drivers/bus/sunxi-rsb.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
sunxi_rsb_device_match
sunxi_rsb_device_probe
sunxi_rsb_device_remove
sunxi_rsb_dev_release
sunxi_rsb_device_create
sunxi_rsb_device_unregister
sunxi_rsb_remove_devices
sunxi_rsb_driver_register
_sunxi_rsb_run_xfer
sunxi_rsb_read
sunxi_rsb_write
regmap_sunxi_rsb_reg_read
regmap_sunxi_rsb_reg_write
regmap_sunxi_rsb_free_ctx
regmap_sunxi_rsb_init_ctx
__devm_regmap_init_sunxi_rsb
sunxi_rsb_irq
sunxi_rsb_init_device_mode
sunxi_rsb_get_rtaddr
of_rsb_register_devices
sunxi_rsb_probe
sunxi_rsb_remove
sunxi_rsb_init
sunxi_rsb_exit
   1 /*
   2  * RSB (Reduced Serial Bus) driver.
   3  *
   4  * Author: Chen-Yu Tsai <wens@csie.org>
   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  * The RSB controller looks like an SMBus controller which only supports
  11  * byte and word data transfers. But, it differs from standard SMBus
  12  * protocol on several aspects:
  13  * - it uses addresses set at runtime to address slaves. Runtime addresses
  14  *   are sent to slaves using their 12bit hardware addresses. Up to 15
  15  *   runtime addresses are available.
  16  * - it adds a parity bit every 8bits of data and address for read and
  17  *   write accesses; this replaces the ack bit
  18  * - only one read access is required to read a byte (instead of a write
  19  *   followed by a read access in standard SMBus protocol)
  20  * - there's no Ack bit after each read access
  21  *
  22  * This means this bus cannot be used to interface with standard SMBus
  23  * devices. Devices known to support this interface include the AXP223,
  24  * AXP809, and AXP806 PMICs, and the AC100 audio codec, all from X-Powers.
  25  *
  26  * A description of the operation and wire protocol can be found in the
  27  * RSB section of Allwinner's A80 user manual, which can be found at
  28  *
  29  *     https://github.com/allwinner-zh/documents/tree/master/A80
  30  *
  31  * This document is officially released by Allwinner.
  32  *
  33  * This driver is based on i2c-sun6i-p2wi.c, the P2WI bus driver.
  34  *
  35  */
  36 
  37 #include <linux/clk.h>
  38 #include <linux/clk/clk-conf.h>
  39 #include <linux/device.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/io.h>
  42 #include <linux/iopoll.h>
  43 #include <linux/module.h>
  44 #include <linux/of.h>
  45 #include <linux/of_irq.h>
  46 #include <linux/of_platform.h>
  47 #include <linux/platform_device.h>
  48 #include <linux/regmap.h>
  49 #include <linux/reset.h>
  50 #include <linux/slab.h>
  51 #include <linux/sunxi-rsb.h>
  52 #include <linux/types.h>
  53 
  54 /* RSB registers */
  55 #define RSB_CTRL        0x0     /* Global control */
  56 #define RSB_CCR         0x4     /* Clock control */
  57 #define RSB_INTE        0x8     /* Interrupt controls */
  58 #define RSB_INTS        0xc     /* Interrupt status */
  59 #define RSB_ADDR        0x10    /* Address to send with read/write command */
  60 #define RSB_DATA        0x1c    /* Data to read/write */
  61 #define RSB_LCR         0x24    /* Line control */
  62 #define RSB_DMCR        0x28    /* Device mode (init) control */
  63 #define RSB_CMD         0x2c    /* RSB Command */
  64 #define RSB_DAR         0x30    /* Device address / runtime address */
  65 
  66 /* CTRL fields */
  67 #define RSB_CTRL_START_TRANS            BIT(7)
  68 #define RSB_CTRL_ABORT_TRANS            BIT(6)
  69 #define RSB_CTRL_GLOBAL_INT_ENB         BIT(1)
  70 #define RSB_CTRL_SOFT_RST               BIT(0)
  71 
  72 /* CLK CTRL fields */
  73 #define RSB_CCR_SDA_OUT_DELAY(v)        (((v) & 0x7) << 8)
  74 #define RSB_CCR_MAX_CLK_DIV             0xff
  75 #define RSB_CCR_CLK_DIV(v)              ((v) & RSB_CCR_MAX_CLK_DIV)
  76 
  77 /* STATUS fields */
  78 #define RSB_INTS_TRANS_ERR_ACK          BIT(16)
  79 #define RSB_INTS_TRANS_ERR_DATA_BIT(v)  (((v) >> 8) & 0xf)
  80 #define RSB_INTS_TRANS_ERR_DATA         GENMASK(11, 8)
  81 #define RSB_INTS_LOAD_BSY               BIT(2)
  82 #define RSB_INTS_TRANS_ERR              BIT(1)
  83 #define RSB_INTS_TRANS_OVER             BIT(0)
  84 
  85 /* LINE CTRL fields*/
  86 #define RSB_LCR_SCL_STATE               BIT(5)
  87 #define RSB_LCR_SDA_STATE               BIT(4)
  88 #define RSB_LCR_SCL_CTL                 BIT(3)
  89 #define RSB_LCR_SCL_CTL_EN              BIT(2)
  90 #define RSB_LCR_SDA_CTL                 BIT(1)
  91 #define RSB_LCR_SDA_CTL_EN              BIT(0)
  92 
  93 /* DEVICE MODE CTRL field values */
  94 #define RSB_DMCR_DEVICE_START           BIT(31)
  95 #define RSB_DMCR_MODE_DATA              (0x7c << 16)
  96 #define RSB_DMCR_MODE_REG               (0x3e << 8)
  97 #define RSB_DMCR_DEV_ADDR               0x00
  98 
  99 /* CMD values */
 100 #define RSB_CMD_RD8                     0x8b
 101 #define RSB_CMD_RD16                    0x9c
 102 #define RSB_CMD_RD32                    0xa6
 103 #define RSB_CMD_WR8                     0x4e
 104 #define RSB_CMD_WR16                    0x59
 105 #define RSB_CMD_WR32                    0x63
 106 #define RSB_CMD_STRA                    0xe8
 107 
 108 /* DAR fields */
 109 #define RSB_DAR_RTA(v)                  (((v) & 0xff) << 16)
 110 #define RSB_DAR_DA(v)                   ((v) & 0xffff)
 111 
 112 #define RSB_MAX_FREQ                    20000000
 113 
 114 #define RSB_CTRL_NAME                   "sunxi-rsb"
 115 
 116 struct sunxi_rsb_addr_map {
 117         u16 hwaddr;
 118         u8 rtaddr;
 119 };
 120 
 121 struct sunxi_rsb {
 122         struct device *dev;
 123         void __iomem *regs;
 124         struct clk *clk;
 125         struct reset_control *rstc;
 126         struct completion complete;
 127         struct mutex lock;
 128         unsigned int status;
 129 };
 130 
 131 /* bus / slave device related functions */
 132 static struct bus_type sunxi_rsb_bus;
 133 
 134 static int sunxi_rsb_device_match(struct device *dev, struct device_driver *drv)
 135 {
 136         return of_driver_match_device(dev, drv);
 137 }
 138 
 139 static int sunxi_rsb_device_probe(struct device *dev)
 140 {
 141         const struct sunxi_rsb_driver *drv = to_sunxi_rsb_driver(dev->driver);
 142         struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
 143         int ret;
 144 
 145         if (!drv->probe)
 146                 return -ENODEV;
 147 
 148         if (!rdev->irq) {
 149                 int irq = -ENOENT;
 150 
 151                 if (dev->of_node)
 152                         irq = of_irq_get(dev->of_node, 0);
 153 
 154                 if (irq == -EPROBE_DEFER)
 155                         return irq;
 156                 if (irq < 0)
 157                         irq = 0;
 158 
 159                 rdev->irq = irq;
 160         }
 161 
 162         ret = of_clk_set_defaults(dev->of_node, false);
 163         if (ret < 0)
 164                 return ret;
 165 
 166         return drv->probe(rdev);
 167 }
 168 
 169 static int sunxi_rsb_device_remove(struct device *dev)
 170 {
 171         const struct sunxi_rsb_driver *drv = to_sunxi_rsb_driver(dev->driver);
 172 
 173         return drv->remove(to_sunxi_rsb_device(dev));
 174 }
 175 
 176 static struct bus_type sunxi_rsb_bus = {
 177         .name           = RSB_CTRL_NAME,
 178         .match          = sunxi_rsb_device_match,
 179         .probe          = sunxi_rsb_device_probe,
 180         .remove         = sunxi_rsb_device_remove,
 181         .uevent         = of_device_uevent_modalias,
 182 };
 183 
 184 static void sunxi_rsb_dev_release(struct device *dev)
 185 {
 186         struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
 187 
 188         kfree(rdev);
 189 }
 190 
 191 /**
 192  * sunxi_rsb_device_create() - allocate and add an RSB device
 193  * @rsb:        RSB controller
 194  * @node:       RSB slave device node
 195  * @hwaddr:     RSB slave hardware address
 196  * @rtaddr:     RSB slave runtime address
 197  */
 198 static struct sunxi_rsb_device *sunxi_rsb_device_create(struct sunxi_rsb *rsb,
 199                 struct device_node *node, u16 hwaddr, u8 rtaddr)
 200 {
 201         int err;
 202         struct sunxi_rsb_device *rdev;
 203 
 204         rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
 205         if (!rdev)
 206                 return ERR_PTR(-ENOMEM);
 207 
 208         rdev->rsb = rsb;
 209         rdev->hwaddr = hwaddr;
 210         rdev->rtaddr = rtaddr;
 211         rdev->dev.bus = &sunxi_rsb_bus;
 212         rdev->dev.parent = rsb->dev;
 213         rdev->dev.of_node = node;
 214         rdev->dev.release = sunxi_rsb_dev_release;
 215 
 216         dev_set_name(&rdev->dev, "%s-%x", RSB_CTRL_NAME, hwaddr);
 217 
 218         err = device_register(&rdev->dev);
 219         if (err < 0) {
 220                 dev_err(&rdev->dev, "Can't add %s, status %d\n",
 221                         dev_name(&rdev->dev), err);
 222                 goto err_device_add;
 223         }
 224 
 225         dev_dbg(&rdev->dev, "device %s registered\n", dev_name(&rdev->dev));
 226 
 227 err_device_add:
 228         put_device(&rdev->dev);
 229 
 230         return ERR_PTR(err);
 231 }
 232 
 233 /**
 234  * sunxi_rsb_device_unregister(): unregister an RSB device
 235  * @rdev:       rsb_device to be removed
 236  */
 237 static void sunxi_rsb_device_unregister(struct sunxi_rsb_device *rdev)
 238 {
 239         device_unregister(&rdev->dev);
 240 }
 241 
 242 static int sunxi_rsb_remove_devices(struct device *dev, void *data)
 243 {
 244         struct sunxi_rsb_device *rdev = to_sunxi_rsb_device(dev);
 245 
 246         if (dev->bus == &sunxi_rsb_bus)
 247                 sunxi_rsb_device_unregister(rdev);
 248 
 249         return 0;
 250 }
 251 
 252 /**
 253  * sunxi_rsb_driver_register() - Register device driver with RSB core
 254  * @rdrv:       device driver to be associated with slave-device.
 255  *
 256  * This API will register the client driver with the RSB framework.
 257  * It is typically called from the driver's module-init function.
 258  */
 259 int sunxi_rsb_driver_register(struct sunxi_rsb_driver *rdrv)
 260 {
 261         rdrv->driver.bus = &sunxi_rsb_bus;
 262         return driver_register(&rdrv->driver);
 263 }
 264 EXPORT_SYMBOL_GPL(sunxi_rsb_driver_register);
 265 
 266 /* common code that starts a transfer */
 267 static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb)
 268 {
 269         if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) {
 270                 dev_dbg(rsb->dev, "RSB transfer still in progress\n");
 271                 return -EBUSY;
 272         }
 273 
 274         reinit_completion(&rsb->complete);
 275 
 276         writel(RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR | RSB_INTS_TRANS_OVER,
 277                rsb->regs + RSB_INTE);
 278         writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB,
 279                rsb->regs + RSB_CTRL);
 280 
 281         if (!wait_for_completion_io_timeout(&rsb->complete,
 282                                             msecs_to_jiffies(100))) {
 283                 dev_dbg(rsb->dev, "RSB timeout\n");
 284 
 285                 /* abort the transfer */
 286                 writel(RSB_CTRL_ABORT_TRANS, rsb->regs + RSB_CTRL);
 287 
 288                 /* clear any interrupt flags */
 289                 writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
 290 
 291                 return -ETIMEDOUT;
 292         }
 293 
 294         if (rsb->status & RSB_INTS_LOAD_BSY) {
 295                 dev_dbg(rsb->dev, "RSB busy\n");
 296                 return -EBUSY;
 297         }
 298 
 299         if (rsb->status & RSB_INTS_TRANS_ERR) {
 300                 if (rsb->status & RSB_INTS_TRANS_ERR_ACK) {
 301                         dev_dbg(rsb->dev, "RSB slave nack\n");
 302                         return -EINVAL;
 303                 }
 304 
 305                 if (rsb->status & RSB_INTS_TRANS_ERR_DATA) {
 306                         dev_dbg(rsb->dev, "RSB transfer data error\n");
 307                         return -EIO;
 308                 }
 309         }
 310 
 311         return 0;
 312 }
 313 
 314 static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
 315                           u32 *buf, size_t len)
 316 {
 317         u32 cmd;
 318         int ret;
 319 
 320         if (!buf)
 321                 return -EINVAL;
 322 
 323         switch (len) {
 324         case 1:
 325                 cmd = RSB_CMD_RD8;
 326                 break;
 327         case 2:
 328                 cmd = RSB_CMD_RD16;
 329                 break;
 330         case 4:
 331                 cmd = RSB_CMD_RD32;
 332                 break;
 333         default:
 334                 dev_err(rsb->dev, "Invalid access width: %zd\n", len);
 335                 return -EINVAL;
 336         }
 337 
 338         mutex_lock(&rsb->lock);
 339 
 340         writel(addr, rsb->regs + RSB_ADDR);
 341         writel(RSB_DAR_RTA(rtaddr), rsb->regs + RSB_DAR);
 342         writel(cmd, rsb->regs + RSB_CMD);
 343 
 344         ret = _sunxi_rsb_run_xfer(rsb);
 345         if (ret)
 346                 goto unlock;
 347 
 348         *buf = readl(rsb->regs + RSB_DATA) & GENMASK(len * 8 - 1, 0);
 349 
 350 unlock:
 351         mutex_unlock(&rsb->lock);
 352 
 353         return ret;
 354 }
 355 
 356 static int sunxi_rsb_write(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
 357                            const u32 *buf, size_t len)
 358 {
 359         u32 cmd;
 360         int ret;
 361 
 362         if (!buf)
 363                 return -EINVAL;
 364 
 365         switch (len) {
 366         case 1:
 367                 cmd = RSB_CMD_WR8;
 368                 break;
 369         case 2:
 370                 cmd = RSB_CMD_WR16;
 371                 break;
 372         case 4:
 373                 cmd = RSB_CMD_WR32;
 374                 break;
 375         default:
 376                 dev_err(rsb->dev, "Invalid access width: %zd\n", len);
 377                 return -EINVAL;
 378         }
 379 
 380         mutex_lock(&rsb->lock);
 381 
 382         writel(addr, rsb->regs + RSB_ADDR);
 383         writel(RSB_DAR_RTA(rtaddr), rsb->regs + RSB_DAR);
 384         writel(*buf, rsb->regs + RSB_DATA);
 385         writel(cmd, rsb->regs + RSB_CMD);
 386         ret = _sunxi_rsb_run_xfer(rsb);
 387 
 388         mutex_unlock(&rsb->lock);
 389 
 390         return ret;
 391 }
 392 
 393 /* RSB regmap functions */
 394 struct sunxi_rsb_ctx {
 395         struct sunxi_rsb_device *rdev;
 396         int size;
 397 };
 398 
 399 static int regmap_sunxi_rsb_reg_read(void *context, unsigned int reg,
 400                                      unsigned int *val)
 401 {
 402         struct sunxi_rsb_ctx *ctx = context;
 403         struct sunxi_rsb_device *rdev = ctx->rdev;
 404 
 405         if (reg > 0xff)
 406                 return -EINVAL;
 407 
 408         return sunxi_rsb_read(rdev->rsb, rdev->rtaddr, reg, val, ctx->size);
 409 }
 410 
 411 static int regmap_sunxi_rsb_reg_write(void *context, unsigned int reg,
 412                                       unsigned int val)
 413 {
 414         struct sunxi_rsb_ctx *ctx = context;
 415         struct sunxi_rsb_device *rdev = ctx->rdev;
 416 
 417         return sunxi_rsb_write(rdev->rsb, rdev->rtaddr, reg, &val, ctx->size);
 418 }
 419 
 420 static void regmap_sunxi_rsb_free_ctx(void *context)
 421 {
 422         struct sunxi_rsb_ctx *ctx = context;
 423 
 424         kfree(ctx);
 425 }
 426 
 427 static struct regmap_bus regmap_sunxi_rsb = {
 428         .reg_write = regmap_sunxi_rsb_reg_write,
 429         .reg_read = regmap_sunxi_rsb_reg_read,
 430         .free_context = regmap_sunxi_rsb_free_ctx,
 431         .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
 432         .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 433 };
 434 
 435 static struct sunxi_rsb_ctx *regmap_sunxi_rsb_init_ctx(struct sunxi_rsb_device *rdev,
 436                 const struct regmap_config *config)
 437 {
 438         struct sunxi_rsb_ctx *ctx;
 439 
 440         switch (config->val_bits) {
 441         case 8:
 442         case 16:
 443         case 32:
 444                 break;
 445         default:
 446                 return ERR_PTR(-EINVAL);
 447         }
 448 
 449         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 450         if (!ctx)
 451                 return ERR_PTR(-ENOMEM);
 452 
 453         ctx->rdev = rdev;
 454         ctx->size = config->val_bits / 8;
 455 
 456         return ctx;
 457 }
 458 
 459 struct regmap *__devm_regmap_init_sunxi_rsb(struct sunxi_rsb_device *rdev,
 460                                             const struct regmap_config *config,
 461                                             struct lock_class_key *lock_key,
 462                                             const char *lock_name)
 463 {
 464         struct sunxi_rsb_ctx *ctx = regmap_sunxi_rsb_init_ctx(rdev, config);
 465 
 466         if (IS_ERR(ctx))
 467                 return ERR_CAST(ctx);
 468 
 469         return __devm_regmap_init(&rdev->dev, &regmap_sunxi_rsb, ctx, config,
 470                                   lock_key, lock_name);
 471 }
 472 EXPORT_SYMBOL_GPL(__devm_regmap_init_sunxi_rsb);
 473 
 474 /* RSB controller driver functions */
 475 static irqreturn_t sunxi_rsb_irq(int irq, void *dev_id)
 476 {
 477         struct sunxi_rsb *rsb = dev_id;
 478         u32 status;
 479 
 480         status = readl(rsb->regs + RSB_INTS);
 481         rsb->status = status;
 482 
 483         /* Clear interrupts */
 484         status &= (RSB_INTS_LOAD_BSY | RSB_INTS_TRANS_ERR |
 485                    RSB_INTS_TRANS_OVER);
 486         writel(status, rsb->regs + RSB_INTS);
 487 
 488         complete(&rsb->complete);
 489 
 490         return IRQ_HANDLED;
 491 }
 492 
 493 static int sunxi_rsb_init_device_mode(struct sunxi_rsb *rsb)
 494 {
 495         int ret = 0;
 496         u32 reg;
 497 
 498         /* send init sequence */
 499         writel(RSB_DMCR_DEVICE_START | RSB_DMCR_MODE_DATA |
 500                RSB_DMCR_MODE_REG | RSB_DMCR_DEV_ADDR, rsb->regs + RSB_DMCR);
 501 
 502         readl_poll_timeout(rsb->regs + RSB_DMCR, reg,
 503                            !(reg & RSB_DMCR_DEVICE_START), 100, 250000);
 504         if (reg & RSB_DMCR_DEVICE_START)
 505                 ret = -ETIMEDOUT;
 506 
 507         /* clear interrupt status bits */
 508         writel(readl(rsb->regs + RSB_INTS), rsb->regs + RSB_INTS);
 509 
 510         return ret;
 511 }
 512 
 513 /*
 514  * There are 15 valid runtime addresses, though Allwinner typically
 515  * skips the first, for unknown reasons, and uses the following three.
 516  *
 517  * 0x17, 0x2d, 0x3a, 0x4e, 0x59, 0x63, 0x74, 0x8b,
 518  * 0x9c, 0xa6, 0xb1, 0xc5, 0xd2, 0xe8, 0xff
 519  *
 520  * No designs with 2 RSB slave devices sharing identical hardware
 521  * addresses on the same bus have been seen in the wild. All designs
 522  * use 0x2d for the primary PMIC, 0x3a for the secondary PMIC if
 523  * there is one, and 0x45 for peripheral ICs.
 524  *
 525  * The hardware does not seem to support re-setting runtime addresses.
 526  * Attempts to do so result in the slave devices returning a NACK.
 527  * Hence we just hardcode the mapping here, like Allwinner does.
 528  */
 529 
 530 static const struct sunxi_rsb_addr_map sunxi_rsb_addr_maps[] = {
 531         { 0x3a3, 0x2d }, /* Primary PMIC: AXP223, AXP809, AXP81X, ... */
 532         { 0x745, 0x3a }, /* Secondary PMIC: AXP806, ... */
 533         { 0xe89, 0x4e }, /* Peripheral IC: AC100, ... */
 534 };
 535 
 536 static u8 sunxi_rsb_get_rtaddr(u16 hwaddr)
 537 {
 538         int i;
 539 
 540         for (i = 0; i < ARRAY_SIZE(sunxi_rsb_addr_maps); i++)
 541                 if (hwaddr == sunxi_rsb_addr_maps[i].hwaddr)
 542                         return sunxi_rsb_addr_maps[i].rtaddr;
 543 
 544         return 0; /* 0 is an invalid runtime address */
 545 }
 546 
 547 static int of_rsb_register_devices(struct sunxi_rsb *rsb)
 548 {
 549         struct device *dev = rsb->dev;
 550         struct device_node *child, *np = dev->of_node;
 551         u32 hwaddr;
 552         u8 rtaddr;
 553         int ret;
 554 
 555         if (!np)
 556                 return -EINVAL;
 557 
 558         /* Runtime addresses for all slaves should be set first */
 559         for_each_available_child_of_node(np, child) {
 560                 dev_dbg(dev, "setting child %pOF runtime address\n",
 561                         child);
 562 
 563                 ret = of_property_read_u32(child, "reg", &hwaddr);
 564                 if (ret) {
 565                         dev_err(dev, "%pOF: invalid 'reg' property: %d\n",
 566                                 child, ret);
 567                         continue;
 568                 }
 569 
 570                 rtaddr = sunxi_rsb_get_rtaddr(hwaddr);
 571                 if (!rtaddr) {
 572                         dev_err(dev, "%pOF: unknown hardware device address\n",
 573                                 child);
 574                         continue;
 575                 }
 576 
 577                 /*
 578                  * Since no devices have been registered yet, we are the
 579                  * only ones using the bus, we can skip locking the bus.
 580                  */
 581 
 582                 /* setup command parameters */
 583                 writel(RSB_CMD_STRA, rsb->regs + RSB_CMD);
 584                 writel(RSB_DAR_RTA(rtaddr) | RSB_DAR_DA(hwaddr),
 585                        rsb->regs + RSB_DAR);
 586 
 587                 /* send command */
 588                 ret = _sunxi_rsb_run_xfer(rsb);
 589                 if (ret)
 590                         dev_warn(dev, "%pOF: set runtime address failed: %d\n",
 591                                  child, ret);
 592         }
 593 
 594         /* Then we start adding devices and probing them */
 595         for_each_available_child_of_node(np, child) {
 596                 struct sunxi_rsb_device *rdev;
 597 
 598                 dev_dbg(dev, "adding child %pOF\n", child);
 599 
 600                 ret = of_property_read_u32(child, "reg", &hwaddr);
 601                 if (ret)
 602                         continue;
 603 
 604                 rtaddr = sunxi_rsb_get_rtaddr(hwaddr);
 605                 if (!rtaddr)
 606                         continue;
 607 
 608                 rdev = sunxi_rsb_device_create(rsb, child, hwaddr, rtaddr);
 609                 if (IS_ERR(rdev))
 610                         dev_err(dev, "failed to add child device %pOF: %ld\n",
 611                                 child, PTR_ERR(rdev));
 612         }
 613 
 614         return 0;
 615 }
 616 
 617 static const struct of_device_id sunxi_rsb_of_match_table[] = {
 618         { .compatible = "allwinner,sun8i-a23-rsb" },
 619         {}
 620 };
 621 MODULE_DEVICE_TABLE(of, sunxi_rsb_of_match_table);
 622 
 623 static int sunxi_rsb_probe(struct platform_device *pdev)
 624 {
 625         struct device *dev = &pdev->dev;
 626         struct device_node *np = dev->of_node;
 627         struct resource *r;
 628         struct sunxi_rsb *rsb;
 629         unsigned long p_clk_freq;
 630         u32 clk_delay, clk_freq = 3000000;
 631         int clk_div, irq, ret;
 632         u32 reg;
 633 
 634         of_property_read_u32(np, "clock-frequency", &clk_freq);
 635         if (clk_freq > RSB_MAX_FREQ) {
 636                 dev_err(dev,
 637                         "clock-frequency (%u Hz) is too high (max = 20MHz)\n",
 638                         clk_freq);
 639                 return -EINVAL;
 640         }
 641 
 642         rsb = devm_kzalloc(dev, sizeof(*rsb), GFP_KERNEL);
 643         if (!rsb)
 644                 return -ENOMEM;
 645 
 646         rsb->dev = dev;
 647         platform_set_drvdata(pdev, rsb);
 648         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 649         rsb->regs = devm_ioremap_resource(dev, r);
 650         if (IS_ERR(rsb->regs))
 651                 return PTR_ERR(rsb->regs);
 652 
 653         irq = platform_get_irq(pdev, 0);
 654         if (irq < 0)
 655                 return irq;
 656 
 657         rsb->clk = devm_clk_get(dev, NULL);
 658         if (IS_ERR(rsb->clk)) {
 659                 ret = PTR_ERR(rsb->clk);
 660                 dev_err(dev, "failed to retrieve clk: %d\n", ret);
 661                 return ret;
 662         }
 663 
 664         ret = clk_prepare_enable(rsb->clk);
 665         if (ret) {
 666                 dev_err(dev, "failed to enable clk: %d\n", ret);
 667                 return ret;
 668         }
 669 
 670         p_clk_freq = clk_get_rate(rsb->clk);
 671 
 672         rsb->rstc = devm_reset_control_get(dev, NULL);
 673         if (IS_ERR(rsb->rstc)) {
 674                 ret = PTR_ERR(rsb->rstc);
 675                 dev_err(dev, "failed to retrieve reset controller: %d\n", ret);
 676                 goto err_clk_disable;
 677         }
 678 
 679         ret = reset_control_deassert(rsb->rstc);
 680         if (ret) {
 681                 dev_err(dev, "failed to deassert reset line: %d\n", ret);
 682                 goto err_clk_disable;
 683         }
 684 
 685         init_completion(&rsb->complete);
 686         mutex_init(&rsb->lock);
 687 
 688         /* reset the controller */
 689         writel(RSB_CTRL_SOFT_RST, rsb->regs + RSB_CTRL);
 690         readl_poll_timeout(rsb->regs + RSB_CTRL, reg,
 691                            !(reg & RSB_CTRL_SOFT_RST), 1000, 100000);
 692 
 693         /*
 694          * Clock frequency and delay calculation code is from
 695          * Allwinner U-boot sources.
 696          *
 697          * From A83 user manual:
 698          * bus clock frequency = parent clock frequency / (2 * (divider + 1))
 699          */
 700         clk_div = p_clk_freq / clk_freq / 2;
 701         if (!clk_div)
 702                 clk_div = 1;
 703         else if (clk_div > RSB_CCR_MAX_CLK_DIV + 1)
 704                 clk_div = RSB_CCR_MAX_CLK_DIV + 1;
 705 
 706         clk_delay = clk_div >> 1;
 707         if (!clk_delay)
 708                 clk_delay = 1;
 709 
 710         dev_info(dev, "RSB running at %lu Hz\n", p_clk_freq / clk_div / 2);
 711         writel(RSB_CCR_SDA_OUT_DELAY(clk_delay) | RSB_CCR_CLK_DIV(clk_div - 1),
 712                rsb->regs + RSB_CCR);
 713 
 714         ret = devm_request_irq(dev, irq, sunxi_rsb_irq, 0, RSB_CTRL_NAME, rsb);
 715         if (ret) {
 716                 dev_err(dev, "can't register interrupt handler irq %d: %d\n",
 717                         irq, ret);
 718                 goto err_reset_assert;
 719         }
 720 
 721         /* initialize all devices on the bus into RSB mode */
 722         ret = sunxi_rsb_init_device_mode(rsb);
 723         if (ret)
 724                 dev_warn(dev, "Initialize device mode failed: %d\n", ret);
 725 
 726         of_rsb_register_devices(rsb);
 727 
 728         return 0;
 729 
 730 err_reset_assert:
 731         reset_control_assert(rsb->rstc);
 732 
 733 err_clk_disable:
 734         clk_disable_unprepare(rsb->clk);
 735 
 736         return ret;
 737 }
 738 
 739 static int sunxi_rsb_remove(struct platform_device *pdev)
 740 {
 741         struct sunxi_rsb *rsb = platform_get_drvdata(pdev);
 742 
 743         device_for_each_child(rsb->dev, NULL, sunxi_rsb_remove_devices);
 744         reset_control_assert(rsb->rstc);
 745         clk_disable_unprepare(rsb->clk);
 746 
 747         return 0;
 748 }
 749 
 750 static struct platform_driver sunxi_rsb_driver = {
 751         .probe = sunxi_rsb_probe,
 752         .remove = sunxi_rsb_remove,
 753         .driver = {
 754                 .name = RSB_CTRL_NAME,
 755                 .of_match_table = sunxi_rsb_of_match_table,
 756         },
 757 };
 758 
 759 static int __init sunxi_rsb_init(void)
 760 {
 761         int ret;
 762 
 763         ret = bus_register(&sunxi_rsb_bus);
 764         if (ret) {
 765                 pr_err("failed to register sunxi sunxi_rsb bus: %d\n", ret);
 766                 return ret;
 767         }
 768 
 769         return platform_driver_register(&sunxi_rsb_driver);
 770 }
 771 module_init(sunxi_rsb_init);
 772 
 773 static void __exit sunxi_rsb_exit(void)
 774 {
 775         platform_driver_unregister(&sunxi_rsb_driver);
 776         bus_unregister(&sunxi_rsb_bus);
 777 }
 778 module_exit(sunxi_rsb_exit);
 779 
 780 MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
 781 MODULE_DESCRIPTION("Allwinner sunXi Reduced Serial Bus controller driver");
 782 MODULE_LICENSE("GPL v2");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/bus/sunxi-rsb.c

DEFINITIONS
