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
sunxi_rsb_device_match(struct device * dev,struct device_driver * drv)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
sunxi_rsb_device_probe(struct device * dev)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
sunxi_rsb_device_remove(struct device * dev)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
sunxi_rsb_dev_release(struct device * dev)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 */
sunxi_rsb_device_create(struct sunxi_rsb * rsb,struct device_node * node,u16 hwaddr,u8 rtaddr)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 */
sunxi_rsb_device_unregister(struct sunxi_rsb_device * rdev)237 static void sunxi_rsb_device_unregister(struct sunxi_rsb_device *rdev)
238 {
239 device_unregister(&rdev->dev);
240 }
241
sunxi_rsb_remove_devices(struct device * dev,void * data)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 */
sunxi_rsb_driver_register(struct sunxi_rsb_driver * rdrv)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 */
_sunxi_rsb_run_xfer(struct sunxi_rsb * rsb)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
sunxi_rsb_read(struct sunxi_rsb * rsb,u8 rtaddr,u8 addr,u32 * buf,size_t len)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);
349
350 unlock:
351 mutex_unlock(&rsb->lock);
352
353 return ret;
354 }
355
sunxi_rsb_write(struct sunxi_rsb * rsb,u8 rtaddr,u8 addr,const u32 * buf,size_t len)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
regmap_sunxi_rsb_reg_read(void * context,unsigned int reg,unsigned int * val)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
regmap_sunxi_rsb_reg_write(void * context,unsigned int reg,unsigned int val)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
regmap_sunxi_rsb_free_ctx(void * context)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
regmap_sunxi_rsb_init_ctx(struct sunxi_rsb_device * rdev,const struct regmap_config * config)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
__devm_regmap_init_sunxi_rsb(struct sunxi_rsb_device * rdev,const struct regmap_config * config,struct lock_class_key * lock_key,const char * lock_name)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, ®map_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 */
sunxi_rsb_irq(int irq,void * dev_id)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
sunxi_rsb_init_device_mode(struct sunxi_rsb * rsb)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
sunxi_rsb_get_rtaddr(u16 hwaddr)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
of_rsb_register_devices(struct sunxi_rsb * rsb)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
sunxi_rsb_probe(struct platform_device * pdev)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
sunxi_rsb_remove(struct platform_device * pdev)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
sunxi_rsb_init(void)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
sunxi_rsb_exit(void)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");
783