret = -EIO;
 217         }
 218
 219         return ret;
 220 }
 221
 222 static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)
 223 {
 224         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 225 }
 226
 227 static int i2c_sirfsoc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 228         int num)
 229 {
 230         struct sirfsoc_i2c *siic = adap->algo_data;
 231         int i, ret;
 232
 233         clk_enable(siic->clk);
 234
 235         for (i = 0; i < num; i++) {
 236                 siic->buf = msgs[i].buf;
 237                 siic->msg_len = msgs[i].len;
 238                 siic->msg_read = !!(msgs[i].flags & I2C_M_RD);
 239                 siic->err_status = 0;
 240                 siic->cmd_ptr = 0;
 241                 siic->finished_len = 0;
 242                 siic->last = (i == (num - 1));
 243
 244                 ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]);
 245                 if (ret) {
 246                         clk_disable(siic->clk);
 247                         return ret;
 248                 }
 249         }
 250
 251         clk_disable(siic->clk);
 252         return num;
 253 }
 254
 255 /* I2C algorithms associated with this master controller driver */
 256 static const struct i2c_algorithm i2c_sirfsoc_algo = {
 257         .master_xfer = i2c_sirfsoc_xfer,
 258         .functionality = i2c_sirfsoc_func,
 259 };
 260
 261 static int __devinit i2c_sirfsoc_probe(struct platform_device *pdev)
 262 {
 263         struct sirfsoc_i2c *siic;
 264         struct i2c_adapter *adap;
 265         struct resource *mem_res;
 266         struct clk *clk;
 267         int bitrate;
 268         int ctrl_speed;
 269         int irq;
 270
 271         int err;
 272         u32 regval;
 273
 274         clk = clk_get(&pdev->dev, NULL);
 275         if (IS_ERR(clk)) {
 276                 err = PTR_ERR(clk);
 277                 dev_err(&pdev->dev, "Clock get failed\n");
 278                 goto err_get_clk;
 279         }
 280
 281         err = clk_prepare(clk);
 282         if (err) {
 283                 dev_err(&pdev->dev, "Clock prepare failed\n");
 284                 goto err_clk_prep;
 285         }
 286
 287         err = clk_enable(clk);
 288         if (err) {
 289                 dev_err(&pdev->dev, "Clock enable failed\n");
 290                 goto err_clk_en;
 291         }
 292
 293         ctrl_speed = clk_get_rate(clk);
 294
 295         siic = devm_kzalloc(&pdev->dev, sizeof(*siic), GFP_KERNEL);
 296         if (!siic) {
 297                 dev_err(&pdev->dev, "Can't allocate driver data\n");
 298                 err = -ENOMEM;
 299                 goto out;
 300         }
 301         adap = &siic->adapter;
 302         adap->class = I2C_CLASS_HWMON;
 303
 304         mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 305         if (mem_res == NULL) {
 306                 dev_err(&pdev->dev, "Unable to get MEM resource\n");
 307                 err = -EINVAL;
 308                 goto out;
 309         }
 310
 311         siic->base = devm_request_and_ioremap(&pdev->dev, mem_res);
 312         if (siic->base == NULL) {
 313                 dev_err(&pdev->dev, "IO remap failed!\n");
 314                 err = -ENOMEM;
 315                 goto out;
 316         }
 317
 318         irq = platform_get_irq(pdev, 0);
 319         if (irq < 0) {
 320                 err = irq;
 321                 goto out;
 322         }
 323         err = devm_request_irq(&pdev->dev, irq, i2c_sirfsoc_irq, 0,
 324                 dev_name(&pdev->dev), siic);
 325         if (err)
 326                 goto out;
 327
 328         adap->algo = &i2c_sirfsoc_algo;
 329         adap->algo_data = siic;
 330
 331         adap->dev.parent = &pdev->dev;
 332         adap->nr = pdev->id;
 333
 334         strlcpy(adap->name, "sirfsoc-i2c", sizeof(adap->name));
 335
 336         platform_set_drvdata(pdev, adap);
 337         init_completion(&siic->done);
 338
 339         /* Controller Initalisation */
 340
 341         writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
 342         while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
 343                 cpu_relax();
 344         writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
 345                 siic->base + SIRFSOC_I2C_CTRL);
 346
 347         siic->clk = clk;
 348
 349         err = of_property_read_u32(pdev->dev.of_node,
 350                 "clock-frequency", &bitrate);
 351         if (err < 0)
 352                 bitrate = SIRFSOC_I2C_DEFAULT_SPEED;
 353
 354         if (bitrate < 100000)
 355                 regval =
 356                         (2 * ctrl_speed) / (2 * bitrate * 11);
 357         else
 358                 regval = ctrl_speed / (bitrate * 5);
 359
 360         writel(regval, siic->base + SIRFSOC_I2C_CLK_CTRL);
 361         if (regval > 0xFF)
 362                 writel(0xFF, siic->base + SIRFSOC_I2C_SDA_DELAY);
 363         else
 364                 writel(regval, siic->base + SIRFSOC_I2C_SDA_DELAY);
 365
 366         err = i2c_add_numbered_adapter(adap);
 367         if (err < 0) {
 368                 dev_err(&pdev->dev, "Can't add new i2c adapter\n");
 369                 goto out;
 370         }
 371
 372         clk_disable(clk);
 373
 374         dev_info(&pdev->dev, " I2C adapter ready to operate\n");
 375
 376         return 0;
 377
 378 out:
 379         clk_disable(clk);
 380 err_clk_en:
 381         clk_unprepare(clk);
 382 err_clk_prep:
 383         clk_put(clk);
 384 err_get_clk:
 385         return err;
 386 }
 387
 388 static int __devexit i2c_sirfsoc_remove(struct platform_device *pdev)
 389 {
 390         struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 391         struct sirfsoc_i2c *siic = adapter->algo_data;
 392
 393         writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
 394         i2c_del_adapter(adapter);
 395         clk_unprepare(siic->clk);
 396         clk_put(siic->clk);
 397         return 0;
 398 }
 399
 400 #ifdef CONFIG_PM
 401 static int i2c_sirfsoc_suspend(struct device *dev)
 402 {
 403         struct platform_device *pdev = to_platform_device(dev);
 404         struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 405         struct sirfsoc_i2c *siic = adapter->algo_data;
 406
 407         clk_enable(siic->clk);
 408         siic->sda_delay = readl(siic->base + SIRFSOC_I2C_SDA_DELAY);
 409         siic->clk_div = readl(siic->base + SIRFSOC_I2C_CLK_CTRL);
 410         clk_disable(siic->clk);
 411         return 0;
 412 }
 413
 414 static int i2c_sirfsoc_resume(struct device *dev)
 415 {
 416         struct platform_device *pdev = to_platform_device(dev);
 417         struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 418         struct sirfsoc_i2c *siic = adapter->algo_data;
 419
 420         clk_enable(siic->clk);
 421         writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
 422         writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
 423                 siic->base + SIRFSOC_I2C_CTRL);
 424         writel(siic->clk_div, siic->base + SIRFSOC_I2C_CLK_CTRL);
 425         writel(siic->sda_delay, siic->base + SIRFSOC_I2C_SDA_DELAY);
 426         clk_disable(siic->clk);
 427         return 0;
 428 }
 429
 430 static const struct dev_pm_ops i2c_sirfsoc_pm_ops = {
 431         .suspend = i2c_sirfsoc_suspend,
 432         .resume = i2c_sirfsoc_resume,
 433 };
 434 #endif
 435
 436 static const struct of_device_id sirfsoc_i2c_of_match[] __devinitconst = {
 437         { .compatible = "sirf,prima2-i2c", },
 438         {},
 439 };
 440 MODULE_DEVICE_TABLE(of, sirfsoc_i2c_of_match);
 441
 442 static struct platform_driver i2c_sirfsoc_driver = {
 443         .driver = {
 444                 .name = "sirfsoc_i2c",
 445                 .owner = THIS_MODULE,
 446 #ifdef CONFIG_PM
 447                 .pm = &i2c_sirfsoc_pm_ops,
 448 #endif
 449                 .of_match_table = sirfsoc_i2c_of_match,
 450         },
 451         .probe = i2c_sirfsoc_probe,
 452         .remove = __devexit_p(i2c_sirfsoc_remove),
 453 };
 454 module_platform_driver(i2c_sirfsoc_driver);
 455
 456 MODULE_DESCRIPTION("SiRF SoC I2C master controller driver");
 457 MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>, "
 458         "Xiangzhen Ye <Xiangzhen.Ye@csr.com>");
 459 MODULE_LICENSE("GPL v2");