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14#include <linux/module.h>
15#include <linux/interrupt.h>
16#include <linux/i2c.h>
17#include <linux/platform_device.h>
18#include <linux/completion.h>
19#include <linux/io.h>
20#include <linux/delay.h>
21#include <linux/slab.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 bool 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) {
95 *dst++ = be16_to_cpup((__be16 *)src);
96 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) {
106 *(__be16 *)dst = cpu_to_be16p(src++);
107 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
184
185
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
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
229
230
231
232
233
234
235
236
237
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 u16 tmp;
285
286 init_completion(&dev->cmd_complete);
287
288 dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
289 addr, command, read_write, size);
290
291
292
293
294 switch (size) {
295 case I2C_SMBUS_BYTE_DATA:
296 dev->buf = &data->byte;
297 dev->buf_len = 1;
298 break;
299 case I2C_SMBUS_I2C_BLOCK_DATA:
300 dev->buf = &data->block[1];
301 dev->buf_len = data->block[0];
302 break;
303 default:
304 dev_err(dev->dev, "unsupported command %d\n", size);
305 return -EINVAL;
306 }
307
308
309
310
311 tmp = ioread16(dev->base + SMMR);
312 tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
313
314 switch (dev->buf_len) {
315 case 1:
316
317 break;
318 case 8:
319 tmp |= SMMR_MODE0;
320 break;
321 case 16:
322 tmp |= SMMR_MODE1;
323 break;
324 case 32:
325 tmp |= (SMMR_MODE0 | SMMR_MODE1);
326 break;
327 default:
328 dev_err(dev->dev, "unsupported xfer size %d\n", dev->buf_len);
329 return -EINVAL;
330 }
331
332 iowrite16(tmp, dev->base + SMMR);
333
334
335 highlander_i2c_done(dev);
336
337
338 iowrite16((addr << 1) | read_write, dev->base + SMSMADR);
339
340 highlander_i2c_command(dev, command, dev->buf_len);
341
342 if (read_write == I2C_SMBUS_READ)
343 return highlander_i2c_read(dev);
344 else
345 return highlander_i2c_write(dev);
346}
347
348static u32 highlander_i2c_func(struct i2c_adapter *adapter)
349{
350 return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
351}
352
353static const struct i2c_algorithm highlander_i2c_algo = {
354 .smbus_xfer = highlander_i2c_smbus_xfer,
355 .functionality = highlander_i2c_func,
356};
357
358static int highlander_i2c_probe(struct platform_device *pdev)
359{
360 struct highlander_i2c_dev *dev;
361 struct i2c_adapter *adap;
362 struct resource *res;
363 int ret;
364
365 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366 if (unlikely(!res)) {
367 dev_err(&pdev->dev, "no mem resource\n");
368 return -ENODEV;
369 }
370
371 dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
372 if (unlikely(!dev))
373 return -ENOMEM;
374
375 dev->base = ioremap_nocache(res->start, resource_size(res));
376 if (unlikely(!dev->base)) {
377 ret = -ENXIO;
378 goto err;
379 }
380
381 dev->dev = &pdev->dev;
382 platform_set_drvdata(pdev, dev);
383
384 dev->irq = platform_get_irq(pdev, 0);
385 if (iic_force_poll)
386 dev->irq = 0;
387
388 if (dev->irq) {
389 ret = request_irq(dev->irq, highlander_i2c_irq, 0,
390 pdev->name, dev);
391 if (unlikely(ret))
392 goto err_unmap;
393
394 highlander_i2c_irq_enable(dev);
395 } else {
396 dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
397 highlander_i2c_irq_disable(dev);
398 }
399
400 dev->last_read_time = jiffies;
401
402 highlander_i2c_setup(dev);
403
404 adap = &dev->adapter;
405 i2c_set_adapdata(adap, dev);
406 adap->owner = THIS_MODULE;
407 adap->class = I2C_CLASS_HWMON;
408 strlcpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
409 adap->algo = &highlander_i2c_algo;
410 adap->dev.parent = &pdev->dev;
411 adap->nr = pdev->id;
412
413
414
415
416 ret = highlander_i2c_reset(dev);
417 if (unlikely(ret)) {
418 dev_err(&pdev->dev, "controller didn't come up\n");
419 goto err_free_irq;
420 }
421
422 ret = i2c_add_numbered_adapter(adap);
423 if (unlikely(ret)) {
424 dev_err(&pdev->dev, "failure adding adapter\n");
425 goto err_free_irq;
426 }
427
428 return 0;
429
430err_free_irq:
431 if (dev->irq)
432 free_irq(dev->irq, dev);
433err_unmap:
434 iounmap(dev->base);
435err:
436 kfree(dev);
437
438 return ret;
439}
440
441static int highlander_i2c_remove(struct platform_device *pdev)
442{
443 struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
444
445 i2c_del_adapter(&dev->adapter);
446
447 if (dev->irq)
448 free_irq(dev->irq, dev);
449
450 iounmap(dev->base);
451 kfree(dev);
452
453 return 0;
454}
455
456static struct platform_driver highlander_i2c_driver = {
457 .driver = {
458 .name = "i2c-highlander",
459 },
460
461 .probe = highlander_i2c_probe,
462 .remove = highlander_i2c_remove,
463};
464
465module_platform_driver(highlander_i2c_driver);
466
467MODULE_AUTHOR("Paul Mundt");
468MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
469MODULE_LICENSE("GPL v2");
470
471module_param(iic_force_poll, bool, 0);
472module_param(iic_force_normal, bool, 0);
473module_param(iic_timeout, int, 0);
474module_param(iic_read_delay, int, 0);
475
476MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
477MODULE_PARM_DESC(iic_force_normal,
478 "Force normal mode (100 kHz), default is fast mode (400 kHz)");
479MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
480MODULE_PARM_DESC(iic_read_delay,
481 "Delay between data read cycles (default 0 ms)");
482
