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Paul Mundt4ad48e62008-10-14 17:30:03 +02001/*
2 * Renesas Solutions Highlander FPGA I2C/SMBus support.
3 *
4 * Supported devices: R0P7780LC0011RL, R0P7785LC0011RL
5 *
6 * Copyright (C) 2008 Paul Mundt
7 * Copyright (C) 2008 Renesas Solutions Corp.
8 * Copyright (C) 2008 Atom Create Engineering Co., Ltd.
9 *
10 * This file is subject to the terms and conditions of the GNU General
11 * Public License version 2. See the file "COPYING" in the main directory
12 * of this archive for more details.
13 */
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/interrupt.h>
17#include <linux/i2c.h>
18#include <linux/platform_device.h>
19#include <linux/completion.h>
20#include <linux/io.h>
21#include <linux/delay.h>
22
23#define SMCR 0x00
24#define SMCR_START (1 << 0)
25#define SMCR_IRIC (1 << 1)
26#define SMCR_BBSY (1 << 2)
27#define SMCR_ACKE (1 << 3)
28#define SMCR_RST (1 << 4)
29#define SMCR_IEIC (1 << 6)
30
31#define SMSMADR 0x02
32
33#define SMMR 0x04
34#define SMMR_MODE0 (1 << 0)
35#define SMMR_MODE1 (1 << 1)
36#define SMMR_CAP (1 << 3)
37#define SMMR_TMMD (1 << 4)
38#define SMMR_SP (1 << 7)
39
40#define SMSADR 0x06
41#define SMTRDR 0x46
42
43struct highlander_i2c_dev {
44 struct device *dev;
45 void __iomem *base;
46 struct i2c_adapter adapter;
47 struct completion cmd_complete;
48 unsigned long last_read_time;
49 int irq;
50 u8 *buf;
51 size_t buf_len;
52};
53
54static int iic_force_poll, iic_force_normal;
55static int iic_timeout = 1000, iic_read_delay;
56
57static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev)
58{
59 iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR);
60}
61
62static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev)
63{
64 iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR);
65}
66
67static inline void highlander_i2c_start(struct highlander_i2c_dev *dev)
68{
69 iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR);
70}
71
72static inline void highlander_i2c_done(struct highlander_i2c_dev *dev)
73{
74 iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR);
75}
76
77static void highlander_i2c_setup(struct highlander_i2c_dev *dev)
78{
79 u16 smmr;
80
81 smmr = ioread16(dev->base + SMMR);
82 smmr |= SMMR_TMMD;
83
84 if (iic_force_normal)
85 smmr &= ~SMMR_SP;
86 else
87 smmr |= SMMR_SP;
88
89 iowrite16(smmr, dev->base + SMMR);
90}
91
92static void smbus_write_data(u8 *src, u16 *dst, int len)
93{
94 for (; len > 1; len -= 2) {
Harvey Harrison2b895c32008-12-11 12:11:21 +010095 *dst++ = be16_to_cpup((__be16 *)src);
Paul Mundt4ad48e62008-10-14 17:30:03 +020096 src += 2;
97 }
98
99 if (len)
100 *dst = *src << 8;
101}
102
103static void smbus_read_data(u16 *src, u8 *dst, int len)
104{
105 for (; len > 1; len -= 2) {
Harvey Harrison2b895c32008-12-11 12:11:21 +0100106 *(__be16 *)dst = cpu_to_be16p(src++);
Paul Mundt4ad48e62008-10-14 17:30:03 +0200107 dst += 2;
108 }
109
110 if (len)
111 *dst = *src >> 8;
112}
113
114static void highlander_i2c_command(struct highlander_i2c_dev *dev,
115 u8 command, int len)
116{
117 unsigned int i;
118 u16 cmd = (command << 8) | command;
119
120 for (i = 0; i < len; i += 2) {
121 if (len - i == 1)
122 cmd = command << 8;
123 iowrite16(cmd, dev->base + SMSADR + i);
124 dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd);
125 }
126}
127
128static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev)
129{
130 unsigned long timeout;
131
132 timeout = jiffies + msecs_to_jiffies(iic_timeout);
133 while (ioread16(dev->base + SMCR) & SMCR_BBSY) {
134 if (time_after(jiffies, timeout)) {
135 dev_warn(dev->dev, "timeout waiting for bus ready\n");
136 return -ETIMEDOUT;
137 }
138
139 msleep(1);
140 }
141
142 return 0;
143}
144
145static int highlander_i2c_reset(struct highlander_i2c_dev *dev)
146{
147 iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR);
148 return highlander_i2c_wait_for_bbsy(dev);
149}
150
151static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev)
152{
153 u16 tmp = ioread16(dev->base + SMCR);
154
155 if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) {
156 dev_warn(dev->dev, "ack abnormality\n");
157 return highlander_i2c_reset(dev);
158 }
159
160 return 0;
161}
162
163static irqreturn_t highlander_i2c_irq(int irq, void *dev_id)
164{
165 struct highlander_i2c_dev *dev = dev_id;
166
167 highlander_i2c_done(dev);
168 complete(&dev->cmd_complete);
169
170 return IRQ_HANDLED;
171}
172
173static void highlander_i2c_poll(struct highlander_i2c_dev *dev)
174{
175 unsigned long timeout;
176 u16 smcr;
177
178 timeout = jiffies + msecs_to_jiffies(iic_timeout);
179 for (;;) {
180 smcr = ioread16(dev->base + SMCR);
181
182 /*
183 * Don't bother checking ACKE here, this and the reset
184 * are handled in highlander_i2c_wait_xfer_done() when
185 * waiting for the ACK.
186 */
187
188 if (smcr & SMCR_IRIC)
189 return;
190 if (time_after(jiffies, timeout))
191 break;
192
193 cpu_relax();
194 cond_resched();
195 }
196
197 dev_err(dev->dev, "polling timed out\n");
198}
199
200static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev)
201{
202 if (dev->irq)
203 wait_for_completion_timeout(&dev->cmd_complete,
204 msecs_to_jiffies(iic_timeout));
205 else
206 /* busy looping, the IRQ of champions */
207 highlander_i2c_poll(dev);
208
209 return highlander_i2c_wait_for_ack(dev);
210}
211
212static int highlander_i2c_read(struct highlander_i2c_dev *dev)
213{
214 int i, cnt;
215 u16 data[16];
216
217 if (highlander_i2c_wait_for_bbsy(dev))
218 return -EAGAIN;
219
220 highlander_i2c_start(dev);
221
222 if (highlander_i2c_wait_xfer_done(dev)) {
223 dev_err(dev->dev, "Arbitration loss\n");
224 return -EAGAIN;
225 }
226
227 /*
228 * The R0P7780LC0011RL FPGA needs a significant delay between
229 * data read cycles, otherwise the transciever gets confused and
230 * garbage is returned when the read is subsequently aborted.
231 *
232 * It is not sufficient to wait for BBSY.
233 *
234 * While this generally only applies to the older SH7780-based
235 * Highlanders, the same issue can be observed on SH7785 ones,
236 * albeit less frequently. SH7780-based Highlanders may need
237 * this to be as high as 1000 ms.
238 */
239 if (iic_read_delay && time_before(jiffies, dev->last_read_time +
240 msecs_to_jiffies(iic_read_delay)))
241 msleep(jiffies_to_msecs((dev->last_read_time +
242 msecs_to_jiffies(iic_read_delay)) - jiffies));
243
244 cnt = (dev->buf_len + 1) >> 1;
245 for (i = 0; i < cnt; i++) {
246 data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16)));
247 dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]);
248 }
249
250 smbus_read_data(data, dev->buf, dev->buf_len);
251
252 dev->last_read_time = jiffies;
253
254 return 0;
255}
256
257static int highlander_i2c_write(struct highlander_i2c_dev *dev)
258{
259 int i, cnt;
260 u16 data[16];
261
262 smbus_write_data(dev->buf, data, dev->buf_len);
263
264 cnt = (dev->buf_len + 1) >> 1;
265 for (i = 0; i < cnt; i++) {
266 iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16)));
267 dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]);
268 }
269
270 if (highlander_i2c_wait_for_bbsy(dev))
271 return -EAGAIN;
272
273 highlander_i2c_start(dev);
274
275 return highlander_i2c_wait_xfer_done(dev);
276}
277
278static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
279 unsigned short flags, char read_write,
280 u8 command, int size,
281 union i2c_smbus_data *data)
282{
283 struct highlander_i2c_dev *dev = i2c_get_adapdata(adap);
284 int read = read_write & I2C_SMBUS_READ;
285 u16 tmp;
286
287 init_completion(&dev->cmd_complete);
288
289 dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
290 addr, command, read_write, size);
291
292 /*
293 * Set up the buffer and transfer size
294 */
295 switch (size) {
296 case I2C_SMBUS_BYTE_DATA:
297 dev->buf = &data->byte;
298 dev->buf_len = 1;
299 break;
300 case I2C_SMBUS_I2C_BLOCK_DATA:
301 dev->buf = &data->block[1];
302 dev->buf_len = data->block[0];
303 break;
304 default:
305 dev_err(dev->dev, "unsupported command %d\n", size);
306 return -EINVAL;
307 }
308
309 /*
310 * Encode the mode setting
311 */
312 tmp = ioread16(dev->base + SMMR);
313 tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
314
315 switch (dev->buf_len) {
316 case 1:
317 /* default */
318 break;
319 case 8:
320 tmp |= SMMR_MODE0;
321 break;
322 case 16:
323 tmp |= SMMR_MODE1;
324 break;
325 case 32:
326 tmp |= (SMMR_MODE0 | SMMR_MODE1);
327 break;
328 default:
329 dev_err(dev->dev, "unsupported xfer size %d\n", dev->buf_len);
330 return -EINVAL;
331 }
332
333 iowrite16(tmp, dev->base + SMMR);
334
335 /* Ensure we're in a sane state */
336 highlander_i2c_done(dev);
337
338 /* Set slave address */
339 iowrite16((addr << 1) | read, dev->base + SMSMADR);
340
341 highlander_i2c_command(dev, command, dev->buf_len);
342
343 if (read)
344 return highlander_i2c_read(dev);
345 else
346 return highlander_i2c_write(dev);
347}
348
349static u32 highlander_i2c_func(struct i2c_adapter *adapter)
350{
351 return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
352}
353
354static const struct i2c_algorithm highlander_i2c_algo = {
355 .smbus_xfer = highlander_i2c_smbus_xfer,
356 .functionality = highlander_i2c_func,
357};
358
359static int __devinit highlander_i2c_probe(struct platform_device *pdev)
360{
361 struct highlander_i2c_dev *dev;
362 struct i2c_adapter *adap;
363 struct resource *res;
364 int ret;
365
366 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
367 if (unlikely(!res)) {
368 dev_err(&pdev->dev, "no mem resource\n");
369 return -ENODEV;
370 }
371
372 dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
373 if (unlikely(!dev))
374 return -ENOMEM;
375
376 dev->base = ioremap_nocache(res->start, res->end - res->start + 1);
377 if (unlikely(!dev->base)) {
378 ret = -ENXIO;
379 goto err;
380 }
381
382 dev->dev = &pdev->dev;
383 platform_set_drvdata(pdev, dev);
384
385 dev->irq = platform_get_irq(pdev, 0);
386 if (iic_force_poll)
387 dev->irq = 0;
388
389 if (dev->irq) {
390 ret = request_irq(dev->irq, highlander_i2c_irq, IRQF_DISABLED,
391 pdev->name, dev);
392 if (unlikely(ret))
393 goto err_unmap;
394
395 highlander_i2c_irq_enable(dev);
396 } else {
397 dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
398 highlander_i2c_irq_disable(dev);
399 }
400
401 dev->last_read_time = jiffies; /* initial read jiffies */
402
403 highlander_i2c_setup(dev);
404
405 adap = &dev->adapter;
406 i2c_set_adapdata(adap, dev);
407 adap->owner = THIS_MODULE;
408 adap->class = I2C_CLASS_HWMON;
409 strlcpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
410 adap->algo = &highlander_i2c_algo;
411 adap->dev.parent = &pdev->dev;
412 adap->nr = pdev->id;
413
414 /*
415 * Reset the adapter
416 */
417 ret = highlander_i2c_reset(dev);
418 if (unlikely(ret)) {
419 dev_err(&pdev->dev, "controller didn't come up\n");
420 goto err_free_irq;
421 }
422
423 ret = i2c_add_numbered_adapter(adap);
424 if (unlikely(ret)) {
425 dev_err(&pdev->dev, "failure adding adapter\n");
426 goto err_free_irq;
427 }
428
429 return 0;
430
431err_free_irq:
432 if (dev->irq)
433 free_irq(dev->irq, dev);
434err_unmap:
435 iounmap(dev->base);
436err:
437 kfree(dev);
438
439 platform_set_drvdata(pdev, NULL);
440
441 return ret;
442}
443
444static int __devexit highlander_i2c_remove(struct platform_device *pdev)
445{
446 struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
447
448 i2c_del_adapter(&dev->adapter);
449
450 if (dev->irq)
451 free_irq(dev->irq, dev);
452
453 iounmap(dev->base);
454 kfree(dev);
455
456 platform_set_drvdata(pdev, NULL);
457
458 return 0;
459}
460
461static struct platform_driver highlander_i2c_driver = {
462 .driver = {
463 .name = "i2c-highlander",
464 .owner = THIS_MODULE,
465 },
466
467 .probe = highlander_i2c_probe,
468 .remove = __devexit_p(highlander_i2c_remove),
469};
470
471static int __init highlander_i2c_init(void)
472{
473 return platform_driver_register(&highlander_i2c_driver);
474}
475
476static void __exit highlander_i2c_exit(void)
477{
478 platform_driver_unregister(&highlander_i2c_driver);
479}
480
481module_init(highlander_i2c_init);
482module_exit(highlander_i2c_exit);
483
484MODULE_AUTHOR("Paul Mundt");
485MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
486MODULE_LICENSE("GPL v2");
487
488module_param(iic_force_poll, bool, 0);
489module_param(iic_force_normal, bool, 0);
490module_param(iic_timeout, int, 0);
491module_param(iic_read_delay, int, 0);
492
493MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
494MODULE_PARM_DESC(iic_force_normal,
495 "Force normal mode (100 kHz), default is fast mode (400 kHz)");
496MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
497MODULE_PARM_DESC(iic_read_delay,
498 "Delay between data read cycles (default 0 ms)");