drivers/w1/masters/omap

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This source file includes following definitions.
hdq_reg_in
hdq_reg_out
hdq_reg_merge
hdq_disable_interrupt
hdq_wait_for_flag
hdq_write_byte
hdq_isr
omap_w1_search_bus
_omap_hdq_reset
omap_hdq_break
hdq_read_byte
omap_hdq_get
omap_hdq_put
omap_w1_triplet
omap_w1_reset_bus
omap_w1_read_byte
omap_w1_write_byte
omap_hdq_probe
omap_hdq_remove
   1 /*
   2  * drivers/w1/masters/omap_hdq.c
   3  *
   4  * Copyright (C) 2007,2012 Texas Instruments, Inc.
   5  *
   6  * This file is licensed under the terms of the GNU General Public License
   7  * version 2. This program is licensed "as is" without any warranty of any
   8  * kind, whether express or implied.
   9  *
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18 #include <linux/sched.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/of.h>
  21 
  22 #include <linux/w1.h>
  23 
  24 #define MOD_NAME        "OMAP_HDQ:"
  25 
  26 #define OMAP_HDQ_REVISION                       0x00
  27 #define OMAP_HDQ_TX_DATA                        0x04
  28 #define OMAP_HDQ_RX_DATA                        0x08
  29 #define OMAP_HDQ_CTRL_STATUS                    0x0c
  30 #define OMAP_HDQ_CTRL_STATUS_SINGLE             BIT(7)
  31 #define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK      BIT(6)
  32 #define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE        BIT(5)
  33 #define OMAP_HDQ_CTRL_STATUS_GO                 BIT(4)
  34 #define OMAP_HDQ_CTRL_STATUS_PRESENCE           BIT(3)
  35 #define OMAP_HDQ_CTRL_STATUS_INITIALIZATION     BIT(2)
  36 #define OMAP_HDQ_CTRL_STATUS_DIR                BIT(1)
  37 #define OMAP_HDQ_INT_STATUS                     0x10
  38 #define OMAP_HDQ_INT_STATUS_TXCOMPLETE          BIT(2)
  39 #define OMAP_HDQ_INT_STATUS_RXCOMPLETE          BIT(1)
  40 #define OMAP_HDQ_INT_STATUS_TIMEOUT             BIT(0)
  41 #define OMAP_HDQ_SYSCONFIG                      0x14
  42 #define OMAP_HDQ_SYSCONFIG_SOFTRESET            BIT(1)
  43 #define OMAP_HDQ_SYSCONFIG_AUTOIDLE             BIT(0)
  44 #define OMAP_HDQ_SYSCONFIG_NOIDLE               0x0
  45 #define OMAP_HDQ_SYSSTATUS                      0x18
  46 #define OMAP_HDQ_SYSSTATUS_RESETDONE            BIT(0)
  47 
  48 #define OMAP_HDQ_FLAG_CLEAR                     0
  49 #define OMAP_HDQ_FLAG_SET                       1
  50 #define OMAP_HDQ_TIMEOUT                        (HZ/5)
  51 
  52 #define OMAP_HDQ_MAX_USER                       4
  53 
  54 static DECLARE_WAIT_QUEUE_HEAD(hdq_wait_queue);
  55 
  56 static int w1_id;
  57 module_param(w1_id, int, S_IRUSR);
  58 MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection in HDQ mode");
  59 
  60 struct hdq_data {
  61         struct device           *dev;
  62         void __iomem            *hdq_base;
  63         /* lock status update */
  64         struct  mutex           hdq_mutex;
  65         int                     hdq_usecount;
  66         u8                      hdq_irqstatus;
  67         /* device lock */
  68         spinlock_t              hdq_spinlock;
  69         /*
  70          * Used to control the call to omap_hdq_get and omap_hdq_put.
  71          * HDQ Protocol: Write the CMD|REG_address first, followed by
  72          * the data wrire or read.
  73          */
  74         int                     init_trans;
  75         int                     rrw;
  76         /* mode: 0-HDQ 1-W1 */
  77         int                     mode;
  78 
  79 };
  80 
  81 /* HDQ register I/O routines */
  82 static inline u8 hdq_reg_in(struct hdq_data *hdq_data, u32 offset)
  83 {
  84         return __raw_readl(hdq_data->hdq_base + offset);
  85 }
  86 
  87 static inline void hdq_reg_out(struct hdq_data *hdq_data, u32 offset, u8 val)
  88 {
  89         __raw_writel(val, hdq_data->hdq_base + offset);
  90 }
  91 
  92 static inline u8 hdq_reg_merge(struct hdq_data *hdq_data, u32 offset,
  93                         u8 val, u8 mask)
  94 {
  95         u8 new_val = (__raw_readl(hdq_data->hdq_base + offset) & ~mask)
  96                         | (val & mask);
  97         __raw_writel(new_val, hdq_data->hdq_base + offset);
  98 
  99         return new_val;
 100 }
 101 
 102 static void hdq_disable_interrupt(struct hdq_data *hdq_data, u32 offset,
 103                                   u32 mask)
 104 {
 105         u32 ie;
 106 
 107         ie = readl(hdq_data->hdq_base + offset);
 108         writel(ie & mask, hdq_data->hdq_base + offset);
 109 }
 110 
 111 /*
 112  * Wait for one or more bits in flag change.
 113  * HDQ_FLAG_SET: wait until any bit in the flag is set.
 114  * HDQ_FLAG_CLEAR: wait until all bits in the flag are cleared.
 115  * return 0 on success and -ETIMEDOUT in the case of timeout.
 116  */
 117 static int hdq_wait_for_flag(struct hdq_data *hdq_data, u32 offset,
 118                 u8 flag, u8 flag_set, u8 *status)
 119 {
 120         int ret = 0;
 121         unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
 122 
 123         if (flag_set == OMAP_HDQ_FLAG_CLEAR) {
 124                 /* wait for the flag clear */
 125                 while (((*status = hdq_reg_in(hdq_data, offset)) & flag)
 126                         && time_before(jiffies, timeout)) {
 127                         schedule_timeout_uninterruptible(1);
 128                 }
 129                 if (*status & flag)
 130                         ret = -ETIMEDOUT;
 131         } else if (flag_set == OMAP_HDQ_FLAG_SET) {
 132                 /* wait for the flag set */
 133                 while (!((*status = hdq_reg_in(hdq_data, offset)) & flag)
 134                         && time_before(jiffies, timeout)) {
 135                         schedule_timeout_uninterruptible(1);
 136                 }
 137                 if (!(*status & flag))
 138                         ret = -ETIMEDOUT;
 139         } else
 140                 return -EINVAL;
 141 
 142         return ret;
 143 }
 144 
 145 /* write out a byte and fill *status with HDQ_INT_STATUS */
 146 static int hdq_write_byte(struct hdq_data *hdq_data, u8 val, u8 *status)
 147 {
 148         int ret;
 149         u8 tmp_status;
 150         unsigned long irqflags;
 151 
 152         *status = 0;
 153 
 154         spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
 155         /* clear interrupt flags via a dummy read */
 156         hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
 157         /* ISR loads it with new INT_STATUS */
 158         hdq_data->hdq_irqstatus = 0;
 159         spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
 160 
 161         hdq_reg_out(hdq_data, OMAP_HDQ_TX_DATA, val);
 162 
 163         /* set the GO bit */
 164         hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, OMAP_HDQ_CTRL_STATUS_GO,
 165                 OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
 166         /* wait for the TXCOMPLETE bit */
 167         ret = wait_event_timeout(hdq_wait_queue,
 168                 hdq_data->hdq_irqstatus, OMAP_HDQ_TIMEOUT);
 169         if (ret == 0) {
 170                 dev_dbg(hdq_data->dev, "TX wait elapsed\n");
 171                 ret = -ETIMEDOUT;
 172                 goto out;
 173         }
 174 
 175         *status = hdq_data->hdq_irqstatus;
 176         /* check irqstatus */
 177         if (!(*status & OMAP_HDQ_INT_STATUS_TXCOMPLETE)) {
 178                 dev_dbg(hdq_data->dev, "timeout waiting for"
 179                         " TXCOMPLETE/RXCOMPLETE, %x", *status);
 180                 ret = -ETIMEDOUT;
 181                 goto out;
 182         }
 183 
 184         /* wait for the GO bit return to zero */
 185         ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
 186                         OMAP_HDQ_CTRL_STATUS_GO,
 187                         OMAP_HDQ_FLAG_CLEAR, &tmp_status);
 188         if (ret) {
 189                 dev_dbg(hdq_data->dev, "timeout waiting GO bit"
 190                         " return to zero, %x", tmp_status);
 191         }
 192 
 193 out:
 194         return ret;
 195 }
 196 
 197 /* HDQ Interrupt service routine */
 198 static irqreturn_t hdq_isr(int irq, void *_hdq)
 199 {
 200         struct hdq_data *hdq_data = _hdq;
 201         unsigned long irqflags;
 202 
 203         spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
 204         hdq_data->hdq_irqstatus = hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
 205         spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
 206         dev_dbg(hdq_data->dev, "hdq_isr: %x", hdq_data->hdq_irqstatus);
 207 
 208         if (hdq_data->hdq_irqstatus &
 209                 (OMAP_HDQ_INT_STATUS_TXCOMPLETE | OMAP_HDQ_INT_STATUS_RXCOMPLETE
 210                 | OMAP_HDQ_INT_STATUS_TIMEOUT)) {
 211                 /* wake up sleeping process */
 212                 wake_up(&hdq_wait_queue);
 213         }
 214 
 215         return IRQ_HANDLED;
 216 }
 217 
 218 /* W1 search callback function  in HDQ mode */
 219 static void omap_w1_search_bus(void *_hdq, struct w1_master *master_dev,
 220                 u8 search_type, w1_slave_found_callback slave_found)
 221 {
 222         u64 module_id, rn_le, cs, id;
 223 
 224         if (w1_id)
 225                 module_id = w1_id;
 226         else
 227                 module_id = 0x1;
 228 
 229         rn_le = cpu_to_le64(module_id);
 230         /*
 231          * HDQ might not obey truly the 1-wire spec.
 232          * So calculate CRC based on module parameter.
 233          */
 234         cs = w1_calc_crc8((u8 *)&rn_le, 7);
 235         id = (cs << 56) | module_id;
 236 
 237         slave_found(master_dev, id);
 238 }
 239 
 240 static int _omap_hdq_reset(struct hdq_data *hdq_data)
 241 {
 242         int ret;
 243         u8 tmp_status;
 244 
 245         hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
 246                     OMAP_HDQ_SYSCONFIG_SOFTRESET);
 247         /*
 248          * Select HDQ/1W mode & enable clocks.
 249          * It is observed that INT flags can't be cleared via a read and GO/INIT
 250          * won't return to zero if interrupt is disabled. So we always enable
 251          * interrupt.
 252          */
 253         hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
 254                 OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
 255                 OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
 256 
 257         /* wait for reset to complete */
 258         ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_SYSSTATUS,
 259                 OMAP_HDQ_SYSSTATUS_RESETDONE, OMAP_HDQ_FLAG_SET, &tmp_status);
 260         if (ret)
 261                 dev_dbg(hdq_data->dev, "timeout waiting HDQ reset, %x",
 262                                 tmp_status);
 263         else {
 264                 hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
 265                         OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
 266                         OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
 267                         hdq_data->mode);
 268                 hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
 269                         OMAP_HDQ_SYSCONFIG_AUTOIDLE);
 270         }
 271 
 272         return ret;
 273 }
 274 
 275 /* Issue break pulse to the device */
 276 static int omap_hdq_break(struct hdq_data *hdq_data)
 277 {
 278         int ret = 0;
 279         u8 tmp_status;
 280         unsigned long irqflags;
 281 
 282         ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 283         if (ret < 0) {
 284                 dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 285                 ret = -EINTR;
 286                 goto rtn;
 287         }
 288 
 289         spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
 290         /* clear interrupt flags via a dummy read */
 291         hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
 292         /* ISR loads it with new INT_STATUS */
 293         hdq_data->hdq_irqstatus = 0;
 294         spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
 295 
 296         /* set the INIT and GO bit */
 297         hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
 298                 OMAP_HDQ_CTRL_STATUS_INITIALIZATION | OMAP_HDQ_CTRL_STATUS_GO,
 299                 OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
 300                 OMAP_HDQ_CTRL_STATUS_GO);
 301 
 302         /* wait for the TIMEOUT bit */
 303         ret = wait_event_timeout(hdq_wait_queue,
 304                 hdq_data->hdq_irqstatus, OMAP_HDQ_TIMEOUT);
 305         if (ret == 0) {
 306                 dev_dbg(hdq_data->dev, "break wait elapsed\n");
 307                 ret = -EINTR;
 308                 goto out;
 309         }
 310 
 311         tmp_status = hdq_data->hdq_irqstatus;
 312         /* check irqstatus */
 313         if (!(tmp_status & OMAP_HDQ_INT_STATUS_TIMEOUT)) {
 314                 dev_dbg(hdq_data->dev, "timeout waiting for TIMEOUT, %x",
 315                                 tmp_status);
 316                 ret = -ETIMEDOUT;
 317                 goto out;
 318         }
 319 
 320         /*
 321          * check for the presence detect bit to get
 322          * set to show that the slave is responding
 323          */
 324         if (!(hdq_reg_in(hdq_data, OMAP_HDQ_CTRL_STATUS) &
 325                         OMAP_HDQ_CTRL_STATUS_PRESENCE)) {
 326                 dev_dbg(hdq_data->dev, "Presence bit not set\n");
 327                 ret = -ETIMEDOUT;
 328                 goto out;
 329         }
 330 
 331         /*
 332          * wait for both INIT and GO bits rerurn to zero.
 333          * zero wait time expected for interrupt mode.
 334          */
 335         ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
 336                         OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
 337                         OMAP_HDQ_CTRL_STATUS_GO, OMAP_HDQ_FLAG_CLEAR,
 338                         &tmp_status);
 339         if (ret)
 340                 dev_dbg(hdq_data->dev, "timeout waiting INIT&GO bits"
 341                         " return to zero, %x", tmp_status);
 342 
 343 out:
 344         mutex_unlock(&hdq_data->hdq_mutex);
 345 rtn:
 346         return ret;
 347 }
 348 
 349 static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
 350 {
 351         int ret = 0;
 352         u8 status;
 353 
 354         ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 355         if (ret < 0) {
 356                 ret = -EINTR;
 357                 goto rtn;
 358         }
 359 
 360         if (!hdq_data->hdq_usecount) {
 361                 ret = -EINVAL;
 362                 goto out;
 363         }
 364 
 365         if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
 366                 hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
 367                         OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
 368                         OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
 369                 /*
 370                  * The RX comes immediately after TX.
 371                  */
 372                 wait_event_timeout(hdq_wait_queue,
 373                                    (hdq_data->hdq_irqstatus
 374                                     & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
 375                                    OMAP_HDQ_TIMEOUT);
 376 
 377                 hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, 0,
 378                         OMAP_HDQ_CTRL_STATUS_DIR);
 379                 status = hdq_data->hdq_irqstatus;
 380                 /* check irqstatus */
 381                 if (!(status & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
 382                         dev_dbg(hdq_data->dev, "timeout waiting for"
 383                                 " RXCOMPLETE, %x", status);
 384                         ret = -ETIMEDOUT;
 385                         goto out;
 386                 }
 387         }
 388         /* the data is ready. Read it in! */
 389         *val = hdq_reg_in(hdq_data, OMAP_HDQ_RX_DATA);
 390 out:
 391         mutex_unlock(&hdq_data->hdq_mutex);
 392 rtn:
 393         return ret;
 394 
 395 }
 396 
 397 /* Enable clocks and set the controller to HDQ/1W mode */
 398 static int omap_hdq_get(struct hdq_data *hdq_data)
 399 {
 400         int ret = 0;
 401 
 402         ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 403         if (ret < 0) {
 404                 ret = -EINTR;
 405                 goto rtn;
 406         }
 407 
 408         if (OMAP_HDQ_MAX_USER == hdq_data->hdq_usecount) {
 409                 dev_dbg(hdq_data->dev, "attempt to exceed the max use count");
 410                 ret = -EINVAL;
 411                 goto out;
 412         } else {
 413                 hdq_data->hdq_usecount++;
 414                 try_module_get(THIS_MODULE);
 415                 if (1 == hdq_data->hdq_usecount) {
 416 
 417                         pm_runtime_get_sync(hdq_data->dev);
 418 
 419                         /* make sure HDQ/1W is out of reset */
 420                         if (!(hdq_reg_in(hdq_data, OMAP_HDQ_SYSSTATUS) &
 421                                 OMAP_HDQ_SYSSTATUS_RESETDONE)) {
 422                                 ret = _omap_hdq_reset(hdq_data);
 423                                 if (ret)
 424                                         /* back up the count */
 425                                         hdq_data->hdq_usecount--;
 426                         } else {
 427                                 /* select HDQ/1W mode & enable clocks */
 428                                 hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
 429                                         OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
 430                                         OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
 431                                         hdq_data->mode);
 432                                 hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
 433                                         OMAP_HDQ_SYSCONFIG_NOIDLE);
 434                                 hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
 435                         }
 436                 }
 437         }
 438 
 439 out:
 440         mutex_unlock(&hdq_data->hdq_mutex);
 441 rtn:
 442         return ret;
 443 }
 444 
 445 /* Disable clocks to the module */
 446 static int omap_hdq_put(struct hdq_data *hdq_data)
 447 {
 448         int ret = 0;
 449 
 450         ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 451         if (ret < 0)
 452                 return -EINTR;
 453 
 454         hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
 455                     OMAP_HDQ_SYSCONFIG_AUTOIDLE);
 456         if (0 == hdq_data->hdq_usecount) {
 457                 dev_dbg(hdq_data->dev, "attempt to decrement use count"
 458                         " when it is zero");
 459                 ret = -EINVAL;
 460         } else {
 461                 hdq_data->hdq_usecount--;
 462                 module_put(THIS_MODULE);
 463                 if (0 == hdq_data->hdq_usecount)
 464                         pm_runtime_put_sync(hdq_data->dev);
 465         }
 466         mutex_unlock(&hdq_data->hdq_mutex);
 467 
 468         return ret;
 469 }
 470 
 471 /*
 472  * W1 triplet callback function - used for searching ROM addresses.
 473  * Registered only when controller is in 1-wire mode.
 474  */
 475 static u8 omap_w1_triplet(void *_hdq, u8 bdir)
 476 {
 477         u8 id_bit, comp_bit;
 478         int err;
 479         u8 ret = 0x3; /* no slaves responded */
 480         struct hdq_data *hdq_data = _hdq;
 481         u8 ctrl = OMAP_HDQ_CTRL_STATUS_SINGLE | OMAP_HDQ_CTRL_STATUS_GO |
 482                   OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK;
 483         u8 mask = ctrl | OMAP_HDQ_CTRL_STATUS_DIR;
 484 
 485         omap_hdq_get(_hdq);
 486 
 487         err = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 488         if (err < 0) {
 489                 dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 490                 goto rtn;
 491         }
 492 
 493         hdq_data->hdq_irqstatus = 0;
 494         /* read id_bit */
 495         hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
 496                       ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
 497         err = wait_event_timeout(hdq_wait_queue,
 498                                  (hdq_data->hdq_irqstatus
 499                                   & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
 500                                  OMAP_HDQ_TIMEOUT);
 501         if (err == 0) {
 502                 dev_dbg(hdq_data->dev, "RX wait elapsed\n");
 503                 goto out;
 504         }
 505         id_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
 506 
 507         hdq_data->hdq_irqstatus = 0;
 508         /* read comp_bit */
 509         hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
 510                       ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
 511         err = wait_event_timeout(hdq_wait_queue,
 512                                  (hdq_data->hdq_irqstatus
 513                                   & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
 514                                  OMAP_HDQ_TIMEOUT);
 515         if (err == 0) {
 516                 dev_dbg(hdq_data->dev, "RX wait elapsed\n");
 517                 goto out;
 518         }
 519         comp_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
 520 
 521         if (id_bit && comp_bit) {
 522                 ret = 0x03;  /* no slaves responded */
 523                 goto out;
 524         }
 525         if (!id_bit && !comp_bit) {
 526                 /* Both bits are valid, take the direction given */
 527                 ret = bdir ? 0x04 : 0;
 528         } else {
 529                 /* Only one bit is valid, take that direction */
 530                 bdir = id_bit;
 531                 ret = id_bit ? 0x05 : 0x02;
 532         }
 533 
 534         /* write bdir bit */
 535         hdq_reg_out(_hdq, OMAP_HDQ_TX_DATA, bdir);
 536         hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, ctrl, mask);
 537         err = wait_event_timeout(hdq_wait_queue,
 538                                  (hdq_data->hdq_irqstatus
 539                                   & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
 540                                  OMAP_HDQ_TIMEOUT);
 541         if (err == 0) {
 542                 dev_dbg(hdq_data->dev, "TX wait elapsed\n");
 543                 goto out;
 544         }
 545 
 546         hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, 0,
 547                       OMAP_HDQ_CTRL_STATUS_SINGLE);
 548 
 549 out:
 550         mutex_unlock(&hdq_data->hdq_mutex);
 551 rtn:
 552         omap_hdq_put(_hdq);
 553         return ret;
 554 }
 555 
 556 /* reset callback */
 557 static u8 omap_w1_reset_bus(void *_hdq)
 558 {
 559         omap_hdq_get(_hdq);
 560         omap_hdq_break(_hdq);
 561         omap_hdq_put(_hdq);
 562         return 0;
 563 }
 564 
 565 /* Read a byte of data from the device */
 566 static u8 omap_w1_read_byte(void *_hdq)
 567 {
 568         struct hdq_data *hdq_data = _hdq;
 569         u8 val = 0;
 570         int ret;
 571 
 572         /* First write to initialize the transfer */
 573         if (hdq_data->init_trans == 0)
 574                 omap_hdq_get(hdq_data);
 575 
 576         ret = hdq_read_byte(hdq_data, &val);
 577         if (ret) {
 578                 ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 579                 if (ret < 0) {
 580                         dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 581                         return -EINTR;
 582                 }
 583                 hdq_data->init_trans = 0;
 584                 mutex_unlock(&hdq_data->hdq_mutex);
 585                 omap_hdq_put(hdq_data);
 586                 return -1;
 587         }
 588 
 589         hdq_disable_interrupt(hdq_data, OMAP_HDQ_CTRL_STATUS,
 590                               ~OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
 591 
 592         /* Write followed by a read, release the module */
 593         if (hdq_data->init_trans) {
 594                 ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 595                 if (ret < 0) {
 596                         dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 597                         return -EINTR;
 598                 }
 599                 hdq_data->init_trans = 0;
 600                 mutex_unlock(&hdq_data->hdq_mutex);
 601                 omap_hdq_put(hdq_data);
 602         }
 603 
 604         return val;
 605 }
 606 
 607 /* Write a byte of data to the device */
 608 static void omap_w1_write_byte(void *_hdq, u8 byte)
 609 {
 610         struct hdq_data *hdq_data = _hdq;
 611         int ret;
 612         u8 status;
 613 
 614         /* First write to initialize the transfer */
 615         if (hdq_data->init_trans == 0)
 616                 omap_hdq_get(hdq_data);
 617 
 618         /*
 619          * We need to reset the slave before
 620          * issuing the SKIP ROM command, else
 621          * the slave will not work.
 622          */
 623         if (byte == W1_SKIP_ROM)
 624                 omap_hdq_break(hdq_data);
 625 
 626         ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 627         if (ret < 0) {
 628                 dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 629                 return;
 630         }
 631         hdq_data->init_trans++;
 632         mutex_unlock(&hdq_data->hdq_mutex);
 633 
 634         ret = hdq_write_byte(hdq_data, byte, &status);
 635         if (ret < 0) {
 636                 dev_dbg(hdq_data->dev, "TX failure:Ctrl status %x\n", status);
 637                 return;
 638         }
 639 
 640         /* Second write, data transferred. Release the module */
 641         if (hdq_data->init_trans > 1) {
 642                 omap_hdq_put(hdq_data);
 643                 ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 644                 if (ret < 0) {
 645                         dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
 646                         return;
 647                 }
 648                 hdq_data->init_trans = 0;
 649                 mutex_unlock(&hdq_data->hdq_mutex);
 650         }
 651 }
 652 
 653 static struct w1_bus_master omap_w1_master = {
 654         .read_byte      = omap_w1_read_byte,
 655         .write_byte     = omap_w1_write_byte,
 656         .reset_bus      = omap_w1_reset_bus,
 657 };
 658 
 659 static int omap_hdq_probe(struct platform_device *pdev)
 660 {
 661         struct device *dev = &pdev->dev;
 662         struct hdq_data *hdq_data;
 663         int ret, irq;
 664         u8 rev;
 665         const char *mode;
 666 
 667         hdq_data = devm_kzalloc(dev, sizeof(*hdq_data), GFP_KERNEL);
 668         if (!hdq_data) {
 669                 dev_dbg(&pdev->dev, "unable to allocate memory\n");
 670                 return -ENOMEM;
 671         }
 672 
 673         hdq_data->dev = dev;
 674         platform_set_drvdata(pdev, hdq_data);
 675 
 676         hdq_data->hdq_base = devm_platform_ioremap_resource(pdev, 0);
 677         if (IS_ERR(hdq_data->hdq_base))
 678                 return PTR_ERR(hdq_data->hdq_base);
 679 
 680         hdq_data->hdq_usecount = 0;
 681         hdq_data->rrw = 0;
 682         mutex_init(&hdq_data->hdq_mutex);
 683 
 684         pm_runtime_enable(&pdev->dev);
 685         ret = pm_runtime_get_sync(&pdev->dev);
 686         if (ret < 0) {
 687                 dev_dbg(&pdev->dev, "pm_runtime_get_sync failed\n");
 688                 goto err_w1;
 689         }
 690 
 691         ret = _omap_hdq_reset(hdq_data);
 692         if (ret) {
 693                 dev_dbg(&pdev->dev, "reset failed\n");
 694                 goto err_irq;
 695         }
 696 
 697         rev = hdq_reg_in(hdq_data, OMAP_HDQ_REVISION);
 698         dev_info(&pdev->dev, "OMAP HDQ Hardware Rev %c.%c. Driver in %s mode\n",
 699                 (rev >> 4) + '0', (rev & 0x0f) + '0', "Interrupt");
 700 
 701         spin_lock_init(&hdq_data->hdq_spinlock);
 702 
 703         irq = platform_get_irq(pdev, 0);
 704         if (irq < 0) {
 705                 dev_dbg(&pdev->dev, "Failed to get IRQ: %d\n", irq);
 706                 ret = irq;
 707                 goto err_irq;
 708         }
 709 
 710         ret = devm_request_irq(dev, irq, hdq_isr, 0, "omap_hdq", hdq_data);
 711         if (ret < 0) {
 712                 dev_dbg(&pdev->dev, "could not request irq\n");
 713                 goto err_irq;
 714         }
 715 
 716         omap_hdq_break(hdq_data);
 717 
 718         pm_runtime_put_sync(&pdev->dev);
 719 
 720         ret = of_property_read_string(pdev->dev.of_node, "ti,mode", &mode);
 721         if (ret < 0 || !strcmp(mode, "hdq")) {
 722                 hdq_data->mode = 0;
 723                 omap_w1_master.search = omap_w1_search_bus;
 724         } else {
 725                 hdq_data->mode = 1;
 726                 omap_w1_master.triplet = omap_w1_triplet;
 727         }
 728 
 729         omap_w1_master.data = hdq_data;
 730 
 731         ret = w1_add_master_device(&omap_w1_master);
 732         if (ret) {
 733                 dev_dbg(&pdev->dev, "Failure in registering w1 master\n");
 734                 goto err_w1;
 735         }
 736 
 737         return 0;
 738 
 739 err_irq:
 740         pm_runtime_put_sync(&pdev->dev);
 741 err_w1:
 742         pm_runtime_disable(&pdev->dev);
 743 
 744         return ret;
 745 }
 746 
 747 static int omap_hdq_remove(struct platform_device *pdev)
 748 {
 749         struct hdq_data *hdq_data = platform_get_drvdata(pdev);
 750 
 751         mutex_lock(&hdq_data->hdq_mutex);
 752 
 753         if (hdq_data->hdq_usecount) {
 754                 dev_dbg(&pdev->dev, "removed when use count is not zero\n");
 755                 mutex_unlock(&hdq_data->hdq_mutex);
 756                 return -EBUSY;
 757         }
 758 
 759         mutex_unlock(&hdq_data->hdq_mutex);
 760 
 761         /* remove module dependency */
 762         pm_runtime_disable(&pdev->dev);
 763 
 764         w1_remove_master_device(&omap_w1_master);
 765 
 766         return 0;
 767 }
 768 
 769 static const struct of_device_id omap_hdq_dt_ids[] = {
 770         { .compatible = "ti,omap3-1w" },
 771         { .compatible = "ti,am4372-hdq" },
 772         {}
 773 };
 774 MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids);
 775 
 776 static struct platform_driver omap_hdq_driver = {
 777         .probe = omap_hdq_probe,
 778         .remove = omap_hdq_remove,
 779         .driver = {
 780                 .name = "omap_hdq",
 781                 .of_match_table = omap_hdq_dt_ids,
 782         },
 783 };
 784 module_platform_driver(omap_hdq_driver);
 785 
 786 MODULE_AUTHOR("Texas Instruments");
 787 MODULE_DESCRIPTION("HDQ-1W driver Library");
 788 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/w1/masters/omap_hdq.c

DEFINITIONS
