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11#include <linux/module.h>
12#include <linux/interrupt.h>
13#include <linux/i2c.h>
14#include <linux/platform_device.h>
15#include <linux/completion.h>
16#include <linux/io.h>
17#include <linux/delay.h>
18#include <linux/slab.h>
19
20#define SMCR 0x00
21#define SMCR_START (1 << 0)
22#define SMCR_IRIC (1 << 1)
23#define SMCR_BBSY (1 << 2)
24#define SMCR_ACKE (1 << 3)
25#define SMCR_RST (1 << 4)
26#define SMCR_IEIC (1 << 6)
27
28#define SMSMADR 0x02
29
30#define SMMR 0x04
31#define SMMR_MODE0 (1 << 0)
32#define SMMR_MODE1 (1 << 1)
33#define SMMR_CAP (1 << 3)
34#define SMMR_TMMD (1 << 4)
35#define SMMR_SP (1 << 7)
36
37#define SMSADR 0x06
38#define SMTRDR 0x46
39
40struct highlander_i2c_dev {
41 struct device *dev;
42 void __iomem *base;
43 struct i2c_adapter adapter;
44 struct completion cmd_complete;
45 unsigned long last_read_time;
46 int irq;
47 u8 *buf;
48 size_t buf_len;
49};
50
51static bool iic_force_poll, iic_force_normal;
52static int iic_timeout = 1000, iic_read_delay;
53
54static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev)
55{
56 iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR);
57}
58
59static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev)
60{
61 iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR);
62}
63
64static inline void highlander_i2c_start(struct highlander_i2c_dev *dev)
65{
66 iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR);
67}
68
69static inline void highlander_i2c_done(struct highlander_i2c_dev *dev)
70{
71 iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR);
72}
73
74static void highlander_i2c_setup(struct highlander_i2c_dev *dev)
75{
76 u16 smmr;
77
78 smmr = ioread16(dev->base + SMMR);
79 smmr |= SMMR_TMMD;
80
81 if (iic_force_normal)
82 smmr &= ~SMMR_SP;
83 else
84 smmr |= SMMR_SP;
85
86 iowrite16(smmr, dev->base + SMMR);
87}
88
89static void smbus_write_data(u8 *src, u16 *dst, int len)
90{
91 for (; len > 1; len -= 2) {
92 *dst++ = be16_to_cpup((__be16 *)src);
93 src += 2;
94 }
95
96 if (len)
97 *dst = *src << 8;
98}
99
100static void smbus_read_data(u16 *src, u8 *dst, int len)
101{
102 for (; len > 1; len -= 2) {
103 *(__be16 *)dst = cpu_to_be16p(src++);
104 dst += 2;
105 }
106
107 if (len)
108 *dst = *src >> 8;
109}
110
111static void highlander_i2c_command(struct highlander_i2c_dev *dev,
112 u8 command, int len)
113{
114 unsigned int i;
115 u16 cmd = (command << 8) | command;
116
117 for (i = 0; i < len; i += 2) {
118 if (len - i == 1)
119 cmd = command << 8;
120 iowrite16(cmd, dev->base + SMSADR + i);
121 dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd);
122 }
123}
124
125static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev)
126{
127 unsigned long timeout;
128
129 timeout = jiffies + msecs_to_jiffies(iic_timeout);
130 while (ioread16(dev->base + SMCR) & SMCR_BBSY) {
131 if (time_after(jiffies, timeout)) {
132 dev_warn(dev->dev, "timeout waiting for bus ready\n");
133 return -ETIMEDOUT;
134 }
135
136 msleep(1);
137 }
138
139 return 0;
140}
141
142static int highlander_i2c_reset(struct highlander_i2c_dev *dev)
143{
144 iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR);
145 return highlander_i2c_wait_for_bbsy(dev);
146}
147
148static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev)
149{
150 u16 tmp = ioread16(dev->base + SMCR);
151
152 if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) {
153 dev_warn(dev->dev, "ack abnormality\n");
154 return highlander_i2c_reset(dev);
155 }
156
157 return 0;
158}
159
160static irqreturn_t highlander_i2c_irq(int irq, void *dev_id)
161{
162 struct highlander_i2c_dev *dev = dev_id;
163
164 highlander_i2c_done(dev);
165 complete(&dev->cmd_complete);
166
167 return IRQ_HANDLED;
168}
169
170static void highlander_i2c_poll(struct highlander_i2c_dev *dev)
171{
172 unsigned long timeout;
173 u16 smcr;
174
175 timeout = jiffies + msecs_to_jiffies(iic_timeout);
176 for (;;) {
177 smcr = ioread16(dev->base + SMCR);
178
179
180
181
182
183
184
185 if (smcr & SMCR_IRIC)
186 return;
187 if (time_after(jiffies, timeout))
188 break;
189
190 cpu_relax();
191 cond_resched();
192 }
193
194 dev_err(dev->dev, "polling timed out\n");
195}
196
197static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev)
198{
199 if (dev->irq)
200 wait_for_completion_timeout(&dev->cmd_complete,
201 msecs_to_jiffies(iic_timeout));
202 else
203
204 highlander_i2c_poll(dev);
205
206 return highlander_i2c_wait_for_ack(dev);
207}
208
209static int highlander_i2c_read(struct highlander_i2c_dev *dev)
210{
211 int i, cnt;
212 u16 data[16];
213
214 if (highlander_i2c_wait_for_bbsy(dev))
215 return -EAGAIN;
216
217 highlander_i2c_start(dev);
218
219 if (highlander_i2c_wait_xfer_done(dev)) {
220 dev_err(dev->dev, "Arbitration loss\n");
221 return -EAGAIN;
222 }
223
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227
228
229
230
231
232
233
234
235
236 if (iic_read_delay && time_before(jiffies, dev->last_read_time +
237 msecs_to_jiffies(iic_read_delay)))
238 msleep(jiffies_to_msecs((dev->last_read_time +
239 msecs_to_jiffies(iic_read_delay)) - jiffies));
240
241 cnt = (dev->buf_len + 1) >> 1;
242 for (i = 0; i < cnt; i++) {
243 data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16)));
244 dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]);
245 }
246
247 smbus_read_data(data, dev->buf, dev->buf_len);
248
249 dev->last_read_time = jiffies;
250
251 return 0;
252}
253
254static int highlander_i2c_write(struct highlander_i2c_dev *dev)
255{
256 int i, cnt;
257 u16 data[16];
258
259 smbus_write_data(dev->buf, data, dev->buf_len);
260
261 cnt = (dev->buf_len + 1) >> 1;
262 for (i = 0; i < cnt; i++) {
263 iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16)));
264 dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]);
265 }
266
267 if (highlander_i2c_wait_for_bbsy(dev))
268 return -EAGAIN;
269
270 highlander_i2c_start(dev);
271
272 return highlander_i2c_wait_xfer_done(dev);
273}
274
275static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
276 unsigned short flags, char read_write,
277 u8 command, int size,
278 union i2c_smbus_data *data)
279{
280 struct highlander_i2c_dev *dev = i2c_get_adapdata(adap);
281 u16 tmp;
282
283 init_completion(&dev->cmd_complete);
284
285 dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
286 addr, command, read_write, size);
287
288
289
290
291 switch (size) {
292 case I2C_SMBUS_BYTE_DATA:
293 dev->buf = &data->byte;
294 dev->buf_len = 1;
295 break;
296 case I2C_SMBUS_I2C_BLOCK_DATA:
297 dev->buf = &data->block[1];
298 dev->buf_len = data->block[0];
299 break;
300 default:
301 dev_err(dev->dev, "unsupported command %d\n", size);
302 return -EINVAL;
303 }
304
305
306
307
308 tmp = ioread16(dev->base + SMMR);
309 tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
310
311 switch (dev->buf_len) {
312 case 1:
313
314 break;
315 case 8:
316 tmp |= SMMR_MODE0;
317 break;
318 case 16:
319 tmp |= SMMR_MODE1;
320 break;
321 case 32:
322 tmp |= (SMMR_MODE0 | SMMR_MODE1);
323 break;
324 default:
325 dev_err(dev->dev, "unsupported xfer size %zu\n", dev->buf_len);
326 return -EINVAL;
327 }
328
329 iowrite16(tmp, dev->base + SMMR);
330
331
332 highlander_i2c_done(dev);
333
334
335 iowrite16((addr << 1) | read_write, dev->base + SMSMADR);
336
337 highlander_i2c_command(dev, command, dev->buf_len);
338
339 if (read_write == I2C_SMBUS_READ)
340 return highlander_i2c_read(dev);
341 else
342 return highlander_i2c_write(dev);
343}
344
345static u32 highlander_i2c_func(struct i2c_adapter *adapter)
346{
347 return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
348}
349
350static const struct i2c_algorithm highlander_i2c_algo = {
351 .smbus_xfer = highlander_i2c_smbus_xfer,
352 .functionality = highlander_i2c_func,
353};
354
355static int highlander_i2c_probe(struct platform_device *pdev)
356{
357 struct highlander_i2c_dev *dev;
358 struct i2c_adapter *adap;
359 struct resource *res;
360 int ret;
361
362 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
363 if (unlikely(!res)) {
364 dev_err(&pdev->dev, "no mem resource\n");
365 return -ENODEV;
366 }
367
368 dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
369 if (unlikely(!dev))
370 return -ENOMEM;
371
372 dev->base = ioremap(res->start, resource_size(res));
373 if (unlikely(!dev->base)) {
374 ret = -ENXIO;
375 goto err;
376 }
377
378 dev->dev = &pdev->dev;
379 platform_set_drvdata(pdev, dev);
380
381 dev->irq = platform_get_irq(pdev, 0);
382 if (dev->irq < 0 || iic_force_poll)
383 dev->irq = 0;
384
385 if (dev->irq) {
386 ret = request_irq(dev->irq, highlander_i2c_irq, 0,
387 pdev->name, dev);
388 if (unlikely(ret))
389 goto err_unmap;
390
391 highlander_i2c_irq_enable(dev);
392 } else {
393 dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
394 highlander_i2c_irq_disable(dev);
395 }
396
397 dev->last_read_time = jiffies;
398
399 highlander_i2c_setup(dev);
400
401 adap = &dev->adapter;
402 i2c_set_adapdata(adap, dev);
403 adap->owner = THIS_MODULE;
404 adap->class = I2C_CLASS_HWMON;
405 strlcpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
406 adap->algo = &highlander_i2c_algo;
407 adap->dev.parent = &pdev->dev;
408 adap->nr = pdev->id;
409
410
411
412
413 ret = highlander_i2c_reset(dev);
414 if (unlikely(ret)) {
415 dev_err(&pdev->dev, "controller didn't come up\n");
416 goto err_free_irq;
417 }
418
419 ret = i2c_add_numbered_adapter(adap);
420 if (unlikely(ret)) {
421 dev_err(&pdev->dev, "failure adding adapter\n");
422 goto err_free_irq;
423 }
424
425 return 0;
426
427err_free_irq:
428 if (dev->irq)
429 free_irq(dev->irq, dev);
430err_unmap:
431 iounmap(dev->base);
432err:
433 kfree(dev);
434
435 return ret;
436}
437
438static int highlander_i2c_remove(struct platform_device *pdev)
439{
440 struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
441
442 i2c_del_adapter(&dev->adapter);
443
444 if (dev->irq)
445 free_irq(dev->irq, dev);
446
447 iounmap(dev->base);
448 kfree(dev);
449
450 return 0;
451}
452
453static struct platform_driver highlander_i2c_driver = {
454 .driver = {
455 .name = "i2c-highlander",
456 },
457
458 .probe = highlander_i2c_probe,
459 .remove = highlander_i2c_remove,
460};
461
462module_platform_driver(highlander_i2c_driver);
463
464MODULE_AUTHOR("Paul Mundt");
465MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
466MODULE_LICENSE("GPL v2");
467
468module_param(iic_force_poll, bool, 0);
469module_param(iic_force_normal, bool, 0);
470module_param(iic_timeout, int, 0);
471module_param(iic_read_delay, int, 0);
472
473MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
474MODULE_PARM_DESC(iic_force_normal,
475 "Force normal mode (100 kHz), default is fast mode (400 kHz)");
476MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
477MODULE_PARM_DESC(iic_read_delay,
478 "Delay between data read cycles (default 0 ms)");
479
