drivers/i2c/busses/i2c-hix5hd2.c

   1 /*
   2  * Copyright (c) 2014 Linaro Ltd.
   3  * Copyright (c) 2014 Hisilicon Limited.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * Now only support 7 bit address.
  11  */
  12
  13 #include <linux/clk.h>
  14 #include <linux/delay.h>
  15 #include <linux/i2c.h>
  16 #include <linux/io.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/pm_runtime.h>
  22
  23 /* Register Map */
  24 #define HIX5I2C_CTRL            0x00
  25 #define HIX5I2C_COM             0x04
  26 #define HIX5I2C_ICR             0x08
  27 #define HIX5I2C_SR              0x0c
  28 #define HIX5I2C_SCL_H           0x10
  29 #define HIX5I2C_SCL_L           0x14
  30 #define HIX5I2C_TXR             0x18
  31 #define HIX5I2C_RXR             0x1c
  32
  33 /* I2C_CTRL_REG */
  34 #define I2C_ENABLE              BIT(8)
  35 #define I2C_UNMASK_TOTAL        BIT(7)
  36 #define I2C_UNMASK_START        BIT(6)
  37 #define I2C_UNMASK_END          BIT(5)
  38 #define I2C_UNMASK_SEND         BIT(4)
  39 #define I2C_UNMASK_RECEIVE      BIT(3)
  40 #define I2C_UNMASK_ACK          BIT(2)
  41 #define I2C_UNMASK_ARBITRATE    BIT(1)
  42 #define I2C_UNMASK_OVER         BIT(0)
  43 #define I2C_UNMASK_ALL          (I2C_UNMASK_ACK | I2C_UNMASK_OVER)
  44
  45 /* I2C_COM_REG */
  46 #define I2C_NO_ACK              BIT(4)
  47 #define I2C_START               BIT(3)
  48 #define I2C_READ                BIT(2)
  49 #define I2C_WRITE               BIT(1)
  50 #define I2C_STOP                BIT(0)
  51
  52 /* I2C_ICR_REG */
  53 #define I2C_CLEAR_START         BIT(6)
  54 #define I2C_CLEAR_END           BIT(5)
  55 #define I2C_CLEAR_SEND          BIT(4)
  56 #define I2C_CLEAR_RECEIVE       BIT(3)
  57 #define I2C_CLEAR_ACK           BIT(2)
  58 #define I2C_CLEAR_ARBITRATE     BIT(1)
  59 #define I2C_CLEAR_OVER          BIT(0)
  60 #define I2C_CLEAR_ALL           (I2C_CLEAR_START | I2C_CLEAR_END | \
  61                                 I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \
  62                                 I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \
  63                                 I2C_CLEAR_OVER)
  64
  65 /* I2C_SR_REG */
  66 #define I2C_BUSY                BIT(7)
  67 #define I2C_START_INTR          BIT(6)
  68 #define I2C_END_INTR            BIT(5)
  69 #define I2C_SEND_INTR           BIT(4)
  70 #define I2C_RECEIVE_INTR        BIT(3)
  71 #define I2C_ACK_INTR            BIT(2)
  72 #define I2C_ARBITRATE_INTR      BIT(1)
  73 #define I2C_OVER_INTR           BIT(0)
  74
  75 #define HIX5I2C_MAX_FREQ        400000          /* 400k */
  76 #define HIX5I2C_READ_OPERATION  0x01
  77
  78 enum hix5hd2_i2c_state {
  79         HIX5I2C_STAT_RW_ERR = -1,
  80         HIX5I2C_STAT_INIT,
  81         HIX5I2C_STAT_RW,
  82         HIX5I2C_STAT_SND_STOP,
  83         HIX5I2C_STAT_RW_SUCCESS,
  84 };
  85
  86 struct hix5hd2_i2c_priv {
  87         struct i2c_adapter adap;
  88         struct i2c_msg *msg;
  89         struct completion msg_complete;
  90         unsigned int msg_idx;
  91         unsigned int msg_len;
  92         int stop;
  93         void __iomem *regs;
  94         struct clk *clk;
  95         struct device *dev;
  96         spinlock_t lock;        /* IRQ synchronization */
  97         int err;
  98         unsigned int freq;
  99         enum hix5hd2_i2c_state state;
 100 };
 101
 102 static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
 103 {
 104         u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);
 105
 106         writel_relaxed(val, priv->regs + HIX5I2C_ICR);
 107
 108         return val;
 109 }
 110
 111 static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
 112 {
 113         writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
 114 }
 115
 116 static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
 117 {
 118         writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
 119 }
 120
 121 static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
 122 {
 123         writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL,
 124                        priv->regs + HIX5I2C_CTRL);
 125 }
 126
 127 static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
 128 {
 129         u32 rate, val;
 130         u32 scl, sysclock;
 131
 132         /* close all i2c interrupt */
 133         val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
 134         writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);
 135
 136         rate = priv->freq;
 137         sysclock = clk_get_rate(priv->clk);
 138         scl = (sysclock / (rate * 2)) / 2 - 1;
 139         writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
 140         writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);
 141
 142         /* restore original interrupt*/
 143         writel_relaxed(val, priv->regs + HIX5I2C_CTRL);
 144
 145         dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
 146                 __func__, sysclock, rate, scl);
 147 }
 148
 149 static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
 150 {
 151         hix5hd2_i2c_disable_irq(priv);
 152         hix5hd2_i2c_drv_setrate(priv);
 153         hix5hd2_i2c_clr_all_irq(priv);
 154         hix5hd2_i2c_enable_irq(priv);
 155 }
 156
 157 static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
 158 {
 159         clk_disable_unprepare(priv->clk);
 160         msleep(20);
 161         clk_prepare_enable(priv->clk);
 162         hix5hd2_i2c_init(priv);
 163 }
 164
 165 static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
 166 {
 167         unsigned long stop_time;
 168         u32 int_status;
 169
 170         /* wait for 100 milli seconds for the bus to be idle */
 171         stop_time = jiffies + msecs_to_jiffies(100);
 172         do {
 173                 int_status = hix5hd2_i2c_clr_pend_irq(priv);
 174                 if (!(int_status & I2C_BUSY))
 175                         return 0;
 176
 177                 usleep_range(50, 200);
 178         } while (time_before(jiffies, stop_time));
 179
 180         return -EBUSY;
 181 }
 182
 183 static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
 184 {
 185         if (priv->state == HIX5I2C_STAT_SND_STOP)
 186                 dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
 187         else
 188                 dev_dbg(priv->dev, "%s: have not data to send\n", __func__);
 189
 190         priv->state = HIX5I2C_STAT_RW_SUCCESS;
 191         priv->err = 0;
 192 }
 193
 194 static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
 195 {
 196         if (priv->stop) {
 197                 priv->state = HIX5I2C_STAT_SND_STOP;
 198                 writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
 199         } else {
 200                 hix5hd2_rw_over(priv);
 201         }
 202 }
 203
 204 static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
 205 {
 206         if (priv->msg_len == 1) {
 207                 /* the last byte don't need send ACK */
 208                 writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM);
 209         } else if (priv->msg_len > 1) {
 210                 /* if i2c master receive data will send ACK */
 211                 writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
 212         } else {
 213                 hix5hd2_rw_handle_stop(priv);
 214         }
 215 }
 216
 217 static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
 218 {
 219         u8 data;
 220
 221         if (priv->msg_len > 0) {
 222                 data = priv->msg->buf[priv->msg_idx++];
 223                 writel_relaxed(data, priv->regs + HIX5I2C_TXR);
 224                 writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
 225         } else {
 226                 hix5hd2_rw_handle_stop(priv);
 227         }
 228 }
 229
 230 static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
 231 {
 232         u8 data;
 233
 234         if (priv->state == HIX5I2C_STAT_INIT) {
 235                 priv->state = HIX5I2C_STAT_RW;
 236         } else if (priv->state == HIX5I2C_STAT_RW) {
 237                 if (priv->msg->flags & I2C_M_RD) {
 238                         data = readl_relaxed(priv->regs + HIX5I2C_RXR);
 239                         priv->msg->buf[priv->msg_idx++] = data;
 240                 }
 241                 priv->msg_len--;
 242         } else {
 243                 dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
 244                         __func__, priv->state, priv->msg_len);
 245                 return -EAGAIN;
 246         }
 247         return 0;
 248 }
 249
 250 static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
 251 {
 252         struct hix5hd2_i2c_priv *priv = dev_id;
 253         u32 int_status;
 254         int ret;
 255
 256         spin_lock(&priv->lock);
 257
 258         int_status = hix5hd2_i2c_clr_pend_irq(priv);
 259
 260         /* handle error */
 261         if (int_status & I2C_ARBITRATE_INTR) {
 262                 /* bus error */
 263                 dev_dbg(priv->dev, "ARB bus loss\n");
 264                 priv->err = -EAGAIN;
 265                 priv->state = HIX5I2C_STAT_RW_ERR;
 266                 goto stop;
 267         } else if (int_status & I2C_ACK_INTR) {
 268                 /* ack error */
 269                 dev_dbg(priv->dev, "No ACK from device\n");
 270                 priv->err = -ENXIO;
 271                 priv->state = HIX5I2C_STAT_RW_ERR;
 272                 goto stop;
 273         }
 274
 275         if (int_status & I2C_OVER_INTR) {
 276                 if (priv->msg_len > 0) {
 277                         ret = hix5hd2_rw_preprocess(priv);
 278                         if (ret) {
 279                                 priv->err = ret;
 280                                 priv->state = HIX5I2C_STAT_RW_ERR;
 281                                 goto stop;
 282                         }
 283                         if (priv->msg->flags & I2C_M_RD)
 284                                 hix5hd2_read_handle(priv);
 285                         else
 286                                 hix5hd2_write_handle(priv);
 287                 } else {
 288                         hix5hd2_rw_over(priv);
 289                 }
 290         }
 291
 292 stop:
 293         if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
 294              priv->msg->len == priv->msg_idx) ||
 295             (priv->state == HIX5I2C_STAT_RW_ERR)) {
 296                 hix5hd2_i2c_disable_irq(priv);
 297                 hix5hd2_i2c_clr_pend_irq(priv);
 298                 complete(&priv->msg_complete);
 299         }
 300
 301         spin_unlock(&priv->lock);
 302
 303         return IRQ_HANDLED;
 304 }
 305
 306 static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
 307 {
 308         unsigned long flags;
 309
 310         spin_lock_irqsave(&priv->lock, flags);
 311         hix5hd2_i2c_clr_all_irq(priv);
 312         hix5hd2_i2c_enable_irq(priv);
 313
 314         if (priv->msg->flags & I2C_M_RD)
 315                 writel_relaxed((priv->msg->addr << 1) | HIX5I2C_READ_OPERATION,
 316                                priv->regs + HIX5I2C_TXR);
 317         else
 318                 writel_relaxed(priv->msg->addr << 1,
 319                                priv->regs + HIX5I2C_TXR);
 320
 321         writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM);
 322         spin_unlock_irqrestore(&priv->lock, flags);
 323 }
 324
 325 static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
 326                                 struct i2c_msg *msgs, int stop)
 327 {
 328         unsigned long timeout;
 329         int ret;
 330
 331         priv->msg = msgs;
 332         priv->msg_idx = 0;
 333         priv->msg_len = priv->msg->len;
 334         priv->stop = stop;
 335         priv->err = 0;
 336         priv->state = HIX5I2C_STAT_INIT;
 337
 338         reinit_completion(&priv->msg_complete);
 339         hix5hd2_i2c_message_start(priv, stop);
 340
 341         timeout = wait_for_completion_timeout(&priv->msg_complete,
 342                                               priv->adap.timeout);
 343         if (timeout == 0) {
 344                 priv->state = HIX5I2C_STAT_RW_ERR;
 345                 priv->err = -ETIMEDOUT;
 346                 dev_warn(priv->dev, "%s timeout=%d\n",
 347                          msgs->flags & I2C_M_RD ? "rx" : "tx",
 348                          priv->adap.timeout);
 349         }
 350         ret = priv->state;
 351
 352         /*
 353          * If this is the last message to be transfered (stop == 1)
 354          * Then check if the bus can be brought back to idle.
 355          */
 356         if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
 357                 ret = hix5hd2_i2c_wait_bus_idle(priv);
 358
 359         if (ret < 0)
 360                 hix5hd2_i2c_reset(priv);
 361
 362         return priv->err;
 363 }
 364
 365 static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
 366                             struct i2c_msg *msgs, int num)
 367 {
 368         struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
 369         int i, ret, stop;
 370
 371         pm_runtime_get_sync(priv->dev);
 372
 373         for (i = 0; i < num; i++, msgs++) {
 374                 stop = (i == num - 1);
 375                 ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
 376                 if (ret < 0)
 377                         goto out;
 378         }
 379
 380         if (i == num) {
 381                 ret = num;
 382         } else {
 383                 /* Only one message, cannot access the device */
 384                 if (i == 1)
 385                         ret = -EREMOTEIO;
 386                 else
 387                         ret = i;
 388
 389                 dev_warn(priv->dev, "xfer message failed\n");
 390         }
 391
 392 out:
 393         pm_runtime_mark_last_busy(priv->dev);
 394         pm_runtime_put_autosuspend(priv->dev);
 395         return ret;
 396 }
 397
 398 static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
 399 {
 400         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 401 }
 402
 403 static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
 404         .master_xfer            = hix5hd2_i2c_xfer,
 405         .functionality          = hix5hd2_i2c_func,
 406 };
 407
 408 static int hix5hd2_i2c_probe(struct platform_device *pdev)
 409 {
 410         struct device_node *np = pdev->dev.of_node;
 411         struct hix5hd2_i2c_priv *priv;
 412         struct resource *mem;
 413         unsigned int freq;
 414         int irq, ret;
 415
 416         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 417         if (!priv)
 418                 return -ENOMEM;
 419
 420         if (of_property_read_u32(np, "clock-frequency", &freq)) {
 421                 /* use 100k as default value */
 422                 priv->freq = 100000;
 423         } else {
 424                 if (freq > HIX5I2C_MAX_FREQ) {
 425                         priv->freq = HIX5I2C_MAX_FREQ;
 426                         dev_warn(priv->dev, "use max freq %d instead\n",
 427                                  HIX5I2C_MAX_FREQ);
 428                 } else {
 429                         priv->freq = freq;
 430                 }
 431         }
 432
 433         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 434         priv->regs = devm_ioremap_resource(&pdev->dev, mem);
 435         if (IS_ERR(priv->regs))
 436                 return PTR_ERR(priv->regs);
 437
 438         irq = platform_get_irq(pdev, 0);
 439         if (irq <= 0) {
 440                 dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
 441                 return irq;
 442         }
 443
 444         priv->clk = devm_clk_get(&pdev->dev, NULL);
 445         if (IS_ERR(priv->clk)) {
 446                 dev_err(&pdev->dev, "cannot get clock\n");
 447                 return PTR_ERR(priv->clk);
 448         }
 449         clk_prepare_enable(priv->clk);
 450
 451         strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
 452         priv->dev = &pdev->dev;
 453         priv->adap.owner = THIS_MODULE;
 454         priv->adap.algo = &hix5hd2_i2c_algorithm;
 455         priv->adap.retries = 3;
 456         priv->adap.dev.of_node = np;
 457         priv->adap.algo_data = priv;
 458         priv->adap.dev.parent = &pdev->dev;
 459         i2c_set_adapdata(&priv->adap, priv);
 460         platform_set_drvdata(pdev, priv);
 461         spin_lock_init(&priv->lock);
 462         init_completion(&priv->msg_complete);
 463
 464         hix5hd2_i2c_init(priv);
 465
 466         ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
 467                                IRQF_NO_SUSPEND | IRQF_ONESHOT,
 468                                dev_name(&pdev->dev), priv);
 469         if (ret != 0) {
 470                 dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
 471                 goto err_clk;
 472         }
 473
 474         pm_suspend_ignore_children(&pdev->dev, true);
 475         pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
 476         pm_runtime_use_autosuspend(priv->dev);
 477         pm_runtime_set_active(priv->dev);
 478         pm_runtime_enable(priv->dev);
 479
 480         ret = i2c_add_adapter(&priv->adap);
 481         if (ret < 0)
 482                 goto err_runtime;
 483
 484         return ret;
 485
 486 err_runtime:
 487         pm_runtime_disable(priv->dev);
 488         pm_runtime_set_suspended(priv->dev);
 489 err_clk:
 490         clk_disable_unprepare(priv->clk);
 491         return ret;
 492 }
 493
 494 static int hix5hd2_i2c_remove(struct platform_device *pdev)
 495 {
 496         struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
 497
 498         i2c_del_adapter(&priv->adap);
 499         pm_runtime_disable(priv->dev);
 500         pm_runtime_set_suspended(priv->dev);
 501
 502         return 0;
 503 }
 504
 505 #ifdef CONFIG_PM
 506 static int hix5hd2_i2c_runtime_suspend(struct device *dev)
 507 {
 508         struct platform_device *pdev = to_platform_device(dev);
 509         struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
 510
 511         clk_disable_unprepare(priv->clk);
 512
 513         return 0;
 514 }
 515
 516 static int hix5hd2_i2c_runtime_resume(struct device *dev)
 517 {
 518         struct platform_device *pdev = to_platform_device(dev);
 519         struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
 520
 521         clk_prepare_enable(priv->clk);
 522         hix5hd2_i2c_init(priv);
 523
 524         return 0;
 525 }
 526 #endif
 527
 528 static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
 529         SET_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
 530                               hix5hd2_i2c_runtime_resume,
 531                               NULL)
 532 };
 533
 534 static const struct of_device_id hix5hd2_i2c_match[] = {
 535         { .compatible = "hisilicon,hix5hd2-i2c" },
 536         {},
 537 };
 538 MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);
 539
 540 static struct platform_driver hix5hd2_i2c_driver = {
 541         .probe          = hix5hd2_i2c_probe,
 542         .remove         = hix5hd2_i2c_remove,
 543         .driver         = {
 544                 .name   = "hix5hd2-i2c",
 545                 .pm     = &hix5hd2_i2c_pm_ops,
 546                 .of_match_table = hix5hd2_i2c_match,
 547         },
 548 };
 549
 550 module_platform_driver(hix5hd2_i2c_driver);
 551
 552 MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
 553 MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
 554 MODULE_LICENSE("GPL");
 555 MODULE_ALIAS("platform:hix5hd2-i2c");