drivers/w1/masters/ds1wm.c

   1 /*
   2  * 1-wire busmaster driver for DS1WM and ASICs with embedded DS1WMs
   3  * such as HP iPAQs (including h5xxx, h2200, and devices with ASIC3
   4  * like hx4700).
   5  *
   6  * Copyright (c) 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
   7  * Copyright (c) 2004-2007, Matt Reimer <mreimer@vpop.net>
   8  *
   9  * Use consistent with the GNU GPL is permitted,
  10  * provided that this copyright notice is
  11  * preserved in its entirety in all copies and derived works.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irq.h>
  17 #include <linux/pm.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/clk.h>
  20 #include <linux/delay.h>
  21 #include <linux/ds1wm.h>
  22
  23 #include <asm/io.h>
  24
  25 #include "../w1.h"
  26 #include "../w1_int.h"
  27
  28
  29 #define DS1WM_CMD       0x00    /* R/W 4 bits command */
  30 #define DS1WM_DATA      0x01    /* R/W 8 bits, transmit/receive buffer */
  31 #define DS1WM_INT       0x02    /* R/W interrupt status */
  32 #define DS1WM_INT_EN    0x03    /* R/W interrupt enable */
  33 #define DS1WM_CLKDIV    0x04    /* R/W 5 bits of divisor and pre-scale */
  34
  35 #define DS1WM_CMD_1W_RESET  (1 << 0)    /* force reset on 1-wire bus */
  36 #define DS1WM_CMD_SRA       (1 << 1)    /* enable Search ROM accelerator mode */
  37 #define DS1WM_CMD_DQ_OUTPUT (1 << 2)    /* write only - forces bus low */
  38 #define DS1WM_CMD_DQ_INPUT  (1 << 3)    /* read only - reflects state of bus */
  39 #define DS1WM_CMD_RST       (1 << 5)    /* software reset */
  40 #define DS1WM_CMD_OD        (1 << 7)    /* overdrive */
  41
  42 #define DS1WM_INT_PD        (1 << 0)    /* presence detect */
  43 #define DS1WM_INT_PDR       (1 << 1)    /* presence detect result */
  44 #define DS1WM_INT_TBE       (1 << 2)    /* tx buffer empty */
  45 #define DS1WM_INT_TSRE      (1 << 3)    /* tx shift register empty */
  46 #define DS1WM_INT_RBF       (1 << 4)    /* rx buffer full */
  47 #define DS1WM_INT_RSRF      (1 << 5)    /* rx shift register full */
  48
  49 #define DS1WM_INTEN_EPD     (1 << 0)    /* enable presence detect int */
  50 #define DS1WM_INTEN_IAS     (1 << 1)    /* INTR active state */
  51 #define DS1WM_INTEN_ETBE    (1 << 2)    /* enable tx buffer empty int */
  52 #define DS1WM_INTEN_ETMT    (1 << 3)    /* enable tx shift register empty int */
  53 #define DS1WM_INTEN_ERBF    (1 << 4)    /* enable rx buffer full int */
  54 #define DS1WM_INTEN_ERSRF   (1 << 5)    /* enable rx shift register full int */
  55 #define DS1WM_INTEN_DQO     (1 << 6)    /* enable direct bus driving ops */
  56
  57
  58 #define DS1WM_TIMEOUT (HZ * 5)
  59
  60 static struct {
  61         unsigned long freq;
  62         unsigned long divisor;
  63 } freq[] = {
  64         { 4000000, 0x8 },
  65         { 5000000, 0x2 },
  66         { 6000000, 0x5 },
  67         { 7000000, 0x3 },
  68         { 8000000, 0xc },
  69         { 10000000, 0x6 },
  70         { 12000000, 0x9 },
  71         { 14000000, 0x7 },
  72         { 16000000, 0x10 },
  73         { 20000000, 0xa },
  74         { 24000000, 0xd },
  75         { 28000000, 0xb },
  76         { 32000000, 0x14 },
  77         { 40000000, 0xe },
  78         { 48000000, 0x11 },
  79         { 56000000, 0xf },
  80         { 64000000, 0x18 },
  81         { 80000000, 0x12 },
  82         { 96000000, 0x15 },
  83         { 112000000, 0x13 },
  84         { 128000000, 0x1c },
  85 };
  86
  87 struct ds1wm_data {
  88         void            *map;
  89         int             bus_shift; /* # of shifts to calc register offsets */
  90         struct platform_device *pdev;
  91         struct ds1wm_platform_data *pdata;
  92         int             irq;
  93         int             active_high;
  94         struct clk      *clk;
  95         int             slave_present;
  96         void            *reset_complete;
  97         void            *read_complete;
  98         void            *write_complete;
  99         u8              read_byte; /* last byte received */
 100 };
 101
 102 static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
 103                                         u8 val)
 104 {
 105         __raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
 106 }
 107
 108 static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
 109 {
 110         return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
 111 }
 112
 113
 114 static irqreturn_t ds1wm_isr(int isr, void *data)
 115 {
 116         struct ds1wm_data *ds1wm_data = data;
 117         u8 intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);
 118
 119         ds1wm_data->slave_present = (intr & DS1WM_INT_PDR) ? 0 : 1;
 120
 121         if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete)
 122                 complete(ds1wm_data->reset_complete);
 123
 124         if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete)
 125                 complete(ds1wm_data->write_complete);
 126
 127         if (intr & DS1WM_INT_RBF) {
 128                 ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
 129                                                             DS1WM_DATA);
 130                 if (ds1wm_data->read_complete)
 131                         complete(ds1wm_data->read_complete);
 132         }
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
 138 {
 139         unsigned long timeleft;
 140         DECLARE_COMPLETION_ONSTACK(reset_done);
 141
 142         ds1wm_data->reset_complete = &reset_done;
 143
 144         ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
 145                 (ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
 146
 147         ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_1W_RESET);
 148
 149         timeleft = wait_for_completion_timeout(&reset_done, DS1WM_TIMEOUT);
 150         ds1wm_data->reset_complete = NULL;
 151         if (!timeleft) {
 152                 dev_dbg(&ds1wm_data->pdev->dev, "reset failed\n");
 153                 return 1;
 154         }
 155
 156         /* Wait for the end of the reset. According to the specs, the time
 157          * from when the interrupt is asserted to the end of the reset is:
 158          *     tRSTH  - tPDH  - tPDL - tPDI
 159          *     625 us - 60 us - 240 us - 100 ns = 324.9 us
 160          *
 161          * We'll wait a bit longer just to be sure.
 162          */
 163         udelay(500);
 164
 165         ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
 166                 DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
 167                 (ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
 168
 169         if (!ds1wm_data->slave_present) {
 170                 dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
 171                 return 1;
 172         }
 173
 174         return 0;
 175 }
 176
 177 static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
 178 {
 179         DECLARE_COMPLETION_ONSTACK(write_done);
 180         ds1wm_data->write_complete = &write_done;
 181
 182         ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);
 183
 184         wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
 185         ds1wm_data->write_complete = NULL;
 186
 187         return 0;
 188 }
 189
 190 static int ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
 191 {
 192         DECLARE_COMPLETION_ONSTACK(read_done);
 193         ds1wm_data->read_complete = &read_done;
 194
 195         ds1wm_write(ds1wm_data, write_data);
 196         wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
 197         ds1wm_data->read_complete = NULL;
 198
 199         return ds1wm_data->read_byte;
 200 }
 201
 202 static int ds1wm_find_divisor(int gclk)
 203 {
 204         int i;
 205
 206         for (i = 0; i < ARRAY_SIZE(freq); i++)
 207                 if (gclk <= freq[i].freq)
 208                         return freq[i].divisor;
 209
 210         return 0;
 211 }
 212
 213 static void ds1wm_up(struct ds1wm_data *ds1wm_data)
 214 {
 215         int gclk, divisor;
 216
 217         if (ds1wm_data->pdata->enable)
 218                 ds1wm_data->pdata->enable(ds1wm_data->pdev);
 219
 220         gclk = clk_get_rate(ds1wm_data->clk);
 221         clk_enable(ds1wm_data->clk);
 222         divisor = ds1wm_find_divisor(gclk);
 223         if (divisor == 0) {
 224                 dev_err(&ds1wm_data->pdev->dev,
 225                         "no suitable divisor for %dHz clock\n", gclk);
 226                 return;
 227         }
 228         ds1wm_write_register(ds1wm_data, DS1WM_CLKDIV, divisor);
 229
 230         /* Let the w1 clock stabilize. */
 231         msleep(1);
 232
 233         ds1wm_reset(ds1wm_data);
 234 }
 235
 236 static void ds1wm_down(struct ds1wm_data *ds1wm_data)
 237 {
 238         ds1wm_reset(ds1wm_data);
 239
 240         /* Disable interrupts. */
 241         ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
 242                              ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0);
 243
 244         if (ds1wm_data->pdata->disable)
 245                 ds1wm_data->pdata->disable(ds1wm_data->pdev);
 246
 247         clk_disable(ds1wm_data->clk);
 248 }
 249
 250 /* --------------------------------------------------------------------- */
 251 /* w1 methods */
 252
 253 static u8 ds1wm_read_byte(void *data)
 254 {
 255         struct ds1wm_data *ds1wm_data = data;
 256
 257         return ds1wm_read(ds1wm_data, 0xff);
 258 }
 259
 260 static void ds1wm_write_byte(void *data, u8 byte)
 261 {
 262         struct ds1wm_data *ds1wm_data = data;
 263
 264         ds1wm_write(ds1wm_data, byte);
 265 }
 266
 267 static u8 ds1wm_reset_bus(void *data)
 268 {
 269         struct ds1wm_data *ds1wm_data = data;
 270
 271         ds1wm_reset(ds1wm_data);
 272
 273         return 0;
 274 }
 275
 276 static void ds1wm_search(void *data, u8 search_type,
 277                          w1_slave_found_callback slave_found)
 278 {
 279         struct ds1wm_data *ds1wm_data = data;
 280         int i;
 281         unsigned long long rom_id;
 282
 283         /* XXX We need to iterate for multiple devices per the DS1WM docs.
 284          * See http://www.maxim-ic.com/appnotes.cfm/appnote_number/120. */
 285         if (ds1wm_reset(ds1wm_data))
 286                 return;
 287
 288         ds1wm_write(ds1wm_data, search_type);
 289         ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
 290
 291         for (rom_id = 0, i = 0; i < 16; i++) {
 292
 293                 unsigned char resp, r, d;
 294
 295                 resp = ds1wm_read(ds1wm_data, 0x00);
 296
 297                 r = ((resp & 0x02) >> 1) |
 298                     ((resp & 0x08) >> 2) |
 299                     ((resp & 0x20) >> 3) |
 300                     ((resp & 0x80) >> 4);
 301
 302                 d = ((resp & 0x01) >> 0) |
 303                     ((resp & 0x04) >> 1) |
 304                     ((resp & 0x10) >> 2) |
 305                     ((resp & 0x40) >> 3);
 306
 307                 rom_id |= (unsigned long long) r << (i * 4);
 308
 309         }
 310         dev_dbg(&ds1wm_data->pdev->dev, "found 0x%08llX", rom_id);
 311
 312         ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
 313         ds1wm_reset(ds1wm_data);
 314
 315         slave_found(ds1wm_data, rom_id);
 316 }
 317
 318 /* --------------------------------------------------------------------- */
 319
 320 static struct w1_bus_master ds1wm_master = {
 321         .read_byte  = ds1wm_read_byte,
 322         .write_byte = ds1wm_write_byte,
 323         .reset_bus  = ds1wm_reset_bus,
 324         .search     = ds1wm_search,
 325 };
 326
 327 static int ds1wm_probe(struct platform_device *pdev)
 328 {
 329         struct ds1wm_data *ds1wm_data;
 330         struct ds1wm_platform_data *plat;
 331         struct resource *res;
 332         int ret;
 333
 334         if (!pdev)
 335                 return -ENODEV;
 336
 337         ds1wm_data = kzalloc(sizeof (*ds1wm_data), GFP_KERNEL);
 338         if (!ds1wm_data)
 339                 return -ENOMEM;
 340
 341         platform_set_drvdata(pdev, ds1wm_data);
 342
 343         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 344         if (!res) {
 345                 ret = -ENXIO;
 346                 goto err0;
 347         }
 348         ds1wm_data->map = ioremap(res->start, res->end - res->start + 1);
 349         if (!ds1wm_data->map) {
 350                 ret = -ENOMEM;
 351                 goto err0;
 352         }
 353         plat = pdev->dev.platform_data;
 354         ds1wm_data->bus_shift = plat->bus_shift;
 355         ds1wm_data->pdev = pdev;
 356         ds1wm_data->pdata = plat;
 357
 358         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 359         if (!res) {
 360                 ret = -ENXIO;
 361                 goto err1;
 362         }
 363         ds1wm_data->irq = res->start;
 364         ds1wm_data->active_high = (res->flags & IORESOURCE_IRQ_HIGHEDGE) ?
 365                 1 : 0;
 366
 367         set_irq_type(ds1wm_data->irq, ds1wm_data->active_high ?
 368                         IRQ_TYPE_EDGE_RISING : IRQ_TYPE_EDGE_FALLING);
 369
 370         ret = request_irq(ds1wm_data->irq, ds1wm_isr, IRQF_DISABLED,
 371                           "ds1wm", ds1wm_data);
 372         if (ret)
 373                 goto err1;
 374
 375         ds1wm_data->clk = clk_get(&pdev->dev, "ds1wm");
 376         if (!ds1wm_data->clk) {
 377                 ret = -ENOENT;
 378                 goto err2;
 379         }
 380
 381         ds1wm_up(ds1wm_data);
 382
 383         ds1wm_master.data = (void *)ds1wm_data;
 384
 385         ret = w1_add_master_device(&ds1wm_master);
 386         if (ret)
 387                 goto err3;
 388
 389         return 0;
 390
 391 err3:
 392         ds1wm_down(ds1wm_data);
 393         clk_put(ds1wm_data->clk);
 394 err2:
 395         free_irq(ds1wm_data->irq, ds1wm_data);
 396 err1:
 397         iounmap(ds1wm_data->map);
 398 err0:
 399         kfree(ds1wm_data);
 400
 401         return ret;
 402 }
 403
 404 #ifdef CONFIG_PM
 405 static int ds1wm_suspend(struct platform_device *pdev, pm_message_t state)
 406 {
 407         struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
 408
 409         ds1wm_down(ds1wm_data);
 410
 411         return 0;
 412 }
 413
 414 static int ds1wm_resume(struct platform_device *pdev)
 415 {
 416         struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
 417
 418         ds1wm_up(ds1wm_data);
 419
 420         return 0;
 421 }
 422 #else
 423 #define ds1wm_suspend NULL
 424 #define ds1wm_resume NULL
 425 #endif
 426
 427 static int ds1wm_remove(struct platform_device *pdev)
 428 {
 429         struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
 430
 431         w1_remove_master_device(&ds1wm_master);
 432         ds1wm_down(ds1wm_data);
 433         clk_put(ds1wm_data->clk);
 434         free_irq(ds1wm_data->irq, ds1wm_data);
 435         iounmap(ds1wm_data->map);
 436         kfree(ds1wm_data);
 437
 438         return 0;
 439 }
 440
 441 static struct platform_driver ds1wm_driver = {
 442         .driver   = {
 443                 .name = "ds1wm",
 444         },
 445         .probe    = ds1wm_probe,
 446         .remove   = ds1wm_remove,
 447         .suspend  = ds1wm_suspend,
 448         .resume   = ds1wm_resume
 449 };
 450
 451 static int __init ds1wm_init(void)
 452 {
 453         printk("DS1WM w1 busmaster driver - (c) 2004 Szabolcs Gyurko\n");
 454         return platform_driver_register(&ds1wm_driver);
 455 }
 456
 457 static void __exit ds1wm_exit(void)
 458 {
 459         platform_driver_unregister(&ds1wm_driver);
 460 }
 461
 462 module_init(ds1wm_init);
 463 module_exit(ds1wm_exit);
 464
 465 MODULE_LICENSE("GPL");
 466 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
 467               "Matt Reimer <mreimer@vpop.net>");
 468 MODULE_DESCRIPTION("DS1WM w1 busmaster driver");